scholarly journals Can a More Variable Species Win Interspecific Competition?

2021 ◽  
Author(s):  
Janusz Uchmański
Keyword(s):  
Population Dynamics ◽  
Growth Period ◽  
Individual Variability ◽  
Symmetric Distribution ◽  
Asymmetric Distribution ◽  
Extinction Time ◽  
Final Body Weight ◽  
Half Saturation Constant ◽  
Variable Species ◽  
The Individual

AbstractAn individual-based approach is used to describe population dynamics. Two kinds of models have been constructed with different distributions illustrating individual variability. In both models, the growth rate of an individual and its final body weight at the end of the growth period, which determines the number of offspring, are functions of the amount of resources assimilated by an individual. In the model with a symmetric distribution, the half saturation constant in the Michaelis–Menten function describing the relationship between the growth of individuals and the amount of resources has a normal distribution. In the model with an asymmetric distribution, resources are not equally partitioned among individuals. The individual who acquired more resources in the past, will acquire more resources in the future. A single population comprising identical individuals has a very short extinction time. If individuals differ in the amount of food assimilated, this time significantly increases irrespectively of the type of model describing population dynamics. Individuals of two populations of competing species use common resources. For larger differences in individual variability, the more variable species will have a longer extinction time and will exclude less variable species. Both populations can also coexist when their variabilities are equal or even when they are slightly different, in the latter case under the condition of high variability of both species. These conclusions have a deterministic nature in the case of the model with the asymmetric distribution—repeated simulations give the same results. In the case of the model with the symmetric distribution, these conclusions are of a statistical nature—if we repeat the simulation many times, then the more variable species will have a longer extinction time more frequently, but some results will happen (although less often) when the less variable species has a longer extinction time. Additionally, in the model with the asymmetric distribution, the result of competition will depend on the way of the introduction of variability into the model. If the higher variability is due to an increase in the proportion of individuals with a low assimilation of resources, it can produce a longer extinction time of the less variable species.

THE STUDY OF THE INDIVIDUAL VARIABILITY OF THE LINEAR DIMENSIONS OF THE SPHENOID SINUS

2019 ◽  
Vol 21 (1) ◽  
pp. 64-70
Author(s):  
O.V. Mareev ◽  
◽  
G.O. Mareev ◽  
M.E. Gutynina ◽  
D.A. Maksimova ◽  
...  
Keyword(s):  
Sphenoid Sinus ◽  
Individual Variability ◽  
Linear Dimensions ◽  
The Individual

scholarly journals Population dynamics and net primary production of the aquatic macrophite Nymphaea rudgeana C. F. Mey in a lotic environment of the Itanhaém River basin (SP, Brazil)

2000 ◽  
Vol 60 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. F. M. CAMARGO ◽  
E. R. FLORENTINO
Keyword(s):  
Population Dynamics ◽  
Primary Production ◽  
Aquatic Macrophytes ◽  
Aquatic Macrophyte ◽  
Net Primary Production ◽  
Growth Period ◽  
Pistia Stratiotes ◽  
Annual Productivity ◽  
Lotic Environment ◽  
Low Levels

In this paper we evaluated the population dynamics and obtained estimates of the net primary production of the aquatic macrophyte Nymphaea rudgeana in an arm of the Itanhaém River (São Paulo State, Brazil). This species presents, in the studied area, a broad seasonal variation of biomass. As from November (13.1 g DW/m²) we observed a gradual increase of biomass that reached a maximum in February (163.1 g DW/m²). Then, the biomass decreased, maintaining low levels until a new growth period. The reduction of biomass is associated to the development of floating aquatic macrophytes (Pistia stratiotes and Salvinia molesta) and, subsequently to environmental factors (higher salinity values) that are unfavorable to their development. The net primary production of N. rudgeana was estimated from the biomass data, and the annual productivity value was estimated between 3.02 and 3.82 t/ha/year.

scholarly journals The promiscuous and highly mobile resistome of a superbug

2021 ◽  
Author(s):  
Ismael Hernández-González ◽  
Valeria Mateo-Estrada ◽  
Santiago Castillo-Ramírez
Keyword(s):  
Population Dynamics ◽  
Gene Content ◽  
Massive Data ◽  
Nosocomial Pathogen ◽  
Data Set ◽  
Massive Data Set ◽  
The Individual ◽  
Global Threat ◽  
And Control ◽  
Global Population

