Okay, let’s look at a concept in Biology called “coevolution”. Coevolution happens when two organisms or species change over time, in a way that means they need each other to live. In other words, the actions carried out by one species to guarantee its survival, aid the survival of another species at the same time. So coevolution is often a mutualistic relationship. You get it? Now let me give you two examples of coevolution.
The first example of coevolution can be found in the relationship betweenHoneybirds and the plants that rely on Honeybirds to pollinate them. These plants have nectar the birds like. The plants have also developed aflower that is constructed in a way that causes them to rub against the Honeybird’s beak as it drinks the nectar. So, as the Honeybird drinks the nectar, pollen from the flower falls on the Honeybird’s beak and head. Now, when the Honeybird moves to the next flower, pollen from the first plant rubs off on the flower of the second. So when this happens, the pollination occurs. So this is a classic example of coevolution and a perfect example of a mutualistic relationship. The plants provide nectar as food for Honeybirds, and Honeybirds help the plants to pollinate.
Okay! Now, another example of coevolution can be found in Acacia ants and Acacia trees. The Acacia trees have large trunks that Acacia ants live in, and the tree produces sap that the ants eat. Acacia ants also eat insects that feed on the Acacia tree. So, Acacia ants are protecting Acacia trees from being attacked by other insects.
Now I want to talk about some interesting plants, Alpine plants. These plants grow in Alpine climates. This, of course, means they live in extremely cold conditions. So how do they survive in such a harsh climate? Well, see, over time Alpine plants have developed some adaptations to help them survive. Let’s look at these adaptations.
So, one adaptation that alpine plants have developed to live in freezing temperatures, is their ability to increase the concentration of chemicals in their tissues. This increase lowers the freezing point of water in those tissues, preventing tissues from freezing. This phenomenon is called freezing-point depression, and it’s the same reason we put antifreeze into our cars during cold weather. The anti-freeze freezes at a much lower temperature than pure water, so the solution can continue to circulate, and cool the engine, even though the temperature is below the freezing point of pure water. Amazing, right? However, freezing point depression is only effective when the temperature is only moderately cold.
Now, in extremely cold temperatures, Alpine plants have to rely on a second adaptation, which is the ability to remove water from their cells. They store this water in the spaces between the cells, so when the water freezes, the ice crystals are outside of the cell. This means that these ice crystals will not cause damage to the cell. Interesting, right?
Now, of course, if all of these strategies fail to prevent frost damage, Alpine plants still have a backup strategy, which is to repair or replace the damaged tissues. Of course, it’s much better to prevent damage in the first place.
Okay! so we said that ritualization is an evolved behavior that can help identify a species. Although humans have adopted rituals like taking a shower before work (or any other grooming really), the best examples of ritualization are found in the animal kingdom. You see, animals live their lives through instinct mostly, so ritualization is more exaggerated in the animal kingdom than it is in humans.
For example, male birds engage in complex courtship rituals to attract a mate. This instinctive behavior can range from highly exaggerated - and sometimes synchronized - song and dance displays, to decorating their nests with stones or other items that might appeal to the potential mate.
Another example of ritualization can be seen in dogs. A dog might raise its lips and growl to tell other dogs that it’s nervous, or defending its territory.
So ultimately, whether it be the dogs' rather frightening way of communicating its feelings, or the various means in which a bird may attract a mate. All animals engage in ritualization as a means to identify themselves to their own species, as well as to communicate with other species.
OK, I want you to remember that parasitism is a relationship between one organism, the parasite, which lives in or on another organism, the host. By definition, this relationship causes some harm to the host. Now, despite the parasite harming the host, it doesn't want to kill it. The host provides nourishment, and can only do that if it’s alive. To reduce the harm done by the parasite, hosts have evolved defensive mechanisms. There are two basic examples of parasitism: One is Mistletoe on trees, the other is fleas on a dog. Let’s look at the first one.
Mistletoe is a flowering plant that is found commonly on trees. It usually establishes itself on these trees when birds transfer the Mistletoe seeds to the tree. The Mistletoe then grows on the tree and uses the tree’s water and minerals to support its growth. But, during the beginning stage of its growth, it doesn’t depend on the tree host. Instead, it relies on its own photosynthesis, which is the process through which plants use carbon dioxide and water to create their food and grow. You get that, right? Ok! So when does the Mistletoe actually start feeding on the tree host? Well, that only happens when the Mistletoe’s root system reaches the tree’s conductive tissues.
Okay! Now, another example of parasitism is fleas on a dog, common, right? Fleas live and multiply on a dog, and they survive by consuming the dog’s blood. But, see, while the fleas never kill the dog, they do actually cause the dog harm and annoyance via blood loss and the characteristic itching.
Okay! Today we are going to look at several examples of camouflage in wildlife. Many species have developed camouflage mechanisms to help them to blend in with their environment. This allows them to either hide from predators, or hunt for food. So, how exactly do they do this? Well, one method is to mimic the color of their environment. For instance, a green insect on a green leaf will be harder for a predator to spot. Pretty basic, isn’t it?
So! Color is one method of camouflage. Another is shape. An example of this is seen in the morphology of the body of the Leafy Sea Dragons. You see, the Leafy Sea Dragons are very well disguised creatures. They have appendages all over their bodies that are shaped like seaweed. These appendages allow them to blend in with the seaweed and kelp of its environment so predators won’t recognize them as food. In addition, the camouflage helps the Leafy Sea Dragons prey on other small ocean creatures, such as crustaceans. And, since the Sea Dragons are so well hidden in their environment, they have no known natural predators. Good for them, anyway.
Okay! Now! Another example of camouflage is the cuttlefish. These fish have a lot of different pigments below their skin. By changing these pigments, they can change their skin color toblend in with their surrounding environment and disguise themselves from predators. So, cuttlefish and Leafy sea dragons are two classic examples of camouflage.
Ok! So, we said that biological clocks are physiological systems that enable organisms to live in harmony with the rhythms of nature. Animals, including humans, show signs of running on biological clocks. For example, animals have internal clocks that tell them when to wake up and when to sleep, right? Now, one important environmental factor that can greatly influence the “settings” of animals’ biological clocks is light. So! Let’s look at the effect of light on our biological clocks.
Humans live all over the world, in different cycles of day and night. Left to natural rhythms, we have a diurnal sleep/wake pattern. We’re active during the day, and sleep at night. However, we can now travel long distances quickly, changing our dark/light cycle environment. Because our biological clocks are still “set” to our point of origin, there is a difference between this “setting”, and the day/night rhythm at our new location. This difference produces the feeling of “jet lag”. The feeling goes away after a few days, as our biological clocks gradually adjust to the new light/dark cycle. So this a typical example of how light affects our biological clocks. But what about the effect of light on animals' biological clocks?
Biologists once did an interesting experiment to study a flying squirrel’s activities under the influence of light. They kept a flying squirrel in a cage in total darkness for twenty-three days. The cage itself was a rotating cage which would move when the flying squirrel ran. So when the cage moved, the movement caused a pen to record when and for how long the squirrel was active. So with this design, biologists could observe, and measure, the impact of light on the flying squirrels' biological clock.
So what were the results? Not surprisingly, they showed the flying squirrels' activities followed the same pattern as it normally would out in the wild during the day to day life, but the activities began about twenty-one minutes later each day. Interesting, right?
Okay, guys, we will be looking at a concept in biology called ‘ecological succession’. By definition, ecological succession is the process of ecological change where species are established, and then replaced over time. There are two types of ecological succession: Primary and Secondary. Let’s look at them.
Primary ecological succession occurs in an area that is originally empty of life, like a place that has been covered by lava. The stages of primary ecological succession go like this: First, weathering breaks down the rock enough so that certain hearty plants can grow. These species are known as pioneer species. They help to further break down the mineral-rich lava into soil, so that other, less hardy species can grow. These new species eventually replace the pioneer species. In addition, as the pioneer species grow and die, their remains are added to the soil, contributing to soil formation. This process repeats multiple times during succession. At each stage, new species move into an area and replace their predecessors. At some point, the community may reach a relatively stable state.
Now, unlike primary succession, secondary succession is much more common. It occurs in an area where life once existed but has since been destroyed. A forest, for example, which has been destroyed by fire, will undergo a series of vegetation changes. So, the first plants to reappear might be annual weeds. Later, annual weeds will be replaced by perennial weeds, and then by shrubs, finally resulting in a mature forest consisting of Oaks, Maples, and other large trees, you get this?
Now, secondary succession is quicker than primary succession. In our forest fire example, the nutrients from the burned vegetation are returned to the ground in the form of ash. Since the burnt area already has nutrient-rich soil (plus the nutrients from the ash) the whole area can be recolonized much more quickly than the bare rock covered by the lava.
So, many scientists believe it would be possible to maintain a permanent human presence on Mars, or the Moon. The possibility of establishing a colony on Venus, on the other hand, is considered highly unlikely. Today I want to talk about the two main reasons why scientists believe it would be difficult for humans to live on Venus.
First of all, very little sunlight reaches the planet’s surface. About 60 percent of the sunlight that hits Venus is reflected back into space by the thick clouds that fill the atmosphere. This means that less than half of the sunlight can even get through the clouds. Then it hits a dense layer of carbon dioxide, which blocks even more light. So very little light actually reaches the surface. This lack of light would, for example, prevent the use of solar cells to power machines and equipment.
Ouch! And that isn’t the only problem. ‘Doesn’t seem there’s much water on Venus’ surface, or much water vapour in its atmosphere either. And that atmosphere is made up mostly of carbon dioxide, nitrogen, and sulfuric acid. Hardly any oxygen. Water and oxygen would have to be supplied from Earth. That would be extremely difficult, and probably prevent setting up a permanent station on Venus.
Okay, today let’s spend some time looking at something in social studies called ‘role distancing’. It’s defined as the act of presenting your “self” as being removed, or distanced from, the role you are being asked to play.Now, there are actually two cases of role distancing.
The first case is a person who chooses not to participate in a common role others are involved in. This is usually because of the high commitment and involvement required by the role. For example, many religions require that you close your eyes when you’re praying. Refusing to do that is a sign that you disagree with that particular role. Another example, is that most schools have assemblies every day. During these assemblies, they might ask students to participate; to perform a role of some kind. Some students may choose to distance themselves from these roles by deliberately being late for school. Make sense?
Okay! The second case of role distancing is to deny that role completely. For example, an unemployed person may insist that they are different from other unemployed people in some way. They may even say that they are employed when they’re not. So in this case or in similar scenarios, role-distancing is often a defensive strategy that may be associated with poor well-being. The cause of this is due to the individual’s inability to accept that role.
Many environmentalists believe that forest fires are part of the forests natural life cycle. Fires can help maintain a broader diversity of habitats for wildlife. They also believe that deliberately setting fires in wild areas can restore ecosystems and prevent wildfires from raging out of control. I know that sounds false, but in fact, it's true. Without a regularly occurring fire, the forest grows extremely dense and becomes a massive source of fuel, so future fires will be much more destructive. Therefore, small fires prevent major fires from occurring. In addition, the ashes caused by the fire are rich in minerals, so it makes the soil more nutrient-rich, thusly more productive.
And finally, with the canopy more open, the sunlight can get through to the forest floor, which helps stimulate small plant growth. Another interesting fact about how trees can benefit from a forest fire is regarding some species of pine trees. Some pine trees require a fire to release its pollen and therefore fertilize to make pine cones. The most famous one of these is the jack pine around the Great Lakes.
So we talked a little about ritualization behavior last week, and we learned that it’s evolved over time, and can help identify a species. We, as humans, have adopted rituals like showering before work, or turning off lights before going to bed. For birds, ritualized behavior is exemplified by complex courtship displays. They make sounds, or showcase their feathers to attract potential mates. The Pigeon and the Peacock both do this.
Most times, when you hear a Pigeon coo in a gentle, sweet sound, it is because they are either trying to attract a mate, protect their territory, or communicate with each other. Besides cooing, these cute birds also fan their tails, bow and strut to attract mates. All of these are ritualized behaviors. In the winter, you might notice that pigeons don’t coo very much. This is because they don’t breed in the Winter. Makes sense, right?
Okay! Now, Peacocks, of course, are recognized immediately by their stunning display of tail-feathers. We all know how beautiful their tail-feathers are when they open into a huge fan, right? Well, a Peacock unfolds its tail feathers as a ritualized courtship behavior, to attract a Peahen.
When you think about Fungi, you usually think about diseases. However, Fungi play an important role in nature. They have a mutualistic relationship with trees meaning the Fungi are beneficial to a tree's growth and necessary to their health.
One example of the Fungi having a mutualistically beneficial relationship with the tree is to be able to produce and provide extra nutrients for the tree. The fungi accomplish this by luring tiny insects to them, then turning the insects into nutrients which they then supply to the tree. The Fungi also break down other material into a decomposed state that the tree also uses as nutrients.
Another method that the Fungi use to help a tree is to create a network for transferring larger quantities of nutrients from the tree’s natural resources. Without harming the tree, the Fungi attach themselves and create a pathway which the tree uses to consume larger amounts of nutrients. Therefore, the Fungi benefit the trees by using different methods to enrich the trees with more nutrients, thus, promoting growth and improving health.
