Theory for Dramatic Evolutionary Change
Dramatic changes in a species evolutionary chain are possible through the relaxing of environmental pressures on a species. A period of relaxed pressures (ex. increased availability of food, reduced predators, improved climate) allow a population to increase in size and genetic variation. When environmental pressures return to a higher level the population will quickly decline. The decline will reduce the number of genetic variants and allow new variants to dominate the reduced population. Older genetic variants will no longer be suitable and will be eliminated. This change creates what appears to be a dramatic change in the species evolution.
Posted by Jeff at January 1, 2004 11:12 AM