Baldwin Effect

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The Baldwin effect is an evolutionary mechanism in which a trait originally acquired through learning is replaced by an inherited , i.e. genetically determined, analogous trait through natural selection within several generations . In contrast to Lamarckian ideas, the learned property is not inherited directly, but rather influences the framework within which the natural selection works. The significance of the Baldwin Effect in evolution is still controversial today.

mechanism

The theory behind the Baldwin Effect assumes that behavior is partly dependent on external circumstances, instincts and what has been learned. Since the behavior as a whole contributes to the biological fitness , i.e. to the reproductive success of the individual, it is initially irrelevant to the success whether a certain characteristic is inherited or individually acquired (the level of selection is the individual). However, in a population of individuals who all show the same modification influenced by environmental influences, it is easy to imagine that a mutation which genetically produces the same trait will subsequently be fixed and prevail in the population. In this way, the learned behavior creates conditions under which the natural selection over numerous generations promotes the success of hereditary variants ( mutations ), so that ultimately the originally learned behavior is reflected in the genetic material of the species. The occurrence and direction of the mutation itself are not affected (this is the main difference to Lamarckism).

There are two types of biological mechanisms that lead to the Baldwin Effect: genetic assimilation and niche formation . These two biological mechanisms seem to contain feedback that can alter the evolutionary process. The idea behind the Baldwin Effect is that sometimes both the direction and speed of evolution are influenced by natural selection of learned behaviors. For example, social behavior influences the genome over time , as the Russian geneticist Beljajew showed in his experiments with foxes .

history

The term "Baldwin Effect" was coined in 1953 by George Gaylord Simpson for the mechanism that James Mark Baldwin , Conwy Lloyd Morgan and Henry Fairfield Osborn had independently described in 1896 . Baldwin in particular developed the idea further in the period that followed. The Baldwin Effect was seen by all three scientists as a way to defuse the dispute between neo-Darwinists and neolamarckists over the question of the inheritance of learned behavior. After the rediscovery of Mendelian heredity at the beginning of the twentieth century, which refuted the neolamarckist assumptions, the Baldwin effect received little attention and was later integrated into the synthetic theory of evolution as a mechanism of lesser importance. The opinion of various evolutionary biologists on the Baldwin effect was divided. While Julian Huxley was positive about the idea and George Gaylord Simpson saw it at least as plausible, the concept was rejected by Ernst Mayr and Theodosius Dobzhansky as either a trivial example of natural selection or relapse into Lamarckism. At the end of the twentieth century, however, the idea was seen by evolutionary biologists and philosophers such as Daniel Dennett as a possible explanation for an accelerated evolution of mental characteristics and the achievement of unusual evolutionary states.

literature

  • Evolution and learning: the Baldwin effect reconsidered . In: Bruce H. Weber, David J. Depew (Eds.): Bradford Books - Life and Mind: Philosophical Issues in Biology and Psychology . MIT Press, 2003, ISBN 978-0-262-23229-6 .

Individual evidence

  1. ↑ Literally from Michael Gazzaniga : The I Illusion: How Consciousness and Free Will arise. Hanser, Munich 2012, ISBN 978-3-446-43011-2 , p. 176, p. 178.
  2. ^ George Gaylord Simpson: The Baldwin effect . In: evolution . tape 7 , no. 2 , 1953, p. 110-117 .
  3. ↑ James Mark Baldwin: A New Factor in Evolution . In: The American Naturalist . tape 30 , 1896, pp. 441-451 .
  4. ^ Conwy Lloyd Morgan: Habitat and instinct . Arnold, London 1896.
  5. ↑ Henry Fairfield Osborn: A mode of evolution requiring neither natural selection nor the inheritance of acquired characters . In: Transactions of the New York Academy of Science . tape 15 , 1896, pp. 141-142 (English).