IELTS Vocabulary ebook

To breed is to have babies. Example sentences:

• Emperor penguins breed annually during the Antarctic winter.
• The reason why emperor penguins breed during the harshest season of the year is unknown, but scientists speculate that when the chicks become independent five months later, environmental conditions are more favorable for the young birds.

As a noun, a brood is a group of young born at the same time — like a brood of chicks. Look a the following example sentences:

• Increased predation affects the survival of nests and broods immediately after hatching
• This nest found in a slight depression in the ground contains a brood of tiny young birds.
• While the young are in the nest, the entire brood is extremely vulnerable to predation.

As a verb, “to brood” is to incubate. To incubate means to sit on eggs to make them warm before they hatch. Example:

• In some species of birds, both the mother and father brood the eggs.
• Birds brood eggs during the incubation period to keep them protected and warm until they are ready to hatch.

Camouflage is the way in which some animals are colored and shaped so that they cannot easily be seen in their natural surroundings. For example:

• The distinctive black and white coloring of jackass penguins is a form of camouflage.
• Underwater predators looking up only see white, and predators looking down only see black.
• Many sea animals have, over time, developed different kinds of camouflage to help them blend in with their environment and avoid detection by predators.
• Sloths live high in the canopy, feeding on a wide variety of leaves and fruits. Green algae grow in the sloths’ fur, which enables it to remain camouflaged from predators. 

Definition: (Of biological processes) recurring naturally on a twenty-four-hour cycle, even in the absence of light fluctuations

Example sentences:

• Although caffeine's effects on alertness and sleep are well known, researchers weren't sure how it affects the circadian clock in humans.

A congregation is a group of people or animals staying together.

Penguins congregate in groups to stay warm. With their group congregations, they are able to reproduce their offspring in extremely cold temperatures.

Example sentences:

• Periodic eruptions of the volcano have destroyed 213 homes since the volcano emerged from a period of dormancy in 1983.

Incubation periods are longer for precocial birds than for altricial birds, allowing for an increased embryonic development in the egg, and therefore they have relatively advanced motor and sensory functions at hatching.

Forage has two meanings.

The first meaning is to search for food. The phrase “forage for something‘ is often used. Here are example sentences:

• Jackass penguins forage at sea and dive to a depth of 130 meters in search of food.
• The foraging behavior varies considerably among penguin species. Adélie penguins feed primarily on small krill, while chinstraps forage for large krill.

The second meaning is to eat grass.

• The cows were foraging in the pasture.

The adjective “foraging” describes the act of searching for food. The term “foraging behavior” is often used.

• Animals exhibit several different types of foraging behavior.​
• Scratching, a common foraging behavior for many ground-feeding birds, including sparrows, uses one foot or both feet simultaneously to remove or loosen debris from the ground to reveal seeds, bugs or other food.

Definition: Of or relating to genes or heredity

Example sentences:

• Scientists believe the world’s famous fruit (banana) could disappear forever in 10 years’ time as it lacks the genetic capability to ward off pests and diseases that are in Central America, Africa and Asia.
• Bees have diminished drastically in recent years due to a variety of factors including pesticides, diseases and habitat degradation resulting in a loss of genetic diversity.
• Due to significant advances in biotechnology, experts predict that within years, doctors will be able to trace the genetic roots of common medical problems such as depression.​

Definition: Make or become accustomed or used to something

Example sentences:

• Bears can become habituated to people very easily.

A hatchling is a young animal that has recently emerged from its egg. Here are example sentences:

• A hatchling is a young animal that has recently emerged from its egg.
• There are many obstacles for turtle hatchlings, such as crabs, birds and many other predators in the ocean.
• Young hatchlings are vulnerable to predation.

Definition: determined by genetic factors and therefore able to be passed on from parents to their offspring or descendants

Example sentences:

• Scientists hope that by genetic manipulation, they will be able to cure hereditary diseases and defects.
• Cells contain hereditary information that is passed on from cell to cell during reproduction.
• Depression is often hereditary.

The broad definition of the verb “hibernate” is to spend the winter sleeping or resting. Hibernation is the act of hibernating, and hibernators are animals that hibernate.  Example sentences:

• Bats hibernate through the cold winter months. During hibernation, bats can survive in freezing temperatures.
• Many species hibernate during the winter, emerging only when the signs of spring promise plenty of food, telling them it is time to eat and breed again.
• Smaller animals tend to be more likely to hibernate, because migration would require an enormous amount of energy relative to their body size.

The broad definition of the verb “hibernate” is to spend the winter sleeping or resting. Hibernation is the act of hibernating, and hibernators are animals that hibernate.  Example sentences:

• In contrast to true hibernators such as woodchucks and hedgehogs, whose body temperatures drop close to the freezing point during the winter months, bears maintain a nearly normal body temperature throughout their prolonged sleep.

Incubation is the process of incubating eggs; it also refers to the development of the embryo within the egg.

Example sentences are:

• Incubation ensures normal egg development.
• Ambient temperature is commonly thought to influence avian incubation behavior.

