Convergent evolution

In some cases, similar phenotypes evolve independently in distantly related species because they adapt to the same environment or similar ecological niches. For example, flight has evolved in both bats and insects, and they both have wings, which are adaptations for flight. However, the wings of bats and insects have evolved from very different original structures. This phenomenon is called convergent evolution, where similar traits evolve independently in species that do not share a recent common ancestor. The two species developed the same function, flying, but did so independently from each other.

Another example: the arctic fox and ptarmigan, in the arctic region, have selected for seasonal white phenotypes during winter to blend in with the snow and ice. These similarities occur not because of common ancestry, but because of similar selection pressures, the benefits of which are not being seen by predators.

On the left, a white arctic fox sits in the white snow. On the right, a white ptarmigan stands on white snow.

Figure 1. Arctic fox and Ptarmingan.

The white winter coat of the arctic fox (left) and the ptarmigan’s plumage (right) are adaptations to their environments. (credit a: modification of work by Keith Morehouse)