It's hard to deny evolution in the presence of insurmountable evidence from thousands of years of archeological records. During this time, countless changes accumulated and led to species' current states. In humans, for example, we can see in the records when our brains expanded in size and when bipedalism began to take hold.
But for all the perfectly adapted traits that we've collected over millions of years, there are some that we carry with us today that don't seem to have a useful function. In particular, did you know we still have tailbones without any apparent tails? We also have ear muscles even though we've long lost the ability to use them.
These biological marks are collectively termed vestigial structures - those that were once useful for our ancestors but no longer have a function for us now. Watch the video to learn three more examples of evolution's marks on your own body!