scholarly journals Positive interactions within and between populations decrease the likelihood of evolutionary rescue

2020 ◽  
Author(s):  
Yaron Goldberg ◽  
Jonathan Friedman
Keyword(s):  
Human Microbiome ◽  
Positive Interactions ◽  
Population Declines ◽  
Evolutionary Forces ◽  
Selective Pressures ◽  
Multiple Phenotypes ◽  
Evolutionary Rescue ◽  
And Function ◽  
Number Of Individuals ◽  
Theoretical Analyses

AbstractPositive interactions, including intraspecies cooperation and interspecies mutualisms, play crucial roles in shaping the structure and function of many ecosystems, ranging from plant communities to the human microbiome. While the evolutionary forces that form and maintain positive interactions have been investigated extensively, the influence of positive interactions on the ability of species to adapt to new environments is still poorly understood. Here, we use numerical simulations and theoretical analyses to study how positive interactions impact the likelihood that populations survive after an environment deteriorates, such that survival in the new environment requires quick adaptation via the rise of new mutants - a scenario known as evolutionary rescue. We find that the probability of evolutionary rescue in populations engaged in positive interactions is reduced significantly. In cooperating populations, this reduction is largely due to the fact that survival may require at least a minimal number of individuals, meaning that adapted mutants must arise and spread before the population declines below this threshold. In mutualistic populations, the rescue probability is decreased further due to two additional effects - the need for both mutualistic partners to adapt to the new environment, and competition between the two species. Finally, we show that the presence of cheaters reduces the likelihood of evolutionary rescue even further, making it extremely unlikely. These results indicate that while positive interactions may be beneficial in stable environments, they can hinder adaptation to changing environments and thereby elevate the risk of population collapse. Furthermore, these results may hint at the selective pressures that drove co-dependent unicellular species to form more adaptable organisms able to differentiate into multiple phenotypes, including multicellular life.

scholarly journals Positive interactions within and between populations decrease the likelihood of evolutionary rescue

2021 ◽  
Vol 17 (2) ◽  
pp. e1008732
Author(s):  
Yaron Goldberg ◽  
Jonathan Friedman
Keyword(s):  
Human Microbiome ◽  
Positive Interactions ◽  
Population Declines ◽  
Evolutionary Forces ◽  
Selective Pressures ◽  
Multiple Phenotypes ◽  
Evolutionary Rescue ◽  
And Function ◽  
Number Of Individuals ◽  
Theoretical Analyses

Positive interactions, including intraspecies cooperation and interspecies mutualisms, play crucial roles in shaping the structure and function of many ecosystems, ranging from plant communities to the human microbiome. While the evolutionary forces that form and maintain positive interactions have been investigated extensively, the influence of positive interactions on the ability of species to adapt to new environments is still poorly understood. Here, we use numerical simulations and theoretical analyses to study how positive interactions impact the likelihood that populations survive after an environment deteriorates, such that survival in the new environment requires quick adaptation via the rise of new mutants—a scenario known as evolutionary rescue. We find that the probability of evolutionary rescue in populations engaged in positive interactions is reduced significantly. In cooperating populations, this reduction is largely due to the fact that survival may require at least a minimal number of individuals, meaning that adapted mutants must arise and spread before the population declines below this threshold. In mutualistic populations, the rescue probability is decreased further due to two additional effects—the need for both mutualistic partners to adapt to the new environment, and competition between the two species. Finally, we show that the presence of cheaters reduces the likelihood of evolutionary rescue even further, making it extremely unlikely. These results indicate that while positive interactions may be beneficial in stable environments, they can hinder adaptation to changing environments and thereby elevate the risk of population collapse. Furthermore, these results may hint at the selective pressures that drove co-dependent unicellular species to form more adaptable organisms able to differentiate into multiple phenotypes, including multicellular life.

scholarly journals Evolutionary rescue and the limits of adaptation

2013 ◽  
Vol 368 (1610) ◽  
pp. 20120080 ◽  
Author(s):  
Graham Bell
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Relative Fitness ◽  
Population Declines ◽  
Genetic Constraints ◽  
Evolutionary Rescue ◽  
Large Populations ◽  
Effective Selection ◽  
The Cost ◽  
Number Of Individuals

