scholarly journals Evolutionary biology today and the call for an extended synthesis

2017 ◽  
Vol 7 (5) ◽  
pp. 20160145 ◽  
Author(s):  
Douglas J. Futuyma

Evolutionary theory has been extended almost continually since the evolutionary synthesis (ES), but except for the much greater importance afforded genetic drift, the principal tenets of the ES have been strongly supported. Adaptations are attributable to the sorting of genetic variation by natural selection, which remains the only known cause of increase in fitness. Mutations are not adaptively directed, but as principal authors of the ES recognized, the material (structural) bases of biochemistry and development affect the variety of phenotypic variations that arise by mutation and recombination. Against this historical background, I analyse major propositions in the movement for an ‘extended evolutionary synthesis’. ‘Niche construction' is a new label for a wide variety of well-known phenomena, many of which have been extensively studied, but (as with every topic in evolutionary biology) some aspects may have been understudied. There is no reason to consider it a neglected ‘process’ of evolution. The proposition that phenotypic plasticity may engender new adaptive phenotypes that are later genetically assimilated or accommodated is theoretically plausible; it may be most likely when the new phenotype is not truly novel, but is instead a slight extension of a reaction norm already shaped by natural selection in similar environments. However, evolution in new environments often compensates for maladaptive plastic phenotypic responses. The union of population genetic theory with mechanistic understanding of developmental processes enables more complete understanding by joining ultimate and proximate causation; but the latter does not replace or invalidate the former. Newly discovered molecular phenomena have been easily accommodated in the past by elaborating orthodox evolutionary theory, and it appears that the same holds today for phenomena such as epigenetic inheritance. In several of these areas, empirical evidence is needed to evaluate enthusiastic speculation. Evolutionary theory will continue to be extended, but there is no sign that it requires emendation.

Author(s):  
Gunter Wagner ◽  
Gary Tomlinson

Since its inception, evolutionary theory has experienced a number of extensions. The most important of these took the forms of the Modern Evolutionary Synthesis (MES), embracing genetics and population biology in the early 20th century, and the Extended Evolutionary Synthesis (EES) of the last thirty years, embracing, among other factors, non-genetic forms of inheritance. While we appreciate the motivation for this recent extension, we argue that it does not go far enough, since it restricts itself to widening explanations of adaptation by adding mechanisms of inheritance and variation. Here we argue that a more thoroughgoing extension is needed, one that broadens the explanatory scope of evolutionary theory. In addition to adaptation and its various mechanisms, evolutionary theory must recognize as a distinct intellectual challenge the origin of what we call “historical kinds.” Under historical kinds we include any process that acquires a quasi-independent and traceable lineage-history in biological and cultural evolution. A limited number of historical kinds have been recognized in evolutionary biology, and corresponding research programs have been formed around them. The best characterized examples are biological species and genes. We propose that the conceptual category of historical kinds can and needs to be extended, and we develop the notion of a historical kind in a series of paradigmatic exemplars, from genes and cell types to rituals and music. The explanation of the origin of historical kinds should be a main objective of biological and cultural sciences.


2015 ◽  
Vol 282 (1813) ◽  
pp. 20151019 ◽  
Author(s):  
Kevin N. Laland ◽  
Tobias Uller ◽  
Marcus W. Feldman ◽  
Kim Sterelny ◽  
Gerd B. Müller ◽  
...  

Scientific activities take place within the structured sets of ideas and assumptions that define a field and its practices. The conceptual framework of evolutionary biology emerged with the Modern Synthesis in the early twentieth century and has since expanded into a highly successful research program to explore the processes of diversification and adaptation. Nonetheless, the ability of that framework satisfactorily to accommodate the rapid advances in developmental biology, genomics and ecology has been questioned. We review some of these arguments, focusing on literatures (evo-devo, developmental plasticity, inclusive inheritance and niche construction) whose implications for evolution can be interpreted in two ways—one that preserves the internal structure of contemporary evolutionary theory and one that points towards an alternative conceptual framework. The latter, which we label the ‘extended evolutionary synthesis' (EES), retains the fundaments of evolutionary theory, but differs in its emphasis on the role of constructive processes in development and evolution, and reciprocal portrayals of causation. In the EES, developmental processes, operating through developmental bias, inclusive inheritance and niche construction, share responsibility for the direction and rate of evolution, the origin of character variation and organism–environment complementarity. We spell out the structure, core assumptions and novel predictions of the EES, and show how it can be deployed to stimulate and advance research in those fields that study or use evolutionary biology.


