How are homologous structures such as forelimbs evidence for common descent and evolution?
“Homologous Structures Homologous structures, on the other hand, are characteristics which are shared by related species because they have been inherited in some way from a common ancestor. For example, the bones on the front fins of a whale are homologous to the bones in a human arm and both are homologous to the bones in a chimpanzee arm. The bones in all of these different body parts on different animals are basically the same bones, but their sizes are different and they serve slightly different functions in the animals where they are found. Homologous structures provide evidence of evolution because they allow biologists to trace the evolutionary path of different species, linking them up in the larger evolutionary tree that links all life back to a common ancestor. Such structures are also strong evidence against creationism and Intelligent Design: if there were a deity who created all the different species, why use the same basic parts over and over in different creatures for di
