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I heartily agree with your first paragraph. It is precisely the same logical fallacy as a "god of the gaps" argument that we need to watch out for here, but in

by wbhart 15y ago

I heartily agree with your first paragraph. It is precisely the same logical fallacy as a "god of the gaps" argument that we need to watch out for here, but in the guise of a "naturalistic theory of origins of the gaps" argument. We don't know how to explain something so we resort to our pet "explain all", rather than continue doing good science. On your second paragraph, I am not sure I agree. If evolution happened as posited by the "concensus" view then it happened over many, many generations. I don't think growing wings on a giraffe is possible in reproducible experiments that anyone could feasibly carry out. Also, are mutations always caused by environmental parameters? I guess radiation may be an example where they are. But I don't know if it has been established that they always are. Sometimes mutations seem to be encouraged by the very mechanisms of the cell itself, within certain parameters. So I would have to differ with you on your second statement. I think it is in general very hard to establish what the restrictions are on systems that evolve. In rapidly reproducing species, such as fruit flies or certain bacterial colonies it is much easier to test the boundaries, and in fact this has been done.

majmun 15y ago
apropos second paragraph , at this point i believe that there are more than one way to evolve some organism or many ways to do the same desired mutation. like for example grow wings on giraffe, for example if i just control environmental parameters it could maybe be possible, but nature does it in many ways. (like viruses that inject DNA and what not.) let us just take mutation by chromosomes (as in Down syndrom and others..), like chromosome deletion, insertion, and other known operations, i believe that by only this mechanism alone its enough power to change any part of DNA desired. (if artificially induced by controlling environmental parameters)but i may be wrong. what mechanism is most common and most likely to occur in evolution i would like to know.
- wbhart 15y ago
  Down Syndrome itself is the duplication of all or part of chromosome 21, usually due to improper separation of chromosome pairs during meiosis. I kind of think of this like going around a factory and turning up every 23rd valve. Gene duplication seems less severe. I agree it is not known how to make wings on a giraffe by manipulating the environment so as to control or "benefit" from gene duplication. Your attempts to study this in nature might be frustrated by the difficulty in identifying paralogs vs orthologs, the fact that gene duplications are often not preserved between generations and the fact that many gene duplications are deleterious. It's also the case that it is not yet fully understood how gene expression regulates the development and structure of body layouts. New body parts like wings are complex biological structures and do not usually just appear due to a change in genes. At least when I last left the debate conditions in the womb, fetal orientation, rna from the mother, "junk" dna and many other things were being examined for their role in the development of body layouts. As you are probably aware, research has been done that shows duplication and deletion of body parts due to genetic abnormality. But this is usually not a good way to make an organism survive. How many people missing a leg or who have an extra arm do you know of who find life easier? Anyhow, my point regarding the giraffes was merely that it is going to take very many generations of giraffes before anything at all happens. You and your great grandchildren will be long dead before then. In that sense I don't think it can be held against science that we haven't been able to demonstrate evolution of wings on a giraffe. I personally don't hold out much hope for it either. The changes that must occur in a giraffe for it to support wings as a viable organism may be so great that it is no longer anything like a giraffe any more. So the entire concept of wings on a giraffe might just be a natural impossibility.

by wbhart 15y ago

majmun 15y ago

apropos second paragraph , at this point i believe that there are more than one way to evolve some organism or many ways to do the same desired mutation. like for example grow wings on giraffe, for example if i just control environmental parameters it could maybe be possible, but nature does it in many ways. (like viruses that inject DNA and what not.) let us just take mutation by chromosomes (as in Down syndrom and others..), like chromosome deletion, insertion, and other known operations, i believe that by only this mechanism alone its enough power to change any part of DNA desired. (if artificially induced by controlling environmental parameters)but i may be wrong. what mechanism is most common and most likely to occur in evolution i would like to know.

wbhart 15y ago
Down Syndrome itself is the duplication of all or part of chromosome 21, usually due to improper separation of chromosome pairs during meiosis. I kind of think of this like going around a factory and turning up every 23rd valve. Gene duplication seems less severe. I agree it is not known how to make wings on a giraffe by manipulating the environment so as to control or "benefit" from gene duplication. Your attempts to study this in nature might be frustrated by the difficulty in identifying paralogs vs orthologs, the fact that gene duplications are often not preserved between generations and the fact that many gene duplications are deleterious. It's also the case that it is not yet fully understood how gene expression regulates the development and structure of body layouts. New body parts like wings are complex biological structures and do not usually just appear due to a change in genes. At least when I last left the debate conditions in the womb, fetal orientation, rna from the mother, "junk" dna and many other things were being examined for their role in the development of body layouts. As you are probably aware, research has been done that shows duplication and deletion of body parts due to genetic abnormality. But this is usually not a good way to make an organism survive. How many people missing a leg or who have an extra arm do you know of who find life easier? Anyhow, my point regarding the giraffes was merely that it is going to take very many generations of giraffes before anything at all happens. You and your great grandchildren will be long dead before then. In that sense I don't think it can be held against science that we haven't been able to demonstrate evolution of wings on a giraffe. I personally don't hold out much hope for it either. The changes that must occur in a giraffe for it to support wings as a viable organism may be so great that it is no longer anything like a giraffe any more. So the entire concept of wings on a giraffe might just be a natural impossibility.