Evolution, survival and adaptation (Evolution)

by dhw, Sunday, September 03, 2017, 14:12 (2419 days ago) @ David Turell

DAVID: This is why I question the significance of competition for survival as a major factor.
dhw: You questioned the concept of “survival of the fittest”. This is not just a matter of competition. Once again you seem to be equating survival with population density and totally ignoring every other environmental factor that threatens life.
DAVID: I don't think population density is an issue. It is something you seemed to mention and I questioned.

It was you who brought it up on the amoeba thread (see my post 31 August at 8.21 am), when you mistakenly assumed that survivability only entailed that one issue:
DAVID: We have no proof that survivability is a major issue due to population density, as you imply. Density is only an issue since WWII when we are displacing animal habitats.
Dhw: I do not imply population density at all! Where did you get that from?
DAVID: From your statement: " more and more new organisms came on the scene".
Dhw: "New organisms" refers to variety, not to population density. It’s a fact of evolution that more and more new organisms came on the scene once multicellularity had occurred, and I am suggesting that the variety entailed more and more new ways of surviving.

DAVID: Darwinists have math models regarding reproductivity as another issue. We've discussed Raup and environment causing extinctions. Survival of the fittest is a tautology.

It’s not a tautology (= saying the same thing twice) but it is a self-evident observation. That does not mean it plays no role, or only a small role, in the development of evolution.

dhw: We have had this discussion many times before, but it’s worth repeating since so much else depends on it. After much ado, you agreed some time ago that environmental factors play a major role in evolution. Minor adaptations clearly take place as a RESPONSE to environmental change. There is no visualizing of the future form, and no design planning in advance. You continue to ignore my question concerning the mechanism that makes this possible - i.e. do you think your God dabbled or preprogrammed the changes in the beaks of finches, or did their cell communities accomplish these autonomously?
DAVID: Not so. I have stated that finch beak changes are epigenetic adaptations, a mechanism given by God.

With my theist hat on, I am happy to accept that the mechanism for autonomous epigenetic changes may have been given by your God, i.e. that he may have given finches the autonomous means of adapting their beaks without being preprogrammed or dabbled with. So maybe he also gave pre-whales the autonomous means of adapting their legs.

dhw: We agree that innovation is far more complex, and that nobody can explain it. Where we do not agree is on the likeliest order of events. You have your God planning major adaptations (innovations) in advance of environmental change, whereas I have my organisms responding to environmental change.
DAVID: Environmental change is only one issue. There is no evidence that humans left trees because of major climate changes. Preparatory anatomic changes for bipedalism started 23 million years ago!

But it IS an issue, even if it is not the ONLY issue. You say later: “Whales entering water is an environmental change for them, but not an environmental change for the Earth.” Who says that species change can only happen if the whole Earth changes? Maybe both pre-whales and pre-humans started off in local areas where it became advantageous to enter the water or to descend from the trees. Convergent evolution suggests that local changes can lead to similar solutions in other areas. And a successful new species can spread.

dhw: Your version requires your God’s advance knowledge of every environmental change that entails innovation, which suggests that he has preprogrammed or manipulated the environment (local and global) as well as the structures of all the creatures that survive the changes. (We’d better leave out the great non sequitur of all this being done for the sake of the human brain!) The complications are enormous, whereas the scenario of life forms RESPONDING to environmental change, either by dying or by adapting or by producing useful new organs to exploit the changes requires only one premise: that they do the designing themselves with an intelligence which your God may have given them in the first place. We know they respond on a minor scale. Perhaps they also respond on a major scale. It’s a hypothesis, but Occam would be delighted with such a simple solution to the mystery.

DAVID: All I can say to this mishmash is that Occam did not accept simplicity beyond all recognition. As for the brain, it evolved, a process you accept. All in a scramble to deny God.

There is no scramble to deny God, since my hypothesis allows for God. Of course I accept that the brain evolved, as did every other organ we can think of, and since I accept that the human brain is a very special instrument, I can even allow for your God doing a dabble. But divine preprogramming or dabbling of the whole history of evolution, including by implication the history of the environment, seems to me to take complexity beyond all reason, especially when there is a simple explanation which – as you have repeatedly acknowledged – fits in perfectly with the history of life.