AP BIOLOGY

Detailed explanation-1: -Organs such as bat’s wing, wings of birds, seal’s flipper, forelimb of a horse, and human arm have a common underlying anatomy that was present in their last common ancestors; therefore their forelimbs are homologous organs.

Detailed explanation-2: -Notice that their forelimbs have the same bone components. They are examples of homologous structures. Although their forelimbs are used differently, the basic skeletal structure is the same and they are derived from the same embryonic origin.

Detailed explanation-3: -All vertebrate forelimbs are homologous, meaning that they all evolved from the same structures. For example, the flipper of a turtle or of a dolphin, the arm of a human, the foreleg of a horse, and the wings of both bats and birds are ultimately homologous, despite the large differences between them.

Detailed explanation-4: -Thus the forelimbs of such widely differing mammals as humans, bats, and deer are homologous; the form of construction and the number of bones in these varying limbs are practically identical, and represent adaptive modifications of the forelimb structure of their common early mammalian ancestors.

Detailed explanation-5: -A common example of homologous structures in evolutionary biology are the wings of bats and the arms of primates. Although these two structures do not look similar or have the same function, genetically, they come from the same structure of the last common ancestor.