Population strategies and random environments

1975 ◽  
Vol 53 (2) ◽  
pp. 160-165 ◽  
Author(s):  
Hugh Barclay
Keyword(s):  
Population Growth ◽  
Stochastic Models ◽  
Carrying Capacity ◽  
Death Rate ◽  
Logistic Model ◽  
Birth Rate ◽  
Environmental Variation ◽  
Random Environments ◽  
Probability Of Extinction ◽  
Established Species

It is shown using several models that r and K selection may result from random environmental variation. Probabilities of extinction are derived for both colonizing and well-established species using stochastic models similar to the logistic model, and it is shown that the probability of extinction of a population can be reduced by increasing the birth rate or the carrying capacity or by decreasing the death rate or the effects of the environmental variation on population growth. It is probable that random environmental variation mainly facilitates r selection.

scholarly journals Psi-Caputo Logistic Population Growth Model

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Muath Awadalla ◽  
Yves Yannick Yameni Noupoue ◽  
Kinda Abu Asbeh
Keyword(s):  
Population Growth ◽  
Fractional Derivative ◽  
Carrying Capacity ◽  
Chinese Population ◽  
Logistic Model ◽  
Logistic Equation ◽  
Logistic Growth ◽  
Growth Equation ◽  
Uniqueness Of The Solution ◽  
Better Than

This article studies modeling of a population growth by logistic equation when the population carrying capacity K tends to infinity. Results are obtained using fractional calculus theories. A fractional derivative known as psi-Caputo plays a substantial role in the study. We proved existence and uniqueness of the solution to the problem using the psi-Caputo fractional derivative. The Chinese population, whose carrying capacity, K, tends to infinity, is used as evidence to prove that the proposed approach is appropriate and performs better than the usual logistic growth equation for a population with a large carrying capacity. A psi-Caputo logistic model with the kernel function x + 1 performed the best as it minimized the error rate to 3.20% with a fractional order of derivative α  = 1.6455.

scholarly journals Population prediction of purwanegara village, Indonesia using modified logistic model with migration factor

2018 ◽  
Vol 7 (3) ◽  
pp. 1962
Author(s):  
Diandra Chika Fransisca ◽  
Padosroha Marbun
Keyword(s):  
Population Growth ◽  
Equilibrium Point ◽  
Growth Model ◽  
Carrying Capacity ◽  
Logistic Model ◽  
Central Java ◽  
Migration Factor ◽  
Central Java Province ◽  
Population Prediction ◽  
Birth Death

Population growth model is a widely been used model to do an estimation and forecasting towards the population of peoples, animals, bac-teria and even in economics growth. Many studies have been carried out on population growth model concerning the factors of birth, death and carrying capacity in order to predict the number of population at certain area. From these studies there is only one study involved the constant value factor of migration as an input in the logistic model. Therefore contradicting with the above modified logistic model, in this study logistic model is modified by adding a migration factor as a function of population. This function takes into account the migration and the interaction between peoples that is limited to the carrying capacity of the environment. This model can be solved qualitatively using the analysis of equilibrium point and quantitatively using the separable variables method. This modified logistic model with migration factor has been applied in the population prediction of Purwanegara village in Central Java Province, Indonesia. Throughout the results, the modified logistic model with migration factor as a function of population gives a better result for population prediction of Purwanegara village in Central Java Province, Indonesia compared with logistic model.  

Medical and demographic indicators of the Orenburg Region

2021 ◽  
pp. 65-71
Author(s):  
Lyubov Kuzminichna Grigorieva ◽  
Sergey Aleksandrovich Kuzmin
Keyword(s):  
Life Expectancy ◽  
Population Growth ◽  
Death Rate ◽  
Birth Rate ◽  
Population Decline ◽  
Female Population ◽  
Orenburg Region ◽  
Managerial Decisions ◽  
Demographic Indicators ◽  
Gradual Process

