Saturday, January 09, 2016

Another Evolution Post- The Absurdity of Crediting Chance for Multicellularity

I know this blog is supposed to be about Arkansas-related matters, but I barely have time keep this one up, much less to found another one for my science interests. I read an article with a fascinating experiment which traced how a protein meant to be used in cell division could have been adapted to permit single-celled organisms to become multiple celled ones. The evolutionary path he described, when viewed by itself, seemed plausible enough. There was the small matter of his calculations showing that the other version of the protein, the one that allowed multi-cellular animals, had been around for perhaps hundreds of millions of years before the multi-cellular animals themselves.

I find this frequently in "evolution." Something that they think is a revolutionary new function is actually just the activation of a latent function which the organism had the potential for all along. Here for example, is an article about a group of fish who can change within a few generations from salt to fresh water species. The article refers to this ability as "evolution", but its really just the activation of a latent trait which as far as we know, fish of this type have always had.

The other problem I had with the article was the naturalistic (nature is all that there is) pre-suppositions of the researchers.  Dr. Thornton claims that is was just by "chance" that the one protein used for mitosis was also able to attach to the anchors from other cells which allows multi-cellular animals to exist. That is not a scientific statement, its a philosophical statement. It is naturalism posing as science again. He can't, scientifically, know whether the shape of the protein working out so that multi-cellular animals can exist is mere happenstance as he believes or the result of an Intelligent Designer.

An actual examination of the process by which cells line up into tissues, as outlined in the article itself, in my view make it highly unreasonable to believe that these abilities came about by unguided chance. And further, while the description of what might have happened to one particular protein sounds plausible when viewed in isolation, the idea that all of the changes needed to bring about multi-cellular animals occurred by the same processes does not. Below is an excerpt from the article, so you can see what I mean:

 To form and maintain organized tissues, cells must orient the direction in which they divide relative to their neighbors. In the flat tissues that line organs, for example, cells divide within the plane of the tissue; otherwise, malformations and cancer can result. Cells accomplish this through a structure called the mitotic spindle -- a network of protein filaments that pulls freshly duplicated chromosomes to opposite ends of the cell before it splits into two.
In cells from a broad range of animal species, the spindle is rotated relative to surrounding cells by a protein scaffold known as the guanylate kinase protein interaction domain (GK-PID). It acts as a kind of molecular carabiner by binding to two different partner molecules: an 'anchor' protein on the inside of the cell membrane that indicates the position of adjacent cells and a motor protein that pulls on mitotic spindle filaments. Once hooked together by GK-PID, the motors pull the chromosomes toward the anchors, orienting new daughter cells in line with neighboring cells.

PS- there is a big difference between multi-cellular organisms with tissues and a group of the same kind of single celled animals operating together as a colony, which is what this study looked at but extrapolated into conclusions about the development of the former.


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