[Physicist]

I have a completely different idea. As far as I know, this is an original scientific hypothesis. To prove that I'm a crackpot, I've cast my hypothesis into the form of a sonnet:

Prometheus

Some theorize that man first walked erect,
To carry simple tools, or throw a spear,
The fossil record proves this incorrect:
Walking predates tools, two million years.

Others think that walking freed the hands,
To gather and to carry precious food,
But this selects the group and not the man,
And won't select at all when times are good.

I think 'twas fire that taught the ape to stand,
It's fearful, but it's pretty, warm and bright,
One stoopéd ape picked up a fire-brand,
And banished cold, and predators, and night.

Encumbered, thus unfettered, torch in hand,
An ape, tempered by fire, became a man.

[Sabertooth]

To prove that I'm a crackpot, I've cast my hypothesis into the form of a sonnet:

Hey now!

Actually, I believe there's some merit to your theory...

Man evolved bipedalism to make fire and free their hands for shadow puppets.

[VadeRetro]

Hmmm. Does evidence for campfires (as opposed to natural fires) predate tools?