Evolutionary Causes Research Articles

Drivers and consequences of female reproductive competition in an egalitarian, sexually monomorphic primate

Even after the 150th anniversary of sexual selection theory, the drivers and mechanisms of female sexual selection remain poorly studied. To understand demographic circumstances favoring female-female competition, trade-offs with kin selection and interactions with male reproductive strategies, we investigated female evictions in redfronted lemurs (Eulemur rufifrons). Based on 24 years of demographic data of known individuals, we show that female redfronted lemurs target close female kin for forcible, permanent, and presumably lethal eviction, even though groups contain multiple unrelated males whose voluntary emigration actually mitigated the probability of future female evictions. Female eviction and male emigration were predicted by group size, but male emigration was primarily driven by a proportional increase of male rivals. Female evictions were more likely than male emigrations when there were more juvenile females in a group, but the identity of evicted females was not predicted by any intrinsic traits. While birth rates were reduced by the number of juvenile females, they were higher when there were more adult females in a group and in years with more rainfall. Early infant survival was reduced with increasing numbers of juvenile females, but variation in female lifetime reproductive success was not related to any of the predictors examined here. Thus, there seems to be a limit on female group size in this lemur species. More generally, our study demonstrates a balanced interplay between female reproductive competition, competition over group membership between both sexes, and kin selection, contributing new insights into the causes and consequences of female competition in animal societies.Significance statementThe evolutionary causes of female competition in vertebrate societies remain poorly known. Evictions represent an extreme form of female competition because even close kin are evicted when same-sized unrelated males are theoretically also available as victims. We studied drivers and consequences of evictions in redfronted lemurs (Eulemur rufifrons) using 24 years of demographic data from multiple groups. We show that while voluntary male emigration mitigates the probability of future female evictions, females nonetheless appear to accept the fitness costs of evicting female kin. While group size seems to be the main driver of departures by either sex, the number of juvenile females present in groups is the key variable triggering eviction events as well as physiological responses that could be interpreted as female reproductive restraint. Our study therefore revealed that competition does trump cooperation under some circumstances in the intricate interplay between sexual selection and kin selection on females.

Integrating neuroplasticity and evolution

Neuroplasticity and evolutionary biology have been prominent fields of study for well over a century. However, they have advanced largely independently, without consideration of the benefits of integration. We propose a new framework by which researchers can begin to examine the evolutionary causes and consequences of neuroplasticity. Neuroplasticity can be defined as changes to the structure, function or connections of the nervous system in response to individual experience. Evolution can alter levels of neuroplasticity if there is variation in neuroplasticity traits within and between populations. Neuroplasticity may be favored or disfavored by natural selection depending on the variability of the environment and the costs of neuroplasticity. Additionally, neuroplasticity may affect rates of genetic evolution in many ways: for example, decreasing rates of evolution by buffering against selection or increasing them via the Baldwin effect, by increasing genetic variation or by incorporating evolved peripheral changes to the nervous system. These mechanisms can be tested using comparative and experimental approaches and by examining patterns and consequences of variation in neuroplasticity among species, populations and individuals.

Adaptive reactions of ancient fossil organisms: Likely evolutionary causes of sociality emergence

The results of the study of stromatolites for the purposes of geology have shown the directed and irreversible nature of their evolution. Further detailed study of the structure made it possible to reveal the subordination of the structures of various hierarchical levels and the consistency of their changes over time, which indicates the presence of morphogenetic and adaptive capabilities in the macroscopic stromatolite-forming agent – the properties of an integral organism. This was in conflict with the ideas existing at that time about the impossibility of the formation of organized communities or multicellular organisms by prokaryotes. It was believed that the formation of multicellular organisms and any communities with developed communication requires a high structural complexity of the elements. Bacteria were considered as solitary or colonial organisms not having sufficient complexity. However, direct observation of their accumulations revealed signs of highly organized communities comparable in their integrity to organisms. This forces a different approach to the nature of the emergence of communities and the sources of their complexity. Based on the unity of the observed processes, in addition to the cyanobacteria themselves, data on other groups of bacteria, as well as on modular organisms and communities of multicellular eukaryotes, are considered.

