AP BIOLOGY

Detailed explanation-1: -Explanation: Biologists often compare the sequences of related (or homologous) genes. If two species have the “same” gene, it is because they inherited it from a common ancestor.

Detailed explanation-2: -Examples of marsupial mammals include kangaroos, wallabies, wombats, the koala, and the Tasmanian devil. These three extant mammal groups-monotremes, marsupials, and placentals-are monophyletic, meaning the members of each group descend from one common evolutionary ancestor.

Detailed explanation-3: -While sequence similarity is a highly probable consequence of common ancestry, similarity alone is insufficient to establish homology by the model selection tests.

Detailed explanation-4: -If different species share common ancestors, we would expect organisms to share similarities inherited from those ancestors. Features inherited from common ancestors-even if their appearance is quite different in close relatives-are known as homologies.

Detailed explanation-5: -In general, organisms that share similar physical features and genomes tend to be more closely related than those that do not. Such features that overlap both morphologically (in form) and genetically are referred to as homologous structures; they stem from developmental similarities that are based on evolution.