Baldwin effect
Template:Short description Template:About Template:Good article
In evolutionary biology, what is now called the Baldwin effect describes the ways agency, imitation and learned behaviour can pioneer evolutionary change. It was first christened as such in the 1950s by George Gaylord Simpson, one of the architects of the modern synthesis, to bring attention to a process highlighted in the previous century by James Mark Baldwin.<ref>Simpson G.G. 1953. The Baldwin Effect. Evolution 7: 110Template:Ndash117. See : [1]</ref>
Inspired to challenge late Victorian neo-darwinism by Darwin's own use of his theory of natural selection (in On the Origin of Species) to reframe the laws of use and disuse in terms of transitional habits<ref>Template:Harvnb</ref>—giving several examples of the ways different organisms' change of habits, as in flying squirrels and flightless beetles, have altered their anatomies' subsequent evolutionary fates—Baldwin and others re-emphasised that an organism's ability to learn new behaviours (e.g., to colonise new habitat or acclimatise to a new stressor) may affect its reproductive success and may, therefore, subsequently affect the genetic makeup of its species through natural selection, if supported by heritable traits. The Baldwin effect posits that, if such new habits prove advantageous, subsequent selection will reinforce those habits and any other structures they affect so that they will become instinctive or in-born over many generations. This process may appear similar to non-Darwinian Lamarckism, a view which proposes that living things may directly inherit their parents' acquired characteristics. But, in contrast to Lamarck, and echoing Darwin's argument about transitional habits in On the Origin of Species, Baldwin proposed that, only if supportable by heritable traits, can changed behaviour lead to adaptive evolutionary change.
The Baldwin effect has been independently proposed several times. It is generally recognized by proponents of the modern synthesis. And it has become a central plank of 21st century evolutionary biologies which challenge the 20th century's modern synthesis by retheorizing the leading role played by organisms' agency in the origin of species (see Extended Evolutionary Synthesis)
"A New Factor in Evolution"
By highlighting the Baldwin effect when he did, Simpson invited evolutionary biologists to reconsider the earlier claim made by Julian Huxley and others that, viewed through the prism of the modern synthesis, Darwin’s theory denied any role for the “purposiveness of organic structure” in the evolution of adaptations (most famously in Evolution: The Modern Synthesis).<ref name=Huxley1942>Template:Cite book</ref> Baldwin’s 1896 paper "A New Factor in Evolution" had christened the 'new factor' Organic Selection, a label which became the title of his second paper on the topic published in 1897.Template:SfnTemplate:Sfn These two papers specified three ways in which an organism might through its own changes become adaptively modified during its life-history: bodily or ‘physico-genetically’, neurally or ‘neuro-genetically’, and through 'conscious agency' or ‘psycho-genetically’. As the historian of science Robert Richards put it in 1987:<ref name=Richards1987>Template:Cite book</ref>
<templatestyles src="Template:Blockquote/styles.css" />
|}}{{#if:|
— {{#if:|, in }}Template:Comma separated entries
}}{{#invoke:Check for unknown parameters|check|unknown=Template:Main other|preview=Page using Template:Blockquote with unknown parameter "_VALUE_"|ignoreblank=y| 1 | 2 | 3 | 4 | 5 | author | by | char | character | cite | class | content | multiline | personquoted | publication | quote | quotesource | quotetext | sign | source | style | text | title | ts }}
Selected offspring would tend to have an increased capacity for developing new skills. The Baldwin effect thus places emphasis on the fact that the sustained behaviour of a species or group can shape the evolution of that species, often being understood in evolutionary developmental biology as a scenario in which a character or trait change occurring in an organism as a result of its interaction with its environment becomes gradually assimilated into its developmental genetic or epigenetic repertoire.Template:SfnTemplate:Sfn In the words of the philosopher of science Daniel Dennett:<ref name=dennett03/>
<templatestyles src="Template:Blockquote/styles.css" />
|}}{{#if:|
— {{#if:|, in }}Template:Comma separated entries
}}{{#invoke:Check for unknown parameters|check|unknown=Template:Main other|preview=Page using Template:Blockquote with unknown parameter "_VALUE_"|ignoreblank=y| 1 | 2 | 3 | 4 | 5 | author | by | char | character | cite | class | content | multiline | personquoted | publication | quote | quotesource | quotetext | sign | source | style | text | title | ts }}
An update to the Baldwin effect was developed by Jean Piaget, Paul Weiss, and Conrad Waddington in the 1960s–1970s. This new version included an explicit role for the social in shaping subsequent natural change in humans (both evolutionary and developmental), with reference to alterations of selection pressures.<ref>Template:Cite journal</ref>
More recently, lack of familiarity with Darwin's exposition of transitional habits in his 1859 book On the Origin of Species has led some scientists to claim that, in 1873, Douglas Spalding was the first to identify the process now known as the Baldwin effect, as discussed by Baldwin in 1896.<ref>Noble, R.; Noble, D. (2017) Was the Watchmaker Blind? Or Was She One-Eyed? Biology 2017, 6(4), 47; doi:10.3390/biology6040047, quoting Bateson, P. The adaptability driver: Links between behaviour and evolution. Biol. Theory 2006, 1, 342–345. See also Stigler's law.</ref>
Controversy and acceptance
