chapter 14 Flashcards
introduced species that spread rapidly and negatively affect other species.
Invasive species
species are introduced to a region of the world where they have not historically existed.
Introduced, exotic, or non-native
unique type of predator that can also limit the abundance of prey.
Parasitoids
relatively small carnivores that consume herbivores (e.g., coyotes, weasels, feral cats).
Mesopredators
predators that typically consume both herbivores and predators (e.g., mountain lions, wolves, sharks).
Top predators
The effects of herbivores may be seen by
fencing areas or removing herbivores to prevent grazing.
The synchrony of population cycles between consumers and the populations they consume suggests
that these oscillations are the result of interactions between them.
conducted a series of experiments using western predatory mites as predators and six-spotted mites as prey.
Carl Huffaker
Wooden posts were placed on trays as jumping points between oranges to give
prey mites a dispersal advantage
a model of predator-prey interactions that incorporates oscillations in predator and prey populations and shows predator numbers lagging behind those of their prey.
Lotka-Volterra model
N =
number of prey
P =
number of 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
the population size of one species that causes the population of another species to be stable
Equilibrium (zero growth) isocline
the simultaneous trajectory of predator and prey populations.
Joint population trajectory
the point at which the equilibrium isoclines for predator and prey populations cross
Joint equilibrium point
relationship btw the density of prey & an individual predator’s rate of food consumption
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 I 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
Type II functional response
when a predator exhibits low, rapid, and slowing prey consumption under low, moderate, and high prey densities, respectively.
Type III functional response
Low consumption at low prey densities may occur for 3 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.
Search image: a learned mental image that helps a predator locate and capture food.
- Predators may exhibit prey switching by changing their diet preferences to the more abundant prey
a change in the number of predators through population growth or population movement due to immigration or emigration.
Numerical response
occurs when a prey moves away from a predator
Spatial avoidance
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).
Crypsis
when palatable species evolve warning
coloration that resembles unpalatable species (e.g., hover flies and hornet clearwings resemble the common wasp).
Batesian mimicry
Defense costs can reduce
growth, development, and reproduction
when two or more species affect each other’s evolution; selection for prey defenses should favor the selection for counter-adaptation in predators.
Coevolution
crab and mussel are exaples of
coevolution
e.g., sharp spines, hair) deter herbivores from consuming leaves, stems, flowers, and fruits.
Structural defenses
