Bitesize has changed! We're updating subjects as fast as we can. Visit our new site to find Bitesize guides and clips - and tell us what you think!
Print

Science

Environmental change

Page:

  1. 1
  2. 2
  3. 3
  1. Next

Changes in the environment - caused by various factors such as a lack of a usual food source - may affect the distribution and behaviour of organisms.

Environmental change

Animals and plants are exposed to environmental change. These changes may be caused by living factors, such as a change in a predator, a food source or a competitor. Environmental changes may also be caused by non-living factors, such as a change in temperature or rainfall.

Effects of environmental change

Changes in the environment affect the distribution and behaviour of living organisms. For example, humans have been cutting down trees for thousands of years. We do this to clear land for farming and building, and for wood to use as a fuel or building material. This deforestation can have local effects, such as a reduction in food and shelter for animals. It can also have more widespread effects, such as changes in rainfall and temperature. These changes may change the distribution of bird species, for example.

The world's forests 8000 BC

The world's forests 2000CE

Predators and prey

If the prey population grows, predator numbers will respond to the increased food supply by increasing as well. Growing predator numbers will eventually reduce the food supply to the point where it can no longer sustain the predator population, and the number of predators will go down.

The animation shows how the numbers of predators (ladybirds) and their prey (aphids) can change over time. The graph would look fairly similar for any two populations of predators and prey.

Page:

  1. 1
  2. 2
  3. 3
  1. Next

Back to Interdependence and adaptation index

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.