predators stalk their chosen prey, and so forth. The genius of â€œinstinctâ€ comes in abundant variety, and breeds true. â€œIt must be in the genesâ€â€“thatâ€™s what we tend to conclude. But when we do, we may be jumping to conclusions, because there are other possibilities: the clever behavior we observe could be the do-it-yourself invention or discovery of the individual behaver or it could be a clever trick copied from an elder member of its species, most likely one of its (...) parents. This last possibility is an ancient doctrine, enshrined in folklore about animal parents sternly but lovingly training their young, and in countless anecdotes, but this appealing idea of animals benefitting from hand-me-down wisdom from earlier generations much the way we do has recently languished in the shadow of the genes, an oversight this book seeks to correct.Â The folklore is not all fanciful; some of it can be supported by good science, which moreover will open up surprising vistas on the role of individual behavior in evolution. The book is fascinating on at least three levels: first, it provides a vivid and insightful survey.. (shrink)
What role does non-genetic inheritance play in evolution? In recent work we have independently and collectively argued that the existence and scope of non-genetic inheritance systems, including epigenetic inheritance, niche construction/ecological inheritance, and cultural inheritance—alongside certain other theory revisions—necessitates an extension to the neo-Darwinian Modern Synthesis (MS) in the form of an Extended Evolutionary Synthesis (EES). However, this argument has been challenged on the grounds that non-genetic inheritance systems are exclusively proximate mechanisms that serve the ultimate function of calibrating organisms (...) to stochastic environments. In this paper we defend our claims, pointing out that critics of the EES (1) conflate non-genetic inheritance with early 20th-century notions of soft inheritance; (2) misunderstand the nature of the EES in relation to the MS; (3) confuse individual phenotypic plasticity with trans-generational non-genetic inheritance; (4) fail to address the extensive theoretical and empirical literature which shows that non-genetic inheritance can generate novel targets for selection, create new genetic equilibria that would not exist in the absence of non-genetic inheritance, and generate phenotypic variation that is independent of genetic variation; (5) artificially limit ultimate explanations for traits to gene-based selection, which is unsatisfactory for phenotypic traits that originate and spread via non-genetic inheritance systems; and (6) fail to provide an explanation for biological organization. We conclude by noting ways in which we feel that an overly gene-centric theory of evolution is hindering progress in biology and other sciences. (shrink)
We suggest that, in animals, the core-affect system is linked to partially assimilated behavioral dispositions that act as developmental scaffolds for the ontogenetic construction of emotions. We also propose that in humans the evolution of language altered the control of emotions, leading to categories that can be adequately captured only by emotion-words.
This volume joins a growing list of books, monographs, and proceedings from scientific meetings that attempt to consolidate the wide spectrum of approaches emphasizing the role of development in evolution into a coherent and productive synthesis, often called evo-devo. Evo-devo is seen as a replacement or amendment of the modern synthesis that has dominated the field of evolution since the 1940s and which, as even its architects confessed, was fundamentally incomplete because development remained outside its theoretical framework (Mayr and Provine (...) 1980).As the volume attests, there is now a strong feeling that the time is ripe for the onsolidation of evo-devo, and that the field is mature enough so that mapping the theoretical terrain and experimental approaches is both feasible and scientifically productive. Now is an appropriate time to try to weave the strands of reasoning leading to the developmental perspective and offer a synthesis. (shrink)
The dichotomy between Nature and Nurture, which has been dismantled within the framework of development, remains embodied in the notions of plasticity and evolvability. We argue that plasticity and evolvability, like development and heredity, are neither dichotomous nor distinct: the very same mechanisms may be involved in both, and the research perspective chosen depends to a large extent on the type of problem being explored and the kinds of questions being asked. Epigenetic inheritance leads to transgenerationally extended plasticity, and developmentally-induced (...) heritable epigenetic variations provide additional foci for selection that can lead to evolutionary change. Moreover, hereditary innovations may result from developmentally induced large-scale genomic repatterning events, which are akin to Goldschmidtian “systemic mutations”. The epigenetic mechanisms involved in repatterning can be activated by both environmental and genomic stress, and lead to phylogenetic as well as ontogenetic changes. Hence, the effects and the mechanisms of plasticity directly contribute to evolvability. (shrink)
The commentaries on Evolution in Four Dimensions reflect views ranging from total adherence to gene-centered neo-Darwinism, to the acceptance of non-genetic and Lamarckian processes in evolution. We maintain that genetic, epigenetic, behavioral, and cultural variations have all been significant, and that the developmental aspects of heredity and evolution are an important bridge that can unite seemingly conflicting research programs and different disciplines.
