Extinctions: Bad Genes or Bad Luck? A nod to D. Raup (Introduction)

by David Turell , Thursday, February 10, 2011, 14:45 (4826 days ago) @ dhw

David has alerted us to the phenomenon of two worms that have evolved backwards.
> 
> DAVID: My theory of increasing complexity from a mechanism in DNA is under attack.
> 
> I don't understand why backwards evolution should undermine your theory. Just as vestigial structures are those that are no longer needed, why shouldn't our friends the worms get rid of complexities not needed for current environmental conditions? That doesn't mitigate against other creatures becoming more complex, in accordance with their needs, does it? But I'm out of my depth, so perhaps you could explain the problem to us non-scientists.-You make a good point. My problem with the finding is the size of the proposed regression. The worms had a distant theoretical relationship to humans in the genome through a common ancestor. The authors of the study have assumed the worms were more complex in their beginning existence, since they are genomically related to a more complex ancestor. However, upon reflection, humans share the same genes with one-celled organisms, and some genes are turned on and some off in various ways in different organisms. These worms may not have been as phenotypically complex as the authors suppose, but were a simple offshoot, filling a necessary niche in evolution. -As a result of this pattern of thought on my part, I'll still vigorously stick to my theory that the original genomes in original life carried a mechanism to drive complexity, as a general pattern.