Habit and instinct.

Morgan, C.

doi:10.1037/12922-000

Cited by 149 publications

(77 citation statements)

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“…However, it is useful to be reminded of Ernst Mayr's constant refrain that behavior is at the leading edge of evolution or Gottlieb's adage that "changes in behavior create the new variants on which natural selection works" [45]; this important point, first made by Bateson [10] and Morgan [72] more than a century ago, never made it into mainstream biology until recently, although it has been occasionally commented on by endocrinologists [25,96,98]. It is necessary to emphasize here though that the individual is the unit of selection and that an approach that integrates both Molecular and Molar epigenetics will be necessary to reveal the mechanisms that underlie behavioral evolution.…”

Section: Molar Epigeneticsmentioning

confidence: 99%

Epigenetics and its implications for behavioral neuroendocrinology

Crews

2008

Frontiers in Neuroendocrinology

146

115

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Individuals vary in their sociosexual behaviors and reactivity. How the organism interacts with the environment to produce this variation has been a focus in psychology since its inception as a scientific discipline. There is now no question that cumulative experiences throughout life history interact with genetic predispositions to shape the individual's behavior. Recent evidence suggests that events in past generations may also influence how an individual responds to events in their own life history. Epigenetics is the study of how the environment can affect the genome of the individual during its development as well as the development of its descendants, all without changing the DNA sequence. Several distinctions must be made if this research is to become a staple in behavioral neuroendocrinology. The first distinction concerns perspective, and the need to distinguish and appreciate, the differences between Molecular versus Molar epigenetics. Each has its own lineage of investigation, yet both appear to be unaware of one another. Second, it is important to distinguish the difference between Context-Dependent versus Germline-Dependent epigenetic modifications. In essence the difference is one of the mechanism of heritability or transmission within, as apposed to across, generations. This review illustrates these distinctions while describing several rodent models that have shown particular promise for unraveling the contribution of genetics and the environment on sociosexual behavior. The first focuses on genetically-modified mice and makes the point that the early litter environment alters subsequent brain activity and behavior. This work emphasizes the need to understand behavioral development when doing research with such animals. The second focuses on a new rat model in which the epigenome is permanently imprinted, an effect that crosses generations to impact the descendants without further exposure to the precipitating agent. This work raises the question of how events in generations past can have consequences at both the mechanistic, behavioral, and ultimately evolutionary levels.

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Section: Molar Epigeneticsmentioning

confidence: 99%

Epigenetics and its implications for behavioral neuroendocrinology

Crews

2008

Frontiers in Neuroendocrinology

146

115

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“…no longer requires the environmental signal for expression). Although the origins of this concept can be traced to the latter half of the 19th century (Spalding, 1873;Baldwin, 1896;Morgan, 1896;Osborn, 1897), its formulation in a genetic context was done independently in the 1940s by Waddington (Waddington, 1942;Waddington, 1952;Waddington, 1953;Waddington, 1961) and Schmalhausen (Schmalhausen, 1949). All of these authors envisioned genetic assimilation as a means of facilitating phenotypic evolution.…”

Section: Why Revisit a 50 Year Old Debate?mentioning

confidence: 99%

Phenotypic plasticity and evolution by genetic assimilation

Pigliucci

Murren

Schlichting

2006

Journal of Experimental Biology

877

737

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SUMMARY In addition to considerable debate in the recent evolutionary literature about the limits of the Modern Synthesis of the 1930s and 1940s, there has also been theoretical and empirical interest in a variety of new and not so new concepts such as phenotypic plasticity, genetic assimilation and phenotypic accommodation. Here we consider examples of the arguments and counter-arguments that have shaped this discussion. We suggest that much of the controversy hinges on several misunderstandings, including unwarranted fears of a general attempt at overthrowing the Modern Synthesis paradigm, and some fundamental conceptual confusion about the proper roles of phenotypic plasticity and natural selection within evolutionary theory.

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“…One hundred and twelve years ago, in a series of influential publications, J. M. Baldwin, H. F. Osborn and C. L. Morgan proposed a process by which withingeneration developmental accommodation of induced environmental inputs, which makes an organism fit in its present environment ('organic selection' in Baldwin's writings), can become internalized in an evolutionary lineage and lead to evolutionary change without violating Weismann's rule of germ plasma continuity (Baldwin 1896;Morgan 1896;Osborn 1896). They proposed that organic selection is the process in which phenotypic accommodation of novel environmental inputs in ontogeny allows survival in changing environments, allowing time for subsequent natural selection to retain suitable adaptation.…”

Section: Introductionmentioning

confidence: 99%

Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

Badyaev

2009

Phil. Trans. R. Soc. B

162

123

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When faced with changing environments, organisms rapidly mount physiological and behavioural responses, accommodating new environmental inputs in their functioning. The ubiquity of this process contrasts with our ignorance of its evolutionary significance: whereas within-generation accommodation of novel external inputs has clear fitness consequences, current evolutionary theory cannot easily link functional importance and inheritance of novel accommodations. One hundred and twelve years ago, J. M. Baldwin, H. F. Osborn and C. L. Morgan proposed a process (later termed the Baldwin effect) by which non-heritable developmental accommodation of novel inputs, which makes an organism fit in its current environment, can become internalized in a lineage and affect the course of evolution. The defining features of this process are initial overproduction of random (with respect to fitness) developmental variation, followed by withingeneration accommodation of a subset of this variation by developmental or functional systems ('organic selection'), ensuring the organism's fit and survival. Subsequent natural selection sorts among resultant developmental variants, which, if recurrent and consistently favoured, can be inherited when existing genetic variance includes developmental components of individual modifications or when the ability to accommodate novel inputs is itself heritable. Here, I show that this process is consistent with the origin of novel adaptations during colonization of North America by the house finch. The induction of developmental variation by novel environments of this species's expanding range was followed by homeostatic channelling, phenotypic accommodation and directional cross-generational transfer of a subset of induced developmental outcomes favoured by natural selection. These results emphasize three principal points. First, contemporary novel adaptations result mostly from reorganization of existing structures that shape newly expressed variation, giving natural selection an appearance of a creative force. Second, evolutionary innovations and maintenance of adaptations are different processes. Third, both the Baldwin and parental effects are probably a transient state in an evolutionary cycle connecting initial phenotypic retention of adaptive changes and their eventual genetic determination and, thus, the origin of adaptation and evolutionary change.

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Habit and instinct.

Cited by 149 publications

References 0 publications

Epigenetics and its implications for behavioral neuroendocrinology

Epigenetics and its implications for behavioral neuroendocrinology

Phenotypic plasticity and evolution by genetic assimilation

Evolutionary significance of phenotypic accommodation in novel environments: an empirical test of the Baldwin effect

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