2019 ◽  
Vol 59 (3) ◽  
pp. 493-502 ◽  
Author(s):  
Mark E Olson

AbstractPlant ecology is increasingly turning to evolutionary questions, just as evolutionary biology pushes out of the strictures of the Modern Synthesis into what some regard as an “Extended Evolutionary Synthesis.” As plant ecology becomes increasingly evolutionary, it is essential to ask how aspects of the Extended Synthesis might impinge on plant ecological theory and practice. I examine the contribution of plant evolutionary ecology to niche construction theory, as well as the potential for developmental systems theory and genes-as-followers adaptive evolution, all important post-Modern Synthesis themes, in providing novel perspectives for plant evolutionary ecology. I also examine ways that overcoming dichotomies such as “genetic vs. plastic” and “constraint vs. adaptation” provide fertile opportunities for plant evolutionary ecologists. Along the same lines, outgrowing vague concepts such as “stress” and replacing them with more precise terminology in all cases provides vastly increased causal clarity. As a result, the synthetic path that plant ecologists are blazing, becoming more evolutionary every year, bodes extremely well for the field, with vast potential for expansion into important scientific territory.


2021 ◽  
Author(s):  
Erik Svensson

The last decades have seen frequent calls for a more extended evolutionary synthesis (EES) that will supposedly overcome the limitations in the current evolutionary framework with its intellectual roots in the Modern Synthesis (MS). Some radical critics even want to entirely abandon the current evolutionary framework, claiming that the MS (often erroneously labelled “Neo-Darwinism”) is outdated, and will soon be replaced by an entirely new framework, such as the Third Way of Evolution (TWE). Such criticisms are not new, but have repeatedly re-surfaced every decade since the formation of the MS, and were particularly articulated by developmental biologist Conrad Waddington and paleontologist Stephen Jay Gould. Waddington, Gould and later critics argued that the MS was too narrowly focused on genes and natural selection, and that it ignored developmental processes, epigenetics, paleontology and macroevolutionary phenomena. More recent critics partly recycle these old arguments and argue that non-genetic inheritance, niche construction, phenotypic plasticity and developmental bias necessitate major revision of evolutionary theory. Here I discuss these supposed challenges, taking a historical perspective and tracing these arguments back to Waddington and Gould. I dissect the old arguments by Waddington, Gould and more recent critics that the MS was excessively gene centric and became increasingly “hardened” over time and narrowly focused on natural selection. Recent critics have consciously or unconsciously exaggerated the long-lasting influence of the MS on contemporary evolutionary biology and have underestimated many post-Synthesis developments, particularly Neutral Theory and evolutionary quantitative genetics. Critics have also painted a biased picture of the MS as a more monolithic research tradition than it ever was, and have downplayed the pluralistic nature of contemporary evolutionary biology, particularly the long-lasting influence of Sewall Wright with his emphasis on gene interactions and stochasticity. Finally, I outline and visualize the conceptually split landscape of contemporary evolutionary biology, with four different stably coexisting analytical frameworks: adaptationism, mutationism, neutralism and selectionism. I suggest that the field can accommodate the challenges raised by critics, although structuralism (“EvoDevo”) and macroevolution remain to be conceptually integrated within mainstream evolutionary theory.


Author(s):  
Idan S. Solon

Here, I introduce a concept called autonomous selection to refer to a source of selection that is part of the individuals upon which it acts. The concept is motivated by a set of phenomena with the following characteristics: Natural selection shaped a variant (e.g., gene, epigenetic mark, or combination thereof) to act in a manner that reduces the frequency of one or more heritable traits of the individual in which it is located if those traits are detrimental to individual or group fitness. Phenomena with these characteristics are peculiar to traditional evolutionary theory but have been identified rather frequently in recent decades. They are also relevant to adaptive evolution: By reducing the frequency of a trait detrimental to fitness, the variant accelerates the evolution of adaptations, which allows its holders to adapt better to constantly changing environments. The variant is shaped by (natural) selection, but also does (autonomous) selection. Several phenomena with these characteristics have been invoked by proponents of the extended evolutionary synthesis (EES). The concept of autonomous selection helps resolve some of the controversy surrounding the EES: EES proponents call attention to the incompleteness of contemporary theory, emphasizing individuals’ processes that influence which adaptations those individuals evolve. I argue for the special importance of individuals’ processes that do not just influence those individuals’ adaptations, but also accelerate the adaptive evolution of those individuals. All known phenomena that fit this description are examples of autonomous selection. Other phenomena raised by EES proponents do not meet this threshold.


