What is an example of an animal that evolved due to environmental change?
Why us homo sapiens of course!
When the dinosaurs were killed off by the giant asteroid 65 million years ago, the environment underwent a huge change. Mammals were around at the time of the dinos, but were small and managed to survive this catastrophe as they could hide in burrows or whatever. Once the dust settled, mammals could fill all the niches the dinos used to occupy and they flourished.
The second environmental change that happened specifically to humans was in East Africa around 2 million years ago - a drying out period forced our early ancestors to leave the forests and stand up and try to survive in the dry grasslands. This probably caused us to walk up right, changed our feet and toes, and perhaps led to no hair on our bodies.