As you learned in the previous lecture, a landslide is only one of the many types of mass movements. Other mass movements include a creep or a slump. First, let’s talk about slump. A slump is a downward slope movement of loosely consolidated materials or rock layers. It moves a short distance down a slope in a short period of time. It occurs when the base can no longer support the weight of the mass on top. This happens when the sediment is wet or claylike. Because water adds mass to the top layer of sediment or wears the soil away from the base, it weakens the connection between the top and bottom layers. You've probably observed a slump if you've ever gone to a lake or the beach and stepped on some wet sand overhanging the shore.
Now a creep, unlike a slump, is a very, very slow movement of sediment down an incline. Sometimes the process can take place over several years. One cause of creep is gravity. Gravity causes the sediment to settle just a little farther down the slopeside than where they started from. This process causes the soil and sediment to slide down year by year. Another cause of creep is the constant alternation of freezing and thawing of soil and sediment. Because of the repeated freezing and thawing, the structure and composition of the soil are changed, as a result, the soil structure becomes unstable, weakening the adherence between the top and bottom layers. If you've ever seen trees or telephone poles bent at strange angles in relation to the ground, that is a creep.
Okay, so we talked about geothermal energy last time. Now, like all other energy sources, using geothermal energy has benefits and drawbacks.
The major benefits of geothermal energy are that it’s very cost-effective, and it’s perhaps the most reliable way to produce electricity. Why? Well, the source of the energy is the heat from the earth’s core, which is always there. Other renewable sources like solar, wind, or biomass, are affected by climate, and can be available or not, depending on the weather or season.
Now, another benefit of using geothermal energy is that the lifespan of the equipment used to collect it is relatively long. Geothermal systems only have a few moving parts, which can be protected by a weatherproof enclosure. As a result, their pipes have warranties of between 25 and 50 years, and pumps can last for 20 years or more. Interesting right?
Okay! Now let’s look at some drawbacks of geothermal. First, when geothermal heat is extracted from the ground, greenhouse gases like carbon dioxide, hydrogen sulfide and others escape. The amount of gas released is much lower than when fossil fuels are burned, but has to be included when you’re comparing methods. Another drawback is the high initial cost of drilling and installing this complex system. But the return on this investment is promising. It’s possible to recover the cost within 2- 10 years.
Okay! Today we’re going to look at the topic of invention. In the long history of humans, thousands of inventions and innovations have been created. And they always have an impact on our day to day life. But, no matter which invention we’re talking about, it was created in only one of two ways, intentionally or accidentally.
Intentional discoveries have given birth to the majority of all great inventions. The light bulb, for example. Before it was invented, people had to use candles or gas, for light; obviously not the safest solutions. So, as soon as the light bulb was invented, it became extremely popular, because it was safer and much more convenient. Intentional discoveries are intended to solve a problem.
Now, as opposed to the intentional invention, half of all inventions happen by accident. People invent new things when they’re not trying to invent anything at all, or when trying to create something quite different. Understand? For example, Coca-Cola. Confederate Colonel, John Pemberton, originally created it as a tonic for nerves, and it was first sold as a pain-reducing medicine. Interesting, right?
So, you can see that accidental inventions are often not the final product, or breakthrough, the inventor was looking for. The discovery of X-rays, is another example. Wilhelm Roentgen, the scientist who discovered x-rays, had no idea what his discovery meant, or how to use this new radiation. The discovery was an accidental result of other work that he was doing. While he did learn to use the radiation to produce medical images, it’s often left to others to come up with a use for the accidental invention.
Okay, let's get started! Last time we talked about the concept of “cultural diffusion”. Cultural diffusion happens when beliefs, ideas, or even social activities spread from one culture to another. This creates a mix of cultures. Now, there are three types of cultural diffusion: direct, indirect, or forced.
Let’s talk about direct diffusion first. Direct diffusion occurs when two cultures are physically close together and can exchange ideas through intermarriage, trade and even warfare. For example, the USA and Canada hold similar cultural values and ideas, likely due to their proximity to each other. Despite having different histories and government systems, people in both countries share, basically, the same cultural references.
Secondly, indirect diffusion happens when two cultures are transmitted indirectly from one culture to another, through a middleman of some sort. By this, we mean that the two cultures do not have direct contact like physical proximity. They will have some kind of communication, like, for example, the Internet. Someone from South Africa might watch a YouTube video about Korean food, love it, and adopt it as part of their everyday diet, you know? Hollywood is watched worldwide, so it’s also an example of indirect diffusion, isn’t it?
Now, forced diffusion happens when one culture conquers or enslaves another and forces its own customs on the defeated one. A good example of this was in the 10th century when Spain and Portugal conquered the areas of Central and South America. Priests from Europe forced the natives to become Catholics. Also, many customs of the conquered natives were prohibited by the Spanish, and were gradually, completely eliminated.
When we think of frogs, we probably don’t think they’re important in our lives. But in fact, frogs do play an important role by eating disease-carrying insects. Now, in recent years, many frog species around the world have declined in numbers, or even gone extinct, due to changes in their environment. These population declines and extinctions have serious negative impacts on the ecosystems in which frogs live. These negative impacts could affect our lives in the future, so scientists have begun to investigate ways to solve the problem of declining frog populations. So far there have been two proposals.
The first proposal is to prohibit farmers from using harmful pesticides near sensitive frog populations. You see, frogs are being harmed by pesticides. Pesticides are chemicals used to prevent insects from damaging farm crops such as corn and sugarcane. But pesticides often spread from farmland into neighboring frog habitats. Once the pesticides enter a frog’s body, they attack the nervous system, leading to severe breathing problems. If laws prohibited the farmers from using harmful pesticides near sensitive frog populations, it would significantly reduce the harm pesticides cause to frogs.
Alright! A second major factor in frog population decline is a fungus that has spread around the world with deadly effect. The fungus causes thickening of the skin, and since frogs use their skin to absorb water, infected frogs die of dehydration. So the second proposal is to develop ways to treat or prevent infection, such as antifungal medications, and treatments that kill the fungus with heat. Those treatments, if applied on a large scale, would protect sensitive frog populations from infection.
Today we will be looking at an interesting animal: pterosaurs. Pterosaurs were an ancient group of winged reptiles that lived alongside the dinosaurs. Many pterosaurs were very large, some as large as a giraffe. Some had a wingspan of over 12 meters! Paleontologists have long wondered whether large pterosaurs were capable of powered flight. When I say powered flight, I mean flying by flapping their wings.
Now, although some evidence suggests that pterosaurs were capable of powered flight, it is reasonable to think that large pterosaurs would not have been able to flap their wings fast enough to stay aloft for any length of time. But this was just a guess. Paleontologists have proposed two major theories that might support the premise that pterosaurs were not able to fly by flapping their wings; that they could only fly by soaring.
First, some paleontologists point out that since modern reptiles are cold-blooded, ancient reptiles such as pterosaurs were probably cold-blooded as well. Cold-blooded animals typically have a slow metabolism, and are unable to produce a lot of energy. Powered flight is an activity requiring a lot of energy, which is why all modern vertebrates that fly are warm-blooded, not cold-blooded. It doesn’t seem likely that pterosaurs would have been able to generate the energy needed to fly.
Second, all animals with powered flight are able to take off from the ground. For example, birds take off by jumping, or running to gain speed and then jumping. But these methods would not have worked for large pterosaurs. Large pterosaurs would have needed big, powerful muscles in their back legs to launch themselves into the air. However, we know from fossil records that their back leg muscles were small and weak. Too small and weak to allow the pterosaurs to run fast enough, or jump high, enough to launch themselves into the air.
There are many organizations that believe that container design plays a very important role in sales. This is because, often, consumers are not buying just the product itself, they’re also buying the container the product comes in. If the container is useful to the customers in some way, it’s more likely that they will buy the product. Let's talk about a couple of ways product containers can be designed to be useful to consumers.
The most common way is to give the container a pleasing appearance, so that consumers will feel comfortable displaying it in their home. For instance, a company that sells cookies. Instead of selling their cookies in a plain cardboard box they might sell them in a nice metal box. Why? Because this metal box can serve many purposes. For example, after the cookies are gone, it can be used to hold other items. Or the metal box might be decorated with beautiful pictures. That way when consumers present the cookies to guests, they look nice, they look classy. Attractive containers like that can make a product more appealing and more successful.
The second way is to make the container as user-friendly as possible. Containers for condiments such as ketchup and mustard are a typical example. In the past, these products came in glass jars with lids. You had to unscrew the lid, and then pour the ketchup or mustard on your food. This could be messy and irritating. But flexible plastic containers don’t have this problem. You just hold the container over your food and give it a little squeeze. It is much faster and easier than having to remove a lid first. Convenient containers like that make a product more appealing to consumers.
Desert frogs have developed ways of adapting to hot and dry climates. Those adaptations to aridity that evolved during dry seasons have helped frogs survive the inevitable droughts. One evolutionary adaptation that a frog uses to survive severe dry climates is to retain and store water in their bladder. Because of a frog's highly flexible bladder, during most seasons, frogs are able to store a substantial amount of water inside their bladder. Therefore, during dry seasons, frogs release the water from their bladders to keep their bodies moist and their organs functioning properly.
Another evolutionary adaptation the desert frog has to survive droughts is a fatty layer below their skin. This fatty layer, in addition to the stored water like the fog’s bladder, also helps reduce water evaporation during those extremely hot seasons. Ultimately, the desert frog has adapted to hot climates by evolving unique methods of storing substantial amounts of water, which the frog retains for an extended period of time and subsists on during these droughts.
Okay! Last time we learned that ant communities are comprised of three different social classes, and all ants belong to one of these social classes. These three social classes are “queen ants”, “worker ants”, and “male ants”. In today’s lecture, we’ll be talking about the “queen” and “worker” classes. Specifically, what their differences are and what their roles are in an ant community?
First of all, queen ants are responsible for producing offspring. In fact, they are the only ants who can reproduce. So, the survival of the whole ant community depends on queens. They spend their entire life laying thousands of eggs to make sure they can produce enough offspring to maintain the workforce of the ant community.
Worker ants, on the other hand, don’t reproduce. They are responsible for foraging for food, and caring for the queen's offspring. They are also responsible for building the nest and protecting the community. Some worker ants are also known as army ants. They are usually bigger than other worker ants, and they are responsible for defending their ant communities and protect them from predators.
Besides their difference in roles, queen ants and worker ants have different physiological characteristics. Like male ants, queen ants are winged and they are much bigger than worker ants. They are about 9 mm long, and have a glossy black color, with light brown stripes on their abdomens. Their wings allow them to move around more easily, but their bigger sizes limit that mobility. On the other hand, worker ants don’t have wings and are much smaller. They are approximately 3–5 mm long and are a dark glossy black, but don’t have the brown stripes on their abdomens. Although queen ants and worker ants have different roles and physical characteristics, they are both females. Both classes live much longer and are generally considered more important than male ants, whose responsibilities are only for mating.
Okay! As we mentioned in the previous lecture, an avalanche is a mass of snow, rock, ice, soil, and other materials that slides down a mountainside. So what are the two main types of snow avalanches? As you can see from the textbook, one is called sluff, and the other is called slab.
Let’s look at sluff avalanches first. So what is a sluff avalanche? Essentially, a sluff avalanche is a small slide of loose snow sliding down a mountainside. It occurs when the weak layer of a snowpack is on the top. So when the weak layer breaks, only a small amount of snow that is on the top of the snowpack becomes unsettled. It then starts sliding down and fans outward as it descends. Now, as I just said, a sluff avalanche is small and loose, so it ismuch less dangerous than a slab avalanche. Few injuries or fatalities actually result from sluff avalanches.
On the other hand, slab avalanches are much different from sluff avalanches. They occur when the weak layer of snow lies lower down in the snowpack. This weak layer is covered with other layers of compressed snow and rock. The avalanche happens when the weak layer breaks. This allows all of the snow and rocks on top of it to slide down the slope, breaking into smaller and smaller pieces as it falls. Some of the pieces rise into the air as a moving cloud of icy particles. The cloud races downhill at very high speeds, so the thickness and speed of slab avalanches make them a huge threat to skiers, snowboarders, mountaineers, and hikers.
Okay! Last time we talked about canyons. We learned that a canyon is a deep split between rock faces resulting from erosion by water. What I want to talk about today is the two main types of canyons: plateau canyons and slot canyons. Even though both types of canyons are created by the erosion of water, the basic difference between them is the source of the water that creates them.
Now let’s talk about plateau canyons first. As their name suggests, plateau canyons form on plateaus. Plateaus are shaped by geological forces that lift them up, and the wind and rain that wears them down. This rain creates rivers on the surface of the plateau. Plateau canyons are created by these rivers that continuously eat into the plateau, and can be very wide.
Now, slot canyons, on the other hand, are very narrow canyons that are much deeper than they are wide. Many slot canyons are so narrow that you can touch both walls at the same time, even though the canyons have vertical walls that are often hundreds of feet deep.
Now, unlike plateau canyons which are formed by rivers constantly eroding the plateau, slot canyons are created by flash floods. Flash floods usually occur after a period of heavy rain, within six hours of the rain event. Because the erosion by flash floods doesn’t last as long as the constant effect of a river, slot canyons of any depth are usually found in softer rock.So,sandstone and limestone beds are typical locations for large slot canyons.
Alright! Let’s get started! So we know that “coadaptation” refers to the process by which one organism adapts to, or adapts with another organism. Today, biologists classify coadaptation into two types: mutualism and mimicry.
In mutualism, two species evolve to benefit from each other. This type of coadaptation can be observed in the relationship between certain species of flowers and hummingbirds. These flowers have altered their nectar and pollen production to appeal to the hummingbirds' nutritional needs. Hummingbirds, in response to this, have adapted long, thin beaks to extract the pollen from these flowers. The benefit of this relationship is that while the hummingbird gets food, the plant’s pollen is distributed. So, we can see that coadaptation is highly beneficial to both organisms.