Author(s):  
Alexander Vucinich

The Russian scientific community welcomed Darwin’s evolutionary theory and made it a basis of research in a wide range of biological sciences. Russian evolutionary studies in embryology, paleontology, microbiology and pathology attracted international attention. The vast scope of Darwin’s popularity in Russia was dramatically manifested in 1909, on the occasion of the national celebration of the 100th anniversary of the birth of the great English scientist and the 50th anniversary of the publication of The Origin of Species. All universities, naturalist societies, and many newspapers and popular journals took part in the celebration, which produced a hundred praiseful publications on Darwinian themes. University philosophers, steeped in metaphysical idealism and spiritualism, linked Darwinism to what they called ‘modern scientific materialism’ and rejected it wholly. They were strongly predisposed to welcome modern revivals of metaphysical vitalism. Freelance philosophers, usually associated with heterodox ideological movements and influenced by Auguste Comte’s positivism or various modern neopositivist and Neo-Kantian currents, credited Darwinism with making science a major topic of modern philosophy. A new discipline, known as ‘scientific philosophy’, rapidly developing in the West, made its first appearance in Russia. In the Soviet Union, Darwin’s evolutionary theory followed a course of cataclysmic ruptures. During the 1920s, Soviet scientists made significant contributions to the study of the role of the genetic environment in biological evolution and helped set the stage for an evolutionary synthesis of Darwinism and genetics. The Stalinist era (1929–53) marked a drastic departure from the prevalent currents in evolutionary biology. It was dominated by the rise of Lysenkoism, a pseudo-science identified as ‘creative Darwinism’, and was guided by a diluted version of the Lamarckian idea of evolution as a product of the inheritance of acquired characteristics. Lysenkoism rejected the Darwinian conception of natural selection, downgraded the role of physico-chemical analysis in biology, and paid no attention to molecular biology. In 1948 Lysenkoism was officially recognized as the Marxist theory of evolution. Under Lysenko’s influence, genetics was proclaimed a ‘bourgeois science’ and was made illegal. The downfall of Lysenkoism in 1964 brought the re-establishment of genetics, a full-scale return to true Darwinism, and a re-intensified interest in ‘evolutionary synthesis’.


2019 ◽  
Vol 127 (4) ◽  
pp. 707-721 ◽  
Author(s):  
Tim Lewens

Abstract Debate over the Extended Evolutionary Synthesis (EES) ranges over three quite different domains of enquiry. Protagonists are committed to substantive positions regarding (1) empirical questions concerning (for example) the properties and prevalence of systems of epigenetic inheritance; (2) historical characterizations of the modern synthesis; and (3) conceptual/philosophical matters concerning (among other things) the nature of evolutionary processes, and the relationship between selection and adaptation. With these different aspects of the debate in view, it is possible to demonstrate the range of cross-cutting positions on offer when well-informed evolutionists consider their stance on the EES. This overview of the multiple dimensions of debate also enables clarification of two philosophical elements of the EES debate, regarding the status of niche-construction and the role of selection in explaining adaptation. Finally, it points the way to a possible resolution of the EES debate, via a pragmatic approach to evolutionary enquiry.


2021 ◽  
Author(s):  
Rasmus Skern-Mauritzen ◽  
Thomas Nygaard Mikkelsen

Life is information dancing through time, embedded in matter and shaped by natural selection. Few biologists or philosophers concerned with evolution would object to this description. This apparent accord could be taken to indicate universal agreement on the forces shaping evolution; but the devil is in the details and disagreement is apparent if one looks behind the curtain. The decade strong prevalent paradigm of the Modern Synthesis holds the position that evolution happens by random changes and natural selection acting on genomic inheritance. But there is a new kid on the block; the proponents of an Extended Evolutionary Synthesis argue that inheritance is more than genomes and includes epigenetic information, niche constructs (ranging from the meerkats dens to humans railroads) and culture among other factors – and that these factors are both inheritance and a force shaping evolution. Here we introduce The Information Continuum Hypothesis of Evolution; a conceptual framework that focus on the inherited information rather than the diverse representations this inherited information may have (DNA, RNA, epigenetic markers, proteins, culture etc.). As a tool we introduce the concept “hereditome” to describe the combined inherited representations of information. We believe this framework may help bridge the apparent gap between the Modern Synthesis and the Extended Evolutionary Synthesis.


2017 ◽  
Vol 7 (5) ◽  
pp. 20160133 ◽  
Author(s):  
Melinda A. Zeder

One of the challenges in evaluating arguments for extending the conceptual framework of evolutionary biology involves the identification of a tractable model system that allows for an assessment of the core assumptions of the extended evolutionary synthesis (EES). The domestication of plants and animals by humans provides one such case study opportunity. Here, I consider domestication as a model system for exploring major tenets of the EES. First I discuss the novel insights that niche construction theory (NCT, one of the pillars of the EES) provides into the domestication processes, particularly as they relate to five key areas: coevolution, evolvability, ecological inheritance, cooperation and the pace of evolutionary change. This discussion is next used to frame testable predictions about initial domestication of plants and animals that contrast with those grounded in standard evolutionary theory, demonstrating how these predictions might be tested in multiple regions where initial domestication took place. I then turn to a broader consideration of how domestication provides a model case study consideration of the different ways in which the core assumptions of the EES strengthen and expand our understanding of evolution, including reciprocal causation, developmental processes as drivers of evolutionary change, inclusive inheritance, and the tempo and rate of evolutionary change.


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