A Study on the Evolution of Digital Marketing

Objective: Digital marketing in the growing world has paved the way for many small-scale businesses to reach every corner of the geographic locations that they could not reach physically. The study focuses on the digital marketing usefulness based on past trends, in forecasting the near future trends in emerging markets when it comes to evolution of digital marketing, the effect of COVID-19 on digital marketing, comparison of past, present and scope for future businessmen to analyse the market to launch digital platform. SWOT analysis is also an integral part of this study as an attempt to dive in depth of positive and negative sides of digital marketing. Methodology: The study on the systematic Evolution of digital marketing is studied depending on the secondary sources with an intention to dive in depth of emergence and evolution of digital marketing. The semi-systematic review is done by studying different reports and articles published from Google Scholar, ResearchGate, SSRN and other such publication websites. Findings: The study on the evolution of digital marketing has come out with the common ground that digital marketing of products, services, businesses and any other things would see an increasingly greater demand in upcoming years. Due to emergence of high-speed internet, electronic gadgets, standard of living has paved the way for people to buy products that make them feel on par with their peers. The intense feeling or want that makes people to find pleasure in buying expensive products has led for the growth of digital marketing. Moreover, the study has been an evidence by itself how rural areas have revolutionized from lack of internet and network to modern way of internet and electronic gadget usages. COVID-19 is found as another reason in this study for the booming of digital marketing. Practical Implications: This study on Evolution of digital marketing would help students, researchers, readers to learn various reasons for the causes for evolution of digital marketing, the base COVID-19 has formed for the dependency of people on internet and electronic gadgets and also the impact digital marketing has on businesses due to which they have gone digital from traditional approach of marketing. Originality/Value: This study is purely a secondary study which would give out understanding of digital marketing, its benefits, the future scope, various strengths, weaknesses, opportunities and Traits for the marketers. The main limitation of the study as this is a secondary study, the study could be better analysed by conducting face-to-face interviews with the involved people like sellers, buyers, patients recovered from COVID-19 virus as they would be in a better position to contribute to the study with their real-life situations. Paper type: Case Study

Reciprocal causation and biological practice

Arguments for an extended evolutionary synthesis often center on the concept of “reciprocal causation.” Proponents argue that reciprocal causation is superior to standard models of evolutionary causation for at least two reasons. First, it leads to better scientific models with more predictive power. Second, it more accurately represents the causal structure of the biological world. Simply put, proponents of an extended evolutionary synthesis argue that reciprocal causation is empirically and explanatorily apt relative to competing causal frameworks. In this paper, I present quantitative survey data from faculty members in biology departments at universities across the United States to evaluate this claim. The survey data indicate that a majority of the participants do not agree (i.e., most either disagree or neither agree nor disagree) that the concept of reciprocal causation confers a larger advantage on research practices. However, a majority of the participants agree that the causal framework of the extended evolutionary synthesis more accurately represents the structure of the biological world. These results demonstrate that the explanatory merits of a conceptual framework and its practical utility can come apart in interesting and informative ways.

Fish personality: meta-theoretical issues, personality dimensions, and applications to neuroscience and psychopathology.

While the field of personality neuroscience has extensively focused on humans and, in a few cases, primates and rodents, a wide range of research on fish personality has emerged in the last decades. This research is focused mainly on the ecological and evolutionary causes of individual differences and also aimed less extensively at proximal mechanisms (e.g., neurochemistry or genetics). We argue that, if consistent and intentional work is made to solve some of the meta-theoretical issues of personality research both on fish and mammals, fish personality research can lead to important advances in personality neuroscience as a whole. The five dimensions of personality in fish (shyness-boldness, exploration-avoidance, activity, aggressiveness, and sociability) need to be translated into models that explicitly recognize the impacts of personality in psychopathology, synergizing research on fish as model organisms in experimental psychopathology, personality neuroscience, and ecological-ethological approaches to the evolutionary underpinnings of personality to produce a powerful framework to understand individual differences.

Evolutionary Origins of ORL Disorders

It is understood that our ancestors gained a strong evolutionary selective advantage in shaping the vocal tract that allowing them speak more intelligibly. However, humans pay heavy prices for the uniqueness of vocal tracts configuration. We precariously swallow our mouthful in exchange for speaking clearly, and the second heavy price humans pay is sleep snoring. Their evolutionary cause is that the respiratory system deriving on the wrong side and too late from the alimentary system. The fact that our nasal septum is usually curved contributes to these disorders. The reason of this is that a few million years ago humans had to compromise from the width of the birth canal with their pelvis in order to stand upright. As for our children’s ears, their development resembles the evolution of hominoids and they are far from smooth.

