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Darwin and the Idea of Natural Selection

  1. Gabriel Dover

Published Online: 15 FEB 2012

DOI: 10.1002/9780470015902.a0005883.pub2

eLS

eLS

How to Cite

Dover, G. 2012. Darwin and the Idea of Natural Selection. eLS. .

Author Information

  1. University of Leicester, Leicester, UK

Publication History

  1. Published Online: 15 FEB 2012

Abstract

Natural selection is a consequence of differences in reproductive success among distinctly unique individual phenotypes living at a given generation and resulting in a biased representation of genes at the next generation. Reproducing, transient phenotypes, not ‘eternally selfish’ genes, form the arena in which selection takes place in a given biotic and abiotic environment. The evolved, complex relationship between genotype and phenotype is largely unknown and perhaps unknowable given the promiscuity of genes to participate in different functional networks at one and the same time, and given the vagaries of the external environment on individual ontogeny and life cycle. Accordingly, there is a many-on-many discourse between genes and traits, making the complex evolutionary role of natural selection difficult to fathom. Hopes for, or fears of, genetic determinism of human behaviour are premature.

Key Concepts:

  • Natural selection is a simple idea widely misunderstood: ‘Adaptation’ has come to mean both the mechanism of natural selection and its product.

  • The ephemeral, reproducing individual phenotype is at the heart of natural selection, not the ‘eternally selfish’ gene.

  • The unique pathway of individual development is not predictable given the ‘degeneracy’ of network interactions among genes, proteins, neurons, etc. within an ever shifting environmental milieu.

  • There is a many-on-many, not a one-to-one, relationship between genes and traits.

  • Natural selection is a means of changing the average genotype/phenotype of a population with the passing of the generations. There are two other means (‘neutral drift’ and ‘molecular drive’) for achieving the same effect.

  • Natural selection is not a process as such as the internal and external factors that influence differences in reproductive success differ at each generation.

  • It is not logically possible, without recourse to ‘just-so’ stories, to determine which of two or more co-extensive traits in a species was naturally selected and which a ‘free-rider’.

  • The pattern of a given set of genetic interactions (network topology) may differ between individuals yet have the same trait outcome (‘degeneracy’).

Keywords:

  • natural selection;
  • genotype;
  • phenotype;
  • genetic determinism;
  • evolution;
  • networks