Morphological and Anatomical Evidences of Evolution

Homologous structures, such as the forelimbs of the ver­tebrates, appear to differ widely from one another. In the horse they are required for locomotion on dry land. In birds they are modified to form the wings for flying.

In the whales, the forelimbs take the form of paddle-like flippers for swimming in water. In man the fore­limbs are typically pentadactyle and adapted for grasping objects, and for fine manipulations.


But an examination of the skeletal archi­tecture of these different types of forelimbs clearly indicates that they are all pentadactyle in nature and consist of practically the same bony elements and are all built on the same fundamental plan.
Vestigial organs are useless structures of reduced size, which are found in many animals. These structures are not function­al in a given species but are homologous with functional structures in other closely related species. The muscles concerned with the movement of the pinna in man serve as a good example of vestigial organ