Evolution: where did cyanobacteria come from? (Introduction)

by dhw, Tuesday, June 20, 2017, 13:10 (2714 days ago) @ David Turell

DAVID: Partially wrong. The Cambrian animals were created after oxygen appeared. Not before. Only the whales appear to fit your comment.

dhw: I sometimes find it difficult to keep up with your different opinions. You told us your God also restructured hominins before they descended from the trees to the plains (“bacterial intelligence”, 24 May: “Speciation first, environment second”) and actually I thought the whales were meant to be a prime example of your God’s advance planning. However, so long as we agree that environmental change can trigger the process of speciation, we can move on.

DAVID: You are correct. I had forgotten that bipedalism skeletal changes appear before Lucy's decedents fully left the trees. But in these examples the changes are in areas of living as environmental change, not Earth's environmental change as in oxygen concentrations. Area change requires pre-planning. As for your word 'trigger' I don't like any more than 'initiate' both of which imply causation, but I now know you have a different view of he meaning of those words. I prefer that changes 'allow'.

If you believe in common descent, clearly all innovations must occur in individual organisms, and so speciation will take place in individual locations (though there could be several locations at the same time). Are you now saying that, for example, if there was an environmental change that was confined to parts of Africa, God would have anticipated the change and restructured beforehand all the organisms he wanted to speciate? In any case I don’t see why, in your scenario, area change requires pre-planning and global change doesn’t.

I accept “allow”, but for me it doesn’t have the dynamic immediacy of “initiate” and “trigger”, which here = this marks the beginning of the process, which would not have taken place without it. Not the cause, but the indispensable event that sets the process in motion. The cause, we have agreed, is the drive to improvement (for me) or complexity (for you.)