Evolution: factors for speed of diversification (Introduction)

by David Turell , Friday, August 16, 2019, 16:01 (1715 days ago) @ dhw

QUOTE: The missing ingredient was a method to alternately connect and isolate populations of species through cycles of vicariance and dispersal. That spark finally occurs in the Darriwilian Stage when ice caps form over the south pole of the Ordovician Earth. The waxing and waning of these ice sheets caused sea level to rise and fall (similar to the Pleistocene), which provided the alternate connection and disconnection needed to facilitate rapid diversity accumulation."

DAVID: All of these factors allowed the diversification to occur in a speedy fashion but it must be remembered, the genome must initiate change and that is the driving factor, not the environment.

dhw: I don’t understand your comment. The changes occur through interaction between the environment and the genome. The genome responds to the environment. The article makes it clear that without these environmental changes, the genome would not have diversified so quickly. One of our favourite examples of this process is the whale’s flipper: you claim that your God designed it before the pre-whale entered the water (genome changes before environment changes), whereas I and probably most other people would argue that the pre-whale’s legs changed to flippers in response to its entering the water.

What changes in a new species is driven by the genome. That is all I have stated. The environment may invite change, but it is secondary to the process of change.