Skillnaden på Gencentrerad syn på Evolution och Developmental Systems Theory

Från Oyama, S. (2000). Evolution's eye: A systems view of the biology-culture divide. Duke University Press. sid 197 -200

1. Argument ( to be read in a stentorian voice) : Genes produce organisms.
Qualitfying parenthesis: (Although they are not , of course, sufficient: raw materials must be available and conditions must be adequate)

DST expansion: Genes themselves don’t “make” anything ,  although they are involved in processes requiring many other molecules and conditions. Other interactants (or resources, or means) are found at scales from the microscopic to the ecological, some living, some not. None is sufficient, and their effects are interdependent. Development never occurs (and could not occur) in a vacuum.

2. Argument: Shared genes are responsible for species characteristics.
Qualitfying parenthesis: (Again, as long as proper conditions are present)

DST expansion: Just as genes can’t make organisms in general, they can’t create species-typical characters in particular.  Typical conditions, again at many scales, contribute to forming these characters, whose uniformity should not be exaggerated. The activity of the organism, including selfstimulation, is often a crucial aspect of species-typical development,  and so are influences from other organisms. Genetic and environmental variation is often underestimated, and flexible processes can sometimes result in typical phenotypes despite atypical phenotypic resourses [emphasis omitted].

3. Argument: Genetic variants specify the heritable phenotypes needed for natural selection.
Qualitfying parenthesis: (Of course, heritability depends on conditions, and it can be hard to separate genetic from environmental effects.)

DST expansion: Unless nongenetic factors are excluded by stipulation, other developmental resoursces can also “specify” phenotypic variants, which can be heritable in a variety of senses. The genotype-phenotype correlations that warrant the talk of genetic specification may not occur under all circumstances, and may change within and across generational time. Specificity, furthermore, is a slippery matter; it depends on the question being asked, the comparison being made, and on the measure beingused, as well as the developmental state if the organisms and the context of the comparision. In fact, the genotype-environment correlations and statistically interactions that plague the behavior geneticist are manifestations of just the interdependent networks that developmental systems theorists describe.

4. Argument: Only genes are passed on in reproduction; phenotypes, and therefore environmental effects, are evanescent, and thus evolutionary irrelevant.
Qualitfying parenthesis: (Of course, the genes are housed in a cell)

DST expansion: If  transmitting or “passing on “ means  “delivering materially unchanged”, then few if any developmental resourses are transmitted across evolutionary time, depending how one measures the material change. If transmission means  “reliably present in the next life cycle”,  which is the biologically relevant meaning in DST, then an indefinitelsy large set of heterogeneuous resourses or means are transmitted. They are sought or produced by the organism itself supplied by other organisms, perhaps through social processes and institutions, or are otherwise available. Although many developmentally important environmental features are exccede

5. Argument: If gene frequencies don’t change , then evolution has not, by definition, occurred.
Qualitfying parenthesis: ( Of course, the gene concept is historically recent, and other definitions of evolution are possible.)

DST expansion: A Historican could tell us  how gene frequencies moved from being index of evolutionary change to be definitional, but we needn’t insist on that one definition. In fact, many branches of biology routinely speak of changes in phenotypes. If one must have a “unit” of evolution, it would be the interactive developmental system: life cycles of organisms in their niches. Evolution would then be change in the constitution ond distribution of these systems. This definition embraces, but is not restricted to more traditional ones.