scholarly journals Self-organized similarity, the evolutionary emergence of groups of similar species

2006 ◽  
Vol 103 (16) ◽  
pp. 6230-6235 ◽  
Author(s):  
M. Scheffer ◽  
E. H. van Nes
Keyword(s):  
Similar Species ◽  
Self Organized ◽  
Evolutionary Emergence

scholarly journals Generalizing clusters of similar species as a signature of coexistence under competition

2018 ◽  
Author(s):  
Rafael D’Andrea ◽  
Maria Riolo ◽  
Annette Ostling
Keyword(s):  
Environmental Gradients ◽  
Species Traits ◽  
Life History Strategies ◽  
Recent Theory ◽  
Similar Species ◽  
Demographic Stochasticity ◽  
Competing Species ◽  
Environmental Preferences ◽  
Self Organized ◽  
Coexisting Species

AbstractPatterns of trait distribution among competing species can potentially reveal the processes that allow them to coexist. It has been recently proposed that competition may drive the spontaneous emergence of niches comprising clusters of similar species, in contrast with the dominant paradigm of greater-than-chance species differences. However, current clustering theory relies largely on heuristic rather than mechanistic models. Furthermore, studies of models incorporating demographic stochasticity and immigration, two key players in community assembly, did not observe clusters. Here we demonstrate clustering under partitioning of resources, partitioning of environmental gradients, and a competition-colonization tradeoff. We show that clusters are robust to demographic stochasticity, and can persist under immigration. While immigration may sustain clusters that are otherwise transient, too much dilutes the pattern. In order to detect and quantify clusters in nature, we introduce and validate metrics which have no free parameters nor require arbitrary trait binning, and weigh species by their abundances rather than relying on a presence-absence count. By generalizing beyond the circumstances where clusters have been observed, our study contributes to establishing them as an update to classical trait patterning theory.Author SummarySpecies traits determine how they compete with each other. As such, patterns in the distributions of traits in a community of competing species may reveal the processes responsible for coexistence. One central idea in theoretical ecology is that the strength of competition relates to similarity in species needs and strategies, and therefore if competition plays out at short timescales, coexisting species should be more different than expected by chance. However, recent theory suggests that competition may lead species to temporarily self-organize into groups with similar traits. Here we show that this clustering is a generic feature of competitive dynamics, which is robust to demographic stochasticity and can be indefinitely maintained by immigration. We show that clustering arises whether species coexist by partitioning resources, environmental preferences, or through tradeoffs in life-history strategies. We introduce and validate metrics that, given species traits and abundances, determine whether they are clustered, and if so, how many clusters occur. By showing the generality of self-organized species clusters and providing a tools for their detection, our study contributes to updating classical ideas about how competition shapes communities, and motivates searches for them in nature.

Problem behavior in autism spectrum disorders: A paradigmatic self-organized perspective of network structures

2019 ◽  
Vol 42 ◽  
Author(s):  
Lucio Tonello ◽  
Luca Giacobbi ◽  
Alberto Pettenon ◽  
Alessandro Scuotto ◽  
Massimo Cocchi ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Problem Behaviors ◽  
Autism Spectrum ◽  
The Self ◽  
Network Structures ◽  
Self Organized ◽  
Critical Equilibrium ◽  
Self Organized Criticality ◽  
Acute Agitation ◽  
Spectrum Disorders

AbstractAutism spectrum disorder (ASD) subjects can present temporary behaviors of acute agitation and aggressiveness, named problem behaviors. They have been shown to be consistent with the self-organized criticality (SOC), a model wherein occasionally occurring “catastrophic events” are necessary in order to maintain a self-organized “critical equilibrium.” The SOC can represent the psychopathology network structures and additionally suggests that they can be considered as self-organized systems.

The identity of Postia lowei (Basidiomycota, Polyporales) and notes on related or similar species.

