GCSE Biology (CIE)

Topic Summaries

Species and classification

Extinction

  • Extinctions occur when there are no remaining individuals of a species still alive.
  • Species that do not successfully adapt to environmental conditions or lack the genetic variation to survive changes in the environment are more likely to go extinct.
  • Factors that may contribute to the extinction of a species:
    • Increasing population of humans increases human impact on the environment (e.g. cutting down rainforests, building bigger cities and urban areas, or drilling for oil and minerals).
    • Natural changes over time, e.g. end of the ice age.
    • Introduction of new predators

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