Gene expression in the female tree swallow brain is associated with inter- and intra-population variation in glucocorticoid levels

Studies of the evolutionary causes and consequences of variation in circulating glucocorticoids (GCs) have begun to reveal how they are shaped by selection. Yet the extent to which variation in circulating hormones reflects variation in other important regulators of the hypothalamic-pituitary-adrenal (HPA) axis, and whether these relationships vary among populations inhabiting different environments, remain poorly studied. Here, we compare gene expression in the brain of female tree swallows (Tachycineta bicolor) from populations that breed in environments that differ in their unpredictability. We find evidence of inter-population variation in the expression of glucocorticoid and mineralocorticoid receptors in the hypothalamus, with the highest gene expression in a population from an extreme environment, and lower expression in a population from a more consistent environment as well as in birds breeding at an environmentally variable high-altitude site that are part of a population that inhabits a mixture of high and low altitude habitats. Within some populations, variation in circulating GCs predicted differences in gene expression, particularly in the hypothalamus. However, some patterns were present in all populations, whereas others were not. These results are consistent with the idea that some combination of local adaptation and phenotypic plasticity may modify components of the HPA axis affecting stress resilience. Our results also underscore that a comprehensive understanding of the function and evolution of the stress response cannot be gained from measuring circulating hormones alone, and that future studies that apply a more explicitly evolutionary approach to important regulatory traits are likely to provide significant insights.

Do microbes have a memory? History-dependent behavior in the adaptation to variable environments.

Microbes are constantly confronted with changes and challenges in their environment. A proper response to these environmental cues is needed for optimal cellular functioning and fitness. Interestingly, past exposure to environmental cues can accelerate or boost the response when this condition returns, even in daughter cells that have not directly encountered the initial cue. Moreover, this behavior is mostly epigenetic and often goes hand in hand with strong heterogeneity in the strength and speed of the response between isogenic cells of the same population, which might function as a bet-hedging strategy. In this review, we discuss examples of history-dependent behavior (HDB) or “memory,” with a specific focus on HDB in fluctuating environments. In most examples discussed, the lag time before the response to an environmental change is used as an experimentally measurable proxy for HDB. We highlight different mechanisms already implicated in HDB, and by using HDB in fluctuating carbon conditions as a case study, we showcase how the metabolic state of a cell can be a key determining factor for HDB. Finally, we consider possible evolutionary causes and consequences of such HDB.

The preservation of cause and effect in the rock record

AbstractEvolutionary events may impact the geological carbon cycle via transient imbalances in silicate weathering, and such events have been implicated as causes of glaciations, mass extinctions, and oceanic anoxia. However, suggested evolutionary causes often substantially predate the environmental effects to which they are linked—problematic when carbon cycle perturbations must be resolved in less than a million years to maintain Earth's habitability. What is more, the geochemical signatures of such perturbations are recorded as they occur in widely distributed marine sedimentary rocks that have been densely sampled for important intervals in Earth history, whereas the fossil record—particularly on land—is governed by the availability of sedimentary basins that are patchy in both space and time, necessitating lags between the origination of an evolutionary lineage and its earliest occurrence in the fossil record. Here, we present a simple model of the impact of preservational filtering on sampling to show that an evolutionary event that causes an environmental perturbation via weathering imbalance should not appear earlier in the rock record than the perturbation itself and, if anything, should appear later rather than simultaneously. The Devonian Hangenberg glaciation provides an example of how evolutionary events might be more fruitfully considered as potential causes of environmental perturbations. Just as the last samplings of species lost in mass extinction are expected to come before the true environmental event, first appearance should be expected to postdate the geological expression of a lineage's environmental impact with important implications for our reading of Earth history.