AbstractAntimicrobial resistance (AR) is a major global threat to public health. Understanding the population dynamics of AR is critical to restrain and control this issue. However, no study has provided a global picture of the resistome of Acinetobacter baumannii, a very important nosocomial pathogen. Here we analyze 1450+ genomes (covering > 40 countries and > 4 decades) to infer the global population dynamics of the resistome of this species. We show that gene flow and horizontal transfer have driven the dissemination of AR genes in A. baumannii. We found considerable variation in AR gene content across lineages. Although the individual AR gene histories have been affected by recombination, the AR gene content has been shaped by the phylogeny. Furthermore, many AR genes have been transferred to other well-known pathogens, such as Pseudomonas aeruginosa or Klebsiella pneumoniae. Finally, despite using this massive data set, we were not able to sample the whole diversity of AR genes, which suggests that this species has an open resistome. Ours results highlight the high mobilization risk of AR genes between important pathogens. On a broader perspective, this study gives a framework for an emerging perspective (resistome-centric) on the genome epidemiology (and surveillance) of bacterial pathogens.

scholarly journals Individual variation of the masticatory system dominates 3D skull shape in the herbivory-adapted marsupial wombats

2019 ◽  
Author(s):  
Vera Weisbecker ◽  
Thomas Guillerme ◽  
Cruise Speck ◽  
Emma Sherratt ◽  
Hyab Mehari Abraha ◽  
...  
Keyword(s):  
Individual Variation ◽  
Principal Component ◽  
Individual Variability ◽  
Shape Variation ◽  
Mandibular Ramus ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Marsupial Species ◽  
Masticatory System ◽  
The Individual

AbstractBackgroundWithin-species skull shape variation of marsupial mammals is widely considered low and strongly size-dependent (allometric), possibly due to developmental constraints arising from the altricial birth of marsupials. However, species whose skulls are impacted by strong muscular stresses – particularly those produced through mastication of tough food items – may not display such intrinsic patterns very clearly because of the known plastic response of bone to muscle activity of the individual. In such cases, shape variation should not be dominated by allometry; ordination of shape in a geometric morphometric context through principal component analysis (PCA) should reveal main variation in areas under masticatory stress (incisor region/zygomatic arches/mandibular ramus); but this main variation should emerge from high individual variability and thus have low eigenvalues.ResultsWe assessed the evidence for high individual variation through 3D geometric morphometric shape analysis of crania and mandibles of thre species of grazing-specialized wombats, whose diet of tough grasses puts considerable strain on their masticatory system. As expected, we found little allometry and low Principal Component 1 (PC1) eigenvalues within crania and mandibles of all three species. Also as expected, the main variation was in the muzzle, zygomatic arches, and masticatory muscle attachments of the mandibular ramus. We then implemented a new test to ask if the landmark variation reflected on PC1 was reflected in individuals with opposite PC1 scores and with opposite shapes in Procrustes space. This showed that correspondence between individual and ordinated shape variation was limited, indicating high levels of individual variability in the masticatory apparatus.DiscussionOur results are inconsistent with hypotheses that skull shape variation within marsupial species reflects a constraint pattern. Rather, they support suggestions that individual plasticity can be an important determinant of within-species shape variation in marsupials (and possibly other mammals) with high masticatory stresses, making it difficult to understand the degree to which intrinsic constraint act on shape variation at the within-species level. We conclude that studies that link micro- and macroevolutionary patterns of shape variation might benefit from a focus on species with low-impact mastication, such as carnivorous or frugivorous species.

scholarly journals Indirect effects on fitness between individuals that have never met via an extended phenotype

2018 ◽  
Author(s):  
David N. Fisher ◽  
Jessica A. Haines ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
Jeffrey E. Lane ◽  
...  
Keyword(s):  
Population Dynamics ◽  
North American ◽  
Indirect Effects ◽  
Tamiasciurus Hudsonicus ◽  
Extended Phenotype ◽  
Red Squirrels ◽  
Lifetime Fitness ◽  
The Past ◽  
North American Red Squirrels ◽  
The Individual

