How can evolutionary cousins be so different?

This is a good little essay on the relationship between humans and chimps in the Naples Daily News.

It’s been known for more than 30 years that human beings and chimpanzees have more than 98 percent of their genes in common.

That’s right. As far as our genes are concerned, the difference between you (or me) and a chimpanzee is less than 2 percent. Chimps are our closest genetic relatives, our cousins, genetically. And in many other ways, physical and behavioral.

…

Then, how do you account for the fact that humans and chimpanzees are so different? Those who doubt Darwin’s evolution point to the obvious differences between us and our “cousins” as evidence that we are separate and apart from the chimps and all other animals.