More about how evolution works: multicellularity (Evolution)

by dhw, Wednesday, October 26, 2016, 12:13 (2948 days ago) @ David Turell

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.
DAVID: 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.

But I am not talking about adaptation! Adaptation can be witnessed even today. Please re-read what I wrote. The problem we have been dealing with year after year is INNOVATION, and that is why I suggest that the two driving forces behind evolution are survival and improvement: survival requires adaptation to unfavourable stress, improvement entails exploiting new opportunities, e.g. a change in the atmosphere such as increased oxygen. This is precisely the argument put forward in the important article you have just posted on the role of the Earth’s magnetic field – changes in the environment provided the opportunity for new forms of life (the Cambrian Explosion).

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.

DAVID: My disjointed point: Why did evolution advance if bacteria were up to all the challenges? Challenges demand improvement or extinction.

I’m surprised you use “improvement” here, since challenges demand adaptation or extinction. Perhaps you are trying to devalue my own use of the term, which I have explained above in the context of why evolution advanced beyond bacteria, namely through innovation.

DAVID: 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?

Stating that humans are the goal is certainly clear, but that doesn’t make it true. Only multicellularity – as I said above – leads to the duckbilled platypus and every other multicellular organism extinct and extant. Even you find it hard to understand your own interpretation of God’s logic (all planned to balance nature to keep life going to provide food till humans came), but for some reason the alternative – that your God might have given organisms free rein (apart from the occasional dabble) – is anathema to you.