Anatomical and embryological characteristics

Anatomical similarities and differences help us understand relationships between organisms and their origin. For example, the arms of humans, wings of a bat, flippers of a whale and foreleg of dogs have a basic similarity that indicate a descent from a common ancestor. These characteristics are called homologous structures. The more taxonomically related organisms are, the more homologies they have.

Anatomical characteristics that have a similar function, but a different developmental origin are called analogous structures. A good example of analogous structures are the wings of insects and the wings of birds.

Embryological features are also useful in determining relationships among organisms. Closely related organisms undergo similar embryonic stages during development. All vertebrates, including humans, have gill pouches on the sides of their throat during embryonic development.

Cheetahs are unique among the large cats since they appeared over 2 million years ago. Would you like to learn more about cheetah taxonomy?