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.

scholarly journals Memahami Sensionalisme dalam Berita Televisi: Perspektif Evolusi Biologi

2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Gentur Agustinus Naru
Keyword(s):  
Human Brain ◽  
Evolutionary Biology ◽  
Evolutionary Process ◽  
Time Difference ◽  
Evolutionary Perspective ◽  
History Of ◽  
The Relationship

Although there have been many studies regarding sensationalism on television, there have not been enough studies to explain why sensational news always attracts viewers' attention regardless of space or time difference. Encouraged by this background, this research tries to answer the question, "What makes sensational news interesting to television viewers?" Inspired by a biological evolutionary perspective, this article formulates a hypothesis that reads, "Sensationalism can draw the attention of the audience because sensational news arouses the most basic instincts of humans, namely the mode of survival (Gurven, 2017)". In this view, the model has become inherent in humans as a result of the evolutionary process. In other words, this hypothesis also believes that audience interest in sensational news is universal rather than contextual.   This article explores a variety of literature in biology, psychology, and communication to try to answer that hypothesis. In order to that, this article is divided into three main sections. We will first explore the history of sensational journalism on television to show the historicity of sensational topics and techniques on television. Second, we will demonstrate the philosophical roots of an evolutionary biology view that explains the relationship between information stimuli and the workings of the human brain and the basic instincts we have carried since evolution thousands of years ago. Finally, we will show studies that prove empirically how news patterns (both sensational topics and production formats) impact viewing interest.

scholarly journals Tumor evolutionary directed graphs and the history of chronic lymphocytic leukemia

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Jiguang Wang ◽  
Hossein Khiabanian ◽  
Davide Rossi ◽  
Giulia Fabbri ◽  
Valter Gattei ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Evolutionary History ◽  
Directed Graphs ◽  
Evolutionary Process ◽  
Genetic Alterations ◽  
Lymphocytic Leukemia ◽  
Cross Sectional ◽  
History Of ◽  
Evolutionary Paths ◽  
Clonal Replacement

Cancer is a clonal evolutionary process, caused by successive accumulation of genetic alterations providing milestones of tumor initiation, progression, dissemination, and/or resistance to certain therapeutic regimes. To unravel these milestones we propose a framework, tumor evolutionary directed graphs (TEDG), which is able to characterize the history of genetic alterations by integrating longitudinal and cross-sectional genomic data. We applied TEDG to a chronic lymphocytic leukemia (CLL) cohort of 70 patients spanning 12 years and show that: (a) the evolution of CLL follows a time-ordered process represented as a global flow in TEDG that proceeds from initiating events to late events; (b) there are two distinct and mutually exclusive evolutionary paths of CLL evolution; (c) higher fitness clones are present in later stages of the disease, indicating a progressive clonal replacement with more aggressive clones. Our results suggest that TEDG may constitute an effective framework to recapitulate the evolutionary history of tumors.

The naked ape as an evolutionary model, 50 years later

2018 ◽  
Vol 68 (3) ◽  
pp. 227-246
Author(s):  
Nico M. van Straalen
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary Model ◽  
Developmental Constraints ◽  
Body Hair ◽  
Product Evolution ◽  
Adaptive Explanation ◽  
History Of ◽  
Popular Texts ◽  
The Brain

AbstractEvolution acts through a combination of four different drivers: (1) mutation, (2) selection, (3) genetic drift, and (4) developmental constraints. There is a tendency among some biologists to frame evolution as the sole result of natural selection, and this tendency is reinforced by many popular texts. “The Naked Ape” by Desmond Morris, published 50 years ago, is no exception. In this paper I argue that evolutionary biology is much richer than natural selection alone. I illustrate this by reconstructing the evolutionary history of five different organs of the human body: foot, pelvis, scrotum, hand and brain. Factors like developmental tinkering, by-product evolution, exaptation and heterochrony are powerful forces for body-plan innovations and the appearance of such innovations in human ancestors does not always require an adaptive explanation. While Morris explained the lack of body hair in the human species by sexual selection, I argue that molecular tinkering of regulatory genes expressed in the brain, followed by positive selection for neotenic features, may have been the driving factor, with loss of body hair as a secondary consequence.

