Explaining natural wonders (Animals)

by dhw, Saturday, March 26, 2016, 12:40 (1592 days ago) @ David Turell

DAVID: You are back to touting Darwinism itty-bitty variation to achieve fully species-hood. Yes, saltation fits.
dhw: We have no idea how any new species (broad sense) appeared. And I have no idea how you can say I am touting Darwinist itty-bitty variation when I have categorically agreed that only saltation fits. Natural selection does not mean itty-bitty innovations.

DAVID: You are correct in that the word 'saltation' is agreed upon, but my interpretation of saltation is different than yours. For me saltation is the arrival of a fully functional organism/ species with no need for natural selection to act. In Darwin-speak NS acts upon variations and chooses/judges which is best. Vast difference.

I'm not sure what you mean by “the arrival”. I would define a saltation as a sudden major change from one generation of an organism to the next. (Please give me your definition if different.) There may well be times when it is difficult to distinguish between a saltation and a variation, but if you believe in common descent, every saltation - just like every variation - must take place in an existing, functioning organism. Otherwise, the “arrival of a fully functional organism/species” is a separate creation. Natural selection, as you know perfectly well, is the process whereby organisms, saltations or variations survive or not, but as Darwin didn't believe in saltations, of course his natural selection only acted on variations! That doesn't change the meaning of natural selection. I agree with your view that the cuttlefish's camouflage required new functioning mechanisms which would have “arrived” suddenly (saltation), but that doesn't mean a new functioning camouflaged CUTTLEFISH “arrived” suddenly. The cuttlefish has certain features in common with other molluscs, like squid, which would seem to suggest common ancestry, and so somewhere along the line, up popped the camouflage mechanism (preprogrammed according to you, possibly invented according to me), and the lucky or intelligent pre-cuttlefish took on a new identity. However, all of this is speculation because, as we keep saying, nobody knows how speciation (broad sense) actually took place.

xxxxxxxxx

As I was checking the meaning of saltation to make sure my interpretation was correct, I came across the following, which surprised me:

Darwin's friend Thomas Henry Huxley, too, felt that evolution could be either gradual or saltatory. In his review of the Origin, he wrote that
Mr. Darwin's position might, we think, have been even stronger than it is if he had not embarrassed himself with the aphorism, "Natura non facit saltum," which turns up so often in his pages. We believe, as we have said above, that Nature does make jumps now and then, and a recognition of the fact is of no small importance in disposing of many minor objections to the doctrine of transmutation [i.e., Darwin's theory].

I hadn't realized that Darwin's commitment to gradualism was already under fire, even from his close friend Huxley!


Complete thread:

 RSS Feed of thread

powered by my little forum