Another word that has the same meaning of incubation is brooding. Here are example sentences:

• Fossils indicate that dinosaurs might have brooding behavior.
• Birds have many adaptations to help make brooding successful and ensure a better hatch rate for eggs

Definition: The active immature form of an insect

Example sentences:

• The army worms are the larval stage of a common moth.
• Animals in the larval stage will consume food to fuel their transition into the adult form.

Definition: A warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, females that secrete milk for the nourishment of the young, and (typically) the birth of live young

Example sentences:

• The domestic animal is the first mammal known to die of the disease in Europe.
• The first small mammals evolved from reptiles about 200 million years ago, and the group diversified rapidly after the extinction of the dinosaurs to become the dominant form of land animal, with around 4,000 living species.

Definition: (Of an animal, typically a bird or fish) move from one region or habitat to another according to the seasons:

Example senences:

• In eastern North America, over two-thirds of breeding bird species migrate.
• Not all birds migrate, but generally speaking the more northerly the breeding ground, the more likely is it that a species will migrate south for the winter. The main reason for this annual shifting of residence is that during the northern winters food becomes scarce and the cold temperatures make survival difficult.
• Roughly half of the world’s nearly 10,000 known bird species migrate, including several songbirds and seabirds, waterfowl and waders, as well as some raptors. The Northern Hemisphere has the most diverse array of migratory birds.

Definition: to copy an action

Example sentences:

• Babies mimic eating behaviors, so it's imperative that you and those regularly around your baby are exemplary food role models.
• Liquid-alternative funds mimic hedge funds by using strategies such as buying some stocks while betting against others, and investing in futures, commodities and derivatives.
• Parrots are probably most well-known for their ability to “talk,” as they can closely mimic the sounds of human voices. However, this is only seen in captive parrots. It is a mystery why wild parrots do not exhibit this behavior.

Definition: relating to the scientific study of the structure and form of animals and plants

Example sentences:

• Like animals, marine plants have both morphological, or structural, adaptations and functional adaptations.
• Many marine plants have flexible stems and leaves, which allow them to move and bend with the movement of the water around them. Some species undergo morphological change during the larva period.

Definition: A distinct form resulting from genetic mutation

Example sentences:

• It is important to realize that mutations in different mutant individuals are not necessarily distinct.

Definition:

Example senences:

• While there may be many mutualistic relationships between plants and animals, often plants are more the victims rather than the beneficiaries of the relationship.

An omnivore is a kind of animal that eats either other animals or plants. Some omnivores will hunt and eat their food, like carnivores, eating herbivores and other omnivores. Some others are scavengers and will eat dead matter. Many will eat eggs from other animals.

Definition: An organism which lives in or on another organism (its host) and benefits by deriving nutrients at the other’s expense

Example senences:

• If a species of parasite is to survive, the host organism must live long enough for the parasite to reproduce; if the host species becomes extinct, so do its parasites.
• Parasitism is a relationship where one organism, known as a parasite lives in or on another organism as a host.

Definition: the relation between two different kinds of organisms in which one receives benefits from the other by causing damage to it (usually not fatal damage)

Example senences:

• Parasitism is a relationship where one organism, known as a parasite lives in or on another organism as a host. Despite the parasite doing harm, it does not want to kill the host because the host provides nourishment but only if it is alive.

A predator is an animal that eats(preys on) other animals. Predators are predatory animals.

Example sentences:

• Penguins are both predators and prey. They hunt and kill and killed and hunted by seals and sharks
• Coyotes are the top natural predator of deer.

Prey is an animal that is hunted or killed by another animal for food. It is an uncountable noun.

• The seals are easy prey for sharks.
• Rodents are prey for avian, reptilian, and mammalian predators.

The phrase “prey on” means to hunt and kill (something) for food. Here are example sentences:

• The wolves prey on small animals.
• Owls prey on mice.

The phrase  “fall prey to” means to be killed by (an animal, disease, etc.)

• The deer fell prey to coyotes.
• Many people fell prey to disease.

The phrase "fall prey to" can be used to describe one's vulnerability exploited by someone or something in a bad way. Look at the following example sentences

• It is very common for elderly people to fall prey to scam artists online, who take advantage of their lack of technological know-how.
• Many major cities, once thought to be untouchable by such attacks, have been falling prey to terrorist activity in recent months.

In biology, to reproduce is to produce offspring. Here are example sentences:

• Most animals reproduce through sexual reproduction because it increases genetic variation.
• Corals reproduce asexually by budding or fragmentation. Through budding, new polyps “bud” off from parent polyps to form new colonies. In fragmentation, an entire colony branches off to form a new colony.
• Sea anemones reproduce both sexually and asexually.

Anything related to reproduction can be described as reproductive. For example:

• Scientists who study reproductive habits of animals analyze how they bear offspring.
• Fertility doctors help people who are having reproductive problems.
• The reproductive behavior of fishes is remarkably diversified: they may be oviparous (lay eggs), ovoviviparous (retain the eggs in the body until they hatch), or viviparous (have a direct tissue connection with the developing embryos and give birth to live young)

A species is a distinct group of animals or plants that have common characteristics and can breed with each other.

Note: The word species can be singular and plural. Therefore, you can say that species is red or these species are yellow.

• More than 700 bird species breed in North America, and the variations in their behaviors are fascinating and complex. 

• The Indian elephant is a vanishing species that needs a protected habitat to survive.