Getting Beyond the Apemen

2021 ◽  
pp. 1-18
Author(s):  
Lesley Newson ◽  
Peter J. Richerson
Keyword(s):  
At Risk ◽  
Natural Selection ◽  
Human Evolution ◽  
Evolutionary Process ◽  
Adult Males ◽  
Evolutionary Processes ◽  
Complex Information ◽  
History Of ◽  
Evolution By Natural Selection

This introductory chapter explains why a new story of human evolution is needed, and also lays the foundations of the story told in this book. One of the reasons we need a new story is that previous stories have concentrated on what our male ancestors were doing. Since survival is most at risk in the first years of life, it makes much more sense to concentrate on children and their mothers than on adult males. A brief account of the history of ideas in evolution by natural selection and human evolution provides readers with a background in evolutionary processes. Humans are a product of evolution, but we are not like other animals, because we are connected and readily share complex information. We are unique and our evolution was the result of a unique evolutionary process. To understand ourselves in evolutionary terms, it’s necessary to consider two intertwined evolutionary processes—genes and culture.

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.

Units and levels of selection

2018 ◽  
Author(s):  
Samir Okasha
Keyword(s):  
Natural Selection ◽  
Kin Selection ◽  
Evolutionary Biology ◽  
Evolutionary Process ◽  
Levels Of Selection ◽  
Evolutionary Transitions ◽  
Individual Organism ◽  
Selection Processes ◽  
Hierarchical Levels ◽  
The Individual

In a standard Darwinian explanation, natural selection takes place at the level of the individual organism, i.e. some organisms enjoy a survival or reproduction advantage over others, which results in evolutionary change. In principle however, natural selection could operate at other hierarchical levels too, above and below that of the organism, for example the level of genes, cells, groups, colonies or even whole species. This possibility gives rise to the ‘levels of selection’ question in evolutionary biology. Group and colony-level selection have been proposed, originally by Darwin, as a means by which altruism can evolve. (In biology, ‘altruism’ refers to behaviour which entails a fitness cost to the individual so behaving, but benefits others.) Though this idea is still alive today, many theorists regard kin selection as a superior explanation for the existence of altruism. Kin selection arises from the fact that relatives share genes, so if an organism behaves altruistically towards its relatives, there is a greater than random chance that the beneficiary of the altruistic action will itself be an altruist. Kin selection is closely bound up with the ‘gene’s eye view’ of evolution, which holds that genes, not organisms, are the true beneficiaries of the evolutionary process. The gene’s eye approach to evolution, though heuristically valuable, does not in itself resolve the levels of selection question, because selection processes that occur at many hierarchical levels can all be seen from a gene’s eye viewpoint. In recent years, the levels of selection discussion has been re-invigorated, and subtly transformed, by the important new work on the ‘major evolutionary transitions’. These transitions occur when a number of free-living biological units, originally capable of surviving and reproducing alone, become integrated into a larger whole, giving rise to a new biological unit at a higher level of organization. Evolutionary transitions are intimately bound up with the levels of selection issue, because during a transition the potential exists for selection to operate simultaneously at two different hierarchical levels.

Adaptation

2014 ◽  
Author(s):  
Jonathan B. Losos
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Evolutionary History ◽  
Scientific Research ◽  
Central Focus ◽  
History Of ◽  
Definition Of

Adaptation—the fit of organisms to their environments—has been a central focus in scientific research for centuries, predating even the rise of evolutionary biology. At its core, the study of adaptation is the study of natural selection—how is it that populations become so well suited to survive and reproduce in the environment in which they occur? Nonetheless, the topic of adaptation has many wrinkles and nuances. Even the definition of adaptation is not agreed on by all. The manner in which adaptations evolve (or fail to evolve) and the consequences they have for the evolutionary history of a lineage have been the subjects of considerable scientific research and discussion for more than a century.

An Evolutionary Approach to Synthetic Biology: Zen and the Art of Creating Life

1993 ◽  
Vol 1 (1_2) ◽  
pp. 179-209 ◽  
Author(s):  
Thomas S. Ray
Keyword(s):  
Natural Selection ◽  
Synthetic Biology ◽  
Evolutionary Biology ◽  
Evolutionary Process ◽  
Life Forms ◽  
Evolutionary Approach ◽  
Artificial Medium ◽  
Natural Form ◽  
Evolution By Natural Selection ◽  
Physical Laws