Initially Baldwin's ideas were not incompatible with the prevailing, but uncertain, ideas about the mechanism of transmission of hereditary information and at least two other biologists put forward very similar ideas in 1896.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> In 1901, Maurice Maeterlinck referred to behavioural adaptations to prevailing climates in different species of bees as "what had merely been an idea, therefore, and opposed to instinct, has thus by slow degrees become an instinctive habit".<ref>Template:Cite book</ref> The Baldwin effect theory subsequently became more controversial, with scholars divided between "Baldwin boosters" and "Baldwin skeptics".<ref name="depew03">Depew, David J. (2003), "Baldwin Boosters, Baldwin Skeptics" in: Template:Cite book</ref> The theory was first called the "Baldwin effect" by George Gaylord Simpson in 1953.<ref name="depew03"/> Simpson "admitted that the idea was theoretically consistent, that is, not inconsistent with the modern synthesis",<ref name="depew03"/> but he doubted that the phenomenon occurred very often, or if so, could be proven to occur. In his discussion of the reception of the Baldwin-effect theory Simpson points out that the theory appears to provide a reconciliation between a neo-Darwinian and a neo-Lamarckian approach and that "Mendelism and later genetic theory so conclusively ruled out the extreme neo-Lamarckian position that reconciliation came to seem unnecessary".Template:Sfn In 1942, the evolutionary biologist Julian Huxley promoted the Baldwin effect as part of the modern synthesis, saying the concept had been unduly neglected by evolutionists.Template:Sfn<ref name="Scheiner 2014">Template:Cite journal</ref><ref name="Belew 2018">Template:Cite book</ref>
In the 1960s, the evolutionary biologist Ernst Mayr contended that the Baldwin effect theory was untenable because
- the argument is stated in terms of the individual genotype, whereas what is really exposed to the selection pressure is a phenotypically and genetically variable population;
- it is not sufficiently emphasized that the degree of modification of the phenotype is in itself genetically controlled;
- it is assumed that phenotypic rigidity is selectively superior to phenotypic flexibility.<ref name="Mayr1963">Template:Cite book</ref>
In 1987 Geoffrey Hinton and Steven Nowlan demonstrated by computer simulation that learning can accelerate evolution, and they associated this with the Baldwin effect.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref name=Puentedura2003>Template:Cite book</ref>
Paul Griffiths<ref name="Griffiths2003">Template:Cite book</ref> suggests two reasons for the continuing interest in the Baldwin effect. The first is the role mind is understood to play in the effect. The second is the connection between development and evolution in the effect. Baldwin's account of how neurophysiological and conscious mental factors may contribute to the effect<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>Template:Sfn brings into focus the question of the possible survival value of consciousness.<ref name=Lindahl2001>Template:Cite book</ref>
Still, David Depew observed in 2003, "it is striking that a rather diverse lot of contemporary evolutionary theorists, most of whom regard themselves as supporters of the Modern Synthesis, have of late become 'Baldwin boosters'".<ref name="depew03" /> These
<templatestyles src="Template:Blockquote/styles.css" />
|}}{{#if:|
— {{#if:|, in }}Template:Comma separated entries
}}{{#invoke:Check for unknown parameters|check|unknown=Template:Main other|preview=Page using Template:Blockquote with unknown parameter "_VALUE_"|ignoreblank=y| 1 | 2 | 3 | 4 | 5 | author | by | char | character | cite | class | content | multiline | personquoted | publication | quote | quotesource | quotetext | sign | source | style | text | title | ts }}
According to Dennett, also in 2003, recent work has rendered the Baldwin effect "no longer a controversial wrinkle in orthodox Darwinism".<ref name="dennett03">Dennett, Daniel (2003), "The Baldwin Effect: a Crane, not a Skyhook" in: Template:Cite book</ref> Potential genetic mechanisms underlying the Baldwin effect have been proposed for the evolution of natural (genetically determinant) antibodies.<ref>Template:Cite journal</ref> In 2009, empirical evidence for the Baldwin effect was provided from the colonisation of North America by the house finch.<ref name=Badyaev>Template:Cite journal</ref>
The Baldwin effect has been incorporated into the extended evolutionary synthesis.<ref>Pigliucci, Massimo. Phenotypic Plasticity. In Massimo Pigliucci, and Gerd B. Müller (eds), Evolution: The Extended Synthesis (Cambridge, MA, 2010; online edn, MIT Press Scholarship Online, 22 Aug. 2013).</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
Comparison with genetic assimilation
The Baldwin effect has been confused with, and sometimes conflated with, a different evolutionary theory also based on phenotypic plasticity, C. H. Waddington's genetic assimilation. The Baldwin effect includes genetic accommodation, of which one type is genetic assimilation.<ref>Template:Cite journal</ref> Science historian Laurent Loison has written that "the Baldwin effect and genetic assimilation, even if they are quite close, should not be conflated".<ref>Template:Cite journal</ref>
See also
- Template:Annotated link
- Template:Annotated link
- Template:Annotated link
- Template:Annotated link
- Template:Annotated link
Notes
References
- Template:Cite journal
- Template:Cite journal
- Template:Cite journal
- Template:Cite book
- Template:Cite journal
- Template:Cite journal
- Template:Cite journal
- Template:Cite journal
- Template:Cite journal
External links
{{#invoke:Navbox|navbox}} Template:Evolutionary psychology