Revista Chilena de Historia Natural 78 (4): 739-752, 2005
COMMENTARY
Beyond selection
It has been argued that the study of natural selection and quantitative
genetics should have a central role in evolutionary thinking and undergraduate teaching in Chile. Extensive operational use of the
concept of natural selection may seem consistent with this argument. However, advances of evolutionary knowledge in independent
fields such as phylogenetic analysis, developmental evolution, and paleontology cannot be ignored. I argue here that the role of natural
selection in contemporary evolutionary biology can be compared to that of Newtonian mechanics in contemporary physics: it can
describe a given domain of observations, but it is insufficient to handle the different sources of evolutionary knowledge. Overemphasis
on natural selection as the immediate mechanism of evolution may lead to disregard phylogenetic-historical evidence, and to ignore the
important evolutionary role of non-adaptive change and epigenetic phenotypic plasticity. Natural selection deals with populations and
leads to conceive the environment as a “sieve” of genetic variation, bypassing the role of the environment as a trigger of phenotypic and
behavioral diversification. Alternatively, it is possible to conceive how part of the medium participates as an ontogenic niche in the
trans-reproductive change or conservation of an ontogenic phenotype. The concept of drift, currently accepted for molecular and
developmental change, can be applied to the level of the phenotype as an alternative to the concept of evolution as adaptation by
natural selection.
Key words:
evolution, history,
development, epigenesis, drift