Alright! So mimicry is also a type of coadaptation. In mimicry, one organism has adapted to resemble, or mimic, another. Like, for example, the harmless king snake (sometimes called a milk snake), which has adapted a color pattern that resembles the deadly coral snake. Obviously, the reason for this mimicry is to keep predators away from the king snake.
Okay! So while there are some advantages to coadaptation, it can also limit an organism's ability to adapt to changes in their habitat. This can lead to co-extinction. For instance, in Southern England, the large blue butterfly adapted to eat red ants. When human development caused a reduction in the red ant population, the lack of food led to the local extinction of the butterfly.
Okay! Let’s talk about an interesting insect: bees. Some paleontologists believe that bees existed on Earth as far back as 200 million years ago. This theory is supported by the discovery of very old fossil structures that resemble beehives. The structures have been found inside 200-million-year-old fossilized trees in the state of Arizona in the southwestern United States. However, many skeptics doubt that the structures were created by bees, for two reasons.
Now, the first reason to doubt that bees existed 200 million years ago, is that there were no flowering plants back then. Today's bees feed almost exclusively on the nectar of flowering plants. In fact, bees and flowering plants have evolved a close, mutually dependent biological relationship. But flowering plants didn’t show up on Earth until 125 million years ago. Given the bees’ close association with flowering plants, it's unlikely that bees could have existed before then.
Second, while the fossilized structures found in Arizona are somewhat similar to hives made by modern bees, they lack some of the finer details of modern beehives. For example, chambers of modern beehives are closed by caps that have a spiral pattern, but the fossilized chambers lack such caps. That suggests the fossilized structures were made by other insects, such as wood-boring beetles.
Generally speaking, we can classify dunes into many different types by their shape. As you can see from the textbook, the two most common types of dune are the crescentic and parabolic. These two types of dunes both form under winds that blow consistently from one direction. In addition, their shapes are very alike. However, there are still some differences between the two of them.
The first difference is the location of a dune’s slip face. For example, a crescentic dune, as its name suggests, is shaped like a crescent moon with points at each end. Now... its slip face is on the onward side which is the concave side of a dune; whereas a parabolic dune's slip face is on its convex side, which is the inward side of the dune.
The next difference is strictly regarding the parabolic dunes. So in order to form a parabolic dune, the sand needs to be covered with vegetation. And as a result, the parabolic dune has a rather longer trailing arm, which is typically anchored by vegetation. Furthermore, you can usually see rim-shaped sand on the outside of a parabolic dune. This rim-shaped sand occurs when wind blows out the center of the dune, leaving just a rim on the outside.
Okay! Let’s get started! As we all know, photography is taken for granted today, so it’s hard to imagine a world without it. And yet, it didn’t exist until the nineteenth century. Before that, the only way to capture a portrait or scene was to paint it. The arrival of photography immediately affected the development of painting. So much so that photography almost put the painting industry out of business! The invention of photography had two major impacts on the development of painting.
First of all, the development of photography, to a great extent, provided the impetus for painting’s movement toward abstraction. Painters abandoned realism to the photographers, and began experimenting with techniques that implied an image, rather than depicting it realistically. For example, a human face might be drawn with a green color. This could give the impression of a human condition, such as jealousy or illness. A realistic painting of a human face is, weil, no different from a photo that a camera produces. This change gave rise to all the art movements, such as impressionism, that have characterized 20th-century art.
Now, the second impact photography had on painting was that photos and the camera became tools for painters. It was certainly a new way for the painter to see amazing visuals, but most importantly, it was now possible to capture that visual for later use in any medium the artist might choose to use. Before photography was invented, it was difficult to capture a tense muscle or the gait of a horse in mid-step. But using photography, a painter could capture the rider pulling back on the reins to control the horse’s pace so that action could later be put to canvas. Or a horse’s leg movements could be recorded in its long strides, and a sculptor could later carve that image into marble. So, we can actually say that photography is of great importance to painters, and artists in general.
Alright class! Today we’ll be talking about the ozone layer. The ozone layer is simply a concentration of ozone that’s located in the lower part of the stratosphere. Make sense? Now, the ozone layer is very important to us because it protects us from the harmful effects of the UV radiation from the Sun. However, at present, there is a widely held concern that the ability of the ozone layer to protect us is deteriorating. . This deterioration is a result of damage caused by chlorine pollution, and has two major adverse effects on Earth.
First, UV radiation can overpower the human immune system. This plays a role in the increase in the rate of skin cancer. Although fair-skinned, fair-haired individuals are at the highest risk for skin cancer, the risk for all skin types increases with exposure to UV radiation.
Secondly, excessive UV rays have a bad effect on plant life on the Earth. Wheat, rice, and many other food crops are being exposed to increased UV. This is resulting in reduced growth, photosynthesis and flowering. As well, the extra ultraviolet radiation inhibits the reproductive cycle of single-celled plant organisms called ‘phytoplankton’. Okay? Now, phytoplankton make up the bottom rung of the food chain, the reduction in phytoplankton populations will, in turn, cause a reduction in the populations of the sea creatures that depend on them for food. And it’s not just phytoplankton that’s been affected. Researchers have also observed a reduction in the reproductive rates of young fish, shrimp, crabs as well as frogs and salamanders exposed to surplus ultraviolet B.
Remember I said in the previous lecture that a slump is the downward slipping of a mass of rock moving on a more or less horizontal axis parallel to a slope from which it descends? Today, I want to point out there are actually two types of slumps. So… what are they and what are their differences?
First, we categorize a slump into two types: traditional slumps and rotational slumps. Both have different characteristics and causes.
Traditional slumps occur when a detached landmass moves along a planar surface, which usually is faults or joints. In addition, traditional slumps can occur on bedding planes where a permeable layer overrides an impermeable surface.
On the other hand, if the slumps move along a curved surface, we call the slide a rotational slide. Rotational slumps usually occur when a slump block slides along a concave-upward slip surface with rotation about an axis parallel to the slope.
Unlike the traditional slumps, the direction of slumps is not always downward. In rotational slumps, the rotational movement causes the original surface of the block to become less steep. As a result, the top of the slump is rotated backward.
Okay! Today I want to talk about oil shale, which is a type of rock containing petroleum that can be burned for energy. We’ve been relying on mining oil shale for producing fuel. But as we keep doing that, we realize that mining oil shale is actually having two negative impacts on our environment.
First, when oil shale is burned, it releases a large amount of carbon dioxide into the atmosphere. And we all know that carbon dioxide is a greenhouse gas that absorbs and retains heat in the Earth’s atmosphere. Okay! So! When we burn too much oil shale, carbon dioxide is released into the atmosphere at a much faster rate than can be absorbed by the trees, water, and ground. So, what does this lead to? It puts the earth’s carbon budget out of balance and inevitably leads to rising temperatures on earth.
Alright! Moving on, other environmental damage that’s the result of taking out shale oil, is the huge amounts of fresh water required. We know that water is necessary for drilling, mining, refining, and generating power, right? So, some experts estimate that three liters of water are required to produce just one liter of shale oil, and this is an outrageously large waste of our water resources. Some of this water is polluted by toxic compounds and is costly to clean up. In addition, in the course of the mining process, contaminated by-products are left underground which may filter into other sources of water, making them dangerous for drinking, hygiene, or development.
Alright! Everyone! Let’s begin! Supply and demand is an economic model of price determination in a market. It is perhaps one of the most fundamental economic concepts and er, it is also the backbone of a market economy. We can also say that, it is the relationship between the quantity of a product that producers wish to sell at numerous prices and the amount and quantity, er, the consumers are willing to buy at. You get that? So, today, we will go through these two fundamental concepts: law of demand and law of supply.
Now, what is the law of demand? The law of demand states that “if all other factors remain equal, the higher the price of a good, the fewer people will demand that good.” In other words, the more money a product costs, the less the demand that the product will have. The quantity of a good that a buyer purchases at a higher price is less because as the price of a good goes up, so does the opportunity cost of buying that good. And as a result, people will naturally avoid buying a product that will force them to forgo the consumption of something else they value more.
Like the law of demand, the law of supply demonstrates the quantities that will be sold at a certain price. But unlike the law of demand, the supply relationship shows an upward slope. This means that the higher the price, the higher the quantity supplied. Producers supply more at a higher price because selling a higher quantity at a higher price increases revenue. ;
Hello! Everyone! The Earth is a magnet. Scientists do not fully understand why, but they think the movement of molten metal in the Earth’s outer core generates electric currents. The currents create a magnetic field with invisible lines of force flowing between the Earth’s magnetic poles. But how did scientists prove that geomagnetic poles exist?
First, the locations of the geomagnetic poles are recorded in rocks that form when molten material called magma wells up through the Earth’s crust and pours out as lava. As lava cools and becomes solid rock, strongly magnetic particles within the rock become magnetized by the Earth’s magnetic field. The particles line up along the lines of force in the Earth’s field. In this way, rocks lock in a record of the position of the Earth’s geomagnetic poles at that time.
However, the magnetic records of rocks formed at the same time seem to point to different locations for the poles. Why? Well, according to the theory of plate tectonics, the rocky plates that make up the Earth’s hard shell are constantly moving. Therefore, the plates on which the rocks solidified have moved since the rocks recorded the position of the geomagnetic poles.
Good morning! Everyone! Wetlands provide habitats for a wide range of plant and animal life and are considered to be the most biologically diverse of all ecosystems. Today, scientists begin to recognize the environmental benefits that wetlands provide and they are now alerting us to the importance of preserving rather than eliminating our wetland resources. so what are the environmental benefits of wetlands?
First, wetlands protect water quality by trapping sediments and retaining excess nutrients and other pollutants such as heavy metals. These functions are especially important when a wetland is connected to groundwater or surface water sources such as rivers and lakes that are in turn used by humans for drinking, swimming, fishing, and other activities. These same functions are also critical for the fish and other wildlife that inhabit these waters.
Second, many species of birds, fish, mammals, reptiles, and amphibians rely on wetland habitat for breeding, foraging, and cover. The special wetland conditions provide a unique habitat for species that cannot survive elsewhere. For example, migratory birds depend on wetlands, and many endangered and threatened animal species require wetlands during part of their life cycle. Wetland plants and small animals -- especially insects -- are essential links at the lowest levels of the food chain. A wetlands environment supports these plants and animals, which in turn supports the larger animals that feed on them.
Third, wetland habitats help clean waterways. Oysters, for instance, live in coastal wetlands and bays. Oysters are filter feeders. As they absorb nutrients from the water, they also absorb runoff and pollutants. /p>
Ok! Let's talk about the memory gap. What is the memory gap? It is the loss of information in the memory system for a specific event. It leads to remembering something that has never occurred or is different from the way things actually happened.
There are a number of reasons why a memory gap occurs. The most common cause is emotional involvement. For example, during a car accident, a person experiences a large emotional change and is unlikely to remember or recall everything accurately. In most cases, the information is lost and the details are distorted. For example, a person that was in a car accident would try to recall what happened for the police, but more often than not can't remember what actually happened. He might be frightened or act angry and he may overexaggerate such as the car did not stop at the red light or the car accelerated. This is a perfect example of the memory gap.
Memory gap can also happen when the presentation of information is influencing the memories that are relevant to the target memory. In other words, memories are likely to be altered when questions are worded differently. For example, in an event...such as... when the police ask a car accident victim “how much they sped up?” instead of “what was the speed when they hit you?”. The recalled speed would most likely be higher in the former question compared to the latter question. The cause of this is the phrase "sped up" because it will influence the victim ’s memory causing it to exaggerate the emotional elements and as such the memory is changed.
When animals cast off a part of their body at specific times of the year or at specific points in their life cycle, we call it molting. Generally speaking, there are two primary reasons why animals molt.
The first one is to help adapt themselves to new environments or weather changes. For example, in the summer when the weather is hot, Mountain hares have a thin short coat of hair. When winter arrives they molt their lighter coat into their winter coat. Their winter coat is twice as long and much thicker than their summer coat. This new coat helps protect them from the extreme winter cold. The losing of hair and regrowing it during the different seasons is what is known as molting and it allows the hares to survive mountain conditions.
The second one is to protect themselves from predators. For example, North American weasels have a brown coat for the summer season. However, they molt into beautiful white color during the winter season. The reason their coat turns white in the winter is to help camouflage themselves in the snow, which helps hide them from predators.
Although animals have the ability to adapt to certain harsh environments, some environments are too extreme and in order to survive, they need to congregate together.
For example. penguins are able to survive on the border of Antarctic where the temperatures are manageable. However, when the breeding season is approaching, penguins need to migrate to the center areas of Antarctica to reproduce their offspring where the temperatures are dangerously low. Because of the extremely low temperatures, the penguins will congregate in groups so they can block the cold wind and use each other's heat to stay warm. With their group congregations, they are able to reproduce their offspring in extremely cold temperatures.
Another example of congregating animals is herds. Herds protect each other by congregating when predators attack such as lions or leopards. When a predator approaches them, the herd will congregate together and fight off the predator. For example, muskoxen congregate together by forming a circle and point their horns out to deter the predators. Baboons will congregate together and mob leopards to chase them off.
