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3.2 origins of biodiversity

3.2 origins of biodiversity. Application and skills. Explain how plate activity has influenced evolution and biodiversity. Discuss the causes of mass extinction. How biodiversity arises from evolutionary processes. How has biodiversity arisen? The answer lies in the theory of evolution

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3.2 origins of biodiversity

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  1. 3.2 origins of biodiversity

  2. Application and skills • Explain how plate activity has influenced evolution and biodiversity. • Discuss the causes of mass extinction

  3. How biodiversity arises from evolutionary processes • How has biodiversity arisen? • The answer lies in the theory of evolution • How species changes gradually over many years from ancestral species into entirely new species

  4. Evolution –Natrual selection • Charles Darwin (5 year-trip including Galapagos 1831-1836) • Produced his theory of evolution and noted that: • All species tend to over-reproduce • This leads to competition for limited resources (a ’struggle for existence’) • Species shows variations (all individuals are not alike, they have subtle differences in appearance or behaviour) • Darwin concludes that: • Those best adapted to their surroundings survive • These can then go on to reproduce

  5. Natural selection • Darwin called the process natural selection because nature does the choosing as opposed to artificial selection. And occurs through the following mechanism: • Within a population of one species there is genetic diversity, which is called variation. • Because of natural variation, some individuals will be fitter than others. • Fitter individuals have an advantage and will reproduce more successfully • The offspring of fitter individuals inherit the genes that give the advantages; these offspring therefore survive and pass on the genes to next generations .

  6. Alfred Russel Wallace • At the same time as Darwin, Wallace traveled to South East Asia • Malthus: Principle of populations • Food supply could not keep up with population growth • Wallace: found a connection between Malthus’ ideas and what he had observed • Species over-reproduce • There is variations within all species • Resources are limited

  7. Natural selection • Darwin called the process natural selection because nature does the choosing as opposed to artificial selection. And occurs through the following mechanism • Within a population of one species there is genetic diversity which is called variation • Because of natural variation, some individuals will be fitter than others • Fitter individuals have an advantage and will reproduce more successfully • The offspring of fitter individuals inherit the genes that give the advantage; those offspring therefore survive and pass on the genes to subsequent generations Animation page 157 in Pearson etextbook

  8. The role of isolation in forming new species

  9. Plate tectonics

  10. Mass extinctions Task • Read page 166-168 (exercise 4 and 5 p 168) • Give a reason why marsupial mammals are only found in Australia.

  11. Mark scheme

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