CIE IGCSE Biology: 复习笔记：20.1.6 Endangered Species

Endangered Species

• An endangered species is at risk of becoming extinct
• There are several reasons why a species can become endangered - the population of the species may fall below a critical level due to
  • hunting
  • climate change
  • pollution
  • loss of habitat
  • introduction of non-native species that outcompete native species

   

• Endangered species can be helped by conservation measures such as:
  • education programmes
  • captive breeding programmes
  • monitoring and legal protection of the species and of their habitats
  • seed banks as a conservation measure for plants - seeds of endangered plant species are carefully stored so that new plants may be grown in the future

   

• A species may be at risk of becoming extinct if there is not enough genetic variation in the population as random changes in the environment may quickly cause extinction because the remaining organisms are all very similar and may not have the adaptations to survive such changes
• There are moral, cultural and scientific reasons for conservation programmes, including:
  • reducing extinction rates of both plant and animal species
  • keeping damage to food chains and food webs to a minimum and protecting vulnerable ecosystems (eg the rainforests)
  • protecting our future food supply and maintaining nutrient cycles and possible sources of future medical drugs and fuels

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