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Patterns of Evolution

Biology (Year 12) - Evidence for Evolution

Ben Whitten

Evolution is the change over time in one or more inherited traits that are found in populations of organisms. Inherited traits include particular characteristics, including anatomical, biochemical, or behavioural characteristics, which are passed on from one generation to the next. There are four predominant types of evolution.

  1. Divergent evolution

  2. Adaptive radiation

  3. Co-evolution

  4. Convergent evolution

Divergent Evolution

Divergent evolution is the accumulation of differences between groups (populations) of one species, which can lead to the formation of 2 or more new species. The new species formed from a single species show underlying similarities due to their common origins. Adaptive Radiation

Adaptive radiation is a rapid form of divergent evolution, in which many new species form from a recent common ancestor due to a diverse range of environmental conditions that have the ability to be exploited. These new species exhibit new, and different structural and physiological traits which are better adapted to the vast range of environments as mentioned above. A key example of adaptive radiation in Darwin's finches, as their beaks develop different shapes after many generations, as their selection pressure is food.


Co-evolution occurs when two different species both change and evolve over time together, at similar rates. This usually occurs when the two species are dependent on one another for survival. For example, flowers and bees are a good examples; the bees need the pollen from the flowers, and the flowers need bees for pollination.

Convergent Evolution

Convergent evolution is the development of the same biological trait or characteristic in totally unrelated lineages/evolutionary paths. The evidence of convergent evolution is often misinterpreted as scientists mistake two species' similar appearance for a recent common ancestry. Traits in two species which show convergence are known as 'analogous' structures, and the organisms which display convergence will often occupy similar environmental positions, or 'niches'.

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