Linking sexual size dimorphism to trophic niche partitioning in a generalist predator

Sexual size dimorphism is a common phenomenon in mammals, and researchers have been trying to demonstrate the evolutionary causes leading to sexual dimorphism. Two main hypotheses emerged: (1) the sexual selection hypothesis and (2) the sexual competition hypothesis (also called resource partitioning hypothesis). Here, we attempted to link sexual dimorphism in fishers ( Pekania pennanti (Erxleben, 1777)) with their fall diet using stable isotope profiling and body and skull measurements. We used the carcasses of 39 fishers which were caught in eastern Québec during fall 2014 by volunteer trappers as well as several potential prey items ranging from small rodents to cervids. We expected minimal niche overlap between sexes, as males should be able to exploit different prey species than females. We also expected to observe an effect of age class (adults vs. juveniles) on trophic niche. As expected, we found great evidence of sexual dimorphism in both body mass and skull measurements: males were heavier and longer than females and had a larger zygomatic and intracanine width and a longer skull. While proportions of prey in diet according to sex and age did not vary greatly, we found some evidence of niche partitioning using Layman's metrics. Indeed, females tended to have a less diversified and more similar diet compared to one another, whereas males showed more diversified and contrasted diets. Despite our limited sample size, our findings provide partial support to the sexual competition hypothesis, as the difference in body and skull size based on sex could have evolved to lessen intraspecific competition in fishers.

Эволюция понятия социального действия

The purpose of the study is to analyze the concept of social action in the context of its evolutionary development, to identify the semantic causes of evolution and promising directions in the evolutionary change of this concept. The scientific novelty lies in the fact that the concept of social action is considered not only in the analytical realities of phenomenological and structural-functional approaches, but also in the context of a holistic review of the issues related to the typification of social action and the variable possibilities of further evolution of this concept. The holistic combination of phenomenological and structural-functional approaches creates justifications for revealing the semantic reasons for the evolution of the concept of social action. In this regard, the dynamic connection between the unique and the social is pointed out, and a conclusion is made about promising evolutionary directions for further semantic disclosure of the concept of social action. As a result, the conclusion is made about promising evolutionary directions for further semantic disclosure of the concept of social action.

Even allocation of benefits stabilizes microbial community engaged in metabolic division of labor.

Microbial communities execute metabolic pathways to drive global nutrient cycles. Within a community, functionally specialized strains can perform different yet complementary steps within a linear pathway, a phenomenon termed metabolic division of labor (MDOL). However, little is known about how such metabolic behaviors shape microbial communities. Here, we derive a theoretical framework to define the assembly of a community that degrades an organic compound through MDOL. The framework indicates that to ensure community stability, the strains performing the initial steps should hold a growth advantage (m) over the "private benefit" (n) of the strain performing the last step. The steady-state frequency of the last strain is then determined by the quotient of n and m. Our experiments show that the framework accurately predicts the assembly of our synthetic consortia that degrade naphthalene through MDOL. Our results provide insights for designing and managing stable microbial systems for metabolic pathway optimization.

Consistent Individual Behavioral Variation: What Do We Know and Where Are We Going?

The study of individual behavioral variation, sometimes called animal personalities or behavioral types, is now a well-established area of research in behavioral ecology and evolution. Considerable theoretical work has developed predictions about its ecological and evolutionary causes and consequences, and studies testing these theories continue to grow. Here, we synthesize the current empirical work to shed light on which theories are well supported and which need further refinement. We find that the major frameworks explaining the existence of individual behavioral variation, the pace-of-life syndrome hypothesis and state-dependent feedbacks models, have mixed support. The consequences of individual behavioral variation are well studied at the individual level but less is known about consequences at higher levels such as among species and communities. The focus of this review is to reevaluate and reestablish the foundation of individual behavioral variation research: What do we know? What questions remain? And where are we going next?

The evolution of recombination in self-fertilizing organisms.