Some of the senses that we and other terrestrial mammals take for granted are either reduced, absent, or fail to function well in fish. For example, some fish have poorly developed eyes so they cannot see well in the environment. Now the question is how do fish that have poor vision navigate their environment. The answer is that fish have another sensory organ called the Lateral Line. A lateral line is a row of special cells inside a special canal along the surface of the fish's skin. The lateral line consists of sensory receptors called neuromasts. When the sensory receptors in the neuromasts vibrate, the fish can feel. The lateral line can also sense and detect water pressure, currents, objects.
Now there is another way fish use to navigate their environment. You're probably familiar with these fish that send out electric currents from their bodies naturally. So what's the purpose of this? Well..Producing electricity helps fish to detect nearby objects successfully. This helps fish to navigate their environment. Here's a fish called the knife fish that produces electricity this creates an electric field around the knife fish's body when the knife fish swims close to say a rock. It senses a disturbance, an interference in its electric field. The fish then realizes that there is a rock nearby and that it has to avoid crashing into it. Once this happens, the knife fish swims away from the Rock and thus avoid harming itself.
So… one of the reasons why America has such a rapidly growing economy was the emergence of railroads. By the 1840s, em, railroads were beginning to emerge in America. This was the period in which the railroad industry emerged as "America's first big business". It gave hundreds of thousands of Americans steady employment and created capital markets and err, mechanisms of finance. This brings the question; how did railroads create such a huge impact on economy and business? In summary, there are two primary reasons behind it. Mm… I will make it easier to understand.
Ehem… first of all, railroads opened the channels for people in business to sell their products. Before the advent of railroads, businesses could only target customers within their reach. What I mean is...they could only sell products as far as their carriages would take them. However, with railroads, things got easier; transportation became much more convenient and even faster. Traders could carry er, larger quantities of products across the country.
Secondly, the railroads provided cheap transportation. This gave businesses more choices to where they could build their factories. Like for example, a company that relies on coal to umm, manufacture products had to open their factory near the coal mine before. Now with the railroad, they can choose to have their factory built in any part of the country. And it’s simply because they can rely on the railroad to umm, transport the coal for them.
Alright! Let’s get started! So, one very tough animal we will take a look at today is the Camel. Camels are adapted to the harsh desert environment in many ways. One of the most interesting camel adaptations is their big humps. I’m guessing you’ve all seen those on the backs of Camels, right? Good.
As you might have guessed, those humps are there for a reason. They store fat, which is converted to water and energy when those are not available. The humps give Camels their ability to endure long periods of travel without water, in extremely hot weather conditions like those in the desert.
Now, in addition to providing nourishment, the fatty tissues that the humps are made of, absorb heat. This is really important to the camel because it allows the rest of its body to remain at a cooler temperature. As a result, its organs are able to function at normal temperatures even in extremely hot weather conditions.
Now, besides physical adaptations like humps, camels use certain behaviors to cope with the desert weather. One such behavior is to keep their body in an inactive state; they don't move too much. Most of the time they just sit on the ground to conserve energy. And not only do they just sit on the ground, they actually like to sit in groups. Why? Well, the reason for this “congregation behavior” is that by sitting together, they create a large shadow. The big shadow helps them to stay cool. Interesting right?
You see, the importance of a powerful logo cannot be overestimated, right? Indeed, a logo is a powerful symbol and ultimately, the most significant tool for brand recognition. Just think about Coca-Cola, or McDonald's. Their logos are recognized all over the world. Coca-Cola did such a great job that even the color red, can sometimes remind you of it. This is no accident, but is the result of purposeful marketing that uses symbols or color to establish "branding".So by using a memorable and easily identifiable logo design, the whole brand is easy for customers to remember. On the other hand, a poorly designed logo can severely hamper the progress of the company as it tries to become a successful business! So, let’s focus for a bit on bad logo designs, and look at a couple of examples of the negative effects a bad logo design can have on a company.
The first example of the negative effects of a bad logo is one in which the logo reminds customers of bad experiences, or of something that isn’t in synch with the company's mission statement. For example, if a company manufacturing toothpaste uses a black color in its logo, customers might associate their toothpaste with something dirty or, ironically, associate it with poor oral health.
Seriously, this is not something you want your customers to feel when you’re selling them toothpaste. So regardless of the quality of the toothpaste, the company has made a bad first impression. Their sales are likely to be poor as a result.
Alright! So, another example of the effect of a bad logo? Well, a bad logo could damage the reputation that a company is trying hard to build. Take a communication company as an example. The equipment that this company manufactures features innovative communication technology solutions. The message that they’re trying to convey to their customers is that the company does build innovative, new, and convenient products.
However, if they were to choose an old-fashioned telephone symbol as their logo, it would contradict their intended message. I mean…customers will think the company is using old, outdated technologies instead of new ones; a perfect example of a bad logo creating a negative impact on the business.
Entrepreneurs who have developed a successful business often wonder if they should franchise as a way to expand their operations. For businesses who want to join the franchise, franchising is a proven method to quickly run a successful business. Like any business model, franchising has its benefits and its drawbacks. Although there are many advantages to franchising, franchising has some common disadvantages.
The franchisee is not completely independent. Franchisees are required to operate their businesses according to the procedures and restrictions set forth by the franchisor in the franchisee agreement. These restrictions usually include the products or services which can be offered, pricing and geographic territory. For some people, this is the most serious disadvantage to becoming a franchisee because it limits their creativity for product differentiation or marketing strategy. For example, a restaurant franchisee can't put other foods on the menu even though they know this food will be very popular among customers.
In addition to the strict restrictions, franchisees must pay ongoing royalties and advertising fees. Even though a franchisee is providing well-known products to customers, the poor choices of location or failure of demographic market research can lead to a poor business. With the pressure of ongoing royalties, many franchisees went into bankruptcy. For example, a cellphone store franchise opened in a quiet neighborhood with a lower population of young people is doomed to failure.
The last disadvantage of franchising is all the franchises are relying on each other. Why is this? Let’s look at an example. If one restaurant is doing a poor job on sanitation, then all the other restaurants of that same franchising chain will also suffer the bad reputation because customers will assume they are operated under the same organization.
So we talked about franchising last week, and we learned that in the franchising business model, a franchisee is a company that is granted a license to do business under another company's trademark. And the company that offers its trademark and its business model for the franchisee is called a franchisor. So essentially, the franchisee purchases a franchise from the franchisor, and the franchisee must follow certain rules and guidelines already established by the franchisor. Also, in most cases, the franchisee has to pay an ongoing franchise royalty fee to the franchisor. You get that, right?
Now, this franchising business model is beneficial for both the franchisor and the franchisee.
For a franchisor, franchising is an excellent way to obtain expansion capital because the franchisee has to pay upfront to buy outlets in a franchisor’s chain. The franchisor can grow its number of locations without tapping much of its own capital, or needing financing from banks or investors.
In addition, the operation of a franchise can generate high financial returns for relatively little risk. Think about this: if you are a franchisor and have a good business model, you can earn high royalties from sales at new outlets opened by franchisees. The percentage returns you earn can be very profitable and you don’t risk losing capital by opening a new outlet.
Now, for a franchisee, a franchise provides an established product or service which may already enjoy widespread brand recognition. This gives the franchisee the benefits of a pre-sold customer base which would ordinarily take years to establish. This is one of franchising’s many impressive advantages. Another advantage is that a franchise can offer products with consistent quality, guaranteed by the franchisor.
So for both the franchisor and the franchisee, the franchising business model has a lot of benefits.
Have you ever wondered how birds migrate to different places so easily? It must require a lot of energy from a bird to migrate from one place to another. The answer is birds have two amazing physiological features that are different from other mammals.
The first one is their special respiratory system. When migrating, birds fly at altitudes where oxygen is in such short supply that no mammal could possibly survive. Birds, therefore, have evolved a respiratory system that is fundamentally different from other mammals' respiratory systems.
In mammals, inhaled air goes into the lungs as the lungs expand, and is expired when the lungs contract. However, a bird’s lungs expand very little because the air goes through them and into their air sacs and then back through the lungs on expiration. Thusly, not only can a greater volume of air pass through the lungs, but since it passes through twice, gas exchange is more efficient.
The second one is their chest muscles, which stores energy during the flight. The energy will be utilized by the bird when the bird feels tired and will allow them to continue flying long-distances. During the migration period, the flying requires a lot of energy, especially for the wings. Having chest muscles reserving energy ensures the birds can continue to fly until they reach their destination.
You should know that earthworms are only really thought about when people are planning to use them for fish bait. However, to the environment and especially soil, earthworms are valuable assets. Surprising right? I would guess so!
So…one of the benefits that worms provide to the soil is eating organic waste mostly from plants and turning it into a form that can easily be absorbed and used by plants. That is… the waste left behind as worms eat their way through the soil becomes a part of the topsoil that they help produce.
Interestingly… this waste is rich in minerals and is capable of helping soil … err, trap and retain moisture. You should also know that this waste also contains up to 11 times the amount of potassium, nitrogen, and phosphorus in normal soil. Err… in this way, the worm’s waste is extremely helpful to plants; it not only furnishes them the err, minerals that they need but also helps to trap water that will be necessary for plants to continue to grow.
Um…so… another benefit that worms provide to the soil is their ability to make tunnels. I mean… as they go through the soil, they carry the digested plant materials several inches to several feet into the ground. This builds a deep layer of rich topsoil, while also making a network of openings into the earth that allow water to err, travel into the ground instead of running off.
The openings created by tunnels store a large quantity of water and air. And as a result, the roots of plants can absorb the water more easily. Even in the drought season, the plants can still stay … err, healthy and grow.
Hello! Eveyone! Let’s talk about the sounds insects make and why they make it. You know… Insects make sounds that carry messages to other insects of the same kind for different purposes. The most common one is to alert each other of danger. Another is to communicate with others while looking for food resources.
So… in the life of an insect, the pupal stage following the larval stage and preceding adulthood is the stage when insects are inactive and unable to move. Now when their parents are out searching for food, they are susceptible to attacks by predators. So… the only way to protect themselves against predators is to make a sound to alert their parents that predators are near. Once their parents hear the sound, they will come back and protect them either by taking them to a different place or fighting the predator. Making sounds to warn their parents of danger is very common in the insect world.
So… another purpose for making sounds is communication during searches for food resources. This is a strategy used by many insects. For example, a lot of insects feed on the leaves of trees and they are constantly searching for a new source of fresh, new leaves. Once their current resource of leaves has turned old, uh… they will make a sound to communicate that it is time to look for a different resource of leaves. Likewise, once they find new resources of leaves, they will make a sound to communicate its location.
Okay! Let’s continue! Here’s a thought: have you ever wondered why trees are capable of living for long periods of time, despite local bad weather conditions, or even global environmental changes? Well, they’re able to do that, because they have special adaptations that allow them to survive and change with the environment.
One adaptation is their ability to release chemicals that can prevent damage from insects. Now, we all know that insects need to eat the trees' leaves and branches to survive, causing damage. Trees can limit this damage by releasing a chemical substance that insects can't live with. This makes the trees less vulnerable to these attacks. For example, redwood trees release gallotannic acid from their leaves and branches to scare off hungry insects.
Another adaptation is their complex root system that helps them to survive during a storm. You see, trees have many roots and the roots can grow in all directions, even tangling with other trees’ roots. So during a big storm, trees can survive by “holding each other up”! Take redwood trees as an example, they have the strongest root system found in trees. Their root system often extends as much as 100 feet around the tree. This is a very long distance compared to other trees' root systems. In addition to that, these underground root networks often end up growing in circular clusters. These circular clusters give them tremendous strength against the forces of nature. This way they can withstand high winds and even floods.
Okay! So, we know that human activities like deforestation and monoculture damage soil. Deforestation is a major factor that contributes to excessive soil erosion. Monoculture causes the depletion of nutrients in the soil, because the same crop, requiring the same nutrients, is grown repeatedly in the same soil. Fortunately, however, human beings have developed methods to prevent these problems. Today, we are going to look at two of these methods.
First, we’ll look at a method to reduce soil erosion, called “contour plowing”. This is an agricultural practice of planting crops across a slope following its elevation contour lines. This method of planting creates a series of parallel dams, or barriers. The crops are planted between these dams. The dams can slow the flow of water down the hillside during heavy rains. This will limit the formation of rills and gullies during those periods of heavy rain, when water frequently erodes the soil.
Contour plowing has the additional advantage of holding water behind the dams, containing it until it can soak into the ground. This can dramatically reduce the amount of water required to grow the crop.
Next, we’ll examine “crop rotation”, a method of combating the depletion of nutrients in the soil. So, with crop rotation, a crop that depletes the soil of one kind of nutrient is only grown for one season. In the next growing season, a different crop is planted. This gives the exhausted soil time to replenish the nutrients previously used up. So, alternating the growing of different types of crops helps the soil replace essential nutrients. This way, the soil can regain much of its original fertility.
Now, carbon currently can be taken out of the emissions from a power plant in two ways: post-combustion methods and pre-combustion methods. The two methods have differences in the way they’re applied, as well as in the results obtained.
So, with post-combustion carbon capture, the CO2 is removed after the fossil fuel has been burned. This process is currently used widely as a means to separate CO2 from natural gas. With pre-combustion carbon capture, CO2 is trapped prior to the fossil fuel being burned. During this process, fossil fuel is converted into a mixture of hydrogen gas and CO2. The hydrogen is then separated and can then be burnt without producing any CO2, as this has been removed. So what about the CO2 separated at the beginning of the process? That CO2 can be compressed for transport and storage.
