scholarly journals On the role played by the carrying capacity and the ancestral population size during a range expansion

Heredity ◽  
2016 ◽  
Vol 118 (2) ◽  
pp. 143-153 ◽  
Author(s):  
S Mona
Keyword(s):  
Population Size ◽  
Carrying Capacity ◽  
Range Expansion ◽  
Ancestral Population

scholarly journals Can we reestablish a self-sustaining population? A case study on reintroduced Crested Ibis with population viability analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yashuai Zhang ◽  
Fang Wang ◽  
Zhenxia Cui ◽  
Min Li ◽  
Xia Li ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Carrying Capacity ◽  
Wild Population ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Viability Analysis ◽  
Crested Ibis ◽  
Reintroduced Population

Abstract Background One of the most challenging tasks in wildlife conservation and management is clarifying which and how external and intrinsic factors influence wildlife demography and long-term viability. The wild population of the Crested Ibis (Nipponia nippon) has recovered to approximately 4400, and several reintroduction programs have been carried out in China, Japan and Korea. Population viability analysis on this endangered species has been limited to the wild population, showing that the long-term population growth is restricted by the carrying capacity and inbreeding. However, gaps in knowledge of the viability of the reintroduced population and its drivers in the release environment impede the identification of the most effective population-level priorities for aiding in species recovery. Methods The field monitoring data were collected from a reintroduced Crested Ibis population in Ningshan, China from 2007 to 2018. An individual-based VORTEX model (Version 10.3.5.0) was used to predict the future viability of the reintroduced population by incorporating adaptive patterns of ibis movement in relation to catastrophe frequency, mortality and sex ratio. Results The reintroduced population in Ningshan County is unlikely to go extinct in the next 50 years. The population size was estimated to be 367, and the population genetic diversity was estimated to be 0.97. Sensitivity analysis showed that population size and extinction probability were dependent on the carrying capacity and sex ratio. The carrying capacity is the main factor accounting for the population size and genetic diversity, while the sex ratio is the primary factor responsible for the population growth trend. Conclusions A viable population of the Crested Ibis can be established according to population viability analysis. Based on our results, conservation management should prioritize a balanced sex ratio, high-quality habitat and low mortality.

scholarly journals On the Number of Ancestors to a DNA Sequence

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1459-1468 ◽  
Author(s):  
Carsten Wiuf ◽  
Jotun Hein
Keyword(s):  
Population Size ◽  
Dna Sequence ◽  
Ancestral Sequence ◽  
Ancestral Population ◽  
Homologous Sequences ◽  
Actual Size

If homologous sequences in a population are not subject to recombination, they can all be traced back to one ancestral sequence. However, the rest of our genome is subject to recombination and will be spread out on a series of individuals. The distribution of ancestral material to an extant chromosome is here investigated by the coalescent with recombination, and the results are discussed relative to humans. In an ancestral population of actual size 1.3 million a minority of <6.4% will carry material ancestral to any present human. The estimated actual population size can be even higher, 5 million, reducing the percentage to 1.7%.

scholarly journals Nuclear pseudogenes of mtDNA (NUMTS) suggest repeated distant inter-species hybridization among direct human ancestors

2017 ◽  
Author(s):  
Konstantin Gunbin ◽  
Konstantin Popadin ◽  
Leonid Peshkin ◽  
Sofia Annis ◽  
Zoe Fleischmann ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Population Size ◽  
Genetic Exchange ◽  
Ancestral Population ◽  
Functional Genes ◽  
Human Lineage ◽  
Present Evidence ◽  
Znf230 Gene ◽  
Species Hybridization ◽  
Human Chromosome 5

