Evolution

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Sources of Heritable variation:

1. Sexual reproduction and meiosis is when the genes are mixed to form new combinations.

2.Crossing over is when new combinations of gene arise. This happens when a piece of one chromosome exchanges with it homologous pair.

3. Mutations is when new variations occur in the gene which allows evolution to work on it.

Agents that change gene frequencies:

1. Natural selection can be broken up into 3 different parts;

  • Stabilising Selection is when the population favours the average over the extremes.
  • Directional Selection is when one

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