Now, pre-combustion carbon capture is already in use for natural gas and provides a much higher concentration of CO2 than, the first method, post-combustion. However, the fuel conversion steps required for pre-combustion are more complex than the processes typically involved in post-combustion. This makes the technology more difficult to apply to most existing power plants.
In summary, the pre-combustion process is lower in cost, compared to the post-combustion process. It’s also able to prevent 80 to 90 percent of a power plant's emissions from entering the atmosphere, but it's not, however, a retrofit for older power generators.
So, em, many insect species live in the arctic and show a wide range of adaptations to its extreme severity and seasonality, that is its adaptation to the different seasons. Long, cold winters are met, for example, by cold hardiness including both wider-spread tolerance to freezing and extreme super-cooling ability. This is the same for Arctic butterflies. The Arctic butterfly has developed two types of adaptation for cold climates.
The first adaptation is called basking. These butterflies gain most of their body heat through this adaptation. When they expose their wings to soak up the sun’s rays, the warmed blood in their wings is then circulated to the rest of the body via the wings’ veins. So, er, this type of behavior is an important cold adaptation for Arctic butterflies because they cannot fly until their body temperature is warmed to at least 10 degrees Celsius.
The second adaptation is the production of cryoprotectants in the blood and body tissues. So, em, a cryoprotectant is a substance preventing fast freezing and formation of ice crystals that destroy cells. Many Arctic animals are able to produce cryoprotectants in their blood during the period of hibernation. This is the same for Arctic butterflies. So, er, by producing cryoprotectants, Arctic butterflies are able to survive in a cold environment without freezing their tissues and cells. Well, er, in some cases, some species of butterflies will live through freezing temperatures, they do not fly when it is cold, because, umm, if they do, they will eventually end up dead. /p>
When we think of bird nests, we typically picture a simple cup-like shape made of twigs and branches, nestled in the crook of a tree. While many birds do build nests like this, other birds create different kinds. Some birds craft elaborate nests for their young, while others simply lay their eggs directly on the ground. Today we’ll be talking about two types of bird nests: ground nests and burrow nests.
Let’s talk about ground nests first. Many shorebirds and some vultures scratch a small depression into the ground or leaf litter, and lay their eggs there. These nests are referred to as ground nests or scrape nests. Now, not all ground nests have a depression. For example, whenbirds, like some species of raptors and owls nest on the ground, they don’t create a depression. These birds just seek out a secluded place and lay their eggs directly on the ground. So instead of digging a pit to protect their eggs, they just find a place that is hard for predators to find.
Now, birds like puffins and burrowing owls dig holes in the ground and build their nests there. These nests are referred to as burrow nests. Now, burrow nests provide a couple of advantages over ground nests. First, they provide betterprotection from predators.
Second, they provide a consistent temperature for eggs and hatchlings. So burrow nests are considered to be a nest type that’s more advanced than ground nests. However, digging a hole takes time and energy. Interestingly, some species like the burrowing owl use pre-existing burrows to rear their young, instead of digging their own, from scratch, so to speak. But this is a special case. Most birds who build burrow nests construct their own.
Many reptile species need to keep their eggs moist for them to hatch. Today I'm going to talk to you about the importance of this moisture, either having the species lay the eggs in a body of water like a frog does or how a certain reptile species like a snake may naturally produce eggs with soft, moist inner membranes.
So let’s talk about frogs first. Frog eggs require moisture so they don’t dry up and also so they can produce healthy tadpoles that will someday grow into healthy frogs. That’s why frogs lay their eggs in water, either on the water’s surface or the pond’s bottom. You may even have seen frog eggs in vernal pools, which are large temporary puddles that form in the spring rain. A very interesting feature of frog eggs is that they are coated in a jelly-like glycoprotein which keeps the eggs moist from the onset. Yet the eggs must receive continuous contact with a moisture source, basically a body of water, so they can form into healthy offspring.
So now let’s talk about snakes. As I mentioned, in addition to some reptiles laying eggs directly in water sources, other reptiles lay eggs that are composed of a moist internal structure. That’s what egg-bearing snakes do! In fact, many of them live far from water. Their eggs are not hard like chicken eggs; not only are they soft on the outside, but their inner membranes are also soft and moist. The composition of this membrane allows an optimal environment for the snakelet to hatch and then grow into a healthy offspring.
Okay, guys, this time we will be looking at a concept in biology called coevolution. So, er, in biology coevolution occurs when two or more species reciprocally affect each other’s evolution. This often happens when two species have close ecological interactions with one another. So for example, an evolutionary change in the morphology of a plant might affect the morphology of an herbivore that eats the plant, which in turn might affect the evolution of the plant, which might affect the evolution of the herbivore...and so on. So this is just one example of coevolution. There are many types of coevolution. Today we will discuss a common type of coevolution: host-parasite coevolution.
In this type of coevolution, one is parasitic on the other. An example of this type of coevolution is the interaction between Heliconius butterflies and passion-flower vines. In this case, Heliconius butterflies are parasites and passion-flower vines are hosts. Interestingly, the passion-flower vines developed two defense mechanisms to avoid the attack from Heliconius butterflies.
First, the passion-flower vines have evolved effective chemical defenses against Heliconius butterflies. The vines produce false eggs which are essentially yellow bumps on a leaf. When the butterflies see these false eggs on a leaf, they assume some insects have laid eggs. They will avoid this leaf and lay their eggs elsewhere. In addition, the passion-flower vines produce extrafloral nectaries which are nectar-producing glands located outside of the flower. These extrafloral nectaries attract ants to take up residence on the leaves. The ants return the favor by protecting the plant from insects, and in particular Heliconius butterflies.
Okay! People! In today’s lecture, we will be looking at ways plants and animals adapt to dry climates. So, both animals and plants in Africa develop special mechanisms to adapt to the dry climate.
Now let’s take a Baobab tree as an example. This tree can store up to, like, 12,000 liters of water in its very large trunk in order to withstand the long droughts of Africa, see? In fact, the Baobab tree has been known to survive ten years with no rain. However, the tree diameter decreases in the dry season as it uses up stored water. So, er, animals like elephants enjoy eating the bark of the Baobab tree during the dry season to obtain moisture.
Another example of the mechanism animals use to adapt to the dry climate is umm, migration. Each year, some East African populations of blue wildebeest have a long-distance migration. So, em, the migration is driven by the rain and the new grass that follows it. In East Africa, the rainy season is er, between December and April. During this period, the wildebeest are on the short grass plains in the southern Serengeti. In April and May, the rains stop and the plains in the south of the Serengeti dry out. This shift causes the herds to, umm, start moving to the north where there is more grass and more constant water.
Alright! In theories of competition in economics, we said that barriers to entry are obstacles that make it difficult to enter a given market. These barriers can exist as a result of government intervention, or they can occur naturally within the business world. Today, I want to talk about two major sources of barriers to market entry.
The first source is the high capital requirements. These are the financial resources required for infrastructure, machinery, and advertising. Let’s say if you want to open a new gym in the neighborhood where there are already multiple gyms opened, you need to purchase gym equipment, pay the rents, and spend money on building the gym. All these costs are capital requirements.
The second source is consumer loyalty. Large incumbent firms may have existing customers loyal to established products. The presence of established strong brands within a market can be a barrier to entry. With a very strong brand image, a new firm would have to spend a lot of money on advertising. Some brands may be so strong that no amount of advertising may be able to dislodge the large firm. For example, many firms have tried to enter the cola market, but none have been able to dislodge Coca-Cola and to a lesser extent, Pepsi. Likewise, the strong brand loyalty of Google means it will be very difficult for any search engine to displace Google, no matter how technically good it is.
Animal domestication is the most important development in the past 13,000 years of human history. This development interests many of us today because it provides most of our food and it was a prerequisite to the rise of civilization. And today I'm going to walk you through two benefits of domesticating animals.
First, the domestication of animals provided food and secured a regular supply of fresh meat. Because the hunter is dependent on the luck of the chase, subsisting by hunting wild animals is unreliable. In comparison, domesticating animals provided a more reliable and regular supply of food. Furthermore, it reduced the risk of living in an unreliable environment, because herds could be moved to more favorable places when times were hard. Now, the first animals known to have been domesticated as a source of food were sheep in the Middle East. Sheep provided meat, milk, and fur. They also were ruminants, which meant they could digest the cellulose from grass, thus making infertile land more useful.
Now, the domestication of animals also provided products. Take goats as an example, they produced milk. People could drink milk and use milk to make cheese. In addition, their hair could be used as fiber for clothing. The skin and the bones were also used as well. Historically, goat hide has been used for water and wine bottles, in both traveling and transporting wine for sale. It has also been used to produce parchment, which was the most common material used for writing in Europe until the invention of the printing press.
Alright! Everyone! When it comes to motivating employees, we must talk about two important techniques: job enrichment and job enlargement. Both are job design techniques used by companies to motivate employees. However, it is generally believed that job enrichment is a better way to motivate employees. To understand this, we need to first understand what these techniques are and their differences.
So first! Let’s talk about job enrichment. Job enrichment is a way to motivate employees by redesigning their jobs so that they are more challenging and varied for the employee and so that the work is less repetitive. Job enrichment is also called “vertical job loading”. This concept is based on a business article by psychologist Frederick Herzberg titled One More Time: How Do You Motivate Employees? You see the concept is like this: Many employers traditionally believed that money was the only true motivating factor for their employees and that if you wanted to get more work out of them, offering more money was the only way to do it. While that may be true for a small group of people, the majority of workers today like to work and be appreciated for the work they do. The idea of job enrichment is exactly like that. It taps into the natural desire of employees wanting to do a good job and wanting to be appreciated for their contributions to the company.
On the other hand, job enlargement does not make the job more challenging. Instead, it adds the same type of activities or tasks to the existing job and increases the scope of the job. Because this technique adds tasks to the job on the same level, we also call job enlargement “horizontal job loading”. Unlike job enrichment, job enlargement contradicts human nature because people tend to feel bored when doing repetitive work. In many cases employees end up being frustrated because increased activities do not result in increased salaries.
So we said that if fish stay together for social reasons they are said to be shoaling, and if they are swimming in the same direction and in a coordinated manner, they are said to be schooling. You might wonder why fish stay together? Well! There are many benefits of shoaling and schooling. For example, they can form better defense against predators and have a higher success in foraging.
Now keep in mind! Although shoaling fish can relate to each other in a loose way, with each fish swimming and foraging somewhat independently, they are actually not aware of the other members of the group. For this reason, shoaling groups are usually fish of different sizes and can include mixed-species subgroups.
On the other hand, schooling fish are usually of the same species and the same size. They move with the individual members precisely spaced from each other. They undertake complicated maneuvers, as though they have minds of their own. The intricacies of schooling are far from being fully understood.
Many hypotheses explaining the function of schooling have been suggested, such as better orientation, predator confusion, and reduced risk of being found. However, schooling has disadvantages. Because they stay together, their excretion builds up and as a result, leads to oxygen and food depletion.
Okay! Everyone! Today we will be discussing a prehistoric animal, the Megatherium. It is probably the most famous giant mammal after the decline of the dinosaurs. To date, there have been a number of theories as to its diet.
One theory is that Megatherium was a herbivore. Megatherium would have eaten plants like other herbivores. But different from most other herbivores, it would have used its large size to reach up into trees to pick out vegetation that was beyond the scope of smaller herbivores. This meant that competition for food between giant ground sloths like Megatherium and other herbivores was comparatively low.
However, just because Megatherium could reach up high to feed, this does not mean that it only fed this way. Megatherium would have been quite capable of feeding upon lower vegetation, and here it may have used its claws for digging at plant roots. Their strong teeth and robust jaws suggest that Megatherium was quite capable of chewing tough vegetation, and this adaptation further suggests that Megatherium was capable of adapting to different plant types.
Another theory about Megatherium’s diet is that Megatherium was an occasional scavenger of carcasses. This idea is centered around the theory that Megatherium may have needed to supplement their diet with meat in order to obtain nutrients that were lacking in their usual herbivorous diet. By approaching the carcasses, they could feed out of opportunity rather than actively aggressing against other animals. The massive size and power of its body would have also worked in Megatherium’s favor, making it virtually immune to attack from the much smaller predators of the time.
Alright! Everyone So, in the last lecture, we talked about the causes of the decline of the newspaper. So, now In this lecture, I’m going to discuss the development of the newspaper and two changes leading to the growth of the newspaper in the 19thand 20thcenturies.
Okay! So the first change leading to the growth of the newspaper in the 19thand 20thcenturies was how the paper was made. Before the late 19thcentury, paper was made from textile fibers like cotton and linen. These textile fibers were frequently taken from recycled rags. Although paper made from these textile fibers was reliable, it was extremely expensive to produce them. Companies wouldn’t be able to afford to produce a large quantity of paper. However, by the 1860s, people figured out how to make paper from wood pulp, a kind of fiber that can be extracted from wood. Compared to paper made from textile fibers, it was much cheaper to produce paper from wood pulp. So this new invention made paper cheap, which meant that newspapers could be printed for reasonable prices. You get it?
Alright! The second change leading to the growth of the newspaper in the 19th and 20th centuries was the perfecting of the stereotyping process. Before the 19th century, people figured out how to easily reprint documents by creating a stereotype. A stereotype is a metal plate with letters on it. By reusing the same metal plate, printers could easily reprint the same document. However, they didn’t create the stereotype for each page. So if they wanted to reprint the same newspaper, they had to reset the stereotype for each page of the newspaper. This was extremely inefficient. But by the 19th century, printers started to create a metal plate for each complete page instead of resetting the type. This allowed for less difficulty in reprinting newspapers because the old stereotypes could be reused instead of setting the type each time
Okay! Everyone one! Let’s move on! Today I want to talk about two risks of price discounting. There is no doubt that discounting the price could boost sales and attract new customers in the short-term, but from a strategic perspective, it can have a negative impact on the product, the quality, and the profitability.
