Where and when did all the different human ancestor species originate?

We put this question to Professor Lord Colin Renfrew:

Colin - Well the fascinating thing is that the fossil remains give us a very clear picture and most of them originated in Africa. There was a theory that to maybe the Homo erectus, form that was about 2 million years ago, might have been ancestral to our species, Homo sapiens. But the DNA helps confirm that you have to go back to Africa to find the ancestors of Homo sapiens. Back to Homo erectus, before that 3 million years ago, Australopithecus... So, Africa is the answer.

Diana - I see and how long ago are we talking? I mean, you mentioned 3 million years.

Colin - Yes. Well, the African ancestors go back before that but things start to happen sort of 3 or 4 million years ago. You've got Australopithecus and then you get the first tool makers, which is very important, about 3 million years ago with Homo habilis. So, once you get people making tools - stone tools, that's when you really feel that you're dealing with our real ancestors.