2014 ◽  
Vol 66 (1) ◽  
pp. 39-52
Author(s):  
Petr Vampola ◽  
Alexander Ordynets ◽  
Josef Vlasák
Keyword(s):  
Similar Species

Identification of sibling species in the genus Eucyclops from water-bodies of Ukraine and Russia using crossbreeding studies

2014 ◽  
Vol 25 (1-2) ◽  
pp. 61-68 ◽  
Author(s):  
V. I. Monchenko ◽  
L. P. Gaponova ◽  
V. R. Alekseev
Keyword(s):  
Cryptic Species ◽  
River Basin ◽  
Black Sea ◽  
Species Complex ◽  
River Basins ◽  
Water Bodies ◽  
Similar Species ◽  
Basin Water ◽  
Different Populations ◽  
Baltic Sea Basin

Crossbreeding experiments were used to estimate cryptic species in water bodies of Ukraine and Russia because the most useful criterion in species independence is reproductive isolation. The problem of cryptic species in the genus Eucyclops was examined using interpopulation crosses of populations collected from Baltic Sea basin (pond of Strelka river basin) and Black Sea basin (water-reservoires of Dnieper, Dniester and Danube rivers basins). The results of reciprocal crosses in Eucyclops serrulatus-group are shown that E. serrulatus from different populations but from water bodies belonging to the same river basin crossed each others successfully. The interpopulation crosses of E. serrulatus populations collected from different river basins (Dnipro, Danube and Dniester river basins) were sterile. In this group of experiments we assigned evidence of sterility to four categories: 1) incomplete copulation or absence of copulation; 2) nonviable eggs; 3) absence of egg membranes or egg sacs 4) empty egg membranes. These crossbreeding studies suggest the presence of cryptic species in the E. serrulatus inhabiting ecologically different populations in many parts of its range. The same crossbreeding experiments were carries out between Eucyclops serrulatus and morphological similar species – Eucyclops macruroides from Baltic and Black Sea basins. The reciprocal crossings between these two species were sterile. Thus taxonomic heterogeneity among species of genus Eucyclops lower in E. macruroides than in E. serrulatus. The interpopulation crosses of E. macruroides populations collected from distant part of range were fertile. These crossbreeding studies suggest that E. macruroides species complex was evaluated as more stable than E. serrulatus species complex.

Two New Species of Aira (Poaceae) from the Iberian Peninsula and the Balearic Islands

2020 ◽  
Vol 45 (1) ◽  
pp. 75-84
Author(s):  
Llorenç Sáez ◽  
Javier López-Alvarado ◽  
Pere Fraga ◽  
Regina Berjano ◽  
M. Ángeles Ortiz ◽  
...  
Keyword(s):  
Risk Assessment ◽  
New Species ◽  
Iberian Peninsula ◽  
Diploid Species ◽  
Balearic Islands ◽  
Similar Species ◽  
Chromosome Counts ◽  
Two New Species

Abstract—Two new diploid species, Aira minoricensis and Aira hercynica, are described and illustrated, along with chromosome counts, risk assessment, distribution and habitat, phenology, and comparisons with morphologically similar species. A comparative table and a key for the species of Aira for the Iberian Peninsula and the Balearic Islands are provided to assist in the identification of these overlooked species, and their relationships to other taxa are discussed.

Paepalanthus fabianeae (Eriocaulaceae): A New Microendemic Species from a Morphologically Coherent Clade

2020 ◽  
Vol 45 (4) ◽  
pp. 794-801
Author(s):  
Caroline Oliveira Andrino ◽  
Marcelo Fragomeni Simon ◽  
Jair Eustáquio Quintino Faria ◽  
André Luiz da Costa Moreira ◽  
Paulo Takeo Sano
Keyword(s):  
New Species ◽  
Iucn Red List ◽  
Phylogenetic Position ◽  
Similar Species ◽  
Infrageneric Classification ◽  
Espinhaço Range ◽  
Nuclear Its ◽  
Two Populations

Abstract—We describe and illustrate Paepalanthus fabianeae, a new species of Eriocaulaceae from the central portion of the Espinhaço Range in Minas Gerais, Brazil. Previous phylogenetic evidence based on analyses of nuclear (ITS and ETS) and plastid (trnL-trnF and psba-trnH) sequences revealed P. fabianeae as belonging to a strongly supported and morphologically coherent clade containing five other species, all of them microendemic, restricted to the Espinhaço range. Due to the infrageneric classification of Paepalanthus being highly artificial, we preferred not assigning P. fabianeae to any infrageneric group. Paepalanthus fabianeae is known from two populations growing in campos rupestres (highland rocky fields) in the meridional Espinhaço Range. The species is characterized by pseudodichotomously branched stems, small, linear, recurved, and reflexed leaves, urceolate capitula, and bifid stigmas. Illustrations, photos, the phylogenetic position, and a detailed description, as well as comments on habitat, morphology, and affinities with similar species are provided. The restricted area of occurrence allied with threats to the quality of the habitat, mainly due to quartzite mining, justifies the preliminary classification of the new species in the Critically Endangered (CR) category using the guidelines and criteria of the IUCN Red List.

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