Evolution of multicellularity (Introduction)

by dhw, Thursday, October 25, 2012, 18:02 (4413 days ago) @ David Turell

DAVID: There is no known mechanism for the jump from the very successful unicellular organisms to multicellular. Bacteria have been around for 3.5 billion years or so, very successful at their level of development. Each cell is highly complex. Yet multicellularity developed. Gould's excuse was that it was the only direction complexity could take, bacteria were as simple as it could get.
 
Here is a study that finds a unicellular organism that will clump when the right diet of a certain bacterium is available. Not a really good reason for multicellarity to develop, but a novel way it might have started. -http://phys.org/news/2012-10-bacteria-evolution-multicellular-life.html -The problem is the Cambrian Explosion. Sheets or tubes of simple cells beforehand and total complexity with many cell types afterward. Nothing stepwise.-Both this article and the Shapiro one lay emphasis on single cells that combine. The cells also communicate with one another. If we anthropomorphize them for the sake of our own understanding, we have A & B saying to each other, "Hey, let's get together and build something new." And if the environment offers conditions suitable for a vast variety of innovations, you may have thousands of individual cells deciding to get together and build something new, while others just carry on as before. The Cambrian problem disappears, and of course there are no steps ... a new combination either works or it doesn't. 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.