4.1 Why does Darwin’s theory matter?

4.1.2 Mechanisms of natural selection (a driving force to speciation)

Speciation according to Darwin and Wallace… Can you identify the four main ideas of natural selection?

  • there is an overproduction of offspring generating a competition for resources
  • there is variation within populations allowing some offspring to have a slight advantage over others
  • individuals which possess characteristics that are poorly adapted for their environment tend to be less successful at surviving and therefore at finding a mate
  • individuals which possess characteristics that are well adapted for their environment tend to be more successful at surviving, finding a mate and passing on their genetic characteristics to the next generation
  • after many generations, slight changes can accumulate to a point where the current generation is very different from its ancestors.

How can the distribution of traits in a species change over time?

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THINKING: How is artificial selection different to natural selection?

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