Vestigiality

Okay kiddo, have you ever had a toy or a game that you used to play with all the time but now you don't use it anymore? Maybe you grew out of it or you found new toys to play with. But sometimes even though you don't use it anymore, you still have it around in case you ever want to play with it again. That's kind of like what vestigiality means.

Vestigiality is about body parts that some animals still have, but they don't really use them anymore. It's like a leftover part that isn't really useful anymore, but it's still there.

For example, lots of snakes still have little legs bones inside their bodies, even though they don't have legs. These bones don't really do anything, but they are still there from when snakes used to have legs a long time ago.

Another example is the human appendix. It's a small tube in our bellies that doesn't really do much. Some people think that it used to help our ancestors digest tough plant material, but now we don't really need it anymore.

So, vestigiality is all about little parts of animals' bodies that used to be helpful a long time ago, but aren't really necessary anymore. They're kind of like old toys or games that we don't play with anymore, but we still have them around just in case.