Introduction: Increasingly, the emergence and evolution of our species is being tied to genetic exchange between divergent lineages within ~1Ma (e.g., Neanderthals, Denisovans). However, little is known about genetic exchange during earlier (pre-1Ma) human evolution and between more divergent lineages. Results: We present evidence of hybridization within human lineage, show that it likely happened between highly divergent (~4.5My) lineages, more than once. We use analysis of nuclear pseudogenes of mtDNA (“NUMTs”). NUMTs are considered “mtDNA fossils”, as they preserve sequences of ancient mtDNA because mutational rate in the nucleus is much lower than in mtDNA. We demonstrate that a NUMT on human chromosome 5, which is shared by chimpanzee and gorilla, had descended from a mitochondrial genome that had been divergent from our ancestor’s mtDNA by ~4.5% at the time of pseudogene insertion. This implies that this pseudogene should have been inserted in a hominid that at that time had been diverged by about 4.5My of evolution from the hominid that at that time carried our mtDNA lineage. In order for this pseudogene and our mtDNA to end up in the same body, these two hominids should have mated with each other. The large divergence implies a distant interspecies (or even inter-generic) hybridization. Additionally, analysis of two other NUMTs (on Chr11 and Chr7) suggests that hybridization events occurred repeatedly. To exclude the large ancestral population size effect we show that mtDNA divergence in extant ape populations does not depend on population size. Discussion: It is thought that within mammals, it takes ~2-4My to establish reproductive isolation. However, fertile inter-generic hybrids have been documented among several primates, separated by ca. 4My. Very recently, hybridization between Colobine genera separated by ~5 My was reported to involve a NUMT scenario similar to what we had proposed human ancestors. Interestingly, phylogenic analysis consistently places the chr5 NUMT insertion around the time of the Homo/Pan split. Intriguingly, certain hominin fossils of that epoch have been interpreted alternately as more human-like or more ape-like. Such morphological mosaicisity could potentially be explained by hybridization. Fixation of NUMTs in question within population should have been rather efficient, since these pseudogenes appear to have been fixed in more than one population. Thus their spread across populations might have been driven by selection. Indeed, NUMTs on chr5 and chr11 are located in 3’ regions of functional genes. Most intriguingly, Ps11 is located 3’ to the RNF141/ZNF230 gene, essential for spermatogenesis. NUMT might have served as an expression modifier for RNF141, resulting in reproductive advantage. Indeed, RNF141 demonstrates selectively driven expression shift in testis of the ancestor of hominines.

scholarly journals About rats and jackfruit trees: modeling the carrying capacity of a Brazilian Atlantic Forest spiny-rat Trinomys dimidiatus (Günther, 1877) – Rodentia, Echimyidae – population with varying jackfruit tree (Artocarpus heterophyllus L.) abundances

2015 ◽  
Vol 75 (1) ◽  
pp. 208-215 ◽  
Author(s):  
JHF Mello ◽  
TP Moulton ◽  
DSL Raíces ◽  
HG Bergallo
Keyword(s):  
Mathematical Model ◽  
Population Size ◽  
Seed Production ◽  
Atlantic Forest ◽  
Small Mammal ◽  
Carrying Capacity ◽  
Real Data ◽  
Brazilian Atlantic Forest ◽  
Artocarpus Heterophyllus ◽  
Small Mammal Community

We carried out a six-year study aimed at evaluating if and how a Brazilian Atlantic Forest small mammal community responded to the presence of the invasive exotic species Artocarpus heterophyllus, the jackfruit tree. In the surroundings of Vila Dois Rios, Ilha Grande, RJ, 18 grids were established, 10 where the jackfruit tree was present and eight were it was absent. Previous results indicated that the composition and abundance of this small mammal community were altered by the presence and density of A. heterophyllus. One observed effect was the increased population size of the spiny-rat Trinomys dimidiatus within the grids where the jackfruit trees were present. Therefore we decided to create a mathematical model for this species, based on the Verhulst-Pearl logistic equation. Our objectives were i) to calculate the carrying capacity K based on real data of the involved species and the environment; ii) propose and evaluate a mathematical model to estimate the population size of T. dimidiatus based on the monthly seed production of jackfruit tree, Artocarpus heterophyllus and iii) determinate the minimum jackfruit tree seed production to maintain at least two T. dimidiatus individuals in one study grid. Our results indicated that the predicted values by the model for the carrying capacity K were significantly correlated with real data. The best fit was found considering 20~35% energy transfer efficiency between trophic levels. Within the scope of assumed premises, our model showed itself to be an adequate simulator for Trinomys dimidiatus populations where the invasive jackfruit tree is present.

scholarly journals Carrying Capacity of a Population Diffusing in a Heterogeneous Environment

