Unfinished Synthesis

1986 ◽  
Author(s):  
Niles Eldredge
Keyword(s):  
Modern Synthesis ◽  
Ernst Mayr ◽  
Conventional Theory ◽  
Higher Taxa ◽  
Evolutionary Thought ◽  
Wide Range ◽  
Theodosius Dobzhansky ◽  
George Gaylord Simpson

This study provides a stimulating critique of contemporary evolutionary thought, analyzing the Modern Synthesis first developed by Theodosius Dobzhansky, Ernst Mayr, and George Gaylord Simpson. The author argues that although only genes and organisms are taken as historic "individuals" in conventional theory, species, higher taxa, and ecological entities such as populations and communities should also be construed as individuals--an approach that yields the ecological and genealogical hierarchies that interact to produce evolution. This clearly stated, controversial work will provoke much debate among evolutionary biologists, systematists, paleontologists, and ecologists, as well as a wide range of educated lay readers.

The Equally Wonderful Field: Ernst Mayr and Organismic Biology

2010 ◽  
Vol 40 (3) ◽  
pp. 279-317 ◽  
Author(s):  
Erika Lorraine Milam
Keyword(s):  
Biological Sciences ◽  
Animal Behavior ◽  
Living Systems ◽  
Ernst Mayr ◽  
Physical Sciences ◽  
Mechanistic Approach ◽  
Theodosius Dobzhansky ◽  
Historical Identity ◽  
The 1960S ◽  
George Gaylord Simpson

Biologists in the 1960s witnessed a period of intense intra-disciplinary negotiations, especially the positioning of organismic biologists relative to molecular biologists. The perceived valorization of the physical sciences by "molecular" biologists became a catalyst creating a unified front of "organismic" biology that incorporated not just evolutionary biologists, but also students of animal behavior, ecology, systematics, botany——in short, almost any biological community that predominantly conducted their research in the field or museum and whose practitioners felt the pinch of the prestige and funding accruing to molecular biologists and biochemists. Ernst Mayr, Theodosius Dobzhansky, and George Gaylord Simpson took leading roles in defending alternatives to what they categorized as the mechanistic approach of chemistry and physics applied to living systems——the "equally wonderful field of organismic biology." Thus, it was through increasingly tense relations with molecular biology that organismic biologists cohered into a distinct community, with their own philosophical grounding, institutional security, and historical identity. Because this identity was based in large part on a fundamental rejection of the physical sciences as a desirable model within biology, organismic biologists succeeded in protecting the future of their field by emphasizing the deep divisions that ran through the biological sciences as a whole.

Genetics and the Races of Man. William C. Boyd. Boston (Little, Brown, & Co.), 1950. xvii + 453 pp. 6.00. (Reviewed by Ashley Montagu in the Saturday Review of Literature, 17 February 1.951; by Leslie C. Dunn in the Scientific American 183-6, December 1950; in Theodosius Dobzhansky, “Race and Humanity,” Science 113 (2932): 264-265, March 9, 1951; by J. N. Spuhler in the American Anthropologist 53-2, April-June 1951. Vol. 9, reviewed by Joseph B. Birdsell in American Journal of Physical Anthropology, No. 2, June 1951; by A. E. Mourant in the American Journal of Human Genetics, Vol. 3, No. 1, March 1951). - Principles of Human Genetics. Curt Stern. San Francisco (W. H. Freeman), 1949. xi + 617 pp. $7.50. (Reviewed by Theodosius Dobzhansky in the American Journal of Physical Anthropology 8-4, December 1950). - Races. A study of the problems of race formation in man. C. S. Coon, Stanley M. Garn, and Joseph B. Birdsell. American Lecture Series No. 77, Springfield, 111. (C. C. Thomas), 1950. xiv + 153 pp., 15 plates and 11 figs. $3.00. (Reviewed by J. Lawrence Angel in the American Journal of Physical Anthropology 8-4, December 1950; by Marshall T. Newman in the Boletin Bibliografico de Antropologia Americana, XIII (1950), Part II, Mexico, 1951, pp. 188-192; by Leslie C. Dunn in the American Anthropologist 53-1, January-March 1951; in Theodosius Dobzhansky, “Race and Humanity,” Science 113 (2932): 264-265, March 9, 1951). - Genetics, Paleontology, and Evolution. A symposium edited by Glenn L. Jepson, Ernst Mayr, and George Gaylord Simpson. Princeton University Press, 1949. xvi + 479 pp. $6.00. (Reviewed by S. L. Washburn in American Journal of Physical Anthropology 8-2, June 1950; by W. W. Howells in the American Anthropologist 52-4, October-December 1950).

