The Darwinian Outlook

2021 ◽  
pp. 53-63
Author(s):  
Franklin M. Harold
Keyword(s):  
Natural Selection ◽  
Gene Transfer ◽  
20Th Century ◽  
Lateral Gene Transfer ◽  
Eukaryotic Cell ◽  
Cellular Mechanisms ◽  
Ongoing Research ◽  
Research Challenges ◽  
Gene Level ◽  
History Of

The contemporary view of evolution crystallized in the mid-20th century in a hard-edged form that puts genes central: It sees organisms as vehicles for their genes, the material basis of the instructions encoded therein. Heredity, variation, natural selection, and adaptation all result from events that take place at the gene level. Organisms evolve by small mutational steps, never by sudden jumps. Mutations occur at random, not in response to need. Acquired characteristics are never inherited. Ongoing research challenges all these premises, and reinforces the criticism that the received doctrine is too narrow. Two important sources of novelty are lateral gene transfer across all boundaries, and the creation of new patterns of order by symbiosis. (The origin and history of the eukaryotic cell is a prime example.) In the renovated synthesis now emerging, genes retain their hold on organismal identity that is passed from parents to offspring and not easily altered. But this genetic framework is supplemented by a variety of more cellular mechanisms to acquire new traits, making cells more flexible and cohesive than imagined in classical theory.

Contributions to the History of Psychology: XCV. Possible Relations between Theories of Evolution and Animal Learning

1993 ◽  
Vol 73 (1) ◽  
pp. 211-223 ◽  
Author(s):  
Jesse E. Purdy ◽  
Arthur Harriman ◽  
Joseph Molitorisz
Keyword(s):  
Natural Selection ◽  
20Th Century ◽  
Learning Theory ◽  
World View ◽  
A Priori ◽  
Learning Theories ◽  
Late 19Th Century ◽  
Theory Of Evolution ◽  
History Of ◽  
Theories Of Evolution

It is proposed that the dominance of continuity learning theory as set against noncontinuity learning theory during the middle third of the 20th century rested importantly on its derivation from Darwin's theory of evolution. The kinship is shown in several ways. First, Thorndike and Hull echoed the principle of natural selection in their belief that behaviors underwent gradual modification because acts that were attended steadily by favorable consequences tended to occur with increasing frequency. Second, they denied both nonphysical explanations of behavior and a priori purposes which might guide that behavior. Third, the laws of learning were said to hold for all organisms. It is argued that the continuity approach may have enjoyed success because it was consistent with the Darwinian world view. Had punctualist, rather than gradualist, explanations of evolution come to the fore in the late 19th century, learning theories might have proceeded quite differently with the dominance of noncontinuity approaches.

scholarly journals Horizontal Gene Transfers from Bacteria toEntamoebaComplex: A Strategy for Dating Events along Species Divergence

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Miguel Romero ◽  
R. Cerritos ◽  
Cecilia Ximenez
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Entamoeba Histolytica ◽  
Lateral Gene Transfer ◽  
Adaptive Radiation ◽  
Fossil Record ◽  
Evolutionary History ◽  
Divergence Time ◽  
Eukaryotic Evolution ◽  
History Of

Horizontal gene transfer has proved to be relevant in eukaryotic evolution, as it has been found more often than expected and related to adaptation to certain niches. A relatively large list of laterally transferred genes has been proposed and evaluated for the parasiteEntamoeba histolytica. The goals of this work were to elucidate the importance of lateral gene transfer along the evolutionary history of some members of the genusEntamoeba, through identifying donor groups and estimating the divergence time of some of these events. In order to estimate the divergence time of some of the horizontal gene transfer events, the dating of someEntamoebaspecies was necessary, following an indirect dating strategy based on the fossil record of plausible hosts. The divergence betweenE. histolyticaandE. nuttalliiprobably occurred 5.93 million years ago (Mya); this lineage diverged fromE. dispar9.97 Mya, while the ancestor of the latter separated fromE. invadens68.18 Mya. We estimated times for 22 transferences; the most recent occurred 31.45 Mya and the oldest 253.59 Mya. Indeed, the acquisition of genes through lateral transfer may have triggered a period of adaptive radiation, thus playing a major role in the evolution of theEntamoebagenus.

scholarly journals Towards an intellectual history of evolutionary economics: competition and struggle versus cooperation and mutual aid

