bch@unc.UUCP (10/19/83)
So...Creation Scientists maintain that evolution has never been observed. If I remember correctly, the process of evolution is not some unitary driving unintelligent force, but the product of at least three different phenomenon: (1) Natural selection (survival of the fittest): simply put -- in a competetive environment the species most well adapted to that environment survive, most likely at the expense of species less well adapted. The most obvious example of this is the human being. The species has not only adapted to its environment, but gone one step further and has begun adapting the environment to itself! For an example of species failing to compete, see any list of extinct or endangered species. (2) Random mutation: While this doesn't happen to complex critters in ways that are generally observable, it does happen to viruses and bacteria all the time. Some biologist correct me if I'm wrong, but I believe that Swine Flu virus that caused such a panic in the medical industry in 1976 was a mutated form of the swine flu virus responsible for the pandemic of 1918. There is a marvelous book called "Rats, Lice, and History" which describes developments in human history as a result of a genetic shift in the Typhus bacteria from Biblical times until today. The more complex the critter, the longer it takes to show up, but the evidence is there. (3) Genetic Drift: See the newspapers of two weeks ago for the Nobel Prize for observations of this exact phenomenon. Hybridization of plants -- a naturally occurring phenomenon -- has been observed and studied for centuries and is the basis for most of modern agriculture. Have I left anything out? Byron Howes UNC - Chapel Hill decvax!duke!unc!bch
nazgul@apollo.UUCP (Kee Hinckley) (10/25/83)
*
For that matter, anyone who doesn't believe in evolution should take a
look at the effect of pesticides on insects. Funny how they don't work
very well, the insects keep adapting from one generation to the next.
-keecrm@duke.UUCP (11/01/83)
Would someone enlighten me on the difference between "classic Modern Synthesis Evolution" and "natural selection" which is not evolution? It seems to me that if changes in characteristics are seem which a) are inherited and b) are causing those possessing the characteristic to occupy a growing proportion or the population, thereby indicating that this characteristic results in a higher probability of survival, that this demonstrates the natural selection which is claimed as the central factor in evolution.
eich@uiuccsb.UUCP (11/08/83)
#R:duke:-369600:uiuccsb:11900007:000:1520 uiuccsb!eich Nov 4 21:22:00 1983 I didn't say natural selection is not evolution, just that it is not nearly the whole story. I think I meant by `natural selection' something narrower than what you mean. Most texts I have read treat the issue of what genotypes the survival criterion selects separately from the selection itself. Thus natural selection acting on primordial organisms doesn't account for new species. For that you need (and the Modern synthesis posits) mutations. So part of the synthesis is the observation that mutagens and ionizing radiation create a background of `spontaneous' mutations, and the postulate that enough of these over a long period result in beneficial changes (beneficial by the survival of the fittest criterion) sufficient to produce a new species. Microbiology supports this by finding an evolutionary history in genetic material (`Ontogeny recapitulates Phylogeny' in miniature). On the other hand the Modern Synthesis is under quiet attack right now from biologists like Stephen Gould, partly because steady, slow progress by random mutation isn't too well supported, especially by (not to give Creationists comfort, but I must say it) the fossil record. Gould holds that evolution is a saltational process, occuring disjuctively in a fury of mutation and selection between the epochs. But the point I was making is that all of this evolution controversy in biology deals with more than natural selection: namely, where does the great variety of life come from, granted that it obviously was selected?