Miscellany (General)

by dhw, Sunday, January 10, 2021, 09:31 (584 days ago) @ David Turell

Cambrian Explosion

dhw: The crucial point was your statement that the new finds show that “there certainly isn’t an abrupt dividing line in evolution”. This removes the great question mark over the Cambrian’s sudden explosion of entirely new species. If there were precursors, 55 million years seems to me to be ample time for further speciation, especially if we embrace the concept of cellular intelligence responding to new conditions and opportunities.

DAVID: The real gap is the new advanced complexities appearing in the Cambrian suddenly.

dhw: I don’t know why you have added “suddenly” when you agree that there is no “abrupt dividing line in evolution”, and you have ignored my point that 55 million years does not constitute “suddenly”, especially if...see above.

DAVID: The 'suddenly' applies in the Cambrian in terms of complexity. After the initial slope, the next animals are enormously complex compared to the few fossils on the slope.

Agreed, but my point is that 55 million years is a long time, especially if we embrace the concept of cellular intelligence responding to new conditions and opportunities.


dhw: I really don’t know why a bang in the centre of the Milky Way 15-20 million years ago “makes us agree that God knows what he is doing”, or what it has to do with creation, since life goes back thousands of millions of years.[…]

DAVID: God does what God does. We usually figure out why after more research.

dhw: If God exists, no one will argue with your first sentence. Your second is on a par with Dawkins: “...if there is something that appears to lie beyond the natural world as it is now imperfectly understood, we hope eventually to understand it and embrace it within the natural.” (The God Delusion, p. 14). You simply hope to embrace it within the divine. And both of you regard yourselves as scientists!

DAVID: You are ignoring the history of science. After time we usually figure it out. Here I know Dawkins is correct.

There is a huge difference between a prophecy and a belief! And there is an equally huge difference between “eventually science will figure it out” and “eventually science will confirm my belief that there is/isn’t a God”. Both of you claim that science is already the basis of your diametrically opposed conclusions! In your case, you also prophesy that science will vindicate your theory concerning how and why your God created life. You and Dawkins can both believe what you like, but your respective utterances of faith have nothing to do with science.


QUOTE: "The rate of their evolution is generally slow, but occasionally they evolve more quickly because the environment has changed. In particular, this new research suggests that their evolution speeds up when the climate is warmer, and that their body size increases.”

dhw: Although this is adaptation and not speciation, it emphasizes the crucial link between cellular change and current conditions. The body size increases in response to the warmer climate – not in anticipation of it!

You have not commented on the important point that structural change takes place in response to environmental change and not in advance of it.

DAVID: It shows not all species are driven to change. Hominins changed and the environmental evidence is not strong as a reason to arrive at us.

dhw: When conditions change, some species survive intact, some adapt, some die out, and some change into new species. Nobody knows for sure, but there is no reason to suppose that this general pattern did not apply to hominins and humans.

DAVID: It doesn't explain our unusual brains, and you know it.

Sorry, but I think it does, and our long discussion on “brain expansion” covered all aspects of this explanation, which I’m reluctant to go through again. But nobody “knows” how speciation or brain expansion occurred – we can only theorize.

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