2017 ◽  
Vol 37 (3) ◽  
pp. 551-564
Author(s):  
JOHN HALL ◽  
SVETLANA KIRDINA-CHANDLER
Keyword(s):  
Natural Selection ◽  
Intellectual History ◽  
20Th Century ◽  
Evolutionary Economics ◽  
Early 20Th Century ◽  
Mutual Aid ◽  
Thorstein Veblen ◽  
Origin Of Species ◽  
History Of

ABSTRACT Our inquiry considers the origins of Evolutionary Economics by reintroducing a debate that took place in Russia in the 19th and early 20th century. Responses to Charles Darwin’s The origin of Species are considered, especially critiques stressing Darwin’s emphasis upon competition and struggle in natural selection, that can be traced directly to Thomas Robert Malthus. Considering challenging contributions made by several Russian scholars, we place special emphasis upon Peter Kropotkin’s focus on cooperation and “mutual aid” in natural selection and evolution. We then speculate upon the commonality found in the evolutionary views advanced by Kropotkin and his American contemporary, Thorstein Veblen.

scholarly journals Gene transfers, like fossils, can date the Tree of Life

2017 ◽  
Author(s):  
Adrián A. Davín ◽  
Eric Tannier ◽  
Tom A. Williams ◽  
Bastien Boussau ◽  
Vincent Daubin ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Lateral Gene Transfer ◽  
Gene Families ◽  
Tree Of Life ◽  
Molecular Clocks ◽  
Geological Record ◽  
Microbial Eukaryotes ◽  
Phylogenetic Methods ◽  
History Of ◽  
Source Of Information

Biodiversity has always been predominantly microbial and the scarcity of fossils from bacteria, archaea and microbial eukaryotes has prevented a comprehensive dating of the tree of life. Here we show that patterns of lateral gene transfer deduced from the analysis of modern genomes encode a novel and abundant source of information about the temporal coexistence of lineages throughout the history of life. We use new phylogenetic methods to reconstruct the history of thousands of gene families and demonstrate that dates implied by gene transfers are consistent with estimates from relaxed molecular clocks in Bacteria, Archaea and Eukaryotes. An inspection of discrepancies between transfers and clocks and a comparison with mammal fossils show that gene transfer in microbes is potentially as informative for dating the tree of life as the geological record in macroorganisms.

Reconstruction of the evolutionary history of the LexA-binding sequence

Microbiology ◽  
2004 ◽  
Vol 150 (11) ◽  
pp. 3783-3795 ◽  
Author(s):  
Gerard Mazón ◽  
Ivan Erill ◽  
Susana Campoy ◽  
Pilar Cortés ◽  
Evelyne Forano ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Lateral Gene Transfer ◽  
Evolutionary History ◽  
Bacterial Species ◽  
Evolutionary Relationship ◽  
Gram Positive ◽  
Recognition Motif ◽  
Lexa Binding ◽  
History Of ◽  
Binding Sequence

In recent years, the recognition sequence of the SOS repressor LexA protein has been identified for several bacterial clades, such as the Gram-positive, green non-sulfur bacteria and Cyanobacteria phyla, or the ‘Alphaproteobacteria’, ‘Deltaproteobacteria’ and ‘Gammaproteobacteria’ classes. Nevertheless, the evolutionary relationship among these sequences and the proteins that recognize them has not been analysed. Fibrobacter succinogenes is an anaerobic Gram-negative bacterium that branched from a common bacterial ancestor immediately before the Proteobacteria phylum. Taking advantage of its intermediate position in the phylogenetic tree, and in an effort to reconstruct the evolutionary history of LexA-binding sequences, the F. succinogenes lexA gene has been isolated and its product purified to identify its DNA recognition motif through electrophoretic mobility assays and footprinting experiments. After comparing the available LexA DNA-binding sequences with the F. succinogenes one, reported here, directed mutagenesis of the F. succinogenes LexA-binding sequence and phylogenetic analyses of LexA proteins have revealed the existence of two independent evolutionary lanes for the LexA recognition motif that emerged from the Gram-positive box: one generating the Cyanobacteria and ‘Alphaproteobacteria’ LexA-binding sequences, and the other giving rise to the F. succinogenes and Myxococcus xanthus ones, in a transitional step towards the current ‘Gammaproteobacteria’ LexA box. The contrast between the results reported here and the phylogenetic data available in the literature suggests that, some time after its emergence as a distinct bacterial class, the ‘Alphaproteobacteria’ lost its vertically received lexA gene, but received later through lateral gene transfer a new lexA gene belonging to either a cyanobacterium or a bacterial species closely related to this phylum. This constitutes the first report based on experimental evidence of lateral gene transfer in the evolution of a gene governing such a complex regulatory network as the bacterial SOS system.

scholarly journals How big is the iceberg of which organellar genes in nuclear genomes are but the tip?

