Physical differences between the cranium of the gorilla, australopithecus, and modern human. what does this difference tell you about each species?

The gorilla and Australopithecus have a more defined pushed out face feature unlike the modern human who evolved to have a more rounded face. The cranium for the gorilla and Australopithecus happen to be more sunken in unlike the rounded human face. This tells us that the Australopithecus most likely evolved from the gorilla. This also tells us that they lived in different environments because of their different evolutions. 

Mutations are changes in the dna