AbstractInteractions between organisms are ubiquitous and have important consequences for phenotypes and fitness. Individuals can even influence those they never meet, if they have extended phenotypes which mean the environments others experience are altered. North American red squirrels (Tamiasciurus hudsonicus) guard food hoards, an extended phenotype that typically outlives the individual and is almost always inherited by non relatives. Hoarding by previous owners can therefore influence subsequent owners. We found that red squirrels bred earlier and had higher lifetime fitness if the previous owner was a male. This was driven by hoarding behaviour, as males and mid-aged squirrels had the largest hoards, and these effects persisted across owners, such that if the previous owner was male or died in mid-age subsequent occupants had larger hoards. Individuals can, therefore, influence each other’s resource dependent traits and fitness without meeting via extended phenotypes, and so the past can influence contemporary population dynamics.

scholarly journals GENDER FEATURES OF THE ALVEOLAR PROCESS OF THE UPPER JAW

2020 ◽  
Vol 19 (4) ◽  
pp. 10-14
Author(s):  
Z. Masna
Keyword(s):  
Morphological Characteristics ◽  
Individual Variability ◽  
Functional Restoration ◽  
Occlusal Plane ◽  
Dental Arch ◽  
Alveolar Process ◽  
Dental Examination ◽  
Upper Jaw ◽  
The Individual ◽  
Alveolar Arch

The individual face shape, the ratio of its proportions, the articulation capabilities of each person to a significant extent depend on the characteristics of occlusion and occlusion, in turn, are determined by the size, shape and ratio of dental, alveolar and basal arches. Two of them - alveolar and basal - pass at the corresponding levels of the alveolar areas of the jaws, which means that it is almost impossible to correct them, therefore they play the role of landmarks for setting the dental arch during dental prosthetics. A full-fledged aesthetic and functional restoration of the maxillofacial region after prosthetics largely depends on the dentist taking into account the individual morphological characteristics of the jaws, their cellular areas and specifically the morphometric parameters of the collar and basal arches. In order to determine the possible variants of the shape of the alveolar and basal arches of the upper jaw and the patterns of their ratio during the routine dental examination, 55 people (27 men and 28 women) aged 21-60 years with preserved maxillary dentition were examined. It has been established that the alveolar and basal arches of the upper jaw can have the shape of five geometric shapes: an oval, a semicircle, an ellipse, a trapezoid or a square. In this case, the shape of the collar and basal arches can coincide or be combined in various combinations. The analysis of the obtained results showed that in men the alveolar arch most often had the shape of an oval (70%), in women - an oval or semicircle (43%, respectively). With the aim of possible variants of the alveolar and basal arches form determination and peculiarities of their correlation 55 individuals (27 men and 28 women) in age of 21-60 years with the preserved teeth row were examined during planned dental examination. All examined were patients of the “Dental clinic of dr. Dakhno” (Kyiv). Computer tomographic investigation was made to these patients according to medical indications, scanning was made parallely to the occlusal plane. Image reconstruction was conducted with the use of highly dimentional bone algorithm. Alveolar and basal arch form of the upper jaw were determined on the images. It was established that alveolar and basal arches of the upper jaw can have a form of five geometrical figures: oval, semicircle, ellipse, trapeze or square. Form of the alveolar and basal arches can match or can combine in different combinations. Received results analysis testified that alveolar arch has a form of the oval in men and oval or semicircle – in women. Basal arch in men also most frequently has a form of oval, less often – semicircle, square and trapeze. In women basal arch more often has a form of trapeze or semicircle, less often – oval or square. In men alveolar and basal arches form matched in 41% of cases, in women – only in 31% of cases among total amount of all examined individuals. Most often alveolar and basal arches matched in the form of oval and semicircle, only in one case arches of the trapeze form matched in man, in woman – square form. Maxillary alveolar and basal arches form variants analysis let to determine areas, where distance between alveolar crests was maximal. Most variable this index was in individuals with the oval form of the alveolar arch on the level of 16-26, 17-27 or 18-28 teeth. Peculiarities of the alveolar and basal arches form of the alveolar process of the upper jaw in male and female individuals are characterized with expressed individual variability. These peculiarities consideration during dental prosthesis let avoid series of complications connected with the pressure redistribution on the osseous tissue of the jaws during articulation. 

scholarly journals Analysing the Relationship between Nutrition and the Microbial Composition of the Oral Biofilm—Insights from the Analysis of Individual Variability

