Question

Define convergent evolution and give an example. Why is convergent evolution often tricky for phylogenies?

Answer 1

CONVERGENT EVOLUTION:

In the course of evolutionary research, scientists often find unrelated animals converging on the same form or structure because that form is very adaptive in their common environment. This special case of evolution is called convergent evolution. It describes the acquisition of same biological trait in unrelated species. Example of convergent evolution is the streamlined shape of sharks and dolphins. One is a fish, the other is a mammal, and they are related to one another in only the most distant sense. But if its life depends on swift movement through the water, then a streamlined shape is pretty much essential. Another example is wings in birds, bats and flies. Convergent evolution produces analogous structures, in contrast to homologous structures, which have a common origin.

Similarity among unrelated organisms as result of convergent evolution is called homoplasy. The wings of birds, bats and insects are homoplastic features because the common ancestor of these three groups lacked wings. Spines (modified leaves) and thorns (modified stems) are examples of homoplasy among plants; spines and thorns look similar and both provide protection to the plant, but the plants to which they belong are distantly related. Homoplastic similarity can be anatomical, physiological or behavioural. so, convergent evolution often tricky for phylogenies.