More about how evolution works: multicellularity (Evolution)

by David Turell , Tuesday, October 25, 2016, 15:20 (2949 days ago) @ dhw

dhw: It would not have been possible for innovations to take place if the environment had been unfavourable for them. An increase in oxygen may have created the opportunity for new organisms to come into being to exploit the environment in new ways. That is why I link innovation and improvement to opportunities offered by the environment.

Unfavorable stress, not favorable environment, drives the need for adaptation. More oxygen does not require new evolved forms. More oxygen will not act as a suction pulling evolution forward.

DAVID: 'Challanges required adaptation' is correct. It demands improvement or extinction. Bacteria weren't challenged. They solve all problems and survive, need no improvement. Why multicellularity? Can't get to us any other way. Today's bush of life is exceedingly complex. Advancing evolution requires complexity beyond bacteria.

dhw: I can only comment disjointedly on this disjointed paragraph. What demands improvement or extinction? Is this a misprint? Why do you say bacteria weren’t challenged? They have met every challenge by adapting, but yes indeed they are still bacteria. Why multicellularity? You can’t get to the duckbilled platypus and thousands of other species extant and extinct any other way. So why just “us”? Multicellularity by definition is more complex than unicellularity, and of course evolution would not have advanced without it.

My disjointed point: Why did evolution advance if bacteria were up to all the challenges? Challenges demand improvement or extinction. Multicellularity is highly complex and raises all sorts of complex biochemical issues to be solved. Why not sticking with simplicity? Because only multicellularity leads to humans, which is the goal. Clear?