The analysis of the medical and demographic indicators of the Orenburg Region from 2015 to 2019 showed that over this time period, there was a gradual process of population decline. The dynamics of the birth and death rates of the population was characterized by a stable decline. Over a five-year period, the birth rate decreased by 30.78 %, and the death rate by 8.8 %. The natural population growth in 2015 was positive, and since 2016, there has been a negative population growth, i.e. the number of citizens who died annually exceeded the number of births. The region has seen slight changes in the ratio of urban and rural residents. Life expectancy has increased for both sexes from 69.63 years in 2015 to 72.04 years in 2019. The growth of this indicator for men was 4.31 %, and for women — 2.43 %. Studies of the sex composition of the population of the Orenburg Region over the past five years have demonstrated that there have been minor changes in the ratio of the male and female population in the region under study. So, in 2015 and 2016, there were 1149 women per 1000 men; in 2017–1148, in 2018–1147, in 2019–1146. Over the studied period, the number of marriages registered in the Orenburg Region decreased from a maximum of 15418 in 2015 to a minimum of 12304 in 2019, which was 20.2 %. The number of divorces did not decrease so rapidly, from 8,717 maximum in 2015 to 8,424 minimum in 2019, which was 3.36 %. The adoption of managerial decisions aimed at improving the standard of living and health of the population, as well as the environmental situation at the level of legislative and executive authorities will contribute to an increase in life expectancy, reduction in the death rate, and an increase in the birth rate of the population.

Time-dependent solution of the logistic model for population growth in random environment

1980 ◽  
Vol 17 (04) ◽  
pp. 1083-1086
Author(s):  
Prajneshu
Keyword(s):  
Population Growth ◽  
Stationary Solution ◽  
Random Environment ◽  
Carrying Capacity ◽  
Logistic Model ◽  
Time Dependent ◽  
Kolmogorov Equation ◽  
Exact Time ◽  
Time Dependent Solution

The exact time-dependent solution as well as the stationary solution of the logistic model for population growth with varying carrying capacity is worked out in both the Stratonovich and Ito calculi by solving the forward Kolmogorov equation.

scholarly journals A Numerical Model of Philippine Population Growth: Child Policy, Quantitative Insights and Challenges

2014 ◽  
Vol 8 (1) ◽  
Author(s):  
DYLAN ANTONIO SJ. TALABIS ◽  
ERICK JUSTINE V. MANAY ◽  
ARIEL L. BABIERRA ◽  
JABEZ JOSHUA M. FLORES ◽  
JOMAR F. RABAJANTE
Keyword(s):  
Population Growth ◽  
Carrying Capacity ◽  
Birth Rate ◽  
The Philippines ◽  
Child Policy ◽  
The Status ◽  
Zero Growth ◽  
Age Structured ◽  
Age Structured Model ◽  
Transient Stabilization

The study investigates the effect of imposing an n-child policy by forecastingthe population of the Philippines using a discrete age-structured compartmental model. Based on the results of the projection, a policy promoting a maximumof two children per couple leads to a transient stabilization (i.e., the populationeventually declines after attaining zero-growth rate). A three-child policy may alsolead to stabilization yet may converge beyond the calculated Verhulstian carryingcapacity of approximately 200M. However, overshooting the carrying capacity canbe resolved by increasing the available resources that can support the escalatingpopulation size. A child policy dictating a maximum of four or more children percouple results to a similar population growth as the status quo due to the inherentdeclining birth rate. With the declining birth rate trend in the Philippines,population stabilization is realizable even without implementing a child policy butonly after 100 years. Furthermore, this study estimated the future age structure andthe resultant GDP per capita income associated with each child policy.Keywords: Demography, population projection, child policy, zero growth, economy,logistic, carrying capacity, age-structured model, Philippines

scholarly journals Ziebur's matrix equation for population growth

1986 ◽  
Vol 28 (2) ◽  
pp. 220-228
Author(s):  
A. Brown
Keyword(s):  
Population Growth ◽  
Matrix Equation ◽  
Death Rate ◽  
Transition Matrix ◽  
Birth Rate ◽  
Age Groups ◽  
Growth Equation ◽  
Age Dependent ◽  
The Matrix

AbstractThe paper examines a matrix equation given by Ziebur [6] for the growth of a population in which the birth-rate and death-rate are age-dependent. For convenience the population was sub-divided into four age groups, with the same birth-rate and death-rate for individuals in a particular group, and the matrix equation relates the numbers in each sub-division in consecutive years. This avoids delay terms and makes it easier to modify the growth equation but it is shown that the form suggested by Ziebur for the transition matrix leads to some difficulties.

ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI PERTUMBUHAN JUMLAH PENDUDUK DI KABUPATEN ACEH TIMUR

2018 ◽  
Vol 9 (1) ◽  
pp. 23-29
Author(s):  
Murtala Murtala
Keyword(s):  
Linear Regression ◽  
Population Growth ◽  
Multiple Linear Regression ◽  
Death Rate ◽  
Birth Rate ◽  
Secondary Data ◽  
Research Problem ◽  
Independent Variables ◽  
The Future ◽  
External Migration

Tujuan penelitian ini adalah untuk mengetahui pengaruh tingkat kelahiran, kematian, migrasi dari luar dan migrasi dari dalam terhadap pertumbuhan jumlah penduduk di Kabupaten Aceh Timur. Data yang digunakan dalam penelitian ini bersumber dari BPS Aceh, BAPPEDA, dan Kantor Bupati serta berbagai literatur dan terbitan berkala lainnya yang ada kaitan dengan masalah penelitian ini. Jenis data yang digunakan adalah data sekunder selama periode 1995-2004 dengan peralatan regresi linear berganda. Hasil penelitian menunjukkan bahwa semua variabel bebas dalam penelitian ini ternyata berpengaruh signifikan terhadap pertumbuhan penduduk di Kabupataen Aceh Timur. Diharapkan pertumbuhan jumlah penduduk di Aceh Timur dimasa yang akan datang terus meningkat dengan harapan tingkat kematian semakin berkurang dan perbaikan gizi semakin baik.AbstractThe purpose of this study was to determine the effect of birth rate, mortality, external migration and inward migration to population growth in East Aceh district. The data used in this research are sourced from BPS Aceh, BAPEDA, and Bupati's Office as well as various other literature and periodical publications related to this research problem. The type of data used is secondary data during the period 1995-2004 with multiple linear regression equipment. The results showed that all independent variables in this study turned out to have a significant effect on population growth in Kabupataen Aceh Timur. It is expected that population growth in East Aceh in the future will continue to increase with the expectation of decreasing death rate and better nutrition improvement.Keywords: birth rate, death, migration from outside, migration from within, population

Time-dependent solution of the logistic model for population growth in random environment

1980 ◽  
Vol 17 (4) ◽  
pp. 1083-1086 ◽  
Author(s):  
Prajneshu
Keyword(s):  
Population Growth ◽  
Stationary Solution ◽  
Random Environment ◽  
Carrying Capacity ◽  
Logistic Model ◽  
Time Dependent ◽  
Kolmogorov Equation ◽  
Exact Time ◽  
Time Dependent Solution

The exact time-dependent solution as well as the stationary solution of the logistic model for population growth with varying carrying capacity is worked out in both the Stratonovich and Ito calculi by solving the forward Kolmogorov equation.

Population dynamics of cladocerans in Sunfish Lake, Ontario

1974 ◽  
Vol 52 (10) ◽  
pp. 1235-1242 ◽  
Author(s):  
A. S. Clark ◽  
J. C. H. Carter
Keyword(s):  
Carrying Capacity ◽  
Death Rate ◽  
Birth Rate ◽  
Lake Ontario ◽  
Population Parameters ◽  
Strong Negative Correlation ◽  
Southern Ontario ◽  
Population Peak ◽  
Daphnia Rosea ◽  
Population Numbers

Investigation of populations of Daphnia rosea, D. retrocurva, and Diaphanosoma leuchtenbergianum in Sunfish Lake, southern Ontario, during 1969 indicated that, in the absence of predation, food supply was the major factor controlling population size and influencing population parameters. Generally with each species, a population peak was preceded by a rise in fecundity, an increase in birth rate, and a fall in death rate. As the carrying capacity of the environment in terms of food was surpassed the population numbers declined, fecundity dropped off, and the death rate rose. A strong negative correlation between fecundity and death rate was observed.

Dynamic monitoring of changes in medical and demographic indicators in the Republic of Sakha (Yakutia) from 1998 to 2018

2020 ◽  
pp. 33-36
Keyword(s):  
Mortality Rate ◽  
Population Growth ◽  
Russian Federation ◽  
Rural Population ◽  
Urban Population ◽  
Birth Rate ◽  
Dynamic Monitoring ◽  
Demographic Indicators ◽  
The Russian Federation ◽  
The Republic

We studied the medical and demographic indicators in the Republic of Sakha (Yakutia) for the last 20 years (1998–2018). A decrease in the population by 4,7 % (р<0,01) was revealed in the Russian Federation in the period 1998–2008, 3,4 % decrease, followed by its growth by 2,8 % (р<0,01); a decrease in the number of rural population in the republic and an increase in the urban population were observed. By the beginning of 2019, in comparison with the 2003 data, an increase in the population by 1.9% (р<0,01), a decrease in the number of able-bodied people in the Republic of Sakha (Yakutia) at the beginning of 2019, as compared to 1998, were revealed, by 8,2 %, in the Russian Federation – by 4,7 % (р<0,01). In the Republic of Sakha (Yakutia) the birth rate remains high, the mortality rate is relatively low, and the natural population growth is maintained.

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