So what is the first risk? Well, if a company uses discounting to attract customers, it might damage a company’s brand image. By discounting, a company is sending the message that its service or product is just a commodity, rather than something of value to the customer. Furthermore, lowering the price might lead a customer to believe that a company’s product or service is low-quality. So a company must be careful about using discounts because it affects a customer’s perception of a company’s products and brand image.
Now, let’s talk about the second risk of price discounting. The second risk is it will attract price-sensitive customers. Think about it! If you are a customer and see that a company always has a promotion during a certain period of time, you are probably not going to buy the product until the promotion period comes. In addition, customers might as well shop around for the cheapest price anywhere, because they know this company has nothing to offer them but a lower price. The kind of customers that are attracted to a company because the price is low is also the sort of customers who will flee to the nearest competitor the second they have a discount or special offer running.
The protozoans, minute aquatic creatures, each of which consists of a single cell of protoplasm, constitute a classification of the most primitive forms of animal life. The very name protozoan indicates the scientific understanding of the animals. Proto means "first" or "primitive" and zoo refers to the animal. They are fantastically diverse, but three major groups may be identified on the basis of their motility.
The Mastigophora have one or more long tails that they use to propel themselves forward. The Ciliata, which use the same basic means for locomotion as the Mastigophora, have a larger number of short tails.
The Sarcodina, which include amoebae, float or row themselves about on their crusted bodies. In addition to their form of movement, several other features discriminate among the three groups of protozoans. For example, at least two nuclei per cell have been identified in the Ciliata, usually a large nucleus that regulates growth but decomposes during reproduction, and a smaller one that contains the genetic code necessary to generate large nucleus. So all of this seems very straightforward to this, but now we are going to complicate the picture.
Chlorophyll, which is the green substance in plants, is also found in the bodies of some protozoans, enabling them to make at least some of their own food from watered carbon dioxide. Sounds like photosynthesis, doesn't it? But protozoans are animals and plants are the life forms that use photosynthesis. In other words protozoans are not considered plants because, unlike pigmented plants to which some protozoans are otherwise identical, they do not live on simple organic compounds. Their cells demonstrate all of the major characteristics of the cells of higher animals, such as eating, breathing, and reproducing. Now many species of protozoans collect into colonies, physically connected to one another and responding uniformly to outside stimuli. Current research into this phenomenon along with investigations carried out with advanced microscopes may necessitate a redefinition of what constitutes protozoans, even calling into question the basic premise that they have only one cell. Nevertheless, with the current data available, almost 40,000 species of protozoans have been identified. No doubt, as technology improves methods of observation, better models of classification of these simple single cells will propose.
Romanticism was an artistic, literary, and intellectual movement that originated in Europe toward the end of the 18th century and in most areas was at its peak in the approximate period from 1800 to 1850. It was embodied most strongly in the visual arts, music, and literature, but had a major impact on historiography, education and the natural sciences. The movement validated strong emotion as an authentic source of aesthetic experience, placing new emphasis on such emotions as apprehension, horror and terror. Although the movement was rooted in the German Sturm und Drang movement, which prized intuition and emotion over Enlightenment rationalism, the ideologies and events of the French Revolution laid the background from which both Romanticism and the Counter-Enlightenment emerged. The confines of the Industrial Revolution also had their influence on Romanticism, which was in part an escape from modern realities; indeed, in the second half of the 19th century.
The first key Characteristics of romanticism is Emotional Emphasis. The paintings of the Romantic period were emotional powder kegs. Artists expressed as much feeling and passion as could be loaded on to a canvas. A landscape had to evoke a mood, a crowd scene had to show expressions on every face, an animal painting had to depict some, preferably majestic, trait of that animal. Even portraits were not totally straightforward representations -- the sitter would be given eyes meant to be mirrors of the soul, a smile, a grimace, or a certain tilt of the head.
If there is one prevalent theme to Romanticism, it is this: nature can change direction without warning, and we puny mortals are no match for it. You will find many, many examples of shipwrecks in Romantic paintings, for example. Shipwrecks, historically speaking, have always had high mortality rates. If you didn't drown, you stood a good chance of dying slowly of dehydration and starvation. Likewise, Romantic art had more than its fair share of blizzards, fires, thunderstorms, lightning strikes, floods, earthquakes, volcanoes, and biblical disasters. About the only natural disaster Romanticism did not try to portray was an asteroid strike. And that is probably only because no one in the early 19th-century had yet discovered the geological evidence of impact events.
In addition to the emotionally-charged feelings one got from looking at Romantic paintings, contemporary viewers were usually quite knowledgeable of the story behind the subject matter. Why? Because the artists frequently took their inspiration from current events. The best example of movements Romanticism influenced is the American Hudson River School, which got underway in the 1850s. Founder Thomas Cole, Asher Durand, Frederic Edwin Church, et. al., were directly influenced by European Romantic landscapes. Luminism, an offshoot of the Hudson River School, also focused on Romantic landscapes. Certain Romantic artists also made innovations that later movements incorporated as crucial elements. John Constable (1776-1837) had a tendency to use tiny brushstrokes of pure pigments to emphasize dappled light in his landscapes. He discovered that, when viewed from a distance, his dots of color merged. This development was taken up with great enthusiasm by the Barbizon School, the Impressionists, and the Pointillists.
The Feminist Art Movement began with the idea that women’s experiences must be expressed through art, where they had previously been ignored or trivialized. Early proponents of Feminist Art in the United States envisioned a revolution. They called for a new framework in which the universal would include women’s experiences, in addition to men’s. Like others in the Women’s Liberation Movement, feminist artists discovered the impossibility of completely changing their society.
Linda Nochlin’s essay “Why Are There No Great Female Artists?” was published in 1971. Of course, there had been some awareness of female artists before the Feminist Art Movement. Women had created art for centuries. Mid-20th century retrospectives included a 1957 Life magazine photo essay called “Women Artists in Ascendancy” and the 1965 exhibit "Women Artists of America, 1707-1964,” The Feminist Art is becoming a Movement in the 1970s .In 1971, Judy Chicago, one of the most prominent early activists in the Movement, established the Feminist Art program at Cal State Fresno. In 1972, Judy Chicago created Woman house with Miriam Schapiro at the California Institute of the Arts (Cal Arts), which also had a Feminist Art program. Feminist artists played with the ideas of gender, identity, and form. They used performance art, video, and other artistic expression that would come to be significant in Postmodernism but had not traditionally been seen as high art.
Rather than “Individual vs. Society,” Feminist Art idealized connectivity and saw the artist as part of society, not working separately. By asking whether male experience was universal, Feminist Art paved the way for questioning exclusively white and exclusively heterosexual experience as well. Feminist Art also sought to rediscover artists. Many art historians have described pre-feminist women artists as links between various male-dominated art movements. This reinforces the feminist argument that women somehow do not fit into the categories of art that were established for male artists and their work.
Surrealism is a cultural movement that began in the early 1920s, and is best known for its visual artworks and writings. The aim was to "resolve the previously contradictory conditions of dream and reality. Surrealist works feature the element of surprise, unexpected juxtapositions and non sequitur; however, many Surrealist artists and writers regard their work as an expression of the philosophical movement first and foremost, with the works being an artifact. Leader André Breton was explicit in his assertion that Surrealism was above all a revolutionary movement.
Surrealism officially began with "The Manifesto of Surrealism," published in 1924. However, it grew out of Dada. Surrealism developed out of the Dada activities during World War I and the most important center of the movement was Paris. From the 1920s onward, the movement spread around the globe, eventually affecting the visual arts, literature, film, and music of many countries and languages, as well as political thought and practice, philosophy, and social theory.
The word surrealist was coined by Guillaume Apollinaire and first appeared in the preface to his play Les Mamelles de Tirésias. World War I scattered the writers and artists who had been based in Paris, and in the interim many became involved with Dada, believing that excessive rational thought had brought the conflict of the war upon the world. The Dadaists protested with anti-art gatherings, performances, writings and art works. After the war, when they returned to Paris, the Dada activities continued.
Surrealism never died, it simply splintered into numerous directions and influenced new movements, with different names. Some artists still identify themselves as Surrealists and some founding Surrealist artists are still alive.
Just as with Florence, Venice was a Republic during the Renaissance. It enjoyed a stable political climate and thriving trade economy, both of which survived outbreaks of the Black Death and the fall of Constantinople (a major trading partner). Venice was, in fact, so prosperous and healthy that it took someone named Napoleon to undo its empire status...but, that was quite a while after the Renaissance had faded away and had nothing to do with art. The important part is, Venice (again, like Florence) had the economy to support art and artists, and did so in a big way.
As a major port of trade, Venice was able to find ready markets for whatever decorative arts Venetian craftsmen could produce. The whole Republic was crawling with ceramists, glassworkers, woodworkers, lace makers and sculptors (in addition to painters), all of whom made entirely satisfactory livings.
The state and religious communities of Venice sponsored massive amounts of building and decorating, not to mention public statuary. Many private residences (palaces, really) had to have grand facades on at least two sides, since they can be seen from the water as well as land. To the present day, Venice is one of the most beautiful cities on earth because of this building campaign.
Venice's geographic location made it less susceptible to outside influences - another factor which contributed to its unique artistic style. Something about the light in Venice, too, made a difference. This was an intangible variable, to be sure, but it had an enormous impact. For all of these reasons, during the Renaissance Venice gave birth to a distinct school of painting.
The main word here is "light". Four hundred years prior to Impressionism, the Venetian painters were keenly interested in the relationship between light and color. All of their canvases clearly explore this interplay. Additionally, the Venetian painters had a distinct method of brushwork. It's rather smooth, and makes for a velvety surface texture.
It seems, too, that Venice's geographic isolation allowed for a somewhat relaxed attitude toward subject matter. A great deal of painting dealt with religious themes; there was no getting around that. Certain wealthy Venetian patrons, however, created quite a market for what we refer to as "Venus" scenes. (Oh, all right - they were paintings of naked ladies.)
The Venetian School had a brief fling with Mannerism, but mostly resisted depicting the contorted bodies and torturous emotion Mannerism is known for. Instead, Venetian Mannerism relied on vividly painted light and color to achieve its drama. Venice, more than any other location, helped make oil paint popular as a medium. The city is, as you know, constructed on a lagoon which makes for a built-in dampness factor. Venetian painters needed something durable! By the way, the Venetian School is not known for its frescoes...
When did the Venetian School arise? In the mid to late 15th century, Pioneers of the Venetian School were the Bellini and Vivarini (descendants of those marvelous Murano glassworkers) families. The Bellini were of particular importance, for it is they who are credited with bringing the Renaissance "style" to Venetian painting. Who were the important artists? Well, there were the Bellini and Vivarini families, as mentioned. They got the ball rolling. Andrea Mantegna, though from nearby Padua (not Venice) was an influential member of the Venetian School during the 15th-century. Giorgione ushered in 16th century Venetian painting, and is rightly known as its first really big "name". He inspired notable followers such as Titian, Tintoretto, Paolo Veronese and Lorenzo Lotto. Additionally, a lot of famous artists traveled to Venice, thanks to its reputation, and spent time in the workshops there. Antonello da Messina, El Greco and even Albrecht Dürer - to name but a few - all studied in Venice during the 15th and 16th centuries.
The term "Performance Art" got its start in the 1960s in the United States. It was originally used to describe any live artistic event that included poets, musicians, film makers, etc. - in addition to visual artists.
It's worth noting that, even though we're referencing the 1960s here, there were earlier precedents for Performance Art. The live performances of the Dadaists, in particular, meshed poetry and the visual arts. The German Bauhaus, founded in 1919, included a theater workshop to explore relationships between space, sound and light. The Black Mountain College (founded [in the United States] by Bauhaus instructors exiled by the Nazi Party), continued incorporating theatrical studies with the visual arts - a good 20 years before the 1960s Happenings happened. You may also have heard of "Beatniks" - stereotypically: cigarette-smoking, sunglasses and black-beret-wearing, poetry-spouting coffeehouse frequenters of the late 1950s and early 1960s. Though the term hadn't yet been coined, all of these were forerunners of Performance Art.
By 1970, Performance Art was a global term, and its definition a bit more specific. "Performance Art" meant that it was live, and it was art, not theater. Performance Art also meant that it was art that could not be bought, sold or traded as a commodity. Actually, the latter sentence is of major importance. Performance artists saw (and see) the movement as a means of taking their art directly to a public forum, thus completely eliminating the need for galleries, agents, brokers, tax accountants and any other aspect of capitalism. It's a sort of social commentary on the purity of art, you see.
In addition to visual artists, poets, musicians and film makers, Performance Art in the 1970s now encompassed dance (song and dance, yes, but don't forget it's not "theater"). Sometimes all of the above will be included in a performance "piece" (you just never know). Since Performance Art is live, no two performances are ever exactly the same. The 1970s also saw the heyday of "Body Art" (an offshoot of Performance Art), which began in the 1960s. In Body Art, the artist's own flesh (or the flesh of others) is the canvas. Body Art can range from covering volunteers with blue paint and then having them written on a canvas, to self-mutilation in front of an audience. (Body Art is often disturbing, as you may well imagine.)