Populations subject to severe stress may be rescued by natural selection, but its operation is restricted by ecological and genetic constraints. The cost of natural selection expresses the limited capacity of a population to sustain the load of mortality or sterility required for effective selection. Genostasis expresses the lack of variation that prevents many populations from adapting to stress. While the role of relative fitness in adaptation is well understood, evolutionary rescue emphasizes the need to recognize explicitly the importance of absolute fitness. Permanent adaptation requires a range of genetic variation in absolute fitness that is broad enough to provide a few extreme types capable of sustained growth under a stress that would cause extinction if they were not present. This principle implies that population size is an important determinant of rescue. The overall number of individuals exposed to selection will be greater when the population declines gradually under a constant stress, or is progressively challenged by gradually increasing stress. In gradually deteriorating environments, survival at lethal stress may be procured by prior adaptation to sublethal stress through genetic correlation. Neither the standing genetic variation of small populations nor the mutation supply of large populations, however, may be sufficient to provide evolutionary rescue for most populations.

scholarly journals The effects of modern war and military activities on biodiversity and the environment

2015 ◽  
Vol 23 (4) ◽  
pp. 443-460 ◽  
Author(s):  
Michael J. Lawrence ◽  
Holly L.J. Stemberger ◽  
Aaron J. Zolderdo ◽  
Daniel P. Struthers ◽  
Steven J. Cooke
Keyword(s):  
Military Training ◽  
Structure And Function ◽  
Aquatic Systems ◽  
Ecosystem Structure ◽  
Population Declines ◽  
Exclusion Zone ◽  
Negative Effects ◽  
And Function ◽  
Ecosystem Structure And Function ◽  
Modern War

War is an ever-present force that has the potential to alter the biosphere. Here we review the potential consequences of modern war and military activities on ecosystem structure and function. We focus on the effects of direct conflict, nuclear weapons, military training, and military produced contaminants. Overall, the aforementioned activities were found to have overwhelmingly negative effects on ecosystem structure and function. Dramatic habitat alteration, environmental pollution, and disturbance contributed to population declines and biodiversity losses arising from both acute and chronic effects in both terrestrial and aquatic systems. In some instances, even in the face of massive alterations to ecosystem structure, recovery was possible. Interestingly, military activity was beneficial under specific conditions, such as when an exclusion zone was generated that generally resulted in population increases and (or) population recovery; an observation noted in both terrestrial and aquatic systems. Additionally, military technological advances (e.g., GPS technology, drone technology, biotelemetry) have provided conservation scientists with novel tools for research. Because of the challenges associated with conducting research in areas with military activities (e.g., restricted access, hazardous conditions), information pertaining to military impacts on the environment are relatively scarce and are often studied years after military activities have ceased and with no knowledge of baseline conditions. Additional research would help to elucidate the environmental consequences (positive and negative) and thus reveal opportunities for mitigating negative effects while informing the development of optimal strategies for rehabilitation and recovery.

scholarly journals Vulnerability of individual fish to capture by trawling is influenced by capacity for anaerobic metabolism

2015 ◽  
Vol 282 (1813) ◽  
pp. 20150603 ◽  
Author(s):  
Shaun S. Killen ◽  
Julie J. H. Nati ◽  
Cory D. Suski
Keyword(s):  
Large Scale ◽  
Swimming Performance ◽  
Anaerobic Capacity ◽  
Standard Metabolic Rate ◽  
Metabolic Demand ◽  
Evolutionary Forces ◽  
Individual Fish ◽  
Fundamental Information ◽  
Behavioural Phenotypes ◽  
And Function

The harvest of animals by humans may constitute one of the strongest evolutionary forces affecting wild populations. Vulnerability to harvest varies among individuals within species according to behavioural phenotypes, but we lack fundamental information regarding the physiological mechanisms underlying harvest-induced selection. It is unknown, for example, what physiological traits make some individual fish more susceptible to capture by commercial fisheries. Active fishing methods such as trawling pursue fish during harvest attempts, causing fish to use both aerobic steady-state swimming and anaerobic burst-type swimming to evade capture. Using simulated trawling procedures with schools of wild minnows Phoxinus phoxinus , we investigate two key questions to the study of fisheries-induced evolution that have been impossible to address using large-scale trawls: (i) are some individuals within a fish shoal consistently more susceptible to capture by trawling than others?; and (ii) if so, is this related to individual differences in swimming performance and metabolism? Results provide the first evidence of repeatable variation in susceptibility to trawling that is strongly related to anaerobic capacity and swimming ability. Maximum aerobic swim speed was also negatively correlated with vulnerability to trawling. Standard metabolic rate was highest among fish that were least vulnerable to trawling, but this relationship probably arose through correlations with anaerobic capacity. These results indicate that vulnerability to trawling is linked to anaerobic swimming performance and metabolic demand, drawing parallels with factors influencing susceptibility to natural predators. Selection on these traits by fisheries could induce shifts in the fundamental physiological makeup and function of descendent populations.

