Dr. Capellini, individual selection is what I learned in my genetics class several decades ago, but I have since been exposed to a concept that says group selection may also occur (I understand it's now called multilevel selection theory). As a non-academic-feet-in-the-mud field ecologist, I have a hard time understanding the evolution of some behaviors and traits without calling on group selection as the process at work. Perhaps those more learned on the topic, such as yourself, have individual selection explanations for such things as the evolution of non-reciprocal altruism and kin groups.
One example that comes to mind is the adoption of orphaned elephant calves by other herd females -- certainly at a cost for the adopters including a possible reduction in survival for their own individual alleles. The only explanation seems to be that survival of the orphaned calf means, since the calf is closely related, that there is an overall improvement in survival of group alleles. Or maybe I really am just another naïve naturalist with a shallow understanding of evolution. Warren Aney -----Original Message----- From: Ecological Society of America: grants, jobs, news [mailto:[EMAIL PROTECTED] Behalf Of isab972 Sent: Tuesday, 14 February, 2006 12:49 To: [email protected] Subject: Re: current natural selection pressures Dear Warren, Your reasoning on selection is almost correct but there is one important flow: natural selection does not act on clans or groups but only on individuals. Group selection indeed does not work in nature. In very few cases, there might be traits selected under kin-selection, but very very few. You talked about helping the others and cooperative behaviours. Under the word "cooperation" there are many different behaviours and in many cases the individual advantage is what drives the evolution of "cooperative behaviours", not group selection. A simple example: you have an antipredator advantage in larger groups through dilution effect and improved detection of approaching predators. So, the costs of alerting the group about the presence of a nearby predator are small for the caller, the call helps the others to escape but the apparent cooperation is driven by selfish individual advantage. Isabella -- Isabella Capellini, PhD Research Associate Evolutionary Anthropology Research Group Department of Anthropology Durham University 43 Old Elvet DH1 3HN Durham (UK) phone: +44 (0)191 3346177 fax: +44 (0)191 3346101 > -----Original Message----- > From: Ecological Society of America: grants, jobs, news > [mailto:[EMAIL PROTECTED] On Behalf Of Warren W. Aney > Sent: 14 February 2006 20:04 > To: [email protected] > Subject: Re: current natural selection pressures > > I may not be the person to raise this discussion to a more > rigorous ecological level, but let me try: > > As I understand one view of natural selection, it is a > process that favors those qualities that increase the > likelihood of a particular set of genes being passed on to > succeeding generations. So we have the obvious, e.g., > selecting for opposable thumbs and bigger brains led to > selecting for learning the use of tools (and weapons) which > improved that particular clan's survivability -- and the > survival of its gene set. It also explains some altruistic > behaviors -- taking care of elderly clan members may have > cost a little in terms of resource allocation, but that may > have been more than offset by their providing services > beneficial to the clan's survival. > Services such as infant care, child mentoring and the > transfer of accrued skills, knowledge and wisdom. > > It also may have led to learning some other behaviors such as > killing the males and enslaving the females of competing > clans -- not very altruistic but certainly improving the > survival of the victorious clan's gene set. > > So why do we now seem to be learning behaviors that would > appear to work against the survival of the gene set of the > "clan" we belong to? Behaviors such as being kind to > strangers instead of killing the males and raping the > females, sending aid to foreign countries instead of engaging > in genocide, promoting birth control instead of large > families, honoring monogamy and celibacy instead of > promiscuity, protecting and conserving other species instead > of eliminating them as competitors or threats, honoring > humility instead of belligerence, honoring artists more than > soldiers (okay, this may be a bad example since we expend > much more of our resources on the military than we do on the arts). > > It appears, at least to this field ecologist, that we are > practicing behaviors aimed at improving the survival of a > whole host of competing and maybe even antagonistic gene > sets. And most of us (but not all of us) believe that is > exactly what we should be doing. Where and how is natural > selection at work in all this? > > > Warren Aney > Senior Wildlife Ecologist > Tigard, Oregon > > > -----Original Message----- > From: Ecological Society of America: grants, jobs, news > [mailto:[EMAIL PROTECTED] Behalf Of isabella capellini > Sent: Tuesday, 14 February, 2006 08:36 > To: [email protected] > Subject: Re: current natural selection pressures > > > > > Perhaps human intelligence and humility will become > > > > a selective pressure. > > Really?? How? will more intelligent and humile people have > more offspring??? > Isabella > > > Dr. Isabella Capellini, PhD > Research Associate > > Department of Anthropology > Durham University > 43 Old Elvet > Durham > DH1 3HN (UK) > > phone: +44 (0)191 3346177 > fax: +44-(0)191-3346101 > email: [EMAIL PROTECTED] > webpage: http://www.dur.ac.uk/anthropology/staff/ > > > > ___________________________________________________________ > Yahoo! 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