Natures wonders: bacteria can spear amoebas (Introduction)

by dhw, Tuesday, August 29, 2017, 13:21 (2426 days ago) @ David Turell

dhw: My point is that complexity for the sake of complexity seems pointless unless each complexity serves some kind of purpose, e.g. improving the chances of evading prey, access to food, degree of comfort.
DAVID: The purpose may be to eventually evolve our brain.

Do you really want me to ask you yet again how the complexities of the 8-stage whale, the monarch’s lifestyle and the weaverbird’s nest have contributed to the evolution of the human brain?

DAVID: Improvement led to 99% of all species disappearing! All other recent primates survived without having human 'improvements'.

The disappearance of 99% of all species must in some way relate to changes in the environment (in the broadest possible sense). This means that when a new organ/organism first appears and survives, it has improved its chances of evading prey, gaining access to food, making life more comfortable. Then comes a change in the environment, and the improvements no longer serve those purposes. Hence the extinction of some (but not all) species. And then the changes in the environment may lead to different innovations and improvements among the surviving species (including primates) though that doesn't mean the old species have to disappear. So it has gone on throughout the history of life, with constant comings and goings, in a process known as evolution.

DAVID: Your approval of the concept improvement runs into a problem. How do you define improvement and prove the point? The bacteria didn't need improvement yet here we are.
dhw:I would say that, for instance, the subsequent ability to see, hear, walk, swim, fly, talk, build, think complex thoughts, invent machines etc. represented improved means of coping with the environment, communicating, enriching experience of life, but you may not agree.
DAVID: Again, for survivability, not needed, but yes our life is nicer.

See above. Once multicellularity had occurred, and more and more new organisms came on the scene, survivability would have been a crucial factor, though not the only factor.

DAVID: As for the brain, it is the most complex object in the universe.
dhw: And in terms of communicating, inventing, creating, destroying, killing, healing, recording, exploring etc. etc., I’d say our methods are an improvement over those of any other species, But again you may disagree.
DAVID: No, I agree, but not necessary if evolution is driven by survivability. per Darwin. that is what I question.

You are not discussing this with Darwin, you are discussing it with me. Once and for all: bacteria have survived, so NO further evolution was necessary for survivability. Multicellularity happened, and then there were new ways of exploiting the environment, new threats to survival, new means of surviving those threats…etc.

DAVID: As for the whales, the biologic complexities and challenges clearly deny your 'lala land' approach that they simply wandered into the water and changed.
dhw: I never said it was simple. But I find it more logical than the belief that a god changed them and then sent them into the water for no particular purpose, except to make them more complex, and then changed them again, and again, and again x 8, although his primary purpose was to create the human brain.
DAVID: More and more complexity led to the brain, the most complex object of all.

So how does that make it logical for your God to have designed and redesigned and re-redesigned pre-whales, although his primary aim was to produce the human brain?

dhw: Neither you nor I know where the borderline exists between adaptation and innovation.
DAVID: Innovation brings new species. Adaptation is finches beaks. Genetic studies show they are all one species.
dhw: Agreed. But when fins change to legs to allow a marine organism to walk on land, or legs change to fins to allow a land animal to live more easily in the water, the end product may be a different species, and then it’s difficult to draw the line between adaptation and innovation.
DAVID: Major phenotypic changes, as you describe, produces new species. that is the dividing line.

Phenotype simply means characteristics determined by genes or modified by the environment. Of course major changes produce new species. So if an organism moves from land to water, and its legs change into fins, enabling it to adapt and improve its lifestyle in the water, what is the dividing line between adaptation and innovation?