scholarly journals Exploring the microbiome in health and disease

2017 ◽  
Vol 1 ◽  
pp. 239784731774188 ◽  
Author(s):  
Elena Scotti ◽  
Stéphanie Boué ◽  
Giuseppe Lo Sasso ◽  
Filippo Zanetti ◽  
Vincenzo Belcastro ◽  
...  
Keyword(s):  
Human Health ◽  
Metabolic Diseases ◽  
Skin Diseases ◽  
Human Microbiome ◽  
Chronic Obstructive ◽  
Microbial Composition ◽  
Obstructive Pulmonary Disease ◽  
New Findings ◽  
Dynamics And Function ◽  
And Function

The analysis of human microbiome is an exciting and rapidly expanding field of research. In the past decade, the biological relevance of the microbiome for human health has become evident. Microbiome comprises a complex collection of microorganisms, with their genes and metabolites, colonizing different body niches. It is now well known that the microbiome interacts with its host, assisting in the bioconversion of nutrients and detoxification, supporting immunity, protecting against pathogenic microbes, and maintaining health. Remarkable new findings showed that our microbiome not only primarily affects the health and function of the gastrointestinal tract but also has a strong influence on general body health through its close interaction with the nervous system and the lung. Therefore, a perfect and sensitive balanced interaction of microbes with the host is required for a healthy body. In fact, growing evidence suggests that the dynamics and function of the indigenous microbiota can be influenced by many factors, including genetics, diet, age, and toxicological agents like cigarette smoke, environmental contaminants, and drugs. The disruption of this balance, that is called dysbiosis, is associated with a plethora of diseases, including metabolic diseases, inflammatory bowel disease, chronic obstructive pulmonary disease, periodontitis, skin diseases, and neurological disorders. The importance of the host microbiome for the human health has also led to the emergence of novel therapeutic approaches focused on the intentional manipulation of the microbiota, either by restoring missing functions or eliminating harmful roles. In the present review, we outline recent studies devoted to elucidate not only the role of microbiome in health conditions and the possible link with various types of diseases but also the influence of various toxicological factors on the microbial composition and function.

scholarly journals Raised by aliens: constant exposure to an invasive predator triggers morphological but not behavioural plasticity in a threatened species tadpoles

2021 ◽  
Author(s):  
Andrea Melotto ◽  
Gentile Francesco Ficetola ◽  
Roberta Pennati ◽  
Nicoletta Ancona ◽  
Raoul Manenti
Keyword(s):  
Phenotypic Plasticity ◽  
Native Species ◽  
Procambarus Clarkii ◽  
Muscle Size ◽  
Behavioural Plasticity ◽  
The Novel ◽  
Population Declines ◽  
Selective Pressures ◽  
Invasive Predators ◽  
Behavioural Tests

AbstractDuring biotic invasions, native communities are abruptly exposed to novel and often severe selective pressures. The lack of common evolutionary history with invasive predators can hamper the expression of effective anti-predator responses in native prey, potentially accelerating population declines. Nonetheless, rapid adaptation and phenotypic plasticity may allow native species to cope with the new ecological pressures. We tested the hypothesis that phenotypic plasticity is fostered when facing invasive species and evaluated whether plasticity offers a pool of variability that might help the fixation of adaptive phenotypes. We assessed behavioural and morphological trait variation in tadpoles of the Italian agile frog (Rana latastei) in response to the invasive crayfish predator, Procambarus clarkii, by rearing tadpoles under different predation-risk regimes: non-lethal crayfish presence and crayfish absence. After two-month rearing, crayfish-exposed tadpoles showed a plastic shift in their body shape and increased tail muscle size, while behavioural tests showed no effect of crayfish exposure on tadpole behaviour. Furthermore, multivariate analyses revealed weak divergence in morphology between invaded and uninvaded populations, while plasticity levels were similar between invaded and uninvaded populations. Even if tadpoles displayed multiple plastic responses to the novel predator, none of these shifts underwent fixation after crayfish arrival (10–15 years). Overall, these findings highlight that native prey can finely tune their responses to invasive predators through plasticity, but the adaptive value of these responses in whitstanding the novel selective pressures, and the long-term consequences they can entail remain to be ascertained.

scholarly journals Vertebrate cardiac regeneration: evolutionary and developmental perspectives

