Homology can be defined as the presence of common structures because of shared ancestry. Homology can involve genes, proteins, or anatomical structures. As a result of 'descent with modification,' many homologous structures have adapted different purposes. List three anatomical structures in vertebrates that are homologous but have different functions.

Video transcript

Hi everyone. Let's look at our next question. It says which of the following is an example of homologous structures? Let's recall what homologous structures are. And these would be structures that are perhaps different in function but similar in form due to common ancestry. So structures that have been uh a result of descent from a common ancestor, even if they've diverged in the function, they perform often an example of divergent evolution. So when we look at our answer choices, let's see which one would fit this. And we look at choice A. We have tailbone in humans and tail and monkeys. And right away here we have this example of homologous structures. Um The tailbone and humans serves no purpose anymore ah While as the tail and monkeys is used for grasping and for balance. But if you look at the bone structure, it's very similar except that the monkeys is longer. So these are homologous structures due to descent from a common ancestor serving a different function now but retaining the similarity in form. Choice B is wings and birds and wings and butterflies. Well, this would be an example of an analogous structure and that means a structure, structure that is not due to shared ancestry but due to the fact that the they serve a similar function and are in a similar type of environment. So both of the wings of birds and the wings of butterflies used for flying that environment of moving through the air, but their wings are not similar in form. When you look at the structure of the actual anatomy of them and they're not due to common descent, So Choice B is not correct choice C. Eyes and humans and AIS and squids. That's also an example of analogous structures, So not our correct answer choice and the choice. The fins and fish and fin like structures and penguins also analogous structures, so not our correct answer. So again, which the following is an example of homologous structures. Choice A tailbone and humans and tail and monkeys. See you in the next video.