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Well... Pardon me for thinking that you were using AIDS as evidence for evolution. Perhaps you should not have mentioned AIDS.
But we'll move on. If I was mistaken I am sorry."
No need to apologize, mistakes happen. AIDS was only mentioned to say that we have intensely studied retroviruses as support for the assertion that we have enough observationsal evidence to know that the insertions are random.
I'd also prefer not to move on. There is still an outstanding question on these inserts. We still do not know how to string all of the necessary steps together to get these observations in a recently and independently created kinds scenario.
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Here is a very interesting article from a creationist site on Homology. I think you will enjoy it, although I am certain you will disagree."
It is interesting, but it is also incomplete. It, one, leaves out the details which make the areguments much more powerful in reality than the strawman versions that he presents. Second, it tries to divide the many independent lines of evidence in an attempt to raise doubt in a single one when it would be much more difficult to deal with the congruence you get when comparing many different lines of evidence. There is also the curious mixing of quotes from scientists and YEers in a way in which the reader could be confused as to the position of the person who was quoted.
One of the first bits that he attempts to deal with is the homology of the tetropod forelimbs. He claims that these structures are only considered to be homologous because of a prior assumption of evolution to begin with. But he ignores the vast evidence that shows that these creatures are actually related through common descent.
He claims that the forelimbs of the horses, whales, humans and birds "serve similar functions and have similar design constraints." I must question his logic at this point. I do not understand how he can say that an arm, a leg, a wing and a flipper all have similar function.
But he claims that they do without explanation. The logical question that pops out from this is as follows. Surely one would agree that the function and design constraints when comparing the flippers of a whale and those of a shark would be much closer that that of a whale flipper to an arm or a leg. So, if he wants to call upon common design, why are these structures not of the same design for whales and for sharks?
There could be many other such examples where a common designer is arbitrarily postulated to explain homology but then not applied in cases where it would seem to be even more logical.
He also glosses over the details in his comparison of the Tasmanian Tiger to canines. This is a very good example of convergent evolution. There are really many excellent examples of such. But the appearance is only superficial. A layman examining the two might have really had a difficult time in telling them apart. But if you were to take someone skilled in morphology, that would have no difficulty at all pointing out the great differences in the details.
He also confuses the term "vestigal." It really only means that it had a different function in the past, not that it is useless. That is key. For instance, some whales have a vestigal pelvis. It is used for the attachment of some minor muscles, but it is much too complex of a part to have been designed for such a simple task. Instead, it has lost its original function and yet remains in a new, reduced role.
If you want something that is useless, look at your own skin. Go outside tonight and watch the goosebumps pop up. This does you no good. But for your harrier ancestors, this was a means to prop up the hairs to provide additional warmth. It is also useful in dangerous situation to make the animal appear larger.
But in humans, it does not good. We do not have enough hair to get an benefit of warmth or increased size from the goose bump reflex. It is vestigal.
He then skim over some embryology items. He trys to make hay over the fact that the same body part may emerge from different segments in different organisms. Once again, he simplifies the subject too much, making a strawman. Such development is controlled by hox genes. Some code for the development of segments. It is others that code for the location of particular parts. For instance, there is a famil of genes called tinman that tells a wide variety of organisms where to make a heart. Not how, but where. These genes are separate from the body segment genes. There is an analagous family of genes that tell where to put limbs. So he has here knocked down a strawman.
He also trys to make some hay by claiming that the kidney devlopes from different tissues in fish and amphibians than in birds, reptiles and mammals. This is fallacious in that he is equating what are actually different organs and ignoring that birds, reptiles and mammals make and use the structure called a "kidney" in the fish before going on and making what they use as a kidney. It is hard for me to explain better, but here is an in depth description.
http://www.uoguelph.ca/zoology/devobio/210labs/meso3.html
If you read it, you should see that it can actually be considered further evidence for evolution becuase of ontogeny.
He then goes on to biochemical homologies. Again, he ignores the very details that would weaken his case. One example would be the silent mutations that have been mentioned before.
It was an interesting read, but again it was mainly built on attacking straman version of the evidence instead of the real evidence. It is easy to try and convince others that the simple kinds of comparisons which he assertes are the basis for the homology logic. And if things really were that simple, he might have a point. But they are not. They are much more complex and it is these details which undermine the argument he tries to make.
