(April 13, 2009 at 7:55 am)Giff Wrote: Evolutiuion is very expermintal. Sometimes it's good for some species to be very primitive and brutal like the Mantis which is one of the earths most advance creature and the best constructed predator.
I wouldn't say it was "experimental" because that implies a sort of testing/design type concept ... there are various mechanisms required for evolution to occur and to continue occurring. Mechanisms that increase genetic diversity (Natural Selection, Sexual Selection & Genetic Drift) and mechanisms that decrease it (Mutation, Recombination & Gene Flow):
Quote:Natural Selection (Decrease)
Natural selection (see Biston betularia example above) is considered to be the mechanism by which a given organism type within a population have more offspring than others. Less fit animals get killed or simply have no offspring. "Fitness" should not be confused with the common human notion of physical fitness ... "fitness" means adaptation to a given environment. It is also worth noting that individuals amongst a population have a tendency to self-select either by sex or by other factors.
Sexual Selection (Decrease)
Many species (including humans) "choose" their mates and various mechanisms have evolved to use this selective pressure. Sexual selection tends to be self-limiting ... in some species the male can be seen to attract the female by impressive display (e.g. the peacock) but, negatively, that display also decreases the chance of the animals survival. In such cases evolution balances between increased attraction (and thus reproduction) and vulnerability to predators (death).
Genetic Drift (Decrease)
Genetic drift is the change in allele frequency due to chance alone and is a "binomial sampling error of the gene pool". In smaller populations the rate of allele change is greater whereas larger ones have more alleles in the gene pool but lose them more slowly. When a population decreases rapidly in size the remaining alleles may not be representative of the species as a whole and significant genetic drift can be seen to have occurred ... this is known as the "founder effect".
Mutation (Increase)
During the DNA copying process mistakes can be made. A single genetic "letter" might be changed a sequence of code added or deleted or genes can become inverted. The rate of mutation is between 10*10^-10 and 10*10^-12 to 1 per base pair/per generation. Most of these are non-advantageous leading to changes in the shapes of proteins (potentially destroying its function) but some (very few) are potentially advantageous. The ratio of advantageous to disadvantageous change is unknown and likely varies with respect to the organism's environment.
Recombination (Increase)
Recombination ("gene shuffling") occurs during meiosis and creates new combinations of alleles.
Gene Flow (Increase)
Gene flow is the introduction of new genes into a gene pool for instance the addition of a mate from one population into another non-related one.
All of these are non-intelligent so whilst I think I understand what you are getting at I wouldn't call evolution "experimental".
Kyu
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Where those who are hacked off with the stupidity of irrational belief can vent their feelings!
Come over to the dark side, we have cookies!
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