Hi Jeanie

why would there still be apes if we have evolved from them?

You pretty much answered the question in your initial post when you said “I guess we're cousins?”. There are two basic ways species can change over time to form new species. One is that the species simply changes over time to keep up with their niche and they become a distinct species such that if you could take one back in time to meet it’s distant relatives of many generations before they would not recognize them and would not be able to breed with them. The other common mechanism is division of an existing species into two separate populations who don’t interbreed. This can occur in place as the extreme’s of the species specialize on different foods for example. This has been observed in birds under certain conditions in which a small beaked variety and a large beaked variety form to take advantage of food that the original intermediate form could not use. As they diverge they get to the point where the extremes don’t recognize each other and will not mate with them. Another mechanism is geographic isolation, as sea levels rise (or whatever change it is) the population on one side of a divide can’t reach the population on the other side anymore and so again they are reproductively isolated. However it happens the point is that once isolation has occurred the two groups are no longer genetically tied together and changes in their DNA will accumulate separately. For reproduction to be possible the DNA has to be very similar so over time these two populations may well diverge to the point where they will not or even cannot interbreed if they ever meet again and two species have arisen from one progenitor species.

So back to your question, it is not exactly true to say that we evolved from apes, apes and humans shared a common ancestor that was somewhat ape like and somewhat human like. Due to isolation two distinct groups of this creature appeared and evolved off in different directions one leading to us and the other leading to the great apes thus today we have apes and humans.

Does that clear it up Jeanie?

All the best

Russell