Ecology Exam 3 Flashcards
The outcome of a predator-prey interaction depends on
reproductive rates of predator and prey, adaptive capacity of predators to respond to increase in prey density, carrying capacity of prey in absence of predation
kinds of predation on plants and their impact (+/-)
parasitism (-), defoliation (-), consumption of fruit/nuts (+/-)
parasitism always has a negative impact on ___
plant fitness
positive impacts of predation?
moderate grazing can promote grass growth, moderate fruit/nut eating spreads seeds
chemical defenses against predation
accumulate secondary compounds (terpenes, phenolics, resins, alkaloids, tannins) induced by scratching or biting from insects
mimicry defense
uncommon, mimic plants that are inedible, mimicry of crops by weeds
structural defense
least costly, tough leaves, spines, leaf hairs
predator satiation
timing of reproduction so predators can’t consume all seeds, masting
other example of defense shown by lithops
camouflage
chemical defense (animal)
warning odors, repellants, poisons
what is the skunks defense
produce smelly spray to repel predators, produced in two glands by the tail, long-lasting smell, has 2 other functions
what is the milkweed defense
cardenolide aglycones and cardiac glycosides cause illness in birds and other animals
mimicry in animals
Mimicry is a defense strategy that many animals use to
avoid predation by mimicking animals that have a bad taste,
obnoxious secretion, or painful bite or sting, usually have bright colors or bold markings
mullerian mimicry
two unrelated, dangerous species develop similar appearances as a shared protective device
batesian mimicry
a harmless animal mimics a dangerous animals to avoid predation
cryptic coloration defense
Animals can use patterns, shapes, postures, movements and
behaviors that make them less visible to predators
other forms of defense for animals
armor/weapons and behavioral (alarm call, distraction, groups, moment-of-truth defense)
predator satiation in animals
no need for costly defenses, produce more than predator can consume. cicada example
predator offense methods
ambush, trapping, pursuing
up/down side of ambush technique
low reward, low energy cost
up/down side of pursuit
time saving, high reward, very energy costly
coevolution
Reciprocal selection pressure on interacting populations, cycle of adaptation and counteradaptation
parasites
Organisms living on the tissue of their host, often reduce fitness of host but do not kill
parasitoids
Organisms living in their host and killing it, usually insects