18.1.2

Biodiversity

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Biodiversity

Biodiversity is the complexity of a biological community. Biodiversity exists at many different levels and can be measured using species richness.

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Habitats

  • Biodiversity exists in habitats at a range of sizes.
    • A habitat is an area where an organism lives.
  • Biodiversity can be considered in a small, local habitat (e.g. a lake).
  • Biodiversity varies between different habitats.
    • E.g. Coral reefs are typically more biodiverse than meadows.
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Global biodiversity

  • Biodiversity can also be considered on the global scale.
  • Biodiversity varies around the world.
    • E.g. The equator is typically more biodiverse than the poles.
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Species richness

  • Species richness is the number of species in a habitat or community.
  • Species richness can be measured by counting the number of different species in the habitat.

Factors Affecting Biodiversity

Biodiversity can be affected by changes to environmental conditions or the way a population affects its surroundings.

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Human population growth

  • The speed of growth of the human population means there is more forest cleared so that the land can be used for housing and food production.
    • This land would otherwise support a more diverse range of species.
  • Pollution and waste production also increases, putting further burden on fragile ecosystems.
  • Human populations expanding outwards into animal habitats enables the zoonotic transmission of new diseases between species.
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Agriculture (monoculture)

  • It is more efficient to grow crops with the same requirements in terms of nutrition and ease of harvesting.
    • Many farms now have fields set aside for growing only one crop species, such as wheat.
  • Practising monoculture reduces biodiversity and can cause problems.
    • Monocultures lacking genetic diversity may be less resistant to diseases.
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Climate change

  • Changes in global weather patterns, sea levels and temperatures can lead to habitat loss, driving animals to migrate.
    • In other cases, some species and populations may be directly destroyed, decreasing the gene pool available for selection and evolution.
  • The speed of climate change can sometimes be too fast for species to adapt to new conditions, leading to extinction.

Jump to other topics

1Cell Structure

2Biological Molecules

3Enzymes

4Cell Membranes & Transport

5The Mitotic Cell Cycle

6Nucleic Acids & Protein Synthesis

7Transport in Plants

8Transport in Mammals

9Gas Exchange

10Infectious Diseases

11Immunity

12Energy & Respiration (A2 Only)

13Photosynthesis (A2 Only)

14Homeostasis (A2 Only)

15Control & Coordination (A2 Only)

16Inherited Change (A2 Only)

17Selection & Evolution (A2 Only)

18Classification & Conservation (A2 Only)

19Genetic Technology (A2 Only)

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