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The Biology Project > Biomath > Applications > Logistic Population Model

Logistic Population Model

A fundamental population growth model in ecology is the logistic model. In one respect, logistic population growth is more realistic than exponential growth because logistic growth is not unbounded. We can write the logistic model as,
equation:  P(t) = (Po * K)/ [Po + (K - Po) * e ^ rt]

where P(t) is the population size at time t (assume that time is measured in days), P0 is the initial population size, K is the carrying capacity of the environment, defined as the maximum population size an environment can support, and r is a constant representing the rate of population growth or decay.

Use this model to solve the following 7 problems.

A.
Given an initial population of 100 individuals, a carrying capacity of 250 individuals, and r = 0.4, compute the expected population size 4 days later. Round your answer to the nearest individual.
Answer:
individuals   

 

Problem A-Compute the population size

Problem B-Compute the time for a population to double

Problem C-Predict how a population will change over time

Problem D-Predict how a population will change over time

Problem E-Calculate the r value for a given population

Problem F-Predict how a population will change over time

Problem G-Explain what happens to a population given different values of r

 

End of Applications

The Biology Project > Biomath > Applications > Logistic Population Model

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The Biology Project
Department of Biochemistry and Molecular Biophysics

The University of Arizona

January 2006
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