borbor@cuisun.unige.ch (BORIS Borcic) (06/06/91)
In article <1991Jun4.164709.431@gpu.utcs.utoronto.ca> lamoran@gpu.utcs.utoronto.ca (L.A. Moran) writes: > [...] >It is a common misconception among non-biologists that evolution is associated >with morphological change. Such a misconception is fostered by the fossil >evidence that emphasizes such change. > I am no biologist, but... isn't this a bit too dogmatic ? It is certainly true that non-biologists show a bias towards a morphological-change view of evolution, but calling this bias a _misconception_ is (I feel) an unwarranted institutionalization of the bias towards the molecular view of all things biological of _present-day_ biologists (as a population). Molecular variation per se doesn't strike me as the only and undisputable fundation for measuring an amount of evolution. Evolution is an ecological process as well as a molecular one, and it is not obvious (to me, at least) that a measure of the evolution of a particular organism/species by what is significant at the molecular level should be automatically congruent to a measure of the same by what is significant at the ecological level. As a matter of fact, the human species is a counter-example of one type (e.g. very little evolution at the molecular level in, say, 5000 years, but a very significant one as an ecological actor). So-called living fossils could be counter-examples of the other kind - significant molecular evolution, but (perhaps) little evolution as ecological actors. Software engineering distinguishes between interface and implementation. Both can evolve independently (Well.. one can't really change the interface without changing _anything_ to the implementation, but never mind). Some similar dichotomy could be used in evolution theory, if I may humbly suggest. (It would be parent but not identical to the genotype/phenotype dichotomy, since a selectively neutral variation to an expressed protein counts as a difference in phenotype but should not count as a difference of "ecological interface"). Of course single molecular changes with no morphological impact can play very significant ecological roles, most often with plants, also with animals - but isn't it the case with the latter that morphology _is_ quite sensitive to a change of niche ? Anyway, and whatever, you can't deny that orphan species such as Coelocanth or Sphaenodon are a remarkable evolutionary phenomenon. B. Borcic - borbor@divsun.unige.ch (... and please excuse the awkward English)