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Cold Environments » Cold Environment Adaptations and Biodiversity

What you'll learn this session

Study time: 30 minutes

AQA spec: 3.1.2.4

How plants adapt to the cold, windy tundra
How the Arctic fox, polar bear and caribou survive
Why cold environments have low biodiversity
Issues that threaten biodiversity in cold environments

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Surviving the cold

Thick fur and small ears help Arctic animals keep their heat in

Cold environments are tough places to live. Winters are long, dark and freezing, summers are short and cool, and there is very little precipitation. The ground is frozen for much of the year, so plants and animals need special features to survive. Remember, an adaptation is a feature that helps a living thing survive in its environment.

The organisms that live here have three big problems to solve: keeping warm, finding food and water, and coping with a very short growing season. Each adaptation below solves one of these problems.

Key terms:

Insulation: a layer, such as fur or fat, that stops body heat escaping.
Blubber: a thick layer of fat under the skin that keeps an animal warm and stores energy.
Migration: a regular journey made by animals to find food or a better climate.
Hibernation: a long, deep sleep through the winter, which saves energy when food is scarce.

How plants adapt

Tundra plants have to survive strong winds, thin soils and permafrost beneath them. Trees cannot grow here, so the plants are small and tough. Typical tundra plants include mosses, lichens, cotton grass and Arctic willow.

🌱 Low growing

Plants stay close to the ground. This keeps them out of the strong, freezing wind and lets them use the warmer air near the surface. Many grow tightly together in clumps, which gives extra shelter.

🌿 Shallow roots

Permafrost lies just below the surface, and roots cannot grow into frozen ground. Plants have shallow roots that spread out wide in the thin active layer, which thaws in summer.

☀ Fast growth and flowering

The growing season is only about two months long. Many plants grow and flower very quickly in the long daylight of summer, so they can make seeds before the cold returns.

❄ Small leaves and hairs

Small, waxy or hairy leaves lose less water to the dry, windy air and are less damaged by the wind.

How animals adapt

Animals in cold environments cannot easily escape the weather. They have adaptations of their body, and adaptations of their behaviour.

Arctic fox

Thick fur keeps it warm, even on the paws, which helps when walking on snow and ice.
Its coat is white in winter and brown or grey in summer, so it is camouflaged all year round.
Small, rounded ears and a short nose lose less heat.
It stores fat in autumn to survive when food is scarce.

Polar bear

Thick, white fur gives insulation and camouflage on the ice.
A layer of blubber under the skin keeps it warm in freezing water and stores energy.
Large, wide paws spread its weight on thin ice and help it swim.
It hunts seals from the sea ice, which gives it food rich in fat.

Caribou

A thick coat and a layer of fat keep it warm.
Wide hooves spread its weight on snow and can be used to dig for lichen beneath it.
It migrates in large herds, moving south to forests in winter and north to the tundra in summer to find food.

Other animals avoid the worst of the cold. Some hibernate. Many birds migrate to warmer places for the winter.

Worked example: linking an adaptation to a purpose

Question: why does a polar bear have blubber? Link three steps. The bear lives in freezing air and water. Blubber is a thick layer of fat, which is a good insulator. This stops body heat escaping, so the bear stays warm and can survive. Always give the feature, then what it does, then why it helps.

Biodiversity in cold environments

Few species can survive the cold, so biodiversity is low

Remember, biodiversity is the variety of plant and animal life in an area. Biodiversity in cold environments is low. Few species can cope with the extreme cold, the short growing season and the frozen ground. There are far fewer species than in a tropical rainforest.

This means food chains are short and simple, for example lichen, caribou, wolf. If one species is lost, the animals that depend on it have few other foods to turn to. For this reason cold environments are described as fragile.

Issues related to biodiversity

Slow recovery: with such a short growing season, plants grow very slowly. Damage from vehicles or building can take many years to heal.
Climate change: warming melts permafrost and sea ice. Polar bears need sea ice to hunt seals, so less ice means less food. Warmer conditions can also let new species move north and compete with native ones.
Economic development: mining, oil and gas, and tourism bring roads, buildings and pipelines. These break up habitats and can cause pollution. Oil spilt in cold conditions breaks down very slowly.
Hunting and fishing: if too many animals are taken, populations can fall quickly because they breed slowly.

How these environments can be protected is covered in the lesson Protecting Cold Environments.

Common mistakes

Saying that animals "choose" to grow thick fur. Adaptations come from generations of survival, not choice. Another mistake is writing "to keep warm" and stopping there. Always say how: fur and blubber trap heat so less escapes. Also, do not say that a cold environment has high biodiversity just because a few animals are well known, such as polar bears.

Exam-style question

(a) Describe two ways in which plants are adapted to the tundra. [2 marks]

(b) Explain how the polar bear is adapted to survive in a cold environment. [3 marks]

Model answer

(a) Plants grow low to the ground to avoid strong winds (1). They have shallow roots because permafrost stops roots growing deeper (1).

(b) It has thick white fur, which gives insulation and camouflage (1). It has blubber, which keeps it warm in cold water (1). Its wide paws spread its weight on thin ice (1).

Exam tip

In "explain" questions such as (b), each mark needs a feature and a reason. Use the word "so" or "because" to join them.

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