Evolution: a different view (Introduction)

by David Turell , Tuesday, May 05, 2015, 00:15 (3490 days ago) @ dhw


> 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?-Of course it had a digestive system, just using different enzymes in a different way than it now needed and adapted. than it now
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> dhw: I have a problem with your concept of uselessness. Even now there is a huge kerfuffle over “junk” DNA, which suddenly scientists are finding serves a useful purpose. How does anyone know that the features which changed their function were useless before? The examples mentioned - feathers, fins and limbs, the lowered uvula, digestion - do not relate to anything originally useless.-Not uvula, but larynx. The larynx descended the uvula ascended, all many thousands of years before any use was found for them. Tattersall makes this point strongly as does McCrone. And why create the choking problem which can kill?
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> 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. -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.-> dhw: Perhaps if you can explain to me how you know Lucy did not use her lowered uvula to make sounds intelligible to her peers, and how you know that whatever examples you can think of were useless (hundreds of) thousands of years before they became useful, it would help. -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.