Mathematics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 49 ◽  
Author(s):  
D.L. DeAngelis ◽  
Bo Zhang ◽  
Wei-Ming Ni ◽  
Yuanshi Wang
Keyword(s):  
Population Size ◽  
Carrying Capacity ◽  
Heterogeneous System ◽  
Total Population ◽  
Reaction Diffusion ◽  
Maximum Growth ◽  
Reaction Diffusion Equations ◽  
Logistic Growth ◽  
Chemostat Model ◽  
Total Population Size

The carrying capacity of the environment for a population is one of the key concepts in ecology and it is incorporated in the growth term of reaction-diffusion equations describing populations in space. Analysis of reaction-diffusion models of populations in heterogeneous space have shown that, when the maximum growth rate and carrying capacity in a logistic growth function vary in space, conditions exist for which the total population size at equilibrium (i) exceeds the total population that which would occur in the absence of diffusion and (ii) exceeds that which would occur if the system were homogeneous and the total carrying capacity, computed as the integral over the local carrying capacities, was the same in the heterogeneous and homogeneous cases. We review here work over the past few years that has explained these apparently counter-intuitive results in terms of the way input of energy or another limiting resource (e.g., a nutrient) varies across the system. We report on both mathematical analysis and laboratory experiments confirming that total population size in a heterogeneous system with diffusion can exceed that in the system without diffusion. We further report, however, that when the resource of the population in question is explicitly modeled as a coupled variable, as in a reaction-diffusion chemostat model rather than a model with logistic growth, the total population in the heterogeneous system with diffusion cannot exceed the total population size in the corresponding homogeneous system in which the total carrying capacities are the same.

scholarly journals On the estimation of ancestral population sizes of modern humans

1997 ◽  
Vol 69 (2) ◽  
pp. 111-116 ◽  
Author(s):  
ZIHENG YANG
Keyword(s):  
Population Size ◽  
Sequence Data ◽  
Divergence Time ◽  
Ancestral Population ◽  
Rate Variation ◽  
Effective Population ◽  
Modern Humans ◽  
Extant Species ◽  
Population Sizes ◽  
Highly Correlated

The theory developed by Takahata and colleagues for estimating the effective population size of ancestral species using homologous sequences from closely related extant species was extended to take account of variation of evolutionary rates among loci. Nuclear sequence data related to the evolution of modern humans were reanalysed and computer simulations were performed to examine the effect of rate variation on estimation of ancestral population sizes. It is found that the among-locus rate variation does not have a significant effect on estimation of the current population size when sequences from multiple loci are sampled from the same species, but does have a significant effect on estimation of the ancestral population size using sequences from different species. The effects of ancestral population size, species divergence time and among-locus rate variation are found to be highly correlated, and to achieve reliable estimates of the ancestral population size, effects of the other two factors should be estimated independently.

scholarly journals Historical population size of the threatened New Zealand sea lion Phocarctos hookeri

2015 ◽  
Vol 97 (2) ◽  
pp. 436-443 ◽  
Author(s):  
Catherine J. Collins ◽  
B. Louise Chilvers ◽  
Matthew Taylor ◽  
Bruce C. Robertson
Keyword(s):  
New Zealand ◽  
Population Size ◽  
Effective Population Size ◽  
Carrying Capacity ◽  
Effective Population ◽  
Sea Lion ◽  
Sea Lions ◽  
Target Values ◽  
Phocarctos Hookeri

Abstract Marine mammal species were exploited worldwide during periods of commercial sealing in the 18th and 19th centuries. For many of these species, an estimate of the pre-exploitation abundance of the species is lacking, as historical catch records are generally scarce and inaccurate. Genetic estimates of long-term effective population size provide a means to estimate the pre-exploitation abundance. Here, we apply genetic methods to estimate the long-term effective population size of the subantarctic lineage of the New Zealand sea lion (NZ sea lion), Phocarctos hookeri . This species is predominantly restricted to the subantarctic islands, south of mainland New Zealand, following commercial sealing in the 19th century. Today, the population consists of ~9,880 animals and population growth is slow. Auckland Island breeding colonies of NZ sea lion are currently impacted by commercial trawl fisheries via regular sea lion deaths as bycatch. In order to estimate sustainable levels of bycatch, an estimate of the population’s carrying capacity ( K ) is required. We apply the genetically estimated long-term effective population size of NZ sea lions as a proxy for the estimated historical carrying capacity of the subantarctic population. The historical abundance of subantarctic NZ sea lions was significantly higher than the target values of K employed by the contemporary management. The current management strategy may allow unsustainable bycatch levels, thereby limiting the recovery of the NZ sea lion population toward historical carrying capacity.

