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 likely to be evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails.

Detailed explanation-2: -Embryology is important to understanding a species’ evolution, since some homologous structures can be seen only in embryo development. For example, all vertebrate embryos, from humans to chickens to fish, have a tail during early development, even if that tail does not appear in the fully developed organism.

Detailed explanation-3: -The notochord is an embryonic midline structure common to all members of the phylum Chordata, providing both mechanical and signaling cues to the developing embryo.

Detailed explanation-4: -Most embryos look similar in their early stages, but as they develop, the differences between species become more obvious. Embryos of organisms that have a closer genetic relationship to one another tend to look similar for a longer period of time since they share a more recent common ancestor.

Detailed explanation-5: -Fossils. Fossils document the existence of now-extinct past species that are related to present-day species. Direct observation. We can directly observe small-scale evolution in organisms with short lifecycles (e.g., pesticide-resistant insects).