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•  Continuous variation across a geographical range of related populations matches the concept of gradual divergence

Within a population of any given species there will be genetic variation (i.e. variation which is inheritable)

  • Typically this variation will be continuous and follow a normal distribution curve as the rate of change is gradual and cumulative

If two populations of a species become geographically separated then they will likely experience different ecological conditions

  • Over time, the two populations will adapt to the different environmental conditions and gradually diverge from one another

The degree of divergence will depend on the extent of geographical separation and the amount of time since separation 

  • Populations located in close proximity that separated recently will show less variation (less divergence)
  • Distant populations that separated a longer period of time ago will show more variation (more divergence)

Variation Within a Population

cat variation

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•  Populations of a species can gradually diverge into separate species via evolution

The degree of divergence between geographically separated populations will gradually increase the longer they are separated

  • As the genetic divergence between the related populations increase, their genetic compatibility consequently decreases
  • Eventually, the two populations will diverge to an extent where they can no longer interbreed if returned to a shared environment

When two populations can no longer interbreed and produce fertile, viable offspring they are considered to be separate species

  • The evolutionary process by which two related populations diverge into separate species is called speciation

Speciation via Divergent Evolution