Human Evolution and Frameshift Mutations | gmilburn.ca: "This mutation in our human ancestors happened approximately 2.4 million years ago. Right before our ancestors stopped looking like primates and started looking like us. If you lacked the protein that built a powerful jaw muscle, you could not carry a large jawbone around and use it effectively. If you can’t carry a large jawbone around, there is strong selection pressure for those with smaller jaws to survive. If your jaw gets smaller, then the loading of the jaw on the skull decreases - bony ridges disappear, and the skull can get larger and lighter since it doesn’t need to be as strong. A larger and lighter skull can accommodate a bigger brain."
Posted by orekdm at 09:45