AP BIOLOGY

Detailed explanation-1: -Comparative embryology is the study of the similarities and differences in the embryos of different species. Similarities in embryos are evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails (see the Figure below).

Detailed explanation-2: -Embryos of many different kinds of animals: mammals, birds, reptiles, fish, etc. look very similar and it is often difficult to tell them apart. Many traits of one type of animal appear in the embryo of another type of animal. For example, fish embryos and human embryos both have gill slits.

Detailed explanation-3: -Scientists have figured out that species who evolved from a recent common ancestor have very similar patterns of embryonic growth and development. The same groups of cells develop in the same order for these species despite the fact that adult forms of the species look very different.

Detailed explanation-4: -embryology, the study of the formation and development of an embryo and fetus. Before widespread use of the microscope and the advent of cellular biology in the 19th century, embryology was based on descriptive and comparative studies.