In his theory of evolution, Darwin recognized that the conditions of life play a role in the generation of hereditary variations, as well as in their selection. However, as evolutionary theory was developed further, heredity became identified with genetics, and variation was seen in terms of combinations of randomly generated gene mutations. We argue that this view is now changing, because it is clear that a notion of hereditary variation that is based solely on randomly varying genes that are unaffected (...) by developmental conditions is an inadequate basis for evolutionary theories. Such a view not only fails to provide satisfying explanations of many evolutionary phenomena, it also makes assumptions that are not consistent with the data that are emerging from disciplines ranging from molecular biology to cultural studies. These data show that the genome is far more responsive to the environment than previously thought, and that not all transmissible variation is underlain by genetic differences. In Evolution in Four Dimensions (2005) we identify four types of inheritance (genetic, epigenetic, behavioral, and symbol-based), each of which can provide variations on which natural selection will act. Some of these variations arise in response to developmental conditions, so there are Lamarckian aspects to evolution. We argue that a better insight into evolutionary processes will result from recognizing that transmitted variations that are not based on DNA differences have played a role. This is particularly true for understanding the evolution of human behavior, where all four dimensions of heredity have been important. (shrink)
In responding to three reviews of Evolution in Four Dimensions (Jablonka and Lamb, 2005, MIT Press), we briefly consider the historical background to the present genecentred view of evolution, especially the way in which Weismann’s theories have influenced it, and discuss the origins of the notion of epigenetic inheritance. We reaffirm our belief that all types of hereditary information—genetic, epigenetic, behavioural and cultural—have contributed to evolutionary change, and outline recent evidence, mainly from epigenetic studies, that suggests that non-DNA heritable variations (...) are not rare and can be quite stable. We describe ways in which such variations may have influenced evolution. The approach we take leads to broader definitions of terms such as ‘units of heredity’, ‘units of evolution’, and ‘units of selection’, and we maintain that ‘information’ can be a useful concept if it is defined in terms of its effects on the receiver. Although we agree that evolutionary theory is not undergoing a Kuhnian revolution, the incorporation of new data and ideas about hereditary variation, and about the role of development in generating it, is leading to a version of Darwinism that is very different from the gene-centred one that dominated evolutionary thinking in the second half of the twentieth century. (shrink)
The semantic concept of information is one of the most important, and one of the most problematical concepts in biology. I suggest a broad definition of biological information: a source becomes an informational input when an interpreting receiver can react to the form of the source (and variations in this form) in a functional manner. The definition accommodates information stemming from environmental cues as well as from evolved signals, and calls for a comparison between information‐transmission in different types of inheritance (...) systems—the genetic, the epigenetic, the behavioral, and the cultural‐symbolic. This comparative perspective highlights the different ways in which information is acquired and transmitted, and the role that such information plays in heredity and evolution. Focusing on the special properties of the transfer of information, which are very different from those associated with the transfer of materials or energy, also helps to uncover interesting evolutionary effects and suggests better explanations for some aspects of the evolution of communication. (shrink)
Adaptive evolution is usually assumed to be directed by selective processes, development by instructive processes; evolution involves random genetic changes, development involves induced epigenetic changes. However, these distinctions are no longer unequivocal. Selection of genetic changes is a normal part of development in some organisms, and through the epigenetic system external factors can induce selectable heritable variations. Incorporating the effects of instructive processes into evolutionary thinking alters ideas about the way environmental changes lead to evolutionary change, and about the interplay (...) between genetic and epigenetic systems. (shrink)
We claim that much of the confusion associated with the "tautology problem" about survival of the fittest is due to the mistake of attributing fitness to individuals instead of to types. We argue further that the problem itself cannot be solved merely by taking fitness as the aggregate cause of reproductive success. We suggest that a satisfying explanation must center not on logical analysis of the concept of general adaptedness but on the empirical analysis of single adapted traits and their (...) causal relationship to changes in allele frequencies. (shrink)