Chixculub: may not be the whole story (Introduction)

by David Turell , Monday, December 17, 2018, 16:06 (2167 days ago) @ dhw

DAVID: This article could not be more exact in its notation of how important ecosystems (econiches) are and how their imbalance leads to extinctions, and also how important are extinctions which allow new species to appear, while we still have no idea how speciation happens.

dhw: Of course econiches and systems are important, and of course imbalance leads to them ending. And that makes it all the more illogical that your God should specially design each one – not, according to you, to “allow new species to appear”, but simply to provide food, then different food, then more different food, until he could specially design H. sapiens which, according to you, he could have done directly anyway since he has full control. (See "Divine purposes and methods".)

DAVID: The flip side is that it is not every day survival that is important for evolution to happen but extinctions, which result in tremendous changes and challenges. And not all extinctions have to be as dramatic as Chixculub, but can be quite local. There is no evidence that the old theory that species competition drives evolution has any basis.

dhw: Dead species do not produce anything, and we have dealt with "competition" already. It is environmental changes, global or local, that present the challenges to which organisms must respond. Most fail, but the survivors adapt, and I propose that in some cases the new conditions will allow organisms also to invent. I’m delighted that you now acknowledge that these conditions and changes may also be local. Hence the proposal that pre-humans may have taken to ground life in one location while their fellow primates stayed in the trees elsewhere; pre-whales may have entered the water because local conditions meant go fishing or die. Changing conditions mean that organisms must change if they are to SURVIVE. It is therefore patently absurd to argue that survivability has played little or no role in evolutionary change.

You are again ignoring the point of why complexity appears. Of course surviving species produce new more complex ones, but we have no idea why life advanced beyond bacteria which have always been here since the start of life. Why did multicellularity start? It required the addition of many complex changes. Something or someone must drive the complexity, which, if survivability is the reason, the bacteria show it is not necessary. As for pre-whales, they could just as well migrated to better grounds just as you have human leaving the trees because hey needed to. I look at survival as a speciation cause as a non-starter.