Convergent Evolution - What is Convergent evolution?

Convergent Evolution Definition

It is the independent evolution of features that are similar in species spanning over different eras. This evolution produces analogous structures having similar functions or forms. However, they are not seen in the last common ancestor of those units.

Although the structures are analogous, it does not reflect homology. A similarity can rest at the phenotypic level, wherein lineages share the apparent characteristics; however, the implicit DNA sequences vary. This type of evolution takes place when the species take up similar ecological niches, accommodating in a similar manner responding to similar selective pressures. The characteristics arising via convergent evolution are “analogous structures”. It is in contrast with homologous structures, which are known to have a common origin. The contrasting concept to convergent evolution is divergent evolution, wherein the related species go on to evolve having dissimilar traits.

Examples of Convergent Evolution

Parallel evolution occurs when two independent species happen to evolve in the same direction and hence independently obtain the same traits. A good example of this is gliding frogs, which have evolved in parallel from the different kinds of tree frogs.

The repeated development of the C4 photosynthesis, dispersal of seeds by the fleshy fruits, which are adapted to be consumed by animals, are instances of convergent evolution in plants.

The continual evolution of flight is a good example as birds, flying insects, bats etc. have individually evolved the useful ability of flying. Bats, birds and pterosaur wings are analogous structures; however, their forelimbs are homologous, which share an ancestral state, although they serve various functions.

Yet another example is that of the similar shape and colouration of the cetaceans and fish, and both have adapted to the marine ecosystem by the development of neutral buoyancy and fusiform body. Dolphins and Sharks are also counter-shaded with a darker upper surface and a lighter underbelly, causing them to be less visible from above and below. Presumably, countershading is an ancestral state, which appears to have been retained all through the evolution of both groups.

The major influencer of convergent evolution is the availability of particular roles which are offered by the surroundings. The oceans provide predators that are swift swimmers, dolphins or sharks.

Divergent Evolution

Contrary to convergent evolution, divergent evolution is the process wherein the interbreeding species diverge into two or multiple evolutionary groups. In other words, these groups of species were related and similar, but with time, they grew to become dissimilar.

The process of divergent evolution can relate to the process of dating back two or more species to their common ancestor and finding how the species have diverged or diversified. This type of evolution is one of the three types of patterns of evolution, the other two being parallel and convergent evolution.

There is a large influence of predation activities and environmental factors on the evolution of species. One of the classic examples of divergent evolution is Galapagos finches diversifying from its descendant species.

Difference between Convergent Evolution and Divergent Evolution

Let us understand through this table how convergent evolution is different from divergent evolution.

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