What is the difference between homologous, analogous, and vestigial structures?
Homologous structures are characteristics that are shared by related species because they were inherited from a common ancestor. For example, bones in a human arm are homologous to the bones in a chimpanzee arm. A good way to remember this is that “homo” means the same. Analogous structures serve the same function in different species but they evolved independently rather than from the same embryological material or from the same structures in a common ancestor. Examples are the wings on birds, bats, and butterflies. Vestigial structures have marginal use to an organism but once had some function in its ancestor. Examples: eyes for bats and moles, snake legbones, and human tailbone and appendix.
