vestigial structures
I listened to an interview with an evolutionary biologist named Jerry Coyne last week, and a question he was asked was: “If you were to present one piece of evidence for evolution to a non-believer, what would it be?” His answer: “The fossil record.” While I find the fossil record interesting, I find vestigial structures as the most compelling, and best to present to those who are evolution-deniers.
Vestigial structures are features of species that have lost ancestral functions, and either have a new use or no use of the feature. Vestigial eyes are common. When animals live in complete darkness they have little to no use for eyes, so through mutations and long periods of time, many species gradually lost their ability to see. One example is the blind mole rat. It lives underground and has a protective layer of skin over its eye (Coyne, 2009). Another animal often cited for vestigiality are whales. If you visited a museum to observe the skeleton of a whale, you would see the hindlimb and pelvic bones separated from the rest of the skeleton. These two features of whales served a purpose in their ancestors, but disconnected when they were no longer needed (Mayer, 2011).
Using the tools of science, we can take this information and ask questions, and ultimately answer some of them. For example, if an animal has a vestigial structure, we can ask questions like: Why did it lose its function? Which ancestors had the function? Why is the structure still present and not gone altogether?
We can also use the tools of science to make predictions. Whales for example, have hindlimbs they no longer use, so we can hypothesize that their ancestors were land animals. We can then go out and look for fossils of specific animals in specific areas to find out if we were correct. We have done this over and over again using the tools of science, and we will continue to do it to contribute to the theory of evolution.
Vestigial structures are features of species that have lost ancestral functions, and either have a new use or no use of the feature. Vestigial eyes are common. When animals live in complete darkness they have little to no use for eyes, so through mutations and long periods of time, many species gradually lost their ability to see. One example is the blind mole rat. It lives underground and has a protective layer of skin over its eye (Coyne, 2009). Another animal often cited for vestigiality are whales. If you visited a museum to observe the skeleton of a whale, you would see the hindlimb and pelvic bones separated from the rest of the skeleton. These two features of whales served a purpose in their ancestors, but disconnected when they were no longer needed (Mayer, 2011).
Using the tools of science, we can take this information and ask questions, and ultimately answer some of them. For example, if an animal has a vestigial structure, we can ask questions like: Why did it lose its function? Which ancestors had the function? Why is the structure still present and not gone altogether?
We can also use the tools of science to make predictions. Whales for example, have hindlimbs they no longer use, so we can hypothesize that their ancestors were land animals. We can then go out and look for fossils of specific animals in specific areas to find out if we were correct. We have done this over and over again using the tools of science, and we will continue to do it to contribute to the theory of evolution.