2003 ◽  
Vol 358 (1429) ◽  
pp. 39-58 ◽  
Author(s):  
W. F. Doolittle ◽  
Y. Boucher ◽  
C. L. NesbØ ◽  
C. J. Douady ◽  
J. O. Andersson ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Lateral Gene Transfer ◽  
Archaeal Genome ◽  
Genome Sequences ◽  
History Of ◽  
Nuclear Genomes

As more and more complete bacterial and archaeal genome sequences become available, the role of lateral gene transfer (LGT) in shaping them becomes more and more clear. Over the long term, it may be the dominant force, affecting most genes in most prokaryotes. We review the history of LGT, suggesting reasons why its prevalence and impact were so long dismissed. We discuss various methods purporting to measure the extent of LGT, and evidence for and against the notion that there is a core of never–exchanged genes shared by all genomes, from which we can deduce the ‘true’ organismal tree. We also consider evidence for, and implications of, LGT between prokaryotes and phagocytic eukaryotes.

Contingency and determinism in evolution: Replaying life’s tape

Science ◽  
2018 ◽  
Vol 362 (6415) ◽  
pp. eaam5979 ◽  
Author(s):  
Zachary D. Blount ◽  
Richard E. Lenski ◽  
Jonathan B. Losos
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Empirical Studies ◽  
Evolutionary Process ◽  
Random Mutation ◽  
Ongoing Research ◽  
Adaptive Landscapes ◽  
Historical Processes ◽  
History Of ◽  
Evolutionary Paths

Historical processes display some degree of “contingency,” meaning their outcomes are sensitive to seemingly inconsequential events that can fundamentally change the future. Contingency is what makes historical outcomes unpredictable. Unlike many other natural phenomena, evolution is a historical process. Evolutionary change is often driven by the deterministic force of natural selection, but natural selection works upon variation that arises unpredictably through time by random mutation, and even beneficial mutations can be lost by chance through genetic drift. Moreover, evolution has taken place within a planetary environment with a particular history of its own. This tension between determinism and contingency makes evolutionary biology a kind of hybrid between science and history. While philosophers of science examine the nuances of contingency, biologists have performed many empirical studies of evolutionary repeatability and contingency. Here, we review the experimental and comparative evidence from these studies. Replicate populations in evolutionary “replay” experiments often show parallel changes, especially in overall performance, although idiosyncratic outcomes show that the particulars of a lineage’s history can affect which of several evolutionary paths is taken. Comparative biologists have found many notable examples of convergent adaptation to similar conditions, but quantification of how frequently such convergence occurs is difficult. On balance, the evidence indicates that evolution tends to be surprisingly repeatable among closely related lineages, but disparate outcomes become more likely as the footprint of history grows deeper. Ongoing research on the structure of adaptive landscapes is providing additional insight into the interplay of fate and chance in the evolutionary process.

Economic Views of L. Trotsky

2004 ◽  
pp. 142-157
Author(s):  
M. Voeikov ◽  
S. Dzarasov
Keyword(s):  
Civil War ◽  
20Th Century ◽  
Significant Role ◽  
Historical Perspective ◽  
Russian Revolution ◽  
Russian History ◽  
History Of

The paper written in the light of 125th birth anniversary of L. Trotsky analyzes the life and ideas of one of the most prominent figures in the Russian history of the 20th century. He was one of the leaders of the Russian revolution in its Bolshevik period, worked with V. Lenin and played a significant role in the Civil War. Rejected by the party bureaucracy L. Trotsky led uncompromising struggle against Stalinism, defending his own understanding of the revolutionary ideals. The authors try to explain these events in historical perspective, avoiding biases of both Stalinism and anticommunism.

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