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Hello, the story of human evolution stretches back over about six million years.

It's not the story of one species but of several diverse species, some of whom walk the

earth at the same time.

From the earliest hominids to the early homo sapiens,

there seems to be nothing inevitable about the course of human evolution. But what conditions

created the opportunity for diverse human species to thrive, what environmental factors led

to the survival of just one human species but contributed to the extinction of so many others.

What can the fossil record and the science of genetics tell us about our ancestors and how does the brain make modern man so unique in the natural world?

We meet to discuss human evolution is Steve Jones, Professor of Genetics in the Golden Laboratory at UCL University College London.

Fred Spoor, Professor of Evolutionary Anatomy at UCL, and Margaret Clegg, Honorary Research Fellow in the Department of Biological anthropology at UCL.

Steve Jones, can we go as what we might call the beginning when we see the hominids come in? Well we can in a metaphorical sense. You can do it directly with

fossils and of course the fossil record by definition is very incomplete but there's another

way of looking at fossils because we're all

fossils we're all living fossils of our ancestors all chimpanzees are living fossils

of their ancestors and in fact we can draw a family tree in the genes which links us to our joint ancestor

and if you make the rather daring assumption that the DNA changes at a regular rate

uh... and compare ourselves and chimps to let's say mice, which we know the original date of split reasonably well.

You get up with this famous date of a split of around six million years ago

when the lineage that gave rise to us split from the lineage that gave rise to

chimpanzees.

...