Innovation and Speciation: whale changes (Evolution)

by David Turell , Friday, May 26, 2017, 21:29 (2736 days ago) @ dhw

DAVID: You are assuming your drive for improvement (dfi) is triggered by the appearance of more oxygen. We do not have any evidence this is the case.

dhw: It is a theory which you quoted: “Does environment play a role in initiating new species? Yes, it allowed the Cambrian to appear as oxygen levels rose.” You used the word “initiate” (so you meant “cause” instead of set in motion, did you?) but in any case, if it allowed the Cambrian to appear, it is logical to call it the first step that set the process in motion.

Oxygenation is not a first step that set anything in motion. Its appearance simply allowed an opportune level of energy usage. There must be a separate process existent to act on that opportunity. That next step of improvement or complexity is not required to happen. That is why I break the whole process into discontinuous parts.

DAVID: Which brings us back to whales. Environment did not change to trigger any dfi. They had to choose a new environment to force a dfi, which logically had to precede it.

dhw: A neat wriggle away from your Cambrian contradictions! We do not know why whales chose a new environment, but it is not unreasonable to suggest it was for improvement (maybe more food in the water), and once they found the environment was favourable, the changes took place to help them exploit this new opportunity to the full. I find this more convincing than the hypothesis that God only wanted to produce humans, and therefore he redesigned the pre-whale in eight different stages over millions of years before sending it into the water for no particular reason.

Once again you have skipped over the complex issues of planning for the major physiologic and phenotypic changes that must occur to accommodate the shift in environment. "Changes took place" glosses over the magnitude of the accomplishments. We are not discussing the production of humans, an issue you keep dragging in to muddy and confuse the issue. Please address whale planning.

DAVID: As for environment/speciation, I see strong evidence for speciation preceding environmental change (whales), but I also see that environmental change (Chicxulub) can change the course of speciation.

dhw: I'll stick with the Cambrian, since you agree that environmental change is an initiator (you go even further and say it's a cause!) of speciation.

I said the 'course of speciation', nothing more.

DAVID: As for the human form, they changed, apes didn't in the same environment, therefore speciation first.

dhw: Maybe in one particular location (or more than one, leading to convergent evolution of hominins) millions of years ago, the environment changed, leading a particular group of anthropoids to restructure themselves? You always talk as if environmental change and speciation had to be global.

Have you forgotten that early humans were in the Rift Valley, a small part of Kenya in Africa, not global! I am discussing local.