scholarly journals The Existence and Uniqueness of the Solution of a Diusive Predator-Prey Model with Omnivory and General Nonlinear Functional Response

2021 ◽  
pp. 14-25
Author(s):  
Wensheng Yang
Keyword(s):  
Population Size ◽  
Functional Response ◽  
Carrying Capacity ◽  
Existence And Uniqueness ◽  
Nonlinear Functional ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Uniqueness Of The Solution ◽  
Biotic Resource ◽  
Food Web Model

In this work, we consider a three species modified Lesie-Gower food web model with general  nonlinear functional response and omnivory which is defined as feeding on more than one trophic level. The carrying capacity of the model is proportional to the population size of the biotic resource plus a const. The main objective of this paper is to investigate the existence and  uniqueness of the solution of this model. It is shown that the omnivory has important influence on the existence and uniqueness of the solution of the model.

scholarly journals Parental population range expansion before secondary contact promotes heterosis

2020 ◽  
Author(s):  
Ailene MacPherson ◽  
Silu Wang ◽  
Ryo Yamaguchi ◽  
Loren H. Riesesberg ◽  
Sarah P. Otto
Keyword(s):  
Reproductive Isolation ◽  
Range Expansion ◽  
Genomic Analysis ◽  
Population Expansion ◽  
Ancestral Population ◽  
Secondary Contact ◽  
Hybrid Zones ◽  
Deleterious Alleles ◽  
Genomic Divergence ◽  
Slightly Deleterious Mutations

AbstractPopulation genomic analysis of hybrid zones is instrumental to our understanding of the evolution of reproductive isolation. Many temperate hybrid zones are formed by the secondary contact between two parental populations that had undergone post-glacial range expansion. Here we show that explicitly accounting for historical parental isolation followed by range expansion prior to secondary contact is fundamental for explaining genetic and fitness patterns in these hybrid zones. Specifically, ancestral population expansion can result in allele surfing, neutral or slightly deleterious mutations drift high frequency at the front of the expansion. If these surfed deleterious alleles are recessive, they can contribute to substantial heterosis in hybrids produced at secondary contact, counteracting negative-epistatic interactions between BDMI loci and hence can deteriorate reproductive isolation. Similarly, surfing at neutral loci can alter the expected pattern of population ancestry and suggests that accounting for historical population expansion is necessary to develop accurate null genomic models in secondary-contact hybrid zones. Furthermore, this process should be incorporated in macroevolutionary models of divergence as well, since such heterosis facilitated by parental-range expansion could dampen genomic divergence established in the past.

scholarly journals Symbiotic Approach in a Modular Mobile Robot

2021 ◽  
Vol 9 (5) ◽  
pp. 602-607
Keyword(s):  
Mobile Robot ◽  
Population Size ◽  
Carrying Capacity ◽  
General Model ◽  
Mathematical Formulation ◽  
Wheeled Mobile Robot ◽  
Design Model ◽  
Characteristic Behavior ◽  
Number Species ◽  
Or Task

This paper presentsthe application of a symbiotic approachin a modular mobile robot. This characteristic behavior might help addressthe challengesin modular reconfigurable robotoperation. The general model symbiosisalgorithm will help decide if the modular part is harmful or beneficial to the performance or task of the robotic systemthru the carrying capacity. The symbiotic behavior is presented and implemented in this paper viamodel-baseddesign with the aid of MATLABSimulink using a 6 wheeled mobile robot with 3 modular body to identify the carrying capacity of the system.Carrying capacity istranslated and used as thedistance and velocity capacity of the design model robotic system.Carrying capacity is greatly influence by the number species or in our case modules it is shown in this paper that carrying capacity are not fixed in quantities but should be consider as functions of the population sizesand function. The mathematical formulation of the idea is to investigate its consequence. Aside from the population size role or interaction.

Sign in / Sign up

Export Citation Format

Share Document