Just read an interesting article, Dr. Olivia Judson, Biologist and columnist for the NY Times, wrote a column called "The Repeater". I recommend her work to anyone! Not only well thought out, but entertaining as well -- something you cannot always say about science columns, articles, and books. In fact her book "“Dr. Tatiana’s Sex Advice to All Creation: The Definitive Guide to the Evolutionary Biology of Sex,” is unbelievably creative!
But back to this article. What is discusses is the evolutionary differences between a species of fish that was trapped in isolated lakes by the retreating glaciers. The differences between the fish are pretty spectacular. My take is that this article shows that there are more forces than just mutation going on in Evolution. When a Creationist/Intelligent Design supporter whines about the odds of evolution, random mutation and chance, or similar comment, they fails to realize that many of the evolutionary changes we have seen are not all the result of mutation, but simply in how a specific gene is expressed. This means that the odds, for those who are trying to calculate, or life evolving are even lower than you think because many of the changes you calculated as mutations are in fact already built-in functions of the existing gene. Differing environmental factors cause the gene to be expressed in different ways. You really need to read the article!
What the article also does is support common ancestry. By examining the genes across species, Dr. Judson discusses how the same gene does some of the same work in multiple species. Until genetics this wasn't recognized as common because we didn't know the mechanism. But when the same gene is found in human beings and stickleback fish, and in each one the gene is part of the system to regulate skin pigment. Sure doe make one think!
Thanks to the Dr. J of Biology!
Thursday, January 31, 2008
More on the Odds argument
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Ted, assuming for the moment that "the same gene does some of the same work in multiple species," and that in each one "the gene is part of the system to regulate skin pigment," we may ask the following questions:
ReplyDelete. Why is this so only in SOME species? Other species had a different "common descent"?
. To give a very simplistic example, which I hope you will excuse, we do not say cars evolved from one other because they have common characteristics (if they were living entities I am sure many scientists would say they did evolve from each other). Rather, we are aware that these are the elements which their makers want them to have: four wheels, horn, doors, windows, etc.
You would need to explain further why you are led to think that the explanation of common characteristics (when they exist) forces upon the intellectual mind the inevitable conclusion of "common descent"
The fact that the same gene exists in some species to me is an indicator of common ancestry. Let me ask you why does it have to exist in all? Is the only way you could accept common ancestry is if every gene was mapped to each and every other species?
ReplyDeleteIn another one of Dr. J's columns it discusses some experiments in which cells from one species of trout were injected into a species of salmon. (Spawning something different, http://judson.blogs.nytimes.com/2008/01/01/spawning-something-fishy/)
"the transplanted trout cells obey the instructions they get from the salmon body they’ve moved into". Read the article and all I can say is WOW! Two difference species obviously share more than previously realized. of course " . . . the genes inside them are still trout genes. Which means that when the salmon spawned, they produced trout . . ." Again it does make one thinks the relationship, despite several million years of separate evolution, had to come from somewhere.
Change is still happening all the time, an answer doesn't have to be absolute to indicate support of common descent. We have done a lot of gene research, but there is still much to be done.
Cars is a pretty simplistic example, but look past common characteristics, look at one item in a car. If one 'species' of car had an Edlebrock engine and another species of car also had the same engine, wouldn't a relationship be considered a possibility? Would all cars have to have the same engine before you see any relationship?
The same gene, doing the same function certainly makes me look past common characteristics. I don't say it forces anyone, but I certainly is an interesting indicator and should make anyone think!
You do raise interesting questions, does the same gene exist in more species? Is it there doing the same work -- or has it evolved to carry out a different function? Is there some other gene carrying out a similar function in other species? I don't know the answers, but I know scientists are working on them, and I am certainly an interested party!