Mary Jane West-Eberhard

Bio: Mary Jane West-Eberhard is an academic researcher from Smithsonian Tropical Research Institute. The author has contributed to research in topics: Sexual selection & Developmental plasticity. The author has an hindex of 28, co-authored 57 publications receiving 13350 citations. Previous affiliations of Mary Jane West-Eberhard include Louisiana State University & Smithsonian Institution.

Phenotypic Plasticity and the Origins of Diversity

Abstract: Phenotypic plasticity is the ability of a single genotype to produce more than one alternative form of morphology, physiological state, and/or behavior in response to environmental conditions. "Plasticity" and "development" are related terms that are becoming increasingly common in evolutionary biology and ecology. Both phenomena have passed through a period of neglect. In the 1960s Wigglesworth (228, p. 107) described some geneticists as being "apologetic" about environmentally cued polymorphisms, which they considered examples of unfortunate defects in the delicate genetic apparatus: "As R. A. Fisher once said to me, it is not surprising that such elaborate machinery should sometimes go wrong." And Bradshaw (19, p. 148) noted that botanists were carefully avoiding any mention of plasticity; environmental effects in experiments were considered "only an embarrassment." Until recently, genetic considerations have predominated in discussions of evolution and selection. Compared to the enormous progress made in genetics, there has been relatively little systematic effort to analyze environmental effects on the phenotype, and their evolutionary consequences. The plastic phenotype, stigmatized by poorly understood environmental influences and the ghost of Lamarck, has sometimes been lost from view as the focus of selection (e.g. 46; but see 48, 49). Much recent progress has been made toward integrating developmental and evolutionary biology, especially in vertebrate morphology (2, 12, 16, 216), developmental genetics (16, 163, 164), and molecular biology (103; also see 10, 111). "Developmental constraints" is a term symptomatic of this progress, though an unfortunate one because it seems to imply that the main effect of

Sexual selection, social competition, and speciation

Abstract: Rapid divergence and speciation can occur between populations with or without ecological differences under selection for success in intraspecific social competition-competition in which an individual must win in contests or comparisons with conspecific rivals in order to gain access to some resource, including (under sexual selection) mates. Sexual selection theory is extended to encompass social competition for resources other than mates. Characters used in social competition can undergo particularly rapid and divergent evolution owing to (1) their great importance in determining access to critical resources, (2) the absence of a limit to change (except by selection in other contexts), (3) the generation-to-generation relentlessness of selection on these traits. (4) the potential for mutually accelerating evolution of preference and attractiveness in contests involving "choice," and (5) the very large number of factors that can initiate trends, including mutation and drift leading to use of different phy...

Developmental plasticity and the origin of species differences

Abstract: Speciation is the origin of reproductive isolation and divergence between populations, according to the “biological species concept” of Mayr. Studies of reproductive isolation have dominated research on speciation, leaving the origin of species differences relatively poorly understood. Here, I argue that the origin of species differences, and of novel phenotypes in general, involves the reorganization of ancestral phenotypes (developmental recombination) followed by the genetic accommodation of change. Because selection acts on phenotypes, not directly on genotypes or genes, novel traits can originate by environmental induction as well as mutation, then undergo selection and genetic accommodation fueled by standing genetic variation or by subsequent mutation and genetic recombination. Insofar as phenotypic novelties arise from adaptive developmental plasticity, they are not “random” variants, because their initial form reflects adaptive responses with an evolutionary history, even though they are initiated by mutations or novel environmental factors that are random with respect to (future) adaptation. Change in trait frequency involves genetic accommodation of the threshold or liability for expression of a novel trait, a process that follows rather than directs phenotypic change. Contrary to common belief, environmentally initiated novelties may have greater evolutionary potential than mutationally induced ones. Thus, genes are probably more often followers than leaders in evolutionary change. Species differences can originate before reproductive isolation and contribute to the process of speciation itself. Therefore, the genetics of speciation can profit from studies of changes in gene expression as well as changes in gene frequency and genetic isolation.

