scholarly journals STUDY OF SINGLE-SPECIES POPULATION MODELS

2020 ◽  
pp. 161-166
Author(s):  
Marthak Rutu

In this research paper one dimensional population models developed centuries ago shows that growth and/decay of single homogeneous populations But environmental effects spatial heterogeneity or age-structure deterministic models prevailing single species population models.

2020 ◽  
Author(s):  
Olcay Akman ◽  
Leon Arriola ◽  
Aditi Ghosh ◽  
Ryan Schroeder

AbstractStandard heuristic mathematical models of population dynamics are often constructed using ordinary differential equations (ODEs). These deterministic models yield pre-dictable results which allow researchers to make informed recommendations on public policy. A common immigration, natural death, and fission ODE model is derived from a quantum mechanics view. This macroscopic ODE predicts that there is only one stable equilibrium point . We therefore presume that as t → ∞, the expected value should be . The quantum framework presented here yields the same standard ODE model, however with very unexpected quantum results, namely . The obvious questions are: why isn’t , why are the probabilities ≈ 0.37, and where is the missing probability of 0.26? The answer lies in quantum tunneling of probabilities. The goal of this paper is to study these tunneling effects that give specific predictions of the uncertainty in the population at the macroscopic level. These quantum effects open the possibility of searching for “black–swan” events. In other words, using the more sophisticated quantum approach, we may be able to make quantitative statements about rare events that have significant ramifications to the dynamical system.


1977 ◽  
Vol 55 (2) ◽  
pp. 314-324 ◽  
Author(s):  
Barry C. Longstaff

The construction of a matrix model for the growth of populations of soil Collembola is described. Data from four replicate cultures of each of two species kept under laboratory conditions were modelled in the form of difference equations, which took into account the size structure of the populations. These equations were set up so as to effect a Leslie-type matrix model. The effect of density upon population growth rate was incorporated into the model in the form of a density-related function for fecundity.The success of the modelling procedures was varied with some of the models accurately predicting both the pattern of population growth and the population sizes at successive time intervals, whilst others only showed the trends. The deterministic models of each of the replicates for each species were combined to produce a stochastic model for that species. These also met with mixed success. The equilibrium values for the deterministic models were calculated and their stability properties examined. The models for both species predict a stable equilibrium approached by a series of damped oscillations.


2018 ◽  
Vol 31 (4) ◽  
pp. e12167 ◽  
Author(s):  
Eddy Kwessi ◽  
Saber Elaydi ◽  
Brian Dennis ◽  
George Livadiotis

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