IC,
I really hope you stick around and try to at least understand what is being said here. You really have got to understand how insulting it is for those of us who have dedicated our lives to evolutionary theory to have someone wave it all away as lies or ignorance. Especially from people who haven't yet demonstrated any deeper understanding of what they so flippantly dismiss.
Think of it this way... I say I don't believe the Bible because I don't believe that Zeus could turn into a swan. If I made that statement in a Christian debate forum, it would be laughable right? I would be trying to dismiss a concept that I clearly do not understand. To show me how I am wrong would require you (the Christian) to catch me up on my knowledge even before debate could begin. Many, if not most, creationists that come to EvC making equally ridiculous statements regarding biology.
Now onto your topic. For me the best examples of evolution can be seen in the imperfect, flawed design of the human body. Specifically those that exist because of ancestry. One of my favorites is the notochord. The notochord is a cartilaginous rod that runs down the back of primitive chordates. It is also found in the early larvae of the rest of the chordates and their relatives.
In vertebrates the notochord develops early in the embryo then is absorbed. In primitive chordates the notochord serves as support for the body, a function lost in vertebrates as the skeletal system serves this function. Sometimes in vertebrates, even in humans, the notochord does not completely absorb. When this happens it is usually fatal to the embryo. When non-fatal the result is severe birth defects usually involving brain and spinal development.
My point here is that the notochord is a vestige from early chordate evolution. It is true that the notochord triggers body alignment, somite (segment formation), and neural development (It has been years, but I think it triggers the Sonic Hedgehog, SHH cascade). However, these functions are carried out by other structures as well.
What is important is that the function of the notochord does not neccesitate the growth and development of the full notochord. That is, this complicated structure develops, creates a few proteins (most redundant), then goes away. It simply just does not make sense as design but makes perfect sense given the evolutionary history of vertebrates. Evolution works on the raw material on hand. So from an evolutionary view it is 'easier' build a structure already in the genome and then dismantle it than it would to develop unique structures for a particular function.
Doctor Bashir: "Of all the stories you told me, which were true and which weren't?"
Elim Garak: "My dear Doctor, they're all true"
Doctor Bashir: "Even the lies?"
Elim Garak: "Especially the lies"
) but seastars, like all good deuterostomes (echinoderms, chordates, and a few others) have a complete digestive system with a mouth on the oral surface and an anus on the aboral surface.
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