1951 ◽  
Vol 17 (2) ◽  
pp. 166-168
Author(s):  
Erik K. Reed
Keyword(s):  
San Francisco ◽  
Human Genetics ◽  
Physical Anthropology ◽  
Ernst Mayr ◽  
American Anthropologist ◽  
Princeton University ◽  
Theodosius Dobzhansky ◽  
Saturday Review ◽  
George Gaylord Simpson ◽  
Race Formation

scholarly journals Robust anomalous metallic states and vestiges of self-duality in two-dimensional granular In-InOx composites

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xinyang Zhang ◽  
Bar Hen ◽  
Alexander Palevski ◽  
Aharon Kapitulnik
Keyword(s):  
Magnetic Field ◽  
Metallic Phase ◽  
Broadband Noise ◽  
Two Dimensional ◽  
Conventional Theory ◽  
Logarithmic Divergence ◽  
Self Duality ◽  
Low Field ◽  
Wide Range ◽  
Low Temperature Resistance

AbstractMany experiments investigating magnetic-field tuned superconductor-insulator transition (H-SIT) often exhibit low-temperature resistance saturation, which is interpreted as an anomalous metallic phase emerging from a ‘failed superconductor’, thus challenging conventional theory. Here we study a random granular array of indium islands grown on a gateable layer of indium-oxide. By tuning the intergrain couplings, we reveal a wide range of magnetic fields where resistance saturation is observed, under conditions of careful electromagnetic filtering and within a wide range of linear response. Exposure to external broadband noise or microwave radiation is shown to strengthen the tendency of superconductivity, where at low field a global superconducting phase is restored. Increasing magnetic field unveils an ‘avoided H-SIT’ that exhibits granularity-induced logarithmic divergence of the resistance/conductance above/below that transition, pointing to possible vestiges of the original emergent duality observed in a true H-SIT. We conclude that anomalous metallic phase is intimately associated with inherent inhomogeneities, exhibiting robust behavior at attainable temperatures for strongly granular two-dimensional systems.

scholarly journals Changes of arthropod diversity across an altitudinal ecoregional zonation in Northwestern Argentina

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4117 ◽  
Author(s):  
Andrea X. González-Reyes ◽  
Jose A. Corronca ◽  
Sandra M. Rodriguez-Artigas
Keyword(s):  
Species Richness ◽  
Polynomial Regression ◽  
Species Turnover ◽  
Predictor Variable ◽  
Elevational Gradient ◽  
Pitfall Trap ◽  
Northwestern Argentina ◽  
Higher Taxa ◽  
Total Species Richness ◽  
Wide Range

This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna) and two ecotones (Yungas-Monte and Prepuna) of Northwestern Argentina (altitudinal range of 2,500 m), and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500–4,000 m a.s.l) during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation–extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas) of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna). Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate) in addition to a geographic gradient (the distance of decay of similarity), demonstrating that the species turnover is important to explain the beta diversity along the elevational gradient. This suggests that patterns of diversity and distribution of arthropods are regulated by the dissimilarity of ecoregional environments that establish a wide range of geographic and environmental barriers, coupled with a limitation of species dispersal. Therefore, the arthropods of higher taxa respond differently to the altitudinal ecoregional zonation.

scholarly journals Group selection and the development of the biological species concept

2010 ◽  
Vol 365 (1547) ◽  
pp. 1853-1863 ◽  
Author(s):  
James Mallet
Keyword(s):  
Species Concept ◽  
Biological Species ◽  
Second World War ◽  
Species Level ◽  
Biological Species Concept ◽  
Ernst Mayr ◽  
World War ◽  
Mutualistic Interaction ◽  
Theodosius Dobzhansky ◽  
Second World

The development of what became known as the biological species concept began with a paper by Theodosius Dobzhansky in 1935, and was amplified by a mutualistic interaction between Dobzhansky, Alfred Emerson and Ernst Mayr after the second world war. By the 1950s and early 1960s, these authors had developed an influential concept of species as coadapted genetic complexes at equilibrium. At this time many features of species were seen as group advantages maintained by selection to avoid breakdown of beneficial coadaptation and the ‘gene pool’. Speciation thus seemed difficult. It seemed to require, more so than today, an external deus ex machina , such as allopatry or the founder effect, rather than ordinary within-species processes of natural selection, sexual selection, drift and gene flow. In the mid-1960s, the distinctions between group and individual selection were clarified. Dobzhansky and Mayr both understood the implications, but their views on species changed little. These group selectionist ideas now seem peculiar, and are becoming distinctly less popular today. Few vestiges of group selectionism and species-level adaptationism remain in recent reviews of speciation. One wonders how many of our own cherished views on evolution will seem as odd to future biologists.

