Between homologous, analogous structures, and vestigial structures, which suppor the theory of evolution? Explain why.

1 Answer
Apr 25, 2018

All of them.

Explanation:

Homologous structures, or structures that are made of similar things but have very different functions (Example: A human hand and a whale flipper do very different things, but have the same number and basic arrangement of bones) prove that since the structures are slightly similar in appearance, any two species sharing homologous structures must have had a common ancestor, however distant.

This means that evolution had to act on this common ancestor to change it into the different species existing today.

Analogous structures, or structures that look very different but do the same thing (Example: Bird wings and bat wings look very different, with the feathers or lack thereof, and shape, and all, but both are used to fly) prove that despite not being closely related, if two very different organisms have adaptations that do the same thing, then this must be a result of their needs and environment.

In other words, evolution has to exist for two different, unrelated animals to have different solutions to a common problem (Needing to fly to better catch prey)

Vestigial structures, or structures that have no function anymore (Like the human tailbone or appendix. The latter is an extraordinary waste of space and is only good for giving people appendicitis) prove that evolution exists because why would anything have a random, useless structure without it, at least a long time ago, having a purpose?

This means that an ancestor of the species with a vestigial structure must have had some use for the structure (When humans were essentially monkeys, we had tails, and appendixes are thought to have helped with digesting complex proteins), but then it was no longer needed, so it "shrunk".

For a species to have changed, evolution must have happened.