Posted by GaDS on August 26, 1998 at 03:41:35:
In Reply to: Some agreement posted by Joe Meert on August 22, 1998 at 12:59:43:
: For example, there is a small group of fundamentalist
: Christians who assume such absurdities as a 6000 year old earth, a global
: flood and that evolution does not occur...We all know how evolution works...
:
: Cheers
: Joe Meert
Do we know how evolution works? We have seen domestication of animals, and we have seen the development of many varieties of animals and plants based upon what has been of benefit to the human race, but I don't recall ever hearing of humans being able to create something that could be considered a new species. By definition a new species would be one that is reproductively viable with other members of its own species, but not with any other species. It's true that there are some animals that can interbreed (such as tigers and lions) and produce fertile offspring, but they rarely if ever do so in nature and are considered separate species nonetheless. But I have yet to see humans make a dog into a cat, or a salamander into a frog, or a seal into a porpoise.
I don't doubt that animals can speciate to the extent that morphologically they suited to their niche in the environment. But the general idea of evolution progressing from proto-bacteria to humans seems a bit much to take. The entire idea of evolution is that those better suited to survival through genetic variation will tend to dominate in the gene pool as successive generations arise. The catch to all this is that 1) the variation must confer a significant advantage upon the individual, 2) it must be a dominant feature, 3) it must occur often enough to persist in the population, and 4) it must not be so drastic that the individual is rejected by the population. The famous example given in evolutionary biology is that of the giraffe. Those with longer necks and legs would be able to forage for food unavailable to most of the others. But how much longer would the neck and legs have to be to confer a "distinct advantage"? I don't think that anything less than a couple extra feet would give them enough of an advantage over the other giraffes, and yet how often does an individual of this size actually appear?. To the best of my knowledge, the average height of giraffes hasn't really changed much. Also, by foraging in territory exclusive to them, would that not leave more for the remaining members of the herd, consequently defusing some of the "struggle for survival" so often spoken of. Then, too, study has shown that too extreme a deviation from the physical norm is selected against during mating, even among humans - those people considered most physically attractive are actually closest to a phenotypic average of the population. In many animals the mating instinct is very finely-tuned: an incorrect step in the courtship dance, the wrong plumage, or an incorrect note in the mating call will leave a prospective suitor high and dry. This doesn't even consider the difficulties in the mechanics of mating if an individual is too large or small compared to the average - I haven't seen many chihuahua and Great Dane match-ups without artificial intervention.
For more specialized adaptations, the argument is even stronger. How, for example, does a complex eye evolve through the mechanism of natural selection? The development and specialization of the various tissues, the interworkings of all the parts, and development of behavior and neural support mechanisms that allow it to function could not have happened independently. Unless ALL the parts are in place and function correctly, there is no advantage to maintaining them. It would be like saying that a functioning watch could be designed with just one gear. Such a watch would be useless, and if we followed the wokrings of natural selection the design would not sell. Consequently, there would be no income to proceed to the development of a two-gear watch, and so forth until a fully functioning watch had been put together. Many such structures and organs are so tightly interconnected with others to function that the idea of gradual mutation is inadequate to explaing them. On the other hand, the idea that myriad structures arising simultaneously through spontaneious genetic mutation is preposterous. As well say that the next 9.0 earthquake in California will rearrange rubble into high-rise, and not the other way around.
So, DO we know how evolution works?
GaDS
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