predation, herbivory, and symbiosis

ways to avoid going extinct due to predation

• defend yourself

• take shelter

aposematic strategy for defense

bright or conspicuous coloration displayed by toxic or displayed by many toxic or distasteful potential prey species

mullerian mimicry

mimicking of warning signals among different poisonous species

batesian mimicry

a type of mimicry by nontoxic species to resemble toxic species

• exists a mimic and a model

refuge by population

protection from predators by taking refuge in large populations so the chance of one individual being eaten is low

rescue effect

individuals from larger populations may immigrate and ‘rescue’ smaller populations

refuge by size

avoidance of predation by being too big to be eaten

• comes at a cost of taking a lot of energy to maintain size

two types of plant defences

• resistance

• tolerance

constitutive defences

type of resistance where plant produces it continuously, regardless of what happens to the plant

induced defences

concentrations of a defensive chemical increase rapidly in response to herbivore damage

why are fruits toxic?

• they are not ripe

• reduce the risk of seeds being digested

• facilitate seed dispersal

overcompensation

increased plant growth following herbivory, compared to growth of plants that did not experience herbivory

what causes overcompensation

• high resource availability

• partial defoliation can stimulate growth

• growing points like buds or basal meristems

• history of grazing

• timing of herbivory

symbiosis

the intricate and long term living of two organisms

• commensalism, mutualism, and parasitism

facultative symbioses

occurs optionally

• no dependence on specific partners

obligate symbioses

occurs by necessity

• dependance on specific partners

commensalism

ecological interaction that is beneficial for one species but neutral for the other

parasitism

ecological interaction that is beneficial for one organism but detrimental to the other

difference between herbivores and plant parasites

parasites form an intricate long-term relationship with the host, herbivores do not

mutualism

ecological interaction that is beneficial for both organisms

arbuscular mycorrhizal fungi

• penetrate the cortical cells of plant roots

ectomycorrhizal fungi

do not penetrate cortical cells

non-symbiotic mutualism

does not involve constant body to body intricate interactions

pollination

the transfer of pollen grains for reproduction by wind, water, animals, or within the same flower