Our concepts of biology, evolution, and complexity are constrained by having observed only a single instance of life, life on earth. A truly comparative biology is needed to extend these concepts. Because we cannot observe life on other planets, we are left with the alternative of creating Artificial Life forms on earth. I will discuss the approach of inoculating evolution by natural selection into the medium of the digital computer. This is not a physical/chemical medium; it is a logical/informational medium. Thus, these new instances of evolution are not subject to the same physical laws as organic evolution (e.g., the laws of thermodynamics) and exist in what amounts to another universe, governed by the “physical laws” of the logic of the computer. This exercise gives us a broader perspective on what evolution is and what it does. An evolutionary approach to synthetic biology consists of inoculating the process of evolution by natural selection into an artificial medium. Evolution is then allowed to find the natural forms of living organisms in the artificial medium. These are not models of life, but independent instances of life. This essay is intended to communicate a way of thinking about synthetic biology that leads to a particular approach: to understand and respect the natural form of the artificial medium, to facilitate the process of evolution in generating forms that are adapted to the medium, and to let evolution find forms and processes that naturally exploit the possibilities inherent in the medium. Examples are cited of synthetic biology embedded in the computational medium, where in addition to being an exercise in experimental comparative evolutionary biology, it is also a possible means of harnessing the evolutionary process for the production of complex computer software.

Radical Epistasis and the Genotype-Phenotype Relationship

1994 ◽  
Vol 2 (1) ◽  
pp. 117-128 ◽  
Author(s):  
David Sloan Wilson ◽  
Alexandra Wells
Keyword(s):  
Linkage Disequilibrium ◽  
Natural Selection ◽  
Assortative Mating ◽  
Evolutionary Process ◽  
Genetic System ◽  
Adaptive Landscape ◽  
Nk Model ◽  
Phenotypic Distribution ◽  
Adaptive Landscapes

Models of evolution often assume that the offspring of two genotypes, which are genetically intermediate by definition, are also phenotypically intermediate. The continuity between genotype and phenotype interferes with the process of evolution on multipeaked adaptive landscapes because the progeny of genotypes that lie on separate adaptive peaks fall into valleys of low fitness. This problem can be solved by epistasis, which disrupts the continuity between genotype and phenotype. In a five-locus sexual haploid model with maximum epistasis, natural selection in multipeak landscapes evolves a set of genotypes that a) occupy the adaptive peaks and b) give rise to each other by recombination. The epistatic genetic system therefore “molds” the phenotypic distribution to the adaptive landscape, without assortative mating or linkage disequilibrium. If the adaptive landscape is changed, a new set of genotypes quickly evolves that satisfies conditions a and b, above, for the new peaks. Our model may be relevant to a number of recalcitrant problems in biology and also stands in contrast to Kauffman's [3] NK model of evolution on rugged fitness surfaces, in which epistasis and recombination tend to constrain the evolutionary process.

scholarly journals Observational articles: a tool to reconstruct ecological history based on chronicling unusual events

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 168 ◽  
Author(s):  
Ferdinando Boero
Keyword(s):  
Natural Selection ◽  
Natural History ◽  
Evolutionary Biology ◽  
Drivers Of Change ◽  
Testing Hypotheses ◽  
Ecological History ◽  
Modern Ecology ◽  
History Of ◽  
Sudden Appearance ◽  
Non Linear Systems

Natural history is based on observations, whereas modern ecology is mostly based on experiments aimed at testing hypotheses, either in the field or in a computer. Furthermore, experiments often reveal generalities that are taken as norms. Ecology, however, is a historical discipline and history is driven by both regularities (deriving from norms) and irregularities, or contingencies, which occur when norms are broken. If only norms occured, there would be no history. The current disregard for the importance of contingencies and anecdotes is preventing us from understanding ecological history. We need rules and norms, but we also need records about apparently irrelevant things that, in non-linear systems like ecological ones, might become the drivers of change and, thus, the determinants of history. The same arguments also hold in the field of evolutionary biology, with natural selection being the ecological driver of evolutionary change. It is important that scientists are able to publish potentially important observations, particularly those that are unrelated to their current projects that have no sufficient grounds to be framed into a classical eco-evolutionary paper, and could feasibly impact on the history of the systems in which they occurred. A report on any deviation from the norm would be welcome, from the disappearance of species to their sudden appearance in great quantities. Any event that an “expert eye” (i.e. the eye of a naturalist) might judge as potentially important is worth being reported.

Sign in / Sign up

Export Citation Format

Share Document