Norris, I think you have a good point to illustrate the problem:
> Imagine the case where you have two phenotypically identical > populations that have different underlying genetics. If these > populations have different heritabilites, application of the identical > selective pressures could lead to dramatically different outcomes. In > this scenario only the responses to selective pressures would differ. > It would seem inconsistent to me to retro-actively claim that natural > selection was only operating in the one case where there was a > response. Rather, natural selection was only effective in producing > evolutionarily relevant change in one case. There is no inconsistency, because for natural selection to act, the phenotype must have a connection (heritability) with its underlying genotype. So, in your example above, let's just say that one population's phenotype was totally environmental (a good year, perhaps) while the other population's identical phenotype was genetic. Well, in both cases perhaps the individuals with the same, "high quality" phenotype would be favored (leaving more descendants) but only the population with a genetic basis would leave behind the "tendency" that was based on the phenotypic expression of the genotype. The other, in a different environment, would no longer show the same phenotype. Did I explain well? Cheers, Jim -- ------------------------------------- James J. Roper, Ph.D. Universidade Federal do Paraná Depto. de Zoologia Caixa Postal 19020 81531-990 Curitiba, Paraná, Brasil ===================================== E-mail: [EMAIL PROTECTED] Phone/Fone/Teléfono: 55 41 33611764 celular: 55 41 99870543 e-fax: 1-206-202-0173 (in the USA) ===================================== Zoologia na UFPR http://www.bio.ufpr.br/zoologia/ Ecologia e Conservação na UFPR http://www.bio.ufpr.br/ecologia/ ------------------------------------- http://jjroper.sites.uol.com.br
