10.8: Population Models Practice Exercises

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Choosing the Right Model \(\PageIndex{1}\)

Which type of model belongs at each point in this figure?

Answer

a) Leslie Matrix Model

b) Logistic Model

c) Geometric Model

d) Exponential Model

Reading Results \(\PageIndex{1}\)

How does the population change under the following conditions (increase, decrease, or remain stable)?

1) λ = 1.02

2) R0 = 1

3) N > K

4) r = -0.10

Answer

1) increase

2) remains stable

3) decrease (population overshoots carrying capacity)

4) decrease

Geometric Model \(\PageIndex{1}\)

Given Nt (population size at initial time) = 500, B = 300, and D = 350, calculate λ.

1) Is this population increasing, decreasing, or stable?

2) What will the population be in 10 years? What about in 30 years?

Answer

1) Nt+1 = Nt + B –D = 500 + 300 – 350 = 450; λ = Nt+1 /Nt = 450/500 = 9/10 = 0.9; Since λ < 1, the population is decreasing.

2) Nt = N0λt ;N10 = 500*(0.9)10 = 174; N30 = 500*(0.9)30 = 21