Speciation (topic 5, unit 4, Edexcel, A2 Biology)

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  • Created by: Hannah
  • Created on: 03-01-13 10:58


Speciation describes the formation of a new species. This is achieved ultimately through reproductive isolation of two populations initially belonging to the same species, which gradually evolve and become less like each other and eventually unable to interbreed to produce fertile species. This then defines the two populations as belonging to seperate species, and thus creates a new species.

The process of speciation is outlined as follows:

  • Part of a population is isolated from the rest of the population, most commonly by geographical isolation whereby the two groups are isolated by a geographical feature (for example a mountain range, river or ocean). However, isolation can also occur through ecological isolation, temporal isolation, behavioural isolation, physical incompatibility, hybrid sterility or hybrid inviability. 
  • Following this isolation, the two different groups are exposed to different selection pressures within their separate habitats.
  • This encourages random…




Does isolation ENCOURAGE mutations? I though it was a random occurance :/



no it doesnt, the random mutations are still random but they may give an advantage with specific selection pressures so they rise in allele frequency

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