Chapter 14 Flashcards
(36 cards)
Introduced, exotic, or non-native species
introduced to a region of the world where they have not historically existed.
Invasive species
introduced species that spread rapidly and negatively affect other species.
Parasitoids
a unique type of predator that can also limit the abundance of prey.
Mesopredators
relatively small carnivores that consume herbivores (e.g., coyotes, weasels, feral cats).
Top predators
predators that typically consume both herbivores and predators (e.g., mountain lions, wolves, sharks).
Lotka-Volterra model
a model of predator-prey interactions that incorporates oscillations in predator and prey populations and shows predator numbers lagging behind those of their prey.
Growth of prey populations
depends on the growth rate of a prey population (rN) and the rate of individuals killed by predators (cNP)
dN/dt=rN-cNP
growth of predator populations
depends on growth rate of predator populations (acNP) minus the rate of predator death (mP)
dP/dt=acNP-mP
N=
number of prey
P=
number or predators
c=
probability of an encounter between a predator
and prey leading to the prey’s capture
a=
the efficiency of a predator converting consumed prey into predator offspring
m=
per capita mortality rate of predators
Equilibrium (zero growth) isocline
the population size of one species that causes the population of another species to be stable.
Joint population trajectory
the simultaneous trajectory of predator and prey populations.
Joint equilibrium point
the point at which the equilibrium isoclines for predator and prey populations cross.
Functional response
the relationship between the density of prey and an individual predator’s rate of food consumption.
Whenever prey density increases and a predator can consume a higher proportion of those prey, the predator can regulate the growth of the prey population.
Type I functional response
when a predator’s rate of prey consumption increases in a linear fashion with an increase in prey density until satiation occurs.
Type II functional response
when a predator’s rate of prey consumption begins to slow as prey density increases and then plateaus; often happens because predators must spend more time handling more prey.
As prey density increases…
predators consume a constant proportion of prey until satiation.
Any increase in prey density is associated with…
a slowing rate of prey consumption.
Type III functional response
when a predator exhibits low, rapid, and slowing prey consumption under low, moderate, and high prey densities, respectively.
Low consumption at low prey densities may occur for three reasons:
- Prey can easily find refuges to hide.
- Predators may have less practice at locating and catching prey but
develop a search image at higher prey densities. - Predators may exhibit prey switching by changing their diet preferences to the more abundant prey.
Search image
a learned mental image that helps a predator locate
and capture food.