Evolution of multicellularity (Introduction)

by dhw, Friday, October 26, 2012, 17:55 (4412 days ago) @ David Turell

Dhw: We are back to the intelligent cell (or the Margulis concept of cooperation), and David if you could cloak my little fairy tale in suitably complex scientific jargon, you could then challenge the scientific community to find a better explanation.-DAVID: Unfortunately a living organism contains million of cells and many different kinds of functioning cells. The cells themselves are very complex expressions of different parts of DNA. How they would negotiate to combine and organize from single cells to a mass of cells as described is beyond my comprehension. All examples we have of cooperation are relatively simple. A cell swallows another cell and we have mitochondria. I'd love to know how a cell could swallow another cell and make a heart. That is a simple organ, a muscular sack with an electric system. Try for a liver or a kidney. They are both entire chemistry laboratories, disposing of waste and making hormones and other products at the same time, all under feedback loop controls. Yes, cells are obviously using intelligence. I keep asking where did the intelligence come from?-I'm somewhat baffled by your claim that "all examples of cooperation are relatively simple". Isn't every organ a massive community of cells that cooperate, and isn't every body a mass of cell communities cooperating? The problem we are grappling with is how these communities came together in the first place, i.e. what is the mechanism that has made new organs and new organisms possible? You and I are highly sceptical about Darwin's random mutations, and instead I'm simply suggesting that the mutations are not random but guided by intelligence within the cells themselves. You finish up by agreeing ("yes, cells are obviously using intelligence") ... in which case, I don't understand why the rest of the paragraph is so negative, beginning with "unfortunately". Why is it unfortunate? I would have thought this was living proof that cells cooperate, and if they do so now, why should they not have done so over and over again in the past to create the organs and organisms we see now?-Where the intelligence came from initially is a separate question. Darwin didn't attempt to answer it in his Origin of Species, and my focus here is on the mechanics of evolution, not on first causes. To sum up: Darwinism proposes an endless series of random mutations, with a gradual flow of steady refinements, and Natural Selection deciding which of these should survive. The problems with this scenario lie firstly in its reliance on chance for innovation, secondly in the paucity of fossil evidence, and thirdly in leaps such as that from single cell to multicellularity or that of the Cambrian Explosion. If instead we follow the principle of intelligent cells cooperating to form new combinations in accordance with the latitude allowed by a changing environment, these problems disappear. Sometimes I get the impression that you agree, but then you seem to withdraw your support for the idea!