We're not sure this is actually how evolution works, but wouldn't it be brilliant if it did? There would be monkeys and apes slowly becoming more like humans and picking up habits like catching a train to travel, and paying into the zoo to see their cousins. It would be wonderful. Occasionally violent and maybe a little terrifying, but mostly wonderful.
There's probably a point to be made here about not keeping intelligent creatures in cages. Gorillas in particular are very clever. They can be taught sign language and have fairly expansive conversations with humans. They can also communicate emotion and understanding of the world around them. In short, they're probably more like us than they are many of the other animals in the zoo. So, should we be caging them and giving them a feeding time, or letting them live and eat the way they'd prefer to?