What Are the Biggest Gaps in Evolution?

The gaps in what we currently have in evolution are like the doubling in human cranial size from 2 million years ago to 300,000 years ago from Homo habilis to Homo sapiens. And that's one gap. The other gap is why do we have just the last 5% of the existence of Homo sapiens? We have civilization. Maybe there were past civilizations that got to where we are and there were cataclysms that wiped them out. I'm very interested in that. But it's an important question.