scholarly journals The adaptation front equation explains diversification hotspots and living-fossilization

2021 ◽  
Author(s):  
Hiroshi C. Ito ◽  
Akira Sasaki
Keyword(s):  
Resource Competition ◽  
Species Group ◽  
Ecological Niches ◽  
Analytical Prediction ◽  
Biological Communities ◽  
Living Fossils ◽  
Higher Dimensional ◽  
Acting Process ◽  
Source Sink ◽  
Weak Separation

Taxonomic turnovers are common in the evolutionary histories of biological communities. Such turnovers are often associated with the emergence and diversification of groups that have achieved fundamental innovations beneficial in various ecological niches. In the present study, we show that such innovation-driven turnovers could be analyzed using an equation that describes the dynamics of zero-fitness isoclines in a two-dimensional trait space comprising a "fundamental trait" (describing fundamental innovation) and a "niche trait" (describing niche position) or with its higher-dimensional extensions. Our equation allows analytical prediction of evolutionary source-sink dynamics along the niche axis for an arbitrary unimodal (or multimodal with weak separation) carrying capacity distribution. The prediction was confirmed by numerical simulation under different assumptions for resource competition, reproduction, and mutation. In the simulated evolution, biodiversity sources are the central niches having higher carrying capacities than the outer niches, allowing species there the faster evolutionary advancement in fundamental traits and their repeated diversification into outer niches, which outcompete the indigenous less advanced species. The outcompeted species go extinct or evolve directionally toward the far outer niches of the far slower advancement because of the far lower carrying capacities. In consequence of this globally acting process over niches, species occupying peripheral (i.e., the outermost) niches can have significantly primitive fundamental traits and deep divergence times from their closest relatives, and thus, they correspond to living fossils. The extension of this analysis for multiple geographic regions showed that living fossils are also expected in geographically peripheral regions for the focal species group.

scholarly journals Maximising the Edges of Natural and Human Systems: The Case for Sociotones

2019 ◽  
Vol 11 (24) ◽  
pp. 7203
Author(s):  
May East
Keyword(s):  
Spatial Scales ◽  
Social Systems ◽  
Ecological Systems ◽  
Ecological Niches ◽  
Early 20Th Century ◽  
Biological Communities ◽  
Applied Ecology ◽  
Multiple Spatial Scales ◽  
Economic Transformations ◽  
Over Time

In many fields of fundamental and applied ecology, the transition or edge between two distinct biological communities is known as ‘ecotone’. The ecotone concept was first introduced in the early 20th century, describing the edge between two ecological systems which disappear in a transition zone but in opposite directions. This paper examines the evolution of the concept and its different applications over time. It explores the characteristics of ecotones as biodiverse enriched ecological niches occurring at multiple spatial scales. The paper goes further by proposing the concept of sociotone or social systems in tension, first by postulating a series of principles through which many possible interpretations may arise and secondly, by describing the societal interface where diverse worldviews, intentions and experiences meet. The concept is tested against a territory of social tensions between newcomers and stakeholders in Sicily providing evidence of a field of dynamic socio-economic transformations and prospects. The paper concludes by positioning sociotone as a possible framework to realise the systemic potential of multicultural globalised societies.

Molecular phylogeny of black flies in the Simulium tuberosum (Diptera: Simuliidae) species group in Thailand

Genome ◽  
2014 ◽  
Vol 57 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Paradee Sriphirom ◽  
Piyamas Nanork Sopaladawan ◽  
Komgrit Wongpakam ◽  
Pairot Pramual
Keyword(s):  
Genetic Diversity ◽  
Phylogenetic Relationships ◽  
Incomplete Lineage Sorting ◽  
Species Group ◽  
Morphological Data ◽  
Ecological Niches ◽  
Black Flies ◽  
Gene Sequences ◽  
Multiple Gene ◽  
Black Fly

