Bigger Brain
Origins of Us - Guts
600,000 years ago, another species appears in Africa and Europe, Homo heidelbergensis. Thought to be descended from Homo erectus, he was similar in build, but with a bigger brain and its thought that he, in turn, evolved into another two species.
200,000 years ago, someone else appeared on the scene and this time it's us, Homo sapiens. At roughly the same time Homo neanderthalensis or Neanderthal man appeared.
Comparative Skull Size
We originated in Africa and then spread out right across the globe. But, as well as population expansion there's something else very obvious going on here, and that's an increase in brain size over time. Large brains need a lot of energy and it's always been thought that what fuelled brain growth was meat. But a new idea suggests it might be linked to something even more powerful - Fire!
I really don't think we can underestimate the value of fire to our ancestors. It would have offered them protection, warmth during cold nights and in a cold climate, light after the dun had gone down. But its incredibly hard to know when our ancestors first learnt to control fire.
Fires are just so spectacular when they're burning, but of course, when they've burnt out there's so little left, so it's really difficult to pick up the traces.of the first dires that our ancestors would have controlled. There's some evidence going back 1.5 million years ago that our ancestors may have controlled fir, but by the time our own species, Homo sapiens, is around, we're using fire all the time.
And we get an idea of what they were doing with fire from charred remains. Things like pieces of burnt bone, charred hazelnut shells. Thet were cooking. Cooking doesn't only make food more palatable.
Recent research suggests it was cooking, not meat, that duelled the evolution of our big brains. It was cooking that mase us human.
This theory has given rise to a new wave of scientific research investigating the advantages that cooked food has over raw. Digesting raw food uses energy. For every 100 calories of raw food I eat, I use up to 25 calories chewing and digesting it. Cooked food is much easier to digest than raw and this simple fact holds the key to why cooking had been so important in our evolution. Not only is cooked food easier to chew, it takes less energy to digest it once it reaches our guts, which means we effectively get more energy from cooked food because we put less into digesting it.
