Categories or Degrees of Existence (Agnosticism)

by George Jelliss , Crewe, Thursday, August 05, 2010, 23:10 (5223 days ago) @ David Turell

I think the "gradualist Darwinian" answer to these abilities of the guppies and sticklebacks is that they have evolved these strategies by the usual gradual processes. Another example might be the way some plants conform to a cycle of a prime number of years to escape predation by insects that have another cycle.-The webpage linked to by DT states (my emboldening):
"Our study is the first to experimentally show that certain species in the wild could adapt to climate change very rapidly ... in this case, colder water temperature. However, this rapid adaptation is not achieved without a cost. Only rare individuals that possess the ability to tolerate rapid changes in temperature survive, and the number of survivors may not be large enough to sustain the population. It is crucial that knowledge of evolutionary processes is incorporated into conservation and management policy." So they are only able to adapt so quickly because the ability has already been evolved and there is sufficient of it in the population.-Concerning the Cambrian "Explosion" I've been looking at some evolutionary sites about this subject, and it wasn't so sudden or inexplicable as DT tries to suggest.-http://www.fossilmuseum.net/Paleobiology/CambrianExplosion.htm-"It is important to remember that geological history contains numerous periods of slow evolution punctuated by periods of rapid evolution, which Steven J. Gould called Punctuated Equilibrium. The rates of evolution generally depend on rates of selection, which in turn depend on rates of environmental change. It also depends upon the existing genomic diversity on which selection acts. Mutation rates tend to be slow and steady, and in the absence of environmental change, slowly accumulate in a population. It is selective pressure that weeds out the mutations that are detrimental or neutral to survival, and retains and multiplies the mutations that are beneficial within a population. For a population isolated in a new environment, rapid selection can lead to speciation, and in the Lower Cambrian, to radically new forms that we now group in the Phyla of modern times." Thus Gould's ideas do not contradict Darwin's gradualism. It's not a question of jumps but of speed.-
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_02.html-"Internal, genetic factors were also crucial. Recent research suggests that the period prior to the Cambrian explosion saw the gradual evolution of a "genetic tool kit" of genes that govern developmental processes. Once assembled, this genetic tool kit enabled an unprecedented period of evolutionary experimentation -- and competition. Many forms seen in the fossil record of the Cambrian disappeared without trace. Once the body plans that proved most successful came to dominate the biosphere, evolution never had such a free hand again, and evolutionary change was limited to relatively minor tinkering with the body plans that already existed." I suppose this idea of the evolution of a "genetic tool kit" could be what DT calls pre-loading or design, but it doesn't contradict evolution.

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GPJ