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Theories of Evolution

Define:

  • Theory
  • Fossil
  • Evolution
  • Adaption
  • Inherited

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Theories of Evolution

Learning Objectives:

  • To compare and contrast two different theories of evolution

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How did the giraffe get such a long neck?

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Lamarck’s Theory of Evolution

  • He believed that all creatures were linked by a ‘fountain of life’
  • And animals inherited acquired characteristics
  • The characteristics that help that organism to survive are passed to their offspring
  • So if your parents are body builders then you are born that way

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Why was Lamarck’s theory wrong?

  • It cannot account for all the observations on Earth
  • His theory implies that all organisms would gradually become complex
  • Simple organisms would disappear (this is not the case)

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Darwin’s Theory of Evolution

  • Darwin set out in 1831 on a voyage on HMS Beagle
  • At the Galapagos islands he saw different features on a variety of finches

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Darwin’s Theory of Evolution

  • All living organisms have evolved from simpler forms
  • Evolution has come about by a process called natural selection
  • Only those most adapted to their environment will survive
  • Survival of the fittest

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Charles Darwin

https://www.youtube.com/watch?v=bPuXtCs4O3Q

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Galapágos tortoises have different shell shapes depending on their environment

Saddleback

Intermediate

Domed

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Darwin did not publish his theory for many years.

Why reasons could there have been for this?

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