Predation and Herbivory Flashcards
Predators and Herbivores can reduce population size
to levels below K (carrying capacity)
mesopredators
-mid level in food chain
-eat herbivores and insects
-(coyotes, cats, lizards, mantis)
top (apex) predators
-top of food chain
-eat herbivores and mesopredators
-(wolves, sharks, crocodiles, eagles)
Predator-Prey Cycles caused by time delays
1) slower dispersal of predators relative to prey
2) time needed for predator population to reproduce
stable predator-prey population cycles
can be achieved when the environment is complex so that predators cannot easily find prey
Lotka-Volterra Predator/Prey 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)
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
numerical response
a change in the number of predators through population growth or immigration/emigration
type 1 functional response
when a predator’s rate of prey consumption increases in a linear fashion with an increase in prey density (until satiated)
-as prey density increases, predators consume a constant proportion of prey
type 2 functional response
when a predators rate of prey consumption slows as prey density increases and then plateaus; often happens because predator must spend more time handling more prey or become satiated
type 3 functional response
when a predator exhibits low, rapid, and slowing prey consumption under low, moderate, and high prey densities respectively
search image
a learned mental image that helps a predator locate and capture food
active hunting
strategy where predators spend most of their time moving around looking for prey
ambush
hunting strategy where predators lie and wait wait for a prey to pass by
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
warning coloration (aposematism)
a strategy where distastefulness evolve in association with very conspicuous colors and patterns
Batesian mimicry
when palatable species evolve warning coloration that resembles unpalatable species
(hover flies resemble the common wasp)
Mullein mimicry
when several unpalatable species evolve a similar pattern of warning coloration
(poison dart frogs have evolved similar warning coloration)
structural defenses
sharp spines, hair
chemical defenses
caffeine, nicotine, morphine (hard to consume)
tolerance
increased production of plant tissue after herbivory
coevolution
reciprocal process in which adaptations in one population promote the evolution of adaptations in another population