scholarly journals What Future for Evolutionary Biology? Response to Commentaries on “The Illusions of the Modern Synthesis”

Biosemiotics ◽  
2021 ◽  
Author(s):  
Denis Noble
Keyword(s):  
Evolutionary Biology ◽  
Modern Synthesis ◽  
The Other ◽  
Target Article ◽  
Wide Range ◽  
Extensive Range ◽  
The Way

Abstract The extensive range and depth of the twenty commentaries on my target article (Noble, 2021) confirms that something has gone deeply wrong in biology. A wide range of biologists has more than met my invitation for “others to pitch in and develop or counter my arguments.” The commentaries greatly develop those arguments. Also remarkably, none raise issues I would seriously disagree with. I will focus first on the more critical comments, summarise the other comments, and then point the way forward on what I view as a necessary and long-overdue transition in the foundations of biology.

scholarly journals More Arrows in the Ancient DNA Quiver: Use of Paleoepigenomes and Paleomicrobiomes to Investigate Animal Adaptation to Environment

2019 ◽  
Vol 37 (2) ◽  
pp. 307-319 ◽  
Author(s):  
Yichen Liu ◽  
Laura S Weyrich ◽  
Bastien Llamas
Keyword(s):  
Molecular Evolution ◽  
Ancient Dna ◽  
Empirical Data ◽  
Genetic Factors ◽  
Experimental Studies ◽  
Modern Synthesis ◽  
Epigenetic Mechanisms ◽  
Unified Theory ◽  
Animal Evolution ◽  
Wide Range

Abstract Whether and how epigenetic mechanisms and the microbiome play a role in mammalian adaptation raised considerable attention and controversy, mainly because they have the potential to add new insights into the Modern Synthesis. Recent attempts to reconcile neo-Darwinism and neo-Lamarckism in a unified theory of molecular evolution give epigenetic mechanisms and microbiome a prominent role. However, supporting empirical data are still largely missing. Because experimental studies using extant animals can hardly be done over evolutionary timescales, we propose that advances in ancient DNA techniques provide a valid alternative. In this piece, we evaluate 1) the possible roles of epigenomes and microbiomes in animal adaptation, 2) advances in the retrieval of paleoepigenome and paleomicrobiome data using ancient DNA techniques, and 3) the plasticity of either and interactions between the epigenome and the microbiome, while emphasizing that it is essential to take both into account, as well as the underlying genetic factors that may confound the findings. We propose that advanced ancient DNA techniques should be applied to a wide range of past animals, so novel dynamics in animal evolution and adaption can be revealed.

Epistasis and Evolution

2021 ◽  
Keyword(s):  
Evolutionary Theory ◽  
Empirical Studies ◽  
Evolutionary Process ◽  
Adaptive Landscape ◽  
Genomic Complexity ◽  
Evolutionary Thought ◽  
Wide Range ◽  
Evolutionary Consequences ◽  
Main Effects ◽  
The Relationship

The concept of epistasis was introduced into evolutionary theory more than a hundred years ago. Its history is marked by controversies regarding its importance for the evolutionary process, as exemplified by the debate between Ronald Fisher and Sewall Wright in the wake of the modern synthesis. In this case the disagreement was about the shape of the adaptive landscape, which is determined by epistasis. Wright believed that epistasis causes the adaptive landscape to be rugged with many local peaks, whereas Fisher viewed evolution as a smooth, steady progression toward a unique optimum. Even today, the different meanings attributed to epistasis continue to spawn confusion. Nevertheless, a consensus is emerging, according to which the term should be used to designate interactions between genetic effects on phenotypes in the broadest sense. Stated differently, in the presence of epistasis the phenotypic effects of a gene depend on its genetic context. In evolutionary theory the phenotype of primary interest is organismal fitness, but principally the concept applies to any genotype-phenotype map. Reflecting the Fisherian view, throughout the 20th century epistasis was often considered to be a residual perturbation on the main effects of individual genes. Following the advent of sequencing techniques providing insights into the molecular basis of genotype-phenotype maps, over the past two decades it has become clear, however, that epistasis is the rule rather than an exception. This has motivated a large number of empirical studies exploring the patterns and evolutionary consequences of epistasis across a wide range of scales of organismal and genomic complexity. Correspondingly, mathematical and computational tools have been developed for the analysis of experimental data, and models have been constructed to elucidate the mechanistic and statistical origins of genetic interactions. Despite a certain inherent vagueness, the concept takes center stage in modern evolutionary thought as a framework for organizing the accumulating understanding of the relationship among genotype, phenotype, and organism.

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