I would explain it like this.
Chimpanzees and Humans have a common ancestor, we split because a group of that ancestor stayed in the trees, another group of them stayed on the ground, those that stayed in trees, evolved into chimps, those on the ground evolved into humans. Chimpanzees don't entirely have a need for communication and language like we did, we had to work together in order to survive because we are more vulnerable on ground than in trees.
i dont think evolution is based on what you need to do its just something that happens spontaneously
Natural Selection's more about what's treated as gregarious and what leads to increased survival within the current conditions. It's not really random/spontaneous, but a matter of filtering out the dregs.
Normally, non-beneficial traits would die off naturally through not being able to survive, while beneficial mutations would flourish to the point of propagation. Thanks to modern medicine however that system's been hacked to pieces for us humans, and through Neoteny practices we've spread similar problems to wolves/dogs and livestock (effectively Unnatural Selection).
The common ancestor model is as such not about what they need to do so much as those who couldn't keep up with the demands didn't make it far enough along to continue producing offspring.
