(November 3, 2017 at 9:16 am)SteveII Wrote:(November 3, 2017 at 8:54 am)Khemikal Wrote: Tell that to plants. They don't recognize light, they can't "do anything" about it, they have no nervous system whatsoever...and yet the chemical inevitability of auxin transfer means that they grow toward and track the sun....a hell of a survival benefit for a photosynthesizing organism.
All that's required for auxin transfer to be beneficial is for auxin to be a photophobic growth hormone..which it is. As far as we can tell, auxin was present in the algae forerunners of plants and not at all used for phototropism, but a much more general form of regulating morphogenesis.
A plants photosynthetic apparatus is a collection of modified light sensitive cells, supported by photophobic morphogens capable of conferring benefits without the addition of any of those other things you imagine to be so crucial for eye spots to be a survival advantage.
I was not talking about light spots. I specifically said "eye and associated neural functions" as an exact quote of DBP's statement: "From there you can evolve the eye and associated neural functions." A magic wand was waived and I want details how component systems evolved functions when they are dependent on each other to confer a survival benefit.
What's stopping co-current systems evolving at the same time? If they're dependent of the other, both think of it as an AND function, where the off-spring that has both the increments "neural functions" and "eye function" have a better chance of furthering their genes than off-spring that only have 1 of the benefits. It's not that hard to understand.