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 479
Author(s):  
Kirstin Vach ◽  
Ali Al-Ahmad ◽  
Annette Anderson ◽  
Johan Peter Woelber ◽  
Lamprini Karygianni ◽  
...  
Keyword(s):  
Dietary Habits ◽  
Individual Variability ◽  
Oral Microbiota ◽  
Oral Diseases ◽  
Oral Biofilm ◽  
Microbial Composition ◽  
Mean Values ◽  
Individual Variations ◽  
The Individual ◽  
The Relationship

The influence of a change in nutrition on the oral microbiota are discussed in literature, but usually only changes of population mean values are reported. This paper introduces simple methods to also analyse and report the variability of patients’ reactions considering data from the culture analysis of oral biofilm. The framework was illustrated by an experimental study exposing eleven participants to different nutrition schemes in five consecutive phases. Substantial inter-individual variations in the individual reactions were observed. A new coherence index made it possible to identify 14 instances where the direction of individual changes tended to coincide with the direction of the mean change with more than 95% probability. The heterogeneity in variability across different bacteria species was limited. This allowed us to develop recommendations for sample sizes in future studies. For studies measuring the concentration change of bacteria as a reaction to nutrition change, the use of replications and analysis of the variability is recommended. In order to detect moderate effects of a change in nutrition on the concentration of single bacterial taxa, 30 participants with three repetitions are often adequate. Insights into the relationship between nutrition and the microbial composition can be helpful for the development of dietary habits that promote the establishment of a healthy microbial flora and can therefore prevent the initiation of oral diseases such as caries and periodontitis.

scholarly journals Understanding the Lingual Frenulum: Histological Structure, Tissue Composition, and Implications for Tongue Tie Surgery

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Nikki Mills ◽  
Donna T. Geddes ◽  
Satya Amirapu ◽  
S. Ali Mirjalili
Keyword(s):  
Individual Variability ◽  
Histological Structure ◽  
Tissue Composition ◽  
En Bloc ◽  
Structural Explanation ◽  
Fresh Tissue ◽  
Floor Of Mouth ◽  
Variable Extent ◽  
The Individual ◽  
Picrosirius Red

Lingual frenotomy has become an increasingly common surgical procedure, performed for a broad range of indications from birth through adulthood. This study utilizes histology to define the structure and tissue composition of the lingual frenulum and floor of mouth (FOM) fascia. En bloc specimens of anterior tongue, lingual frenulum, and FOM tissues were harvested from ten embalmed adult cadavers. An additional three fresh tissue cadaveric specimens were frozen with the tongue supported in an elevated position, to enable harvesting and paraffin embedding of the elevated lingual frenulum as a discrete specimen. All 13 specimens were prepared as ten-micron coronal sections using stains to determine the general morphology of the lingual frenulum, its relationship to neighbouring structures (Mason’s Trichrome), presence of elastin fibers (Verhoeff-van Gieson), and collagen typing (Picrosirius Red). Our results have shown a submucosal layer of fascia spanning horizontally across the FOM was present in all specimens, with variability in fascial thickness and histologic composition. This FOM fascia suspends the sublingual glands, vessels, and genioglossus from its deep surface. The elevated lingual frenulum is formed by a central fold of this FOM fascia together with the overlying oral mucosa with variability in fascial thickness and composition. With tongue elevation, the fascia mobilizes to a variable extent into the fold forming the frenulum, providing a structural explanation for the individual variability in lingual frenulum morphology seen in clinical practice.

scholarly journals Individual variability in life-history traits drives population size stability

2012 ◽  
Vol 58 (2) ◽  
pp. 358-362 ◽  
Author(s):  
Ned A. Dochtermann ◽  
C. M. Gienger
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Individual Variability ◽  
Population Variation ◽  
Sceloporus Undulatus ◽  
Natural Systems ◽  
Size Stability ◽  
Population Sizes ◽  
The Individual ◽  
Dynamics Of Populations

Abstract Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our understanding of population dynamics has historically been based on an assumption that individuals are identical with homogenous life-history properties. This assumption is certainly false for most natural systems, raising the question of what role individual variation plays in the dynamics of populations. While there has been an increase of interest regarding the effects of within population variation on the dynamics of single populations, there has been little study of the effects of differences in within population variation on patterns observed across populations. We found that life-history differences (clutch size) among individuals explained the majority of the variation observed in the degree to which population sizes of eastern fence lizards Sceloporus undulatus fluctuated. This finding suggests that differences across populations cannot be understood without an examination of differences at the level of a system rather than at the level of the individual [Current Zoology 58 (2): 358–362, 2012].

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