The American Alligator is a variation of alligator that is found in the southern regions of the United States. The American Alligator prefers to live in freshwater wetlands like swamps and marshes. The Alligator is within the family of Alligatoridae. Alligators have been around for about eight-million years in the geological timeline
American Alligator Hatchling
The closest living relative to the american alligator are birds. The percentage they have in similar is 93%. morphological evidence shows that some birds' skulls and skeletal structure are very similar to alligators'
Although two structures look very different on the outside and vary in functions, they could be called homologous if the skeletal structures are similar, which reflect common ancestry. For example, a bat, a human, an alligator, and a penguin are known to evolved from a common ancestor, because they share a common anatomical trait
A vestigial structure is a bone or organ that is no longer used by an organism. A vestigial structure that an alligator has are small horns behind their eyes. Vestigial structures show that evolution happened because bones and organs that we have and don't use today means that they might have been used in the past by the species ancestors.
The american alligator is different from these two ancestors by the Wannaganosuchus having a much shorter snout than the american alligator and the Allognathosuchus is different by having a shorter snout and it's diet eating mostly crustaceans. Transitional fossils are fossils of of ancestors that show differences in skeletons of ancestors and descendants showing that organisms change to best suit their environment.
comparative embryology is a science that compares multiple organisms in their first stages of development. comparative embryology shows that all living organisms have a common ancestor