Chapter 14 Flashcards
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.
Numerical response
a change in the number of predators through population growth or population movement due to immigration or emigration.
Populations of predators usually grow slowly relative to populations of their prey, but the movement of mobile predators can occur rapidly when prey density increases.
active hunting
spend most of their time moving around looking for prey (e.g., birds foraging on lawns for worms).
ambush (sit-and-wait) hunting
lie in wait for a prey to pass by (e.g., chameleons waiting for insect prey).
Spatial avoidance occurs when
a prey moves away from a predator.
Alarm calling
warns relatives that predators are approaching
Crypsis
camouflage that either allows an individual to match its environment or breaks up the outline of an individual to blend in better with the background (e.g., katydids, horned lizards).
Warning coloration (aposematism)
a strategy where distastefulness evolves in association with very conspicuous colors and patterns.
Predators have innate aversions to aposematic colors; others learn to avoid certain colors and markings through experience.
Batesian mimicry
when palatable species evolve warning coloration that resembles unpalatable species (e.g., hover flies and hornet clearwings resemble the common wasp).
Müllerian mimicry
when several unpalatable species evolve a similar pattern of warning coloration (e.g., several species of poison dart frogs have evolved similar warning coloration).
Coevolution
when two or more species affect each other’s evolution; selection for prey defenses should favor the selection for counter-adaptation in predators.
Structural defenses
(e.g., sharp spines, hair) deter herbivores from consuming leaves, stems, flowers, and fruits.
Chemical defenses
include sticky resins and latex compounds that are hard to consume, and alkaloids (e.g., caffeine, nicotine, morphine) that have a wide range of toxic effects.
