10.3 Gene pools and speciation
A common ancestor species can be split into two or more isolated gene pools. Over time as the different natural selective forces change the make up of the gene pools vary. This process can happen repeatedly and in some cases rapidly. Mammals are a good example of this as the common features e.g a five boned limb structure can adapt to become e.g wings, hooved, clawed or finned limbs. This is an example of what is called divergent evolution. Common ancestory but gene pool seperation can lead to different features developing as adaptations to the new selective forces.
Convergent evolution is where a similar feature in form and function arises from non common ancestors. An example could be the streamlined hydrodynamic shape and swimming capabilities of marine predators like sharks and doplhins.