Animals of the same species are not all exactly the same. Differences largely come from an organism's genes. Genes can be thought of as instructions that are passed down from parent to child. They shape how living things look and behave. Some differences help an animal survive and are called adaptations. Adaptations are passed on from one generation to the next. Over time, they spread and become part of the species.

Structural and Behavioral Adaptations

Some adaptations are structural. That means they are a physical part of the organism. Other adaptations are behavioral, affecting the way a living thing acts.

An example of a structural adaptation is the way some plants have adapted to hot, dry deserts. Plants called succulents have found a way to survive there. They do it by storing water in their thick stems and leaves.

Migration is an example of a behavioral adaptation. Gray whales (Eschrichtius robustus) migrate thousands of kilometers every year. They swim from the cold Arctic Ocean to the warm waters off the coast of Mexico. Gray whale calves are born in the warm water. Later, they travel to the Arctic waters to feed.

Some adaptations are called exaptations. An exaptation is an adaptation developed for one purpose but used for another. For example, feathers were probably adaptations for managing temperature. Later, they grew bigger and allowed some species to fly.

Habitat

Adaptations are often a response to a change in the environment.

England's peppered moth (Biston betularia) is a famous example. Before the 1800s, most peppered moths were light with darker spots. Some moths were gray or black. However, these dark moths were rare.

Over time, the rise of factories changed the environment. The darker moths became more common. Their sooty color blended in with the trees stained by pollution. Birds could not see the dark moths, so they ate the light moths instead.

Speciation

Sometimes, an organism develops an adaptation that splits one species into two. This is known as speciation.

One way this can happen is through physical isolation.

A good example is the wide range of marsupials in Oceania. This area includes Australia and New Zealand. Long ago, Oceania was part of Asia. Before it broke away, marsupials arrived. Marsupials are mammals that carry their young in pouches. They are now the main type of mammal in Oceania.

Koalas (Phascolarctos cinereus) are one of the most famous marsupials. They adapted to feed on the eucalyptus trees. These trees grow in Australia. The Tasmanian tiger (Thylacinus cynocephalus) was a meat-eating marsupial. It adapted to fill the role played by big cats, such as tigers, on other continents. These different marsupials are an example of speciation. They developed to fill empty roles in their environment.

Coadaptation

Organisms sometimes adapt with other organisms. This is called coadaptation. Certain flowers have adapted their nectar to appeal to hummingbirds. Hummingbirds have adapted long, thin beaks to drink nectar from certain flowers. This relationship helps both organisms. When a hummingbird drinks nectar, it picks up pollen and spreads it to other flowers. The hummingbird gets food, and the plant's pollen gets distributed.

Mimicry is another type of coadaptation. With mimicry, one organism has adapted to look like another. The harmless king snake is a good example. Over time, it has developed a color pattern that looks like the deadly coral snake. This mimicry keeps predators away from the king snake.

Adaptation and Survival

A koala hugs a tree while her baby clings to her back at the Lone Pine Koala Sanctuary near Brisbane, Queensland, Australia. Koalas have adapted to only eat the leaves of eucalyptus trees. Eucalyptus are very low in protein and toxic to many animal species. Being able to digest eucalyptus leaves is an adaptation that benefits the koala by providing it a food source for which there is little competition.

adapt
Verb

to adjust to new surroundings or a new situation.

Noun

a modification of an organism or its parts that makes it more fit for existence. An adaptation is passed from generation to generation.

adaptive radiation
Noun

process in which many species develop from the same ancestral species to fill a variety of different roles in the environment.

algae
Plural Noun

(singular: alga) diverse group of aquatic organisms, the largest of which are seaweeds.

Noun

region at Earth's extreme north, encompassed by the Arctic Circle.

behavioral adaptation
Noun

way an organism acts in order to survive or thrive in its environment.

big cat
Noun

large predators, including tigers, lions, jaguars, and leopards.

carnivorous
Adjective

meat-eating.

cichlid
Noun

spiny-finned freshwater fish.

climate
Noun

all weather conditions for a given location over a period of time.

coadaptation
Noun

the process in which organisms develop in close relationship to one another.

Noun

edge of land along the sea or other large body of water.

co-extinction
Noun

the process in which the loss of one species leads to the loss of another species.

Noun

one of the seven main land masses on Earth.

Noun

area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

Noun

growth, or changing from one condition to another.

Noun

foods eaten by a specific group of people or other organisms.

distribute
Verb

to divide and spread out materials.

dominate
Verb

to overpower or control.

environment
Noun

conditions that surround and influence an organism or community.

eucalyptus
Noun

tree native to Oceania.

exaptation
Noun

adaptation that developed for one purpose but is used for another.

extinct
Adjective

no longer existing.

extract
Verb

to pull out.

generation
Noun

group in a species made up of members that are roughly the same age.

genetic
Adjective

having to do with genes, inherited characteristics or heredity.

Noun

environment where an organism lives throughout the year or for shorter periods of time.

hummingbird
Noun

type of very small bird.

industrial
Adjective

having to do with factories or mechanical production.

Industrial Revolution
Noun

change in economic and social activities, beginning in the 18th century, brought by the replacement of hand tools with machinery and mass production.

inherit
Verb

to receive from ancestors.

isolation
Noun

state of being alone or separated from a community.

mammal
Noun

animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

marsupial
Noun

mammal that carries its young in a pouch on the mother's body.

migrate
Verb

to move from one place or activity to another.

Noun

movement of a group of people or animals from one place to another.

moth
Noun

flying insect.

Noun

sudden variation in one or more characteristics caused by a change in a gene or chromosome.

Noun

role and space of a species within an ecosystem.

Noun

substance an organism needs for energy, growth, and life.

Oceania
Noun

region including island groups in the South Pacific.

placental mammal
Noun

animal (mammal) characterized by the fetus developing inside the body of the mother, in an organ called the placenta.

pollen
Noun

powdery material produced by plants, each grain of which contains a male gamete capable of fertilizing a female ovule.

Noun

introduction of harmful materials into the environment.

resemble
Verb

to look like.

Noun

process by which one or more populations of a species become genetically different enough to form a new species.

species
Noun

group of similar organisms that can reproduce with each other.

succulent
Noun

type of plant that has thick leaves and stems for storing water.

sympatric speciation
Noun

development of many similar species in a single habitat, each with a different specialization.

thrive
Verb

to develop and be successful.

unique
Adjective

one of a kind.

urban
Adjective

having to do with city life.

vestigial
Adjective

having to do with a body part, or remnant of a body part, that no longer serves any useful function.

womb
Noun

organ in which an embryo and fetus develops. Also called the uterus.

young
Noun

offspring or children.