Black flies are medically and ecologically significant insects. They are also interesting from an evolutionary standpoint regarding the role of chromosomal change and ecological adaptation. In this study, molecular genetic markers based on multiple gene sequences were used to assess genetic diversity and to infer phylogenetic relationships for a group of cytologically highly diverse black flies of the Simulium tuberosum species group in Thailand. Ecological affinities of the species were also investigated. High levels of genetic diversity were found in cytological species complexes, S. tani and S. doipuiense, and also in S. rufibasis, which was cytologically nearly monomorphic. The results highlight the necessity of integrating multilevel markers for fully understanding black fly biodiversity. Phylogenetic relationships based on multiple gene sequences were consistent with an existing dendrogram inferred from cytological and morphological data. Simulium tani is the most distinctive taxa among the members of the S. tubersosum species group in Thailand based on its divergent morphological characters. Molecular data supported the monophyletic status of S. tani, S. weji, and S. yuphae, but S. doipuiense and S. rufibasis were polyphyletic, most likely due to incomplete lineage sorting and inadequate phylogenetic signals. Ecological analyses revealed that members of the S. tuberosum species group have clearly different ecological niches. The results thus supported previous views of the importance of ecology in black fly evolution.

scholarly journals Resource competition shapes biological rhythms and promotes temporal niche differentiation in a community simulation

2020 ◽  
Author(s):  
Vance Difan Gao ◽  
Sara Morley-Fletcher ◽  
Stefania Maccari ◽  
Martha Hotz Vitaterna ◽  
Fred W. Turek
Keyword(s):  
Intraspecific Competition ◽  
Resource Competition ◽  
Biological Rhythms ◽  
Niche Differentiation ◽  
Disruptive Selection ◽  
Ecological Niches ◽  
Temporal Dimension ◽  
Activity Rhythms ◽  
Competition For Resources ◽  
Rest Activity

AbstractCompetition for resources often contributes strongly to defining an organism’s ecological niche. Biological rhythms are important adaptations to the temporal dimension of niches, but the role of other organisms in determining such temporal niches have not been much studied, and the role specifically of competition even less so. We investigate how interspecific and intraspecific competition for resources shapes an organism’s activity rhythms. For this, communities of one or two species in an environment with limited resource input were simulated. We demonstrate that when organisms are arrhythmic, one species will always be competitively excluded from the environment, but the existence of activity rhythms allows niche differentiation and indefinite coexistence of the two species. Two species which are initially active at the same phase will differentiate their phase angle of entrainment over time to avoid each other. When only one species is present in an environment, competition within individuals of the species strongly selects for niche expansion through arrhythmicity, but the addition of an interspecific competitor facilitates evolution of increased rhythmic amplitude when combined with additional adaptations for temporal specialization. Finally, if individuals preferentially mate with others who are active at similar times of day, then disruptive selection by intraspecific competition can split one population into two reproductively isolated groups. In summary, these simulations suggest that biological rhythms are an effective method to temporally differentiate ecological niches, and that competition is an important ecological pressure promoting the evolution of rhythms and sleep.Author summaryWhy do we sleep? We are interested in the ecological factors which promote the evolution of biological rhythms like the sleep-wake cycle, focusing especially on competition. When animals compete with each other for resources, they often evolve to avoid each other by specializing to use different resources or separating their activity in other ways. To test hypotheses about how competition shapes rest-activity rhythms, we performed computer simulations of a community of animals who move, reproduce, and compete for resources. We show that biological rhythms let two species divide time so that one species is active while its competitor is resting, thus avoiding depleting shared resources. When a species has no competitors in the simulation, competition between members of the same species cause population and individual rhythms to decrease, since resource availability is low when everybody is active at the same time. However, having competitors allows strong rhythms to evolve from originally arrhythmic organisms. Competition can even cause a single population to split into two species which are separated in time. In summary, these results suggest that competition is a strong factor promoting rest-activity rhythms.

scholarly journals Coexistence Patterns and Diversity in A Trait-Based Metacommunity On An Environmental Gradient

2021 ◽  
Author(s):  
Mozzamil Mohammed ◽  
Bernd Blasius ◽  
Alexey Ryabov
Keyword(s):  
Environmental Gradient ◽  
Resource Competition ◽  
Environmental Variability ◽  
Environmental Filtering ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Regional Diversity ◽  
Local Species Richness ◽  
Local Species ◽  
Source Sink

