AP BIOLOGY

Detailed explanation-1: -Homologous features If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous.

Detailed explanation-2: -We use homologous characters-characters in different organisms that are similar because they were inherited from a common ancestor that also had that character. An example of homologous characters is the four limbs of tetrapods. Birds, bats, mice, and crocodiles all have four limbs.

Detailed explanation-3: -The opposite of homologous structures are analogous structures, which are physically similar structures between two taxa that evolved separately (rather than being present in the last common ancestor). Bat wings and bird wings evolved independently and are considered analogous structures.

Detailed explanation-4: -A Common Ancestor is a lineage that undergoes cladogenesis, that is, branching evolution, such that more than one species can trace its ancestry back to the common ancestor or, more accurately, to multiple common ancestors.