Reptile tree redrawn
A new study has rewritten the text books on reptile genealogy. The news release notes

The most comprehensive analysis ever performed of the genetic relationships among all the major groups of snakes, lizards, and other scaly reptiles has resulted in a radical reorganization of the family tree of these animals, requiring new names for many of the tree's new branches.

Just remember, the tree of life is often touted as strong evidence for common descent evolution (CDE). Yet here we can see it is rewritten completely for reptiles. Even though 'The resulting family tree has revealed a number of surprising relationships.' they don't question the assumption of CDE, they simply modify the plastic theory to adjust.

These researchers used 'twice the amount of genetic information as was used in previous studies of these species.' This implies that previous studies came to different results based on a different set on genetic information. Does this mean that there is no clear cut progression between the various species? That the tree you come up with depends entirely on which genetic strands you focus on? That would indicate that CDE is a poor explanation for the genetic variety in these species.

Another great assumption of CDE is that similar physical features implies close evolutionary relationships. Yet here we have this study overturning a phylogenic tree that was based on physical features. Obviously the genetic data does not agree with the physical data. This should throw doubt on CDE as it is a fundamental assumption that has been used for a hundred years. Don't hold your breath though. It is business as usual where CDE is assumed as fact and every observation must be made to fit within it.

So how do the authors explain these discrepancies? With the old ad hoc explanation of 'Convergent Evolution'. In the authors own words "For genealogy research this can be a problem if two unrelated species change in the same way, resulting in false evidence of relationships."

Considering how often fundamental 'evidence' for CDE is found to be wrong, I often wonder just how much of the original foundation for believing in CDE is still used. We seem to be constantly discarded old 'evidences' and replacing them with new 'evidences'. Yet still no one doubts CDE.

Maybe one day people will realise just how full of holes common descent evolution really is. Until then, it sure is amazing how much research the constant reworking creates...
- posted by Alan Grey @ Thursday, November 24, 2005