Abstract The dynamics of trait-based metacommunities have attracted much attention, but not much is known about how dispersal and spatial environmental variability mutually interact with each other to drive coexistence patterns and diversity. Here, we present a spatially-explicit model of resource competition in a metacommunity on a one- dimensional environmental gradient. We find that both the strength of dispersal and the range of spatial environmental variability affect coexistence patterns, spatial structure, trait distribution and local and regional diversity. Without dispersal, species are sorted according to their optimal growth conditions on the gradient. With the onset of dispersal source-sink effects are initiated, which increases the effects of environmental filtering and interspecific competition and generates trait lumping, so that only a few species from an environment-defined trait range can survive. Interestingly, for very large dispersal rates the system becomes spatially homogeneous, but nevertheless two species at the extreme ends of the trait-off curve can coexist for large environmental variability. Local species richness follows a classic hump-shaped dependence on dispersal rate, while local and regional diversity exhibit a pronounced peak for intermediate values of the environmental variability. Our findings provide important insights into the factors that shape the structure of trait-based metacommunities.

scholarly journals Mixed-species associations of Diana and Campbell's monkeys: the costs and benefits of a forest phenomenon

Behaviour ◽  
2003 ◽  
Vol 140 (3) ◽  
pp. 371-385 ◽  
Author(s):  
Sonja Wolters ◽  
Klaus Zuberbühler
Keyword(s):  
Resource Competition ◽  
Dilution Effect ◽  
Daily Basis ◽  
Species Group ◽  
Mixed Species ◽  
Predator Detection ◽  
Vocal Behaviour ◽  
Forest Strata ◽  
Species Groups ◽  
Mixed Species Groups

AbstractOne of the most striking behavioural patterns of many forest primates concerns their tendency to live in semi-permanent mixed-species groups. Functional investigations have ascertained that individuals obtain some antipredator benefits without paying the costs of intra-species resource competition. Despite these advances, very little is known about the subtle mechanisms that keep mixed species groups together on a daily basis. Our results showed that in the Diana-Campbell's monkey association both species benefited from each other in diverse and idiosyncratic ways. In the presence of Campbell's monkeys the conspicuous Diana monkeys were more likely to descend into the lower forest strata, increased their foraging behaviour, and individuals became less vigilant. The cryptic Campbell's monkeys, in turn, were able to use the higher forest strata and exposed areas more often, spread out over larger areas, were more likely to travel, and engaged in more conspicuous vocal behaviour when associated with Diana monkeys. These data suggested that both species benefited from each other in ways that went beyond passive group-size related antipredator benefits, such as a dilution effect and increased chances of predator detection. Instead, the increased safety of the mixed species group allowed individuals to exploit their ecological niche more broadly, to forage more efficiently, and to engage in more social behaviour, suggesting that the benefits of mixed species groups are much more varied and diverse than currently thought.

scholarly journals Coexistence patterns and diversity in a trait-based metacommunity on an environmental gradient

2021 ◽  
Author(s):  
Mozzamil Mohammed ◽  
Bernd Blasius ◽  
Alexey Ryabov
Keyword(s):  
Environmental Gradient ◽  
Resource Competition ◽  
Environmental Variability ◽  
Environmental Filtering ◽  
Dispersal Rate ◽  
Optimal Position ◽  
Joint Influence ◽  
Coexistence Mechanisms ◽  
Source Sink ◽  
Resource Variability

The dynamics of trait-based metacommunities have attracted much attention, but not much is known about how dispersal and environmental variability mutually interact with each other to drive coexistence mechanisms and diversity patterns. Here, we present a spatially-explicit model of resource competition in a metacommunity on a one-dimensional environmental gradient and analyse the joint influence of dispersal and environmental variability on coexistence mechanisms, spatial structure, trait distribution and local and regional diversity. We find that without dispersal, species are sorted according to their optimal position on the gradient, but with the onset of dispersal source-sink effects are initiated. Thereby, the dispersal rate and the range of spatial environmental variability strongly affect the competition outcomes, composition, and diversity. That is, at low dispersal rates the number of surviving species increases with the spatial environmental variability. Increasing dispersal rates generates trait lumping and strengthens environmental filtering so that only a few dominant species can survive. Interestingly, for very large dispersal rates the system becomes spatially homogeneous, but nevertheless two specialists at the extreme ends of the trait-off curve can coexist. Global species richness depends in an intricate manner on dispersal strength and resource variability, with a classic hump-shaped dependence of diversity on dispersal rate, but also a pronounced peak of global diversity for intermediate values of resource variability. Our findings thus provide important insights into the factors that shape metacommunity structure and promote coexistence and about how spatial environmental variability can lead to different competition outcomes in metacommunities.

