In reply to Horace Heffner's message of Sun, 24 May 2009 01:03:41 -0800: Hi, [snip] >The distinguishing characteristic is the inability to mate with >the parents, or at least with some of the animals the parents can >mate with, which can be due to a genetic characteristic that does not >manifest in a visible way.
Agreed this is the definition of species. >In any case I don't think speciation >occurs in a single birth, but rather as a gradual migration of >combined traits through a population. Speciation often occurs due to >the geographical separation of populations of a single species. If a >single birth occurred of an animal unable to mate with any others, >then that new species would have no future because it would need >others of its kind with which to mate. This appears to lead to a problem with regard to the definition of species. In short how can any new species exist if it can't mate, and if it can mate, then it is not a new species. We seem to have a paradox. IOW you are suggesting that small populations speciate as a whole, rather than individuals. This would appear to be possible with regard to characteristics that do not influence the ability to produce fertile offspring, however that then is no longer the definition of a new species. The only natural solution I can think of is that a new species is created when a genetic mutation occurs in all the offspring of a single individual, and those offspring mate with one another. The only alternatives I can think of are "unnatural", i.e. genetic manipulation, or the same mutation occurring at the same time in different individuals, that then produce offspring that can mate. The latter would however appear to be far less likely than mating between offspring from the same parent. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/Project.html
