All mammals, whale, dolphin, bat, monkey and horse have some important common characters, but they also show conspicuous differences. This is due to the phenomenon of:
Divergent evolution is the evolution in which one species of animal or plant gives rise to a number of different forms. As the original population increases in size, it spreads out from its centre of origin to exploit new habitats and food resources. As an organism evolves, it develops features and characters which are beneficial and help the organism in adapting to its environment.