h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

What is the general consensus of this theory, that in some point in history we lived in water 'like' amphibians for a great period of time!!!

It seems a lot of the things that was mentioned we had in common with water living animals, has been shown to exist in other land based animals as well. So I don't think the theory is that strong at the moment.

Two things I remember about are that 1) Babies can hold their breath when underwater, which is seemingly inexplicable otherwise, and; 2)the pattern of hairs in humans is such that it could be explained by 'streamlining', as if to help water flow over the skin more quickly.

Point 1 I have no idea about, but I think 2 could be explained by sweating rather than swimming. I don't think the theory is in vogue at the moment.

David Attenborough just finished a BBC Radio 4 series on it, which you can listen to here

http://www.bbc.co.uk/radio4/science/scarsofevolution.shtml

I only caught the end of it, but he seemed to be halfway persuaded.

Humans float; they are lighter than water. All other apes sink; they are denser than water. But that might be because we eat too much junk food!

There's an excellent Edited Guide entry on it: A730531

The aquatic ape hypothesis hopes to explain a few things that distinguish humans from other apes:

- We have less hair
- We stand upright
- We have a subcutaneous fat layer (apes don't but dolphins do)
- We have bigger brains

The theory says:

- Hair slows you down in the water
- Living in and around the beach and foreshore allows for a lot of wading, hence the upright posture
- Insulation for cold water
- We ate a lot of fish, rich in fatty acids which are an essential building block of brain tissue.

It doesn't say that we were amphibians as such, but that we lived around water and used the sea for food (rather than the other two major theories - we lived in trees, and we lived on the savannah plains).

Matt

Aargh, simulpost. Oh well, I enjoy typing

Matt