NEET 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: -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-4: -structures are similar because they come from a common ancestor, such as the bones in the forelimbs of mammals. Homologous structures are similarities throughout a group of closely related species.

Detailed explanation-5: -Scientists can compare the DNA of two organisms; the more similar the DNA, the more closely related the organisms. This method can also help when looks are deceptive. One example of looks being deceptive is: The bat and the crow both have wings, and the squirrel does not.