A population of snails has an annual per capita birth rate o

A population of snails has an annual per capita birth rate of 0.055 and an annual per capita death rate of 0.015. Calculate an estimate of the change in population size over one year, for a given starting population of 1, 000 individuals. Assume that the population grows exponentially according to the equation dN/dt = rN increases by 40 individuals decreases by 15 individuals increases by 400 individuals increases by 55 individuals decreases by 20 individuals

Solution

Increase by 40 individuals.

dN/dt = rN.

Where dN/dt = change in population size;

r = instrinsic rate of increase (= per capita rate of increase and equals birth rate minus death rate);

N = population size.

Here r = birth rate 0.055 - death rate 0.015.

0.055-0.015 = 0.040.

N= 1000.

dN/dt = rN = 0.040 × 1000 = 40.