B3 Life on Earth

Why do some species become extinct, and does it matter?

  • Living organisms are dependent on the environment and other species for their survival.
  • There is competition for resources between different species of animals or plants in the same habitat.
  • Changes affecting one species in a food web affect other species that are part of the same food web.A rapid change in the environment may cause a species to become extinct, for example, if:
    • the environmental conditions change;
    • a new species that is a competitor, predator or disease organism of that species is introduced;
    • another organism in its food web becomes extinct.
  • Species have become extinct (or are in danger of becoming extinct) and this is likely to be due to human activity.
  • You must know two examples of modern extinctions caused by direct human activity, and two caused by indirect human activity.
  • Maintaining biodiversity is an important part of using the environment in a sustainable way.
  • Biodiversity may be important for the future development of food crops and medicines.
Review 9
Review 10
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