scholarly journals Main directions of the study of plant invasions in Russia

2021 ◽  
Vol 9 (4) ◽  
pp. 45-56
Author(s):  
Valeriy K. Tokhtar ◽  
Yulia K. Vinogradova ◽  
Alexander A. Notov ◽  
Аndrey Yu. Kurskoy ◽  
Elena S. Danilova
Keyword(s):  
Invasive Species ◽  
Alien Species ◽  
Statistical Methods ◽  
Plant Invasion ◽  
Species Group ◽  
Ecological Niches ◽  
Multivariate Statistical Methods ◽  
Multivariate Statistical ◽  
Alien Plant ◽  
Invasive Flora

Abstract This article is focused on the analysis of major approaches to plant invasion research used by Russian researchers. They fall within three main groups: 1. Conventional approaches to floristic analysis based on the Russian scientific tradition of floristic research, 2. Approaches focused on the study of the fraction of invasive flora, making blacklists and regional Black books, 3. New comprehensive approaches based on a synthesis of methods used in botany, geo-information technology and population genetics. Multivariate statistical methods allow for the visualization of various data, including those on alien species group structures in various regions. They make it possible to identify boundaries of ecological niches occupied by plants in respect to climate-and-environmental or ecological variables. An assessment of current statistical interdependence between alien plant characteristics and scores of factors limiting their dissemination facilitates the making of predictive models of plant invasion. Examples of multivariate statistical methods used in invasion biology were analyzed, along with different approaches to the study of the variability of alien species. Alien and invasive fractions of the flora of the Trans-Siberian Railway were analyzed not by administrative units but by natural biomes. This approach allowed us to assess the correlation between the number of invasive species with different natural-climatic and floristic characteristics of biomes. The publication of "Black Books" of various administrative subjects of Russia according to a unified methodology allowed us to make an inventory of invasive species over the vast territory of the country. The experience gained by Russian researchers may be further used for developing universal approaches to plant invasion research.

scholarly journals Unifying Large- and Small-Scale Theories of Coordination

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 537
Author(s):  
J. A. Scott Kelso
Keyword(s):  
Gene Networks ◽  
Theoretical Models ◽  
Coordination Dynamics ◽  
Small Scale ◽  
Simple Diffusion ◽  
Living Things ◽  
Large Numbers ◽  
Higher Dimensional ◽  
The Many ◽  
Source Sink

Coordination is a ubiquitous feature of all living things. It occurs by virtue of informational coupling among component parts and processes and can be quite specific (as when cells in the brain resonate to signals in the environment) or nonspecific (as when simple diffusion creates a source–sink dynamic for gene networks). Existing theoretical models of coordination—from bacteria to brains to social groups—typically focus on systems with very large numbers of elements (N→∞) or systems with only a few elements coupled together (typically N = 2). Though sharing a common inspiration in Nature’s propensity to generate dynamic patterns, both approaches have proceeded largely independent of each other. Ideally, one would like a theory that applies to phenomena observed on all scales. Recent experimental research by Mengsen Zhang and colleagues on intermediate-sized ensembles (in between the few and the many) proves to be the key to uniting large- and small-scale theories of coordination. Disorder–order transitions, multistability, order–order phase transitions, and especially metastability are shown to figure prominently on multiple levels of description, suggestive of a basic Coordination Dynamics that operates on all scales. This unified coordination dynamics turns out to be a marriage of two well-known models of large- and small-scale coordination: the former based on statistical mechanics (Kuramoto) and the latter based on the concepts of Synergetics and nonlinear dynamics (extended Haken–Kelso–Bunz or HKB). We show that models of the many and the few, previously quite unconnected, are thereby unified in a single formulation. The research has led to novel topological methods to handle the higher-dimensional dynamics of coordination in complex systems and has implications not only for understanding coordination but also for the design of (biorhythm inspired) computers.

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