Additionally, the 1970s saw the rise of the autobiography being incorporated into a performance piece. This kind of story-telling is much more entertaining to most people than, say, seeing someone shot with a gun. (This actually happened, in a Body Art piece, in Venice, California, in 1971.) The autobiographical pieces are also a great platform for presenting one's views on social causes or issues.
Since the beginning of the 1980s, Performance Art has increasingly incorporated technological media into pieces - mainly because we have acquired exponential amounts of new technology. Recently, in fact, an 80's pop musician made the news for Performance Art pieces which use a Microsoft® PowerPoint presentation as the crux of the performance. Where Performance Art goes from here is only a matter of combining technology and imagination. In other words, there are no foreseeable boundaries for Performance Art.
Performance Art has no rules or guidelines. It is art because the artist says it is art. It is experimental. It may be comprised of painting or sculpture (or both), dialogue, poetry, music, dance, opera, film footage, turned on television sets, laser lights, live animals and fire, or all of the above. There are as many variables as there are artists.
Lowbrow is a movement - slowly gaining momentum - that doesn't necessarily care if The Art World recognizes it as such. What matters to Lowbrow is that most of us average people do recognize it. Anyone who has ever watched cartoons, read Mad magazine, enjoyed a John Waters film, consumed a product with a corporate logo or possessed a sense of humor shouldn't have a hard time getting comfy with Lowbrow.
Lowbrow-the-Movement has here been assigned a "circa" of 1994, as that is the year that Lowbrow artist extraordinaire Robert Williams founded Juxtapoz magazine. Juxtapoz showcases Lowbrow artists and is currently the second best-selling art magazine in the U.S. The roots of Lowbrow, however, go back decades to Southern California hot-rods and surf culture. Ed ("Big Daddy") Roth is frequently credited with getting Lowbrow, as a movement, underway by creating Rat Fink in the late 1950s. Over the years, Lowbrow has unapologetically picked up influences from classic cartoons, 60's TV sitcoms, psychedelic rock music, pulp art, soft porn, comic books, sci-fi, horror movies, Japanese anime and black velvet Elvis, among many other "subcultural" offerings.
Lowbrow was born of underground or "street" culture. The single most common tactic that Lowbrow artists employ is to poke fun at convention. They know the "rules" of art, and consciously choose not to abide by them. Lowbrow art has a sense of humor. Sometimes the humor is gleeful, sometimes it's impish and sometimes it's born of sarcastic comment, but it is always present. Lowbrow draws heavily on icons of popular culture, particularly those now commonly known as "Retro." Tail-end "Baby Boomers" will recognize them straight away, unless said Boomers were raised in an environment that disallowed outside influences. Lowbrow currently suffers something of an identity crisis, due to having a wide variety of artists lumped into it. For example, the designer of a simple, kitschy decal may be accorded the same Lowbrow designation as the artist who composes a technically masterful Lowbrow painting or sci-fi sculpture. Hopefully, this will sort itself out in years to come.
Magnetism is the force exerted by magnets when they attract or repel each other. Magnetism is caused by the motion of electric charges. Every substance is made up of tiny units called atoms. Each atom has electrons, particles that carry electric charges. Spinning like tops, the electrons circle the nucleus, or core, of an atom. Their movement generates an electric current and causes each electron to act like a microscopic magnet.
In most substances, equal numbers of electrons spin in opposite directions, which cancel out their magnetism. That is why materials such as cloth or paper are said to be weakly magnetic. In substances such as iron, cobalt, and nickel, most of the electrons spin in the same direction. This makes the atoms in these substances strongly magnetic—but they are not yet magnets. To become magnetized, another strongly magnetic substance must enter the magnetic field of an existing magnet. The magnetic field is the area around a magnet that has magnetic force. All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The force generated by the aligned atoms creates a magnetic field. The piece of iron has become a magnet. Some substances can be magnetized by an electric current. When electricity runs through a coil of wire, it produces a magnetic field. The field around the coil will disappear, however, as soon as the electric current is turned off.
The Maya lived in a number of separate, and independent, city-states, which were ruled by kings. Some of these counted as many as 90,000 inhabitants. Nobles lived in elaborate and highly decorated houses, while ordinary people dwelled in simple, single-room homes made of wood and adobe.
Daily life revolved around tending crops and domestic animals. Women were concerned with raising the family, while men hunted and engaged in sports. Over the centuries, the Maya developed a number of beliefs concerning royalty. The most important was the belief that people of royal blood were direct descendants of the gods. In life and in death they were considered different from ordinary people. Members of the royal family were expected to offer their blood in religious ceremonies. The royal dead were buried in temple pyramids while ordinary people were laid to rest under the floors of their homes. Religion played an important part in the everyday life of the Maya. The blood of royal people and outright human sacrifices were regular features of religious ceremonies that were dictated by the seemingly infallible Maya calendar.
The arrival of solar and lunar eclipses, as predicted by the priests' calendar, served to reinforce belief among the people at large. A vast number of gods and goddesses represented the forces that had the greatest impact on the lives of the people. Most of these were gods of rain, sunshine, and other natural forces. Others included an array of deities associated with the animal’s native to the tropical Yucatan environment. Animals played a large part in everyday Maya life, both for their practical contribution and for their religious significance.
Effigies of dogs have been found in Maya burial sites, signaling their importance in the journey to the afterlife. Other animals had more mystical significance. The armadillo, for example, was associated with the Maya underworld. The jaguar, also associated with the underworld, was admired for its stealth, cunning, and deadly power.
The first human inhabitants of Meso-America were descendants of Asian peoples who crossed the Bering land bridge. Fanning out southward and eastward, they arrived in present-day Mexico many thousands of years ago.
These first settlers were hunters and gatherers, but eventually they developed settled communities based on cultivation of crops such as maize. The Olmecs and the Zapotecs were two of the first cultures to develop in this region and then Maya developed the most sophisticated of the Pre-Columbian civilizations of Meso-America .
Maya had settled the humid tropical lowlands of the Yucatan Peninsula by about 1000 BCE. Within a few centuries they began draining swamp land, making it into arable farming land. Initially absorbing the advances of the neighboring Zapotecs, they went on to develop a network of prosperous communities. Extensive trading networks linked communities throughout their region, although these same communities often engaged in bitter warfare.
Maya civilization became noted for its works of art and architecture. They developed a distinctive artistic style using many different materials, including wood and stone sculpture, murals, and pottery. Most of the wooden sculpture has decayed, but limestone carvings are full of ornamentation and intricate carving. Murals depicted religious and historical themes while colorful examples of pottery have been found as ornaments in many Maya graves.
Using the main points and examples from the lecture, describe the civilization of the first human inhabitants of Meso-America
California, a land rich with natural resources, plants, and animals, was home to many native peoples. They built many different kinds of homes. The Maidu tribe in the south had one of the most unique types. They lived in dwellings that were dug into the ground and covered with mud roofs. Other tribes built dome-shaped huts with a wooden framework covered with earth, brush, bark, and reeds.
The desert-like landscapes of the Southwest of California can seem as inhospitable as the Arctic, yet this region saw many developments, including the rise of agriculture. There were many different cultures, from the Navajo farmers to the nomadic Apache, who were hunters and raiders.
Although farming was not easy in the Southwest of California , Navajo farmers were able to water the desert soil to grow maize as well as beans, squash, pumpkins, and avocados using complex irrigation systems. They also held public ceremonies to bring rain the dry region and to assure a good harvest.
The nomadic Apache, on the other hand, gained a reputation as fierce warriors. They used their bows and arrows to attach neighboring communities when hunting was poor or to rob them of essential supplies.
There is a lot of movement going on in our solar system. All the planets constantly move at different speeds around the sun. Moons constantly spin around each planet. Every now and then, one of these objects moves into the shadow of another one. We call this an eclipse.
A solar eclipse happens when the Moon, on its journey around the Earth, happens to pass between the sun and the Earth for a moment. A solar eclipse can only happen during anew moon, a phase of the lunar cycle where the Moon lies between the Earth and the sun. At night, the Moon is totally dark during a new moon.
If everything lines up just right, the sun is fully or partially covered by the Moon. That means those of us on Earth see a big, round shadow (the Moon) sliding over and covering the sunlight we normally see in the daytime sky. The shadow covering the sun is called an umbra.
Total solar eclipses, where the moon perfectly blocks out the entire sun, are rare. Partial solar eclipses, where the moon covers only a part of the sun, are much more common.
Between two and five total or partial solar eclipses happen every year. Whether or not you see a full or partial eclipse depends on where you are on Earth. A full eclipse may be visible to people in the Northern Hemisphere when it is facing the sun, for example. In this situation, people in the Southern Hemisphere will not see the eclipse at all.
Solar eclipses are usually over and done with pretty quickly. Scientists say total solar eclipses, in the very best conditions, can only be seen for about 7 minutes. The Moons umbra keeps sliding over until the sun peeks through again.
The Moon is just the right size to perfectly cover the sun. The sun is actually many, many, many, times larger than the Moon, but the Moon is much closer to the Earth, so it appears larger.
Lunar eclipses happen when the Moon passes through the Earth’s shadow. This can only happen when the Moon is on the far side of the Earth, away from the sun. Think of the Earth in the center, with the sun on one side, and the moon on the other. So, lunar eclipses only happen when there is a full moon.
Lunar eclipses are much more common than solar eclipses, and many more people can see them at the same time. In fact, a whole hemisphere can usually see a lunar eclipse happening. Part of why they’re easier to see is that they last longer; lunar eclipses last several hours.
Many plant and animal species thrive in estuaries. The calm waters provide a safe area for small fish, shellfish, migrating birds and shore animals. The waters are rich in nutrients such as plankton and bacteria. Decomposing plant matter, called detritus, provides food for many species.
The estuarine crocodile, for example, is an apex predator of tropical Australian and Southeast Asian estuaries. The estuarine crocodile is the largest reptile in the world. Aspecimen caught in the Philippines in 2011 measured 6.4 meters (21 feet).
Like most apex predators, estuarine crocodiles eat almost anything. This means the estuary must support a wide variety of food webs. Estuarine crocodiles do not usually consume producers—sea grasses, seaweeds, mushrooms, and plankton in the estuary. However, they do prey on consumers in the second trophic level, which rely on these plants and other photosynthetic organisms for food: insects, mollusks, birds, and fruit bats. Estuarine crocodiles also prey on consumers at the third trophic level, such as boars and snakes (and, rarely, people).
Estuarine crocodiles are ideally adapted to the brackish water of river estuaries. They can survive equally well in freshwater and saltwater ecosystems. During the rainy season, estuarine crocodiles live in freshwater rivers and streams. They feed on fish such as barramundi, andterrestrial species such as kangaroos and monkeys. During the dry season, estuarine crocodiles swim to river mouths and even out to sea. Fish remain the main component of their diet. Some estuarine crocodiles have even been known to attack and consume sharks.
Estuarine crocodiles have also adapted to seasonally vanishing estuaries. The reptiles can go months without eating. Estuarine crocodiles can simply not eat when the estuary shrinks and food becomes scarce.
Today I want to talk about Fertility. Fertility has two definitions. It can refer to the ability of soil to sustain plant growth, or it can refer to the number of live births occurring in a population.
Agronomists, or people who study the uses of plants, use the Fertility to refer to soil. Plants grow easily in fertile soil because it contains large amounts of nutrients. These nutrients such as phosphorous, nitrogen, and potassium, which help keep plants healthy, come from minerals and decaying plant and animal matter. Nowadays people use these nutrients to produce Fertilizers . Common fertilizers are humus and Manure.humus, is a natural fertilizer that can improve soil fertility. Manure, or the droppings of some animals such as bats or cows, is also an excellent fertilizer.
For demographers—people who study population statistics—fertility means the number of live births occurring in a population. Governments keep track of the general fertility rate to determine if their population will grow, shrink, or stay the same size.
Fertility rates tend to be lower in industrialized nations, such as the United States, than in underdeveloped countries. There are many reasons for this. One reason is Mothers and children have greater access to health care in industrialized nations. This means children’s mortality rates, or the number of children who die before turning five, are much lower.
Oil shales are classified in three main types based on their mineral content: carbonate-rich shale, siliceous shale, and cannel shale. Carbonate-rich shale deposits have high amounts of carbonate minerals. Carbonate minerals are made of various forms of the carbonate ion (a unique compound of carbon and oxygen). Calcite, for instance, is a carbonate mineral common in carbonate-rich shales. Calcite is a primary component of many marine organisms. Calcite helps form the shells and hard exteriors of oysters, sea stars, and sand dollars. Plankton, red algae, and sponges are also important sources of calcite. Siliceous shale is rich in the mineral silica, or silicon dioxide. Siliceous shale formed from organisms such as algae, sponges, and microorganisms called radiolarians. Algae have a cell wall made of silica, while sponges and radiolarians have skeletons or spicules made of silica. Siliceous oil shale is sometimes not as hard as carbonate-rich shale, and can more easily be mined. Cannel shale has terrestrial origins, and is often classified as coal. It is made up from the remains of resin, spores, and corky materials from woody plants. It can contain the minerals inertinite and vitrinite. Cannel shale is rich in hydrogen, and burns easily.
What are Fossils? Fossils are the preserved remains, or traces of remains, of ancient organisms. The process of remains becoming fossils is called Fossilization. Fossilization is rare. Most organisms decompose fairly quickly after they die. For an organism to be fossilized, the remains usually need to be covered by sediment such as sandy seafloor, lava, and even sticky tar soon after death.
