I would disagree that this behavior promotes zero=20 fitness in all cases. If a sibling has kids,=20 then the childless individual has some level of=20 inclusive fitness. I agree that this would be=20 rare if it caused a loss in fitness, but, aren't=20 there examples of animals/plants/microbes that=20 suffer reduced fecundity due to intraspecific=20 competition? Isn't this behavior in humans=20 related to this in a sense? True, it's much more=20 complex because childlessness is a "conscious=20 choice" (whatever that means) rather than a=20 reduction in fecundity due directly to reduction=20 in resources, disease, or other identifiable cause? Just a thought.
Liane At 08:09 PM 11/28/2007, Lonnie Aarssen wrote: >For a biologist, it is a remarkable thing to find a behavior that promotes >zero fitness. If it were an isolated example, it could easily be dismissed >as a maladaptive oddity, destined always to remain rare =AD as it is in all >wild species =AD because of its intense disfavor under natural selection. *************************** D. Liane Cochran-Stafira, Ph.D. Associate Professor Department of Biological Sciences Saint Xavier University 3700 West 103rd Street Chicago, Illinois 60655 phone: 773-298-3514 fax: 773-298-3536 email: [EMAIL PROTECTED] http://faculty.sxu.edu/~cochran/
