Evolution: a different view (Introduction)

by dhw, Wednesday, May 06, 2015, 21:23 (3488 days ago) @ David Turell

dhw: ...and an experiment proving that organisms might be able to eat foods never before encountered - an ability which you say is “existing, but not used at all until a need arose”. In this case, the organism's existing digestive mechanism could clearly adapt, so are you saying it never used its digestive system before?-DAVID: Of course it had a digestive system, just using different enzymes in a different way than it now needed and adapted. -And this is the point I am trying to make. All the examples you have mentioned are of features which were already in use but changed their function, in contrast to your claim that they hung around for (hundreds of) thousands of years doing nothing.-dhw: It seems to me that there is enormous confusion, your two types involve innovation and adaptation, and both fit in just as well with an autonomous inventive mechanism as they do with pre-planning. 
DAVID: You are right about confusion. There are articles which are currently trying to explain the differences in types of exaptation. Some of them afraid of the pre-planning aspect.-Can you please point me to just one writer who interprets exaptations in terms of God's pre-planning?
 
DAVID: There is no logical reason for the change in larynx, palate and uvula requiring an epiglottis to protect from aspiration. A lot of mechanical change but no intelligible speech it is thought until the last 100,000 years. Lucy at 2.3 million years ago didn't have these changes. They all happened well before speech.
-What is “intelligible speech”? Intelligible to whom? If you define language in terms of English, French and German, with complex syntax and a vast variety of structures, then of course it's a modern phenomenon. But if you define language as signs, sounds, movements etc. used as means of communication, your whole theory becomes highly problematical. All living creatures have language, right down to bacteria, and you have no idea what sort of sounds were used for communication when the changes took place in the larynx, palate and uvula. But I'll bet you the organisms that experienced those changes continued to communicate, using new sounds, and didn't go dumb for (hundreds of) thousands of years.-In your first book, you wrote: “The human larynx is lower than the Neanderthals' was, allowing humans a much better articulation of speech.....language is not thought to have appeared based on “the behavioural record” until one of our most recent ancestors arrived on the scene.” Since you wrote that book, you have alerted us to many recent discoveries of evidence that Neanderthals used relatively sophisticated tools, buried their dead, built dwellings and boats, cooked their food, hunted, and may well have had their own form of speech. You are, of course, covered by “much better articulation”, but "is not thought to have appeared" raises plenty of questions. My point here is that whenever the changes took place, we simply have no idea whether they were or were not used to create more complex sounds to allow greater breadth of communication. Once again, I don't see how you can asssume they hung around doing nothing for (hundreds of) thousands of years.-You have quoted Gould, who sums up the problem: “I cannot present a ‘review article' of empirical cases of exaptation, for the defining notion of quirky functional shift might almost be equated with evolutionary change itself, or at least with the broad and venerable subject of, in textbook parlance, ‘the origin of evolutionary novelties'” (Gould, 2002, p. 1234).-Just where do you draw the line between adaptation, exaptation, and innovation? In fact, is there a line? Once again, I would suggest that they all come under the umbrella of an autonomous inventive mechanism, which enables organisms to adjust themselves in order to cope with new conditions (adaptation), to use existing organisms for new functions (exaptation), and to create new organs in order to exploit new opportunities offered by new conditions (innovation). The borderlines between these three categories must inevitably remain blurred.