Baldwin effect

As Baldwin effect, an evolutionary mechanism is referred to, in which an originally acquired through learning feature is replaced by natural selection over several generations by an inherited, ie genetically specific analog feature. In contrast to Lamarckian ideas while the learned property is not directly inherited, but influenced by them to the framework within which natural selection acts. What is the significance of the Baldwin effect in evolution actually has, is still controversial.

Mechanism

The theory behind the Baldwin effect assumes that behavior is partly dependent on external circumstances, instincts, reflexes and learned each. Since the behavior as a whole contributes to biological fitness, ie the reproductive success of the individual, it is for the success at first indifferent as to whether a particular feature has been inherited or purchased individually ( level of selection is the individual ). In a population of individuals, which all show the same shaped by environmental influences modification, but it is easy to imagine that a mutation that produces genetically the same token, is then fixed and will prevail in the population. In this way, the learned behavior creates conditions under which natural selection over many generations promotes the success of heritable variations ( mutations), so that ultimately originally learned behavior is reflected in the genetic material of the species. The occurrence and direction of the mutation themselves are not affected (this is the main difference between Lamarckism ).

History

The term " Baldwin effect" was coined in 1953 by George Gaylord Simpson for the mechanism, the 1896 James Mark Baldwin, Conwy Lloyd Morgan and Henry Fairfield Osborn had described independently. Especially Baldwin developed the idea in the following time on. The Baldwin effect was seen by all three scientists as a way to defuse the dispute between neo-Darwinists and Neolamarckisten to the question of the heritability of learned behavior. After the rediscovery of Mendelian genetics in the early twentieth century, refuted the neolamarckistischen assumptions, the Baldwin effect was only little attention and later incorporated into the synthetic theory of evolution as a mechanism lesser importance. The opinion of various evolutionary biologists to the Baldwin effect was shared here. While Julian Huxley the idea positively faced and George Gaylord Simpson she looked at least as plausible, the concept of Ernst Mayr and Theodosius Dobzhansky as either trivial example of natural selection, or relapse into Lamarckism was rejected. End of the twentieth century the idea, however, especially by evolutionary biologists and philosophers such as Daniel Dennett as a possible explanation for the accelerated evolution of mental characteristics and the achievement of unusual evolutionary states was seen.