n nature, populations of a species are often subject to predation in addition to the usual
birth and death processes. The evolution of a population subject to these effects can be
modelled by the following modified logistic model:
dp
dt = kp
(
1 − p
a
)
− wp, (a, k, w > 0)
where p is the population of the species at time t, and a, k, w represent the carrying capacity,
growth rate and predation rate respectively.