I suspect that the intent of the original quote is that they'll assess us by our curiosity towards, and effectiveness in discovering, our origins. As Dawkins is a biologist, he is implying that evolution by natural selection is an important part of it, which of course is true. An astronomer or cosmologist might consider a theory on the origins of the universe itself to be more important, a biochemist might consider abiogenesis to be the key, and so on.

Personally, I can see where he's coming from, though I can't say I feel like I know enough about the evolution of intelligence to come up with a valid argument as to whether an alien species would consider this to be a good metric to evaluate us with. One could argue that interest in oneself is an important aspect of intelligence, and scientific enquiry important to the development of space travel, and so a species capable of travelling to us would have those qualities and look for them in the creatures they found.

This is my time posting here, so I'm probably not quite up to the standards of the rest of you just yet. Sorry if I said something stupid.