The Intelligent Cell (Origins)

by David Turell , Saturday, December 17, 2011, 00:40 (4507 days ago) @ dhw

There is obviously something that drives complexity in the genome, such as the newly-discovered epigenetics[/i].

You’d used this as a reason for considering humans to be a “chosen species”, whereas I’m saying the fact that complexity was not needed is no reason for regarding humans as the original goal (pre-planning). It’s clear that something must drive complexity, simply because we have it, and epigenetics is an immensely promising development in our possible understanding of the mechanism.

Correct. Something must drive complexity, because in the facts we are discussing, humans and chimps diverged, and I don't see any driving force.

One theory is that somewhere or the other (in Africa?) the forests disappeared and the common ancestor had to come down from the trees and start a new life on the ground. This would have entailed developing new skills. Is it not possible, then, that the process was the reverse of what you’ve outlined, and the need for new skills entailed developing the brain (much as certain exercises may strengthen and expand our muscles), as well as necessitating certain changes in the anatomy. This in turn entailed less use of other parts of the body, and so in due course the body became smaller and weaker as physical power gave way to intellectual power.

Lets climb up into the trees 6 million years ago. We are two common ancestors looking at a growing savannah. One of us stays roughly the same and the other becomes US, the H. sapiens. Why did we climb down? What drove us? Nothing we know of. We cannot relive ancient history. We can only guess. But one of us did get down. That guy lost those heavy arm and shoulder muscles and as part of the changes grew a giant brain.

The savannah gave both of us the option to try a different lifestyle, but it did not require it. Natural selection requires some sort of challenge. The climate change doesn't seem to offer any. As a result, we really have idea why this happened. But it did, and we are here, in all our glory.

If an open option allows an advantage in complexity, but does not require it, why did it happen? Dumb luck or some push to complexity? I think there is a pushing mechanism and that it will be found in the near future. To be nice, I think your theory is possible, but not reasonable without some pushing somewhere.