Key facts: All organisms are well adapted to the environment in which they live. Whether a population increases or decreases depends on a number of different factors including disease, competition, predation and human influences. The distribution of an organism and how they behave can also be affected by any changes in their environment.

By the end of this section you should understand:

• different ways in which organisms have adapted to their environment
• different types of adaption in a variety of organisms
• how adaptations have helped organisms to survive
• which factors an organism may be competing for in a particular environment
• data which looks into how environmental changes can affect an organism’s distribution and behaviour

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Adaptations

In order for an organism to survive it needs to get particular resources from its habitat and from the other organisms with which it shares the environment. Different organisms need to compete for different resources in order to survive:

• plants tend to compete for light, water, nutrients and space
• animals tend to compete for food, territory and mates

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Extreme conditions

All organisms, including microorganisms, have particular adaptions which let them survive in the conditions they exist in. Even in the most extreme conditions you’ll find some form of life. Extremophiles, for instance, are microbes that live in conditions in which other organisms would die. From the cold of the Arctic to the heat of volcanoes and from the depth of the ocean floor to the very dry conditions of deserts, microbes have been found there.

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Animal adaptations

There are a number of ways in which animals have been able to adapt to the conditions in which they live, whether they come from a very cold climate, like the Arctic, or a very hot environment, like the Sahara deserts.

Surface area

Surface area to volume ratio has a large effect on factors like heat loss. A camel, for example, has a large surface area to volume ratio which helps it to lose more heat in a hot climate. A polar bear, on the other hand, has a small surface area to volume ratio and so can lose less heat in its cold environment.

Thickness of their coat

An animal’s insulating coat is made up from layers of fat and fur. Animals like seals and penguins, which live in very cold conditions, need this kind of insulation to keep them warm. Other animals don’t need as much fur. For instance, you may have noticed that domestic dogs and cats have more hair in the winter then shed much of it in the hotter months to help keep them cooler.

Body fat

As we’ve already seen, body fat is very useful for animals that live in cold conditions. In hot conditions, fat insulation is not so necessary.

Camouflage

Camouflage is used by certain animals to make them look like they’re part of their surroundings. It’s used as a way of hiding from predators or prey. Camouflage can also be used by animals to make them look like they’re dangerous or simply not that interesting. For example, a spotted leopard’s spots allows them to hide within the dappled outback while a zebra can use its stripes to blend into the tall grass. This confuses its main predator, the lion, which is colour-blind.