5.3

Homologous structures are features with similar structures but different functions. The forelimbs of a bird, wale, horse, and human share similar bone arrangements but are used differently. The ancestral forelimb evolved modifications that better served new functions

Homologous features such as the tailbones are used to classify organisms in Linnaeus classification.

The forelimbs of each of these organisms are adapted to carry out different functions yet they have derived from a similar bone structure.

Embryology  is embryology is the study of the development of embryos, the early forms of adult animals.

Vestigial Features are rudimentary structures that serve no useful function.

Biochemistry

Dogs, Pigs, and horses have at least one Vestigal Feature

Vestigial Features are believed that they once served some function in an ancient ancestor. Modern species of whales and snakes have vestigial hip and leg bones that suggests that at one point in evolution they were able to walk on four limbs.