Cytological data from flowering plants suggest that the evolution of recombination rates is affected by the mating system of organisms, as higher chiasma frequencies are often observed in self-fertilizing species compared with their outcrossing relatives. Understanding the evolutionary cause of this effect is of particular interest, as it may shed light on the selective forces favoring recombination in natural populations. While previous models showed that inbreeding may have important effects on selection for recombination, existing analytical treatments are restricted to the case of loosely linked loci and weak selfing rates, and ignore the stochastic effect of genetic interference (Hill-Robertson effect), known to be an important component of selection for recombination in randomly mating populations. In this article, we derive general expressions quantifying the stochastic and deterministic components of selection acting on a mutation affecting the genetic map length of a whole chromosome along which deleterious mutations occur, valid for arbitrary selfing rates. The results show that selfing generally increases selection for recombination caused by interference among mutations as long as selection against deleterious alleles is sufficiently weak. While interference is often the main driver of selection for recombination under tight linkage or high selfing rates, deterministic effects can play a stronger role under intermediate selfing rates and high recombination, selecting against recombination in the absence of epistasis, but favoring recombination when epistasis is negative. Individual-based simulation results indicate that our analytical model often provides accurate predictions for the strength of selection on recombination under partial selfing.

Cancer and Evolution: An Ancient Relation Explored Recently

Cancer is a consequence of multi-cellularity and is a striking example of multilevel selection. The theory of cancer initiation and progression has its root deep within the evolutionary and ecological concepts. Cancer develops through somatic evolution, with genetic and epigenetic precariousness, generating fitness variation among the cells in the body. Epidemiological, genetic, and molecular biological research have cumulatively provided us with a brimming source of data that affirms our current understanding of the etiology and molecular pathogenesis of cancer. But this aspect only focuses on immediate mechanisms and does not competently explain the pervasiveness of tumors and cancer in animal species or what seems to be the exceptional vulnerability of Homo sapiens. At a practical level, analyses suggest that, for evolutionary reasons, as a species, we are inherently more likely to develop cancer (than we might like to admit). Though we cannot reverse our genetic legacies and predilection to cancer, emphasizing inherent vulnerability in an ‘evolutionary’ way strongly ratifies our current attempts to combat cancer. In actuality, neoplasms are microcosms of evolution. Within a neoplasm, a mosaic of mutant cells competes for space and resources, evades predation by the immune system, and can even cooperate to disperse and colonize new organs (metastasis). The evolution of neoplastic cells can explain both why we get cancer and why it has been so difficult to find a cure. Although the idea of cancer as an evolutionary problem is not new at least historically little attention has been delivered to applications of evolutionary biological principles in understanding and controlling neoplastic progression. Already, we have reached the high time when this should be changed. Ernst Mayr aptly said that “No biological problem is solved until both the proximate and the evolutionary causation has been elucidated” Keywords: [Cancer, adaptation, evolution].

Evolvability in the Cephalothoracic Structural Complexity of Aegla araucaniensis (Crustacea: Decapoda) Determined by a Developmental System with Low Covariational Constraint.

Simple SummaryThe origin of complex morphological structures is explained mainly by direct pathways fusing adjacent modules, while the independent effect of parallel pathways acting on different areas of a morphogenetic field is less well-known. The palimpsest model that explains the cephalothoracic structural complexity of decapod crustaceans is composed of two hox-regulatory parallel pathways that tagmatize the anterior metameres early, followed by a direct pathway that fuses the tagmata forming the developmental modules. The cephalothoracic geometry of Aegla araucaniensis shows a marked sexual dimorphism; its adaptive causes also promote dimorphic variations in the evolvability of developmental modularity. We found areas of instability in the variance of the asymmetry in both developmental modules. The direct pathway presents intermediate levels of canalization in the covariation of the developmental modules, although significantly higher in males. This low restrictive potential promotes expressions of gonadic modularity in females and agonistic modularity in males, which differ significantly from developmental modularity. The cephalothoracic palimpsest model of decapods allows studying modularity in an explicit evo–devo context.The integration of complex structures is proportional to the intensity of the structural fusion; its consequences are better known than the covariational effects under less restrictive mechanisms. The synthesis of a palimpsest model based on two early parallel pathways and a later direct pathway explains the cephalothoracic complexity of decapod crustaceans. Using this model, we tested the evolvability of the developmental modularity in Aegla araucaniensis, an anomuran crab with an evident adaptive sexual dimorphism. The asymmetric patterns found on the landmark configurations suggest independent perturbations of the parallel pathways in each module and a stable asymmetry variance near the fusion by canalization of the direct pathway, which was more intense in males. The greater covariational flexibility imposed by the parallel pathways promotes the expression of gonadic modularity that favors the reproductive output in females and agonistic modularity that contributes to mating success in males. Under these divergent expressions of evolvability, the smaller difference between developmental modularity and agonistic modularity in males suggests higher levels of canalization due to a relatively more intense structural fusion. We conclude that: (1) the cephalothorax of A. araucaniensis is an evolvable structure, where parallel pathways promote sexual disruptions in the expressions of functional modularity, which are more restricted in males, and (2) the cephalothoracic palimpsest of decapods has empirical advantages in studying the developmental causes of evolution of complex structures.

