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Flashcards · Biology · Human Impact on Ecosystems

The Benefits of Maintaining Biodiversity

20 cards

  1. What is local biodiversity?

    The variety of species in a small area such as a pond, hedgerow or woodland.

  2. What is global biodiversity?

    The variety of all the species on Earth.

  3. Why is a high biodiversity ecosystem more stable?

    There are many food chains, so if one species declines others can fill the gap.

  4. What is a gene pool?

    All the different alleles in a population or species.

  5. Give two benefits to people of maintaining biodiversity.

    Any two of: food, medicines, materials, pollination, climate, jobs and tourism.

  6. Name a medicine that came from a plant.

    Aspirin from willow bark, quinine from cinchona bark, or a leukaemia drug from the rosy periwinkle.

  7. Why are wild relatives of crops valuable?

    They have alleles for traits such as disease resistance that can be bred into crops.

  8. Why is a monoculture vulnerable?

    A single disease or pest can destroy the whole crop.

  9. What is conservation?

    Protecting and managing species and habitats so that species do not die out.

  10. Name three ways to conserve an endangered animal.

    Protected areas, laws against hunting and trade, and captive breeding.

  11. What is captive breeding?

    Breeding endangered animals in zoos or centres and releasing young into the wild.

  12. Give one problem with captive breeding.

    The population may have little genetic variation, or animals may not survive in the wild.

  13. What is reforestation?

    Planting trees on land that was cleared of forest.

  14. How does reforestation reduce flooding?

    Roots hold the soil and the trees take up water, so less runs off quickly into rivers.

  15. How does reforestation help to slow global warming?

    Trees take in carbon dioxide for photosynthesis and store carbon.

  16. Why can a plantation of one tree species fail to restore biodiversity?

    It gives food and shelter to far fewer species than a mixed native forest.

  17. How do you calculate a percentage change?

    The change divided by the original value, multiplied by 100.

  18. Why is extinction a problem for people?

    The species is lost for ever, with any medicines, genes or ecosystem roles it had.

  19. A field of one crop beside a mixed habitat of many plants and animals, with no labels. Describe the differences in biodiversity between the two panels, and explain why it matters. The same two panels, labelled One crop species, very few other species and Many different plants and animals.

    The left is a crop monoculture with low biodiversity: one species, so a single disease or pest could destroy it, and few animals can live there. The right has high biodiversity: many species, more food sources and shelter, so it is more stable and better able to cope with change.

  20. A bare hillside and a hillside with trees, both with rain falling, with no labels. Explain how reforestation changes what happens to the rain. The same two slopes with six labels showing the effects of having no trees and having trees.

    Without trees, the rain runs off and washes the soil away (erosion) into the river, which becomes muddy and may flood. With trees, the roots hold the soil and the trees take up water, so the river stays clear. The trees also take in carbon dioxide and give animals a habitat.