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephen Cutie ◽  
Guo N. Huang
Keyword(s):  
Cardiac Injury ◽  
Adaptive Immune System ◽  
Cardiac Regeneration ◽  
Heart Regeneration ◽  
Adaptive Immune ◽  
Selective Pressures ◽  
Trade Offs ◽  
Lower Vertebrates ◽  
Complex Adaptive ◽  
And Function

AbstractCardiac regeneration is an ancestral trait in vertebrates that is lost both as more recent vertebrate lineages evolved to adapt to new environments and selective pressures, and as members of certain species developmentally progress towards their adult forms. While higher vertebrates like humans and rodents resolve cardiac injury with permanent fibrosis and loss of cardiac output as adults, neonates of these same species can fully regenerate heart structure and function after injury – as can adult lower vertebrates like many teleost fish and urodele amphibians. Recent research has elucidated several broad factors hypothesized to contribute to this loss of cardiac regenerative potential both evolutionarily and developmentally: an oxygen-rich environment, vertebrate thermogenesis, a complex adaptive immune system, and cancer risk trade-offs. In this review, we discuss the evidence for these hypotheses as well as the cellular participators and molecular regulators by which they act to govern heart regeneration in vertebrates.

scholarly journals The Gut Microbiome as a Component of the Gut–Brain Axis in Cognitive Health

2020 ◽  
Vol 22 (4) ◽  
pp. 485-494
Author(s):  
Wen Gao ◽  
Kelley L. Baumgartel ◽  
Sheila A. Alexander
Keyword(s):  
Cognitive Development ◽  
Gut Microbiome ◽  
Human Microbiome ◽  
Vital Role ◽  
The Body ◽  
Nursing Research ◽  
Brain Physiology ◽  
Cognitive States ◽  
And Function ◽  
Development Stability

Introduction: The human microbiome, the microorganisms living in and on the body, plays a vital role in brain physiology and pathophysiology. The gut microbiome (GMB) has been identified as a link in the gut–brain axis moderating cognitive development and health. Objectives: The objectives of this scoping review are to discuss mechanisms of the microbiome–gut–brain axis in cognition, review the existing literature on the GMB and cognition, and discuss implications for nursing research. Methods: We searched Pubmed using the terms “gut microbiome,” “brain,” and “cognition” and the terms “gut brain axis,” “microbiome,” and “cognition”; removed duplicates, studies not published in English, and unrelated publications; and added additional articles identified through references. We retained the 85 most relevant publications for this review. Results: Common themes in the current literature include GMB components; interactions on cognitive development; effects of GMB–gut–brain interactions on cognition, mild cognitive impairment and Alzheimer’s disease; effects of GMB interactions with physiologic stress on cognition in critical care; and GMB modification for improved cognition. Review of the literature on each of these topics reveals multiple theoretical mechanisms of action for GMB–gut–brain interaction that modify cognitive development and function across the lifespan. Discussion: GMB components and dysbiosis have been implicated in many cognitive states, and specific microbiota constituents contribute to cognitive development, stability, and impairment. The study of these interactions is relevant to nursing research as it addresses the holistic human experience and microbiome constituents are modifiable, facilitating translation into the clinical setting.

The effects of amphibian population declines on the structure and function of Neotropical stream ecosystems

2006 ◽  
Vol 4 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Matt R. Whiles ◽  
Karen R. Lips ◽  
Cathy M. Pringle ◽  
Susan S. Kilham ◽  
Rebecca J. Bixby ◽  
...  
Keyword(s):  
Structure And Function ◽  
Stream Ecosystems ◽  
Population Declines ◽  
Amphibian Population ◽  
Neotropical Stream ◽  
And Function

scholarly journals A Branching Process Model of Evolutionary Rescue

2021 ◽  
Author(s):  
Peter Olofsson ◽  
Ricardo B. R. Azevedo
Keyword(s):  
Population Growth ◽  
Mutation Rate ◽  
Discrete Time ◽  
Growth Curve ◽  
Process Model ◽  
Branching Process ◽  
Selective Advantage ◽  
Population Declines ◽  
Beneficial Mutations ◽  
Evolutionary Rescue

Evolutionary rescue is the process whereby a declining population may start growing again, thus avoiding extinction, via an increase in the frequency of beneficial genotypes. These genotypes may either already be present in the population in small numbers, or arise by mutation as the population declines. We present a simple two-type discrete-time branching process model and use it to obtain results such as the probability of rescue, the shape of the population growth curve of a rescued population, and the time until the first rescuing mutation occurs. Comparisons are made to existing results in the literature in cases where both the mutation rate and the selective advantage of the beneficial mutations are small.

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