Convergent Evolution Throughout Nature, Many

Convergent Evolution

Throughout nature, many organisms can be found that exhibit highly similar characteristics. The bones found in the human hand are similar to those in the pectoral fins of whales and those in the wings of a bat, for example. This is an example of divergent evolution -- all of these structure have the same root in evolutionary history, and developed into different arts as the various organisms grew apart from each other. Another process that takes place in evolution, and that is in many ways even more surprising and compelling, is convergent evolution. This refers to similar structures developing in evolutionary separate sources, or "the development of similar characteristics by taxonomically different organisms" (WGBH 2010). Unlike the similar but different characteristics of hands, fins, and wings, convergent evolution leads to characteristics that are far more similar, but develop from far different evolutionary sources.

One recently discovered example of convergent evolution exists in the White Sands desert of New Mexico. Here, researchers have found three varieties of lizard whose species exist in dark-formed varieties across most of the Southwestern United States, but that are basically white-skinned in the desert (Fountain 2010). The three lizard species have been evolutionarily distinct from each other for some time, but each species developed the same characteristic -- i.e. white skin -- in the six-thousand years or so that have passed since the deserts of this area became white. These lizards are a clear example of convergent evolution, as the same characteristics appeared in a very short evolutionary time period from three completely separate taxonomic branches of the evolutionary tree.

Another example of convergence comes from butterfly wing pattern mimics of their surroundings. Though butterflies all originated from the same basic evolutionary/taxonomic branch, the wing patterns of populations of different species in the same area can develop similar wing patterns when environments change (Hall & Hallgrimsson 2007). This example of convergence is highly similar to what occurred with the various lizard species discovered in New Mexico -- as environments change, organisms that already occupy a similar niche in their environment but that are taxonomically different often change in similar ways, developing the same adaptations to the environmental changes. In this way, the separate evolutionary branches of each of these organisms converges in a way that produces highly similar characteristics that are not closely related.