Predation pt. 2

Question 1

What are the changes expected in predators, BECAUSE OF prey numbers?

Answer 1

too few prey, predator decreases
abundant prey, predator increases

Question 2

What are the changes expected in prey, BECAUSE OF predator numbers?

Answer 2

too many predators, prey decreases
too few predators, prey increases

Question 3

Lotka-Volterra Model

Answer 3

can be used to predict changes in prey population size

Question 4

What is the formula for the lot-volterra model?

Answer 4

dN/dt = rN - cNP

Question 5

What does each stand for in the lot-volterra model?

dN/dt = rN - cNP

Answer 5

dN/dt = instantaneous rate of increase in PREY
r = intrinsic growth rate of prey per capita (max birth and min death rates)
N = number of prey
c = capture efficiency
P = number of predators

Question 6

Suppose that rabbits are the only prey of foxes, and that the predator-prey interaction between these species follow Lotka-Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits is 0.2 per week. The efficiency at which each predator can capture prey is 0.002.

If there are 30 foxes and 400 rabbits in a given habitat, the instantaneous rate of change in the rabbit population will be a net ________ of _____.

A) loss, 24
B) loss, 16
C) gain, 56
D) gain, 80

Answer 6

C) gain, 56

Question 7

What is the formula of the Lotka-Volterra model to predict changes in predator population size?

Answer 7

dP/dt = acNP - mP

Question 8

What does each unit stand for?

dP/dt = acNP - mP

Answer 8

dP/dt = instantaneous rate of increase in predators
a = efficiency of converting 1 prey to 1 predator offspring
N = # of prey
P = # of predators
m = mortality rate of predators

Question 9

Suppose that rabbits are the only prey of foxes, and that the predator-prey interaction between these species follow Lotka-Volterra dynamics.The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits is 0.2 per week. The efficiency at which each predator can capture prey is 0.002, and the efficiency of converting the energy from each capture to a new predator offspring is 0.04.

If there are 30 foxes and 400 rabbits in a given habitat, the instantaneous rate of change in the fox population will be a net ________ of _____.

A) loss, -2.04
B) loss, -1.06
C) gain, 1.06
D) gain, 2.04

Answer 9

A) loss, -2.04