Ecology Exam 3

Principle of Competitive Exclusion

2 species that use a limiting resource in the same way cannot coexist indefinitely. Intraspecific competition must be more intense than interspecific.

Mutualism

interactions between species that benefit both participants

Commensalism

where one species benefits, while the other is neither harmed nor helped

competition

use or defense of a limiting resource by one individual that reduces the availability of that resource to other individuals

amensalism

where one species is negatively affected while the other species is neither harmed nor benefitted

predation

an organism that hunts, kills, and consumes other animals for food

parasitism

one species benefits while other is harmed, but not killed, at least not by a single parasite

parasitoidism

insects which feed inside their hosts while they are alive, but eventually kill host when they emerge

fundamental niche

the range of conditions and resources to which a species is adapted

realized niche

the portion of the fundamental niche that a species actually exploits in the presence of competitors, parasites, etc.

resource partioning/ differentiation

coexisting species must differ in resource use. reduces competition b/c species evolve to use different things

microparasites

small, single-celled that reproduce inside the host

ex. plasmodium

macroparasites

larger, that typically reproduce outside the host

ex. worms, ticks

ectoparasites

live on outside of host body

endoparasite

live inside the host, can be macro or micro parasite

hemiparasite

can do photosynthesis but extract water and nutrients from host

ex. mistletoe

holoparasite

lack chlorophyll, parasitize other plants to obtain nutrients

social parasitism

takes advantage of the social interactions of other species to rear their offspring

ex. kidnapper ants

virulence

the degree to which a parasite/pathogen has a negative impact on its host

How is high virulence achieved?

its achieved by high reproductive rate. if parasite doesn’t depend on mobility of its host for transmission it can evolve high virulence. If host has to stay alive awhile to increase transmission than virulence decreases.

coevolution

describes the process of reciprocal evolutionary change in two or more interacting species

aposematic coloration

pattern or color an animal displays to signal predators its toxic

batesian mimicry

members of a group of species gain protection from predation by resembling or mimicking the defensive signaling of a defended species

mullerian mimicry

two or more species with effective defenses share a similar appearance, and by this it promotes the evolution of refraining from attack by their enemies

Huffaker Mice Experiment

dispersal abilities can stabilize predator-prey interactions, leading to coexistance rather than extinction

Nonlethal Effects of Predators

prey individuals may change their behavior; avoiding preferred habitats, reduce foraging time

Why do plants present nutritional challenges for animals?

they have low nitrogen content and high fiber content making it difficult or impossible to digest

Qualitative Inhibitors

effective against specialists/generalists, increase in effectiveness with higher concentrations

ex. tannins (makes mouth dry)

Quanitative Inhibitors

effective in small doses; low concentrations in plants, most effective against generalists; specialists can adapt to these chemicals

ex. alkaloids- act as toxin that affects nervous system

physical defense in plants

thorns, spikes, needles, latex/resin, trichomes

chemical defense in plants

secondary metabolites, quantitative and qualitative

biotic defense in plants

ant-plant mutualism= plants provide food in exchange for protection

Fast-Growing Plants (high resource)

high indirect cost of defense (opporotunity cost), low potential impact of herbivory, low predicted level of investment of defense

Slow-Growing Plants (Low Resource)

low indirect cost of defense, high potential impact of herbivory, high predicted level of investment of defense

obligate mutualism

one