Shell color polymorphism in marine gastropods.

Marine gastropods are characterized by an incredible variation in shell color. In this review, we aim to introduce researchers to previous studies of shell color polymorphism in this group of animals, trying to provide an overview of the topic and highlighting some potential avenues for future research. For this, we tackle the different aspects of shell color polymorphism in marine gastropods: its biochemical and genetic basis, its patterns of spatial and temporal distribution, as well as its potential evolutionary causes. In particular, we put special emphasis on the evolutionary studies that have been conducted so far to reveal the evolutionary mechanisms responsible for the maintenance of shell color polymorphism in this group of animals, as it constitutes the least addressed aspect in existing literature reviews. Several general conclusions can be drawn from our review: First, natural selection is commonly involved in the maintenance of gastropod color polymorphism; second, although the contribution of neutral forces (gene flow-genetic drift equilibrium) to shell color polymorphism maintenance do not seem to be particularly important, it has rarely been studied systematically; third, a relationship between shell color polymorphism and mode of larval development (related to dispersal capability) may exist. As for future studies, we suggest that a combination of both classical laboratory crossing experiments and -Omics approaches may yield interesting results on the molecular basis of color polymorphism. We believe that understanding the various causes of shell color polymorphism in marine gastropods is of great importance not only to understand how biodiversity works, but also for protecting such biodiversity, as knowledge of its evolutionary causes may help implement conservation measures in those species or ecosystems that are threatened.

Nesting in Anolis Lizards: An Understudied Topic in a Well-Studied Clade

Maternal nesting behavior in oviparous species strongly influences the environmental conditions their embryos experience during development. In turn, these early-life conditions have consequences for offspring phenotypes and many fitness components across an individual’s lifespan. Thus, identifying the evolutionary and ecological causes and effects of nesting behavior is a key goal of behavioral ecology. Studies of reptiles have contributed greatly to our understanding of how nesting behavior shapes offspring phenotypes. While some taxonomic groups have been used extensively to provide insights into this important area of biology, many groups remain poorly studied. For example, the squamate genusAnolishas served as a model to study behavior, ecology, and evolution, but research focused onAnolisnesting behavior and developmental plasticity is comparatively scarce. This dearth of empirical research may be attributed to logistical challenges (e.g., difficulty locating nests), biological factors (e.g., their single-egg clutches may hinder some experimental designs), and a historical focus on males inAnolisresearch. Although there is a gap in the literature concerningAnolisnesting behavior, interest in nesting ecology and developmental plasticity in this group has grown in recent years. In this paper, we (1) review existing studies of anole nesting ecology and developmental plasticity; (2) highlight areas of anole nesting ecology that are currently understudied and discuss how research in these areas can contribute to broader topics (e.g., maternal effects and global change biology); and (3) provide guidelines for studying anole nesting in the field. Overall, this review provides a foundation for establishing anoles as models to study nesting ecology and developmental plasticity.

Evolutionary causes and consequences of ungulate migration.

Ungulate migrations are crucial for maintaining abundant populations and functional ecosystems. However, little is known about how or why migratory behaviour evolved in ungulates. To investigate the evolutionary origins of ungulate migration, we employed phylogenetic path analysis using a comprehensive species-level phylogeny of mammals. We found that 95 of 207 extant ungulate species are at least partially migratory, with migratory behaviour originating independently in 17 lineages. The evolution of migratory behaviour is associated with reliance on grass forage and living at higher latitudes wherein seasonal resource waves are most prevalent. Indeed, originations coincide with mid-Miocene cooling and the subsequent rise of C4 grasslands. Also, evolving migratory behaviour supported the evolution of larger bodies, allowing ungulates to exploit new ecological space. Reconstructions of migratory behaviour further revealed that seven of ten recently extinct species were probably migratory, suggesting that contemporary migrations are important models for understanding the ecology of the past.