Over time, minerals in the sediment seep into the remains. The remains become fossilized. Fossilization usually occurs in organisms with hard, bony body parts, such as skeletons, teeth, or shells. Soft-bodied organisms, such as worms, are rarely fossilized.
Fossils can be very large or very small. We can classify fossils into trace fossils, microfossils, and microfossils.
Trace fossils are rocks that have preserved evidence of biological activity. They are not fossilized remains, just the traces of organisms. The imprint of an ancient leaf or footprint is a trace fossil. Burrows can also create impressions in soft rocks or mud, leaving a trace fossil.
Microfossils are only visible with a microscope. Bacteria and pollen are microfossils. Macrofossils can be several meters long and weigh several tons. Macrofossils can be petrified trees or dinosaur bones.
Native Americans in the north inhabited the forbidding land of the Arctic and Sub-Arctic regions, adapting to cold, prolonged darkness, and lack of vegetation. Using the few materials available to them such as animal furs and ice, they developed the kayak, harpoon, igloo, and dog-sleds more than 2,500 years ago.
The hunter of the Sub-Arctic region used wood , bone to produce tools, weapons, and canoes to transport people and goods across a landscape of forests, plains, rivers, and lakes. Rich natural resources made hunting and fishing easy on the Northwest Coast bordering the Pacific Ocean and many peoples inhabited the region. People had time to build elaborate social systems. Craftsmen perfected the skills of working wood, while boatmen went in search of fish and even whales. But the preoccupation with wealth and social standing led to bitter rivalries and violent disputes among neighboring communities. The people of the Plateau, like those of the Northwest Coast, had plentiful sources of food, including great rivers and streams with an abundance of fish. The river systems of the Plateau facilitated trade and made cultural exchange with tribes of other regions possible.
The people of the Northwest Coast spent a lot of time making handicrafts. These goods were prized possessions and lay at the heart of a bustling trade. Many such goods were the result of long hours of manufacture. The woodcarvers of the Northwest Coast produced elaborately carved pieces that were either put to practical use or prized as decorative possessions. The wealthy and powerful accumulated many such goods, but they strengthened their social standing by giving them away or even destroying them. An important event such as a wedding was celebrated with a feast called potlatch. The host would give his prized goods to the assembled guests, ensuring his strong social position in the process.
Using the main points and examples from the lecture, describe the civilization of the people of Native Americans in the Arctic and Sub-Arctic regions.
A flood can develop in a many ways. The most common is when rivers or streams overflow their banks. These floods are called riverine floods.
Heavy rain, a broken dam or levee, rapid ice melt in the mountains, or even a beaver dam in a vulnerable spot can overwhelm a river and send it spreading over nearby land.The land surrounding a river is called a flood plain.
Coastal flooding, also called estuarine flooding, happens when a large storm or tsunami causes the sea to rush inland.
When flood waters recede, they leave behind sediment and mud that are rich in nutrients; and can benefit cultivation.
However, Floods can cause even more damage when their waters recede. The water and landscape can be contaminated with hazardous materials, such as sharp debris, pesticides, fuel, and untreated sewage. Potentially dangerous mold can quickly overwhelm water-soaked structures. As flood water spreads, it carries disease. Flood victims can be left for weeks without clean water for drinking or hygiene. This can lead to outbreaks of deadly diseases like typhoid, malaria, hepatitis A, and cholera. Severe flooding in Bangladesh 2007 led to more than a million homes being damaged or destroyed.
American colonists' resentment at British authoritarian rule led to the Thirteen Colonies forming a Continental Congress in 1774. The following year, as anti-British feeling grew, the first hostile skirmishes took place between America militiamen and British troops These battles marked the beginning of the American Revolution, also known as the Revolution war in America or the War of American Independence. The French, Spanish, and Dutch took the opportunity to help reduce British control of America. In 1775 Congress unanimously elected him commander in chief of the American forces, though he had not sought the position. He won ordinary American people over to the cause, and they saw him as a symbol of independence.
Washington played a major role in the colonies' struggle for independence. The American forces were first made up of militiamen, who fought for their separate colonies. They expected to fight for a short time and then return home. In1775 Congress established the Continental Army, with an overall commander and a series of generals. They brought training and discipline to their troops, much needed to combat the British soldiers. The British army was a professional force, including foreign mercenaries hired from German princes. In June 1776, Congress set up a committee to draft a declaration, and Thomas Jefferson of Virginia was appointed to complete this. Delegates debated the draft, which was formally adopted on July4. The Declaration was printed and read out to a large crowd in Philadelphia days later. It famously stated: "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain inalienable rights", that among these are life, liberty, and the pursuit of happiness.
Early settler in the American colonies built dwellings based on those they had inhabited in their home countries. But they were forced to adapt styles and building methods to local conditions, and this generally meant a dependence on wood. Though family’s were large, houses did not have many separate living rooms or bedrooms, so great deal of time together. The style of living was simple, and this suited many settlers. Around 1700 the European colonists numbered about 300,000, and by 1775 this population had risen to 2.5 million. Most colonial homes in America were based on the style of late medieval English houses. The most important building material was wood, which was plentiful in the eastern forest of North America. Rectangular timber-frame houses were built around a large chimney, since winters could be very cold. The sloping roof was usually thatched or shingled, and the outside walls were finished with weatherproof clapboard. Interior walls were often made of plaster, and windows were generally small. Families in the colonies generally had many children. Men normally married around the age of 21, and women round 18, but they usually stayed at one of their parents' homes. This was useful to everyone, because a large family made it easier to develop a farm or business. Learning from the difficulties of the earliest settler, colonists came to appreciate native food, such as corn bored, roasted squash, and acorn oil. Women also used maize to make hominy and succotash. The main meal was eaten around midday, and it often consisted of a meat and vegetable stew. The most common meat was pork, and colonists kept sheep and chickens as well as pigs. A favorite drink was home-brewed beer sweetened with molasses or pumpkin.
During the 17th century small American settlements grew into larger colonies. By the mid-1700s, they formed 13 British colonies that stretched down the coast from New England to Georgia. Each colony had its own governor and laws, but all were subject to British control. French territorial claims ended in 1763, but by this time restrictive British trade laws and taxes were causing unrest among the colonists. Powerful governors introduced different "frames of government” to their territories, some more liberal than others. In Pennsylvania, William Penn created a council that proposed laws and an assembly that approved them. Then, in 1701, he granted a new constitution, called the Charter of Privileges, which gave all lawmaking power to the lower house of the assembly, The Charter was a great step forwards liberal self-government. In 1754 war broke out between France and Britain over control of the upper Ohio River valley. American colonists joined the British to fight French troops backed by alliances with Native Americans. As the map shows, by the 1763 Treaty of Paris the French had lost much territory. A British proclamation then drew a line to west of the colonies. This separated them from Native American lands and kept colonist near the coast, where they could trade more easily. Beginning in 1651, Navigation Acts were passed by the English parliament to protect its trade and shipping. Some were aimed at the American colonies and the Dutch, to stop them profiting from trade between the West Indies and Europe. Goods such as sugar, cotton, and tobacco had to be shipped on English vessels, and from 1663 all European goods bound for the American colonies had to pass through and English port and were subject duty.
In 1674, just eleven years after the establishments of New France as a royal province further north, French explorers were canoeing down the Mississippi River. This allowed them to expand their fur-trading activities further south. The provincial governor had hoped that this waterway would lead the west and Asia, but by 1682 the explorers had reached the Gulf of Mexico and claimed the entire region drained by the river for France. This led to the establishment of colony of Louisiana. The French first explored the Mississippi when the governor of New France sent explorer Louis Jolliet and Jesuit missionary Jacques Marquette from Lake Michigan to see whether the great river flowed west to the Pacific. They reached the confluence of the Arkansas River. Eight years later, Rene-Robert Cavelier canoed the entire length of the river and reached its mouth at the Gulf of Mexico. French Policy was to establish fur-trading posts and small colonies over wide areas. In order to develop their fur-trade interests, the French realized that a good relationship with local Native Americans was important. After building Fort St. Louis on the Illinois River, La Salle wanted to found a colony at the mouth of the Mississippi and returned the France to pick up colonists. But his ships missed their destination and eventually set up a colony at Matagorda Bay, Texas.
Spanish colonial territories in the Americas grew during the 15 year rule of the first viceroy of New Spain. This expansion led to the successful exploitation of the gold and silver that the Spanish had been so keen to find. The colonies were run under the system called encomienda, by which the Spanish crown granted colonists the right to demand tribute in gold of labor from native inhabitants. At the same time colonists were responsible for protecting native peoples and instructing them in Christianity, through many did not take this responsibility seriously. The Council of the Indies, which was resident in Spain, was made up of six to ten councillors appointed by the kin. The Council ran the American viceroyalties on behalf of the monarch, preparing expenditure by officials, and acting as an appeal court. Among the councillors were lawyers, clergymen, geographers, mathematicians, and secretaries. Each of the Spanish viceroyalties, or colonial provinces, was run on behalf of the king of Spain by a viceroy. This senior official acted as governor, supervisor of the colonial treasury, captain-general of the military, and vice-patron of the Church. The viceroy was also president of the regional courts and administrative centers that also served as executive councils. As a third tier of the hierarchy, each region dad a number of local parishes and mayors.
Today I want to talk about the use of social media for businesses. Social media use is trending upward according to the survey of more than 1,235 small business owners, no surprise given the attention paid to the various social platforms by big businesses and media outlets. Nearly 50% have increased time spent on social media this year and nearly 55% say they're using platforms like Twitter and Facebook as a primary tool for either acquiring new customers of generating sales leads.
Despite their dedication and belief that social media is the Hail Mary of small business owners everywhere, more than 60% of small business owners say they haven't seen any return on investment from their engagement online. None.
Small business owners are being told social can generate leads and bring in new customers, so they often consider it as another direct marketing vehicle which is easy to measure. You spend $1000, you get 20 new customers as a result.
In contrast, social media is a patience game. People are being sold on social as a place to generate leads, but it's really a place to build loyalty. If people trust you they're going to be loyal. If they're loyal, their average order will be higher, the frequency of their purchases will be higher and the life expectancy of them as a customer will be longer.
When two tectonic plates move toward one another and collide, they form either a Subduction zone or a continental collision. When a dense oceanic plate collides with a less-dense continental plate, the oceanic plate is typically sub ducted beneath the continental plate. When two plates with oceanic crust converge, they form an island arc as one plate is sub ducted below the other. The arc is formed from volcanoes, which erupt through the overriding plate as the descending plate melts below it. When two continental plates collide, either the plates compress or one plate delves under the other. Each action will create extensive mountain ranges. Two plates may collide at an oblique angle or they may collide head-on. At divergent boundaries, two plates move apart from each other and the space that this creates is filled with new crustal material sourced from molten magma that forms below.
Meteorites are meteors that fall to Earth’s surface. A meteor may also be called a shooting star or falling star. Meteors were once meteoroids. Meteoroids are lumps of rock or iron that orbit the sun. Many were once part of larger bodies called asteroids, which orbit the sun between the paths of Mars and Jupiter in a region called the asteroid belt. Others come from the moon, Mars, and the tails of comets.
Dust-sized particles called micrometeorites make up 99 percent of the approximately 50 tons of space debris that fall through Earth’s atmosphere each day.
As meteors fall into Earth’s atmosphere, the gases surrounding them briefly light up. At this point, meteoroids become meteors, or shooting stars. Most meteors are too small to reach the surface of the Earth. They burn up and disintegrate in Earth’s atmosphere.
Very large meteors might explode before reaching the Earth’s surface. This is rare. In 1908, a meteor exploded about 10 kilometers (6 miles) over the Tunguska River in Siberia, Russia. The so-called Tunguska Event is considered an impact, even though the meteor did not actually hit the Earth and become a meteorite. The Tunguska Event instantly knocked down about 80 million trees in the Siberian forest. Many scientists say the explosion was larger than the most devastating nuclear weapon ever detonated.
Scientists have collected hundreds of meteorites. They have divided the meteorites into three main types: stony, iron, and stony-iron.
Stony meteorites are made up of minerals that contain mostly silicon and oxygen. They also contain some metal—nickel and iron. There are two types of stony meteorites. Chondrites are the most common type of meteorite, accounting for 86 percent of all meteorites that have fallen to Earth. They are named for the hardened droplets—or chon rules—of lava embedded in them. A Chondrites do not contain these droplets. They are very rare, constituting about 3 percent of all known meteorites. They form in the outer layer of asteroids, which is similar to Earth’s crust.
Iron meteorites are mostly made of iron and nickel. They come from the cores of asteroids and account for about 5 percent of meteorites on Earth.
Stony-iron meteorites have nearly equal amounts of silicate minerals and metal in them. One group of stony-iron meteorites, the palliates, contains yellow-green olivine crystals encased in shiny metal.
The largest meteorites leave enormous holes in the ground called impact craters. The best example of an impact crater in the United States is Meteor Crater, near Winslow, Arizona. There, more than 20,000 years ago, a meteorite weighing about 270,000 tons slammed into the Earth, making a hole 1.3 kilometers (.8 miles) wide and 175 meters (575 feet) deep.
Many scientists believe a large meteorite triggered the extinction of the dinosaurs 65 million years ago. They believe the Chicxulub Crater in the Yucatán Peninsula in Mexico is the site of that meteorite’s impact.