Sexual selection, social competition and evolution

Abstract: Social behavior holds a special position among natural phenomena in relation to the Darwinian theory of organic evolution. When individuals of the same species live in close proximity they compete directly for essential resources. And intraspecific reproductive competition is the cornerstone of the theory of evolution by natural selection. Thus the drama of what G. E. Hutchinson (1965) referred to as the "evolutionary play" is heightened-or at least more obvious-among members of the same social group. If only by virtue of close physical proximity social

Human biochemical genetics

Abstract: So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Simple Heuristics That Make Us Smart

Abstract: Fast and frugal heuristics - simple rules for making decisions with realistic mental resources - are presented here. These heuristics can enable both living organisms and artificial systems to make smart choices, classifications, and predictions by employing bounded rationality. But when and how can such fast and frugal heuristics work? What heuristics are in the mind's adaptive toolbox, and what building blocks compose them? Can judgments based simply on a single reason be as accurate as those based on many reasons? Could less knowledge even lead to systematically better predictions than more knowledge? This book explores these questions by developing computational models of heuristics and testing them through experiments and analysis. It shows how fast and frugal heuristics can yield adaptive decisions in situations as varied as choosing a mate, dividing resources among offspring, predicting high school drop-out rates, and playing the stock market.

The dilemma of plants: To grow or defend.

Abstract: Physiological and ecological constraints play key roles in the evolution of plant growth patterns, especially in relation to defenses against herbivores. Phenotypic and life history theories are unified within the growth-differentiation balance (GDB) framework, forming an integrated system of theories explaining and predicting patterns of plant defense and competitive interactions in ecological and evolutionary time. Plant activity at the cellular level can be classified as growth (cell division and enlargement) of differentiation (chemical and morphological changes leading to cell maturation and specialization). The GDB hypothesis of plant defense is premised upon a physiological trade-off between growth and differentiation processes. The trade-off between growth and defense exists because secondary metabolism and structural reinforcement are physiologically constrained in dividing and enlarging cells, and because they divert resources from the production of new leaf area. Hence the dilemma of plants: Th...

Sex differences in human mate preferences: Evolutionary hypotheses tested in 37 cultures

Abstract: Contemporary mate preferences can provide important clues to human reproductive history. Little is known about which characteristics people value in potential mates. Five predictions were made about sex differences in human mate preferences based on evolutionary conceptions of parental investment, sexual selection, human reproductive capacity, and sexual asymmetries regarding certainty of paternity versus maternity. The predictions centered on how each sex valued earning capacity, ambition— industriousness, youth, physical attractiveness, and chastity. Predictions were tested in data from 37 samples drawn from 33 countries located on six continents and five islands (total N = 10,047). For 27 countries, demographic data on actual age at marriage provided a validity check on questionnaire data. Females were found to value cues to resource acquisition in potential mates more highly than males. Characteristics signaling reproductive capacity were valued more by males than by females. These sex differences may reflect different evolutionary selection pressures on human males and females; they provide powerful cross-cultural evidence of current sex differences in reproductive strategies. Discussion focuses on proximate mechanisms underlying mate preferences, consequences for human intrasexual competition, and the limitations of this study.

The evolution of social behavior

Abstract: For several years the study of social behavior has been undergoing a revolution with far-reaching consequences for the social and biological sciences. Partly responsible are three recent changes in the attitudes of evolutionary biologists. First was growing acceptance of the evidence that the potency of natural selection is overwhelmingly concentrated at levels no higher than that of the individual. Second was revival of the comparative method, especially as applied to behavior and life histories. Third was spread of the realization that not only are all aspects of structure and function of organisms to be understood solely as products of selection, but because of their peculiarly direct relationship to the forces of selection, behavior and life history phenomena, long neglected by the evolutionists, may be among the most predictable of all phenotypic attributes. These ideas have been appreciated by a few biologists for a long time, but they have only recently begun to characterize the science as a whole. Darwin’s discussion of sterility between species as an incidental effect of evolutionary adaptation (41, p. 260) and his refusal to deal with sex ratio selection (42, p. 399) suggest awareness of the difficult problem of determining the levels at which selection is most powerful. Yet significant clarification of this basic issue did not really commence until publication of Wynne-Edwards’ massive volume (179) championing group selection and inadvertently exposing its unlikelihood. As late as 1958, Fisher felt constrained to add to the revised edition of his 1929 classic, The Genetical Theory of Natural Selection, the admonishment (53, p. 49) that his fundamental theorem and its associated considerations, already misused then by decades of population geneticists dealing (as they saw it) with the fitness of populations, refer strictly to "the progressive modification of structure or function only in so far as variations in these are ofadvantage to the individual... [and afford] no corresponding explanation for any properties of animals and plants.., supposed to be of service to the species to which they belong." Williams’ critique (171) provided a significant turning point. Nevertheless, one has only to pick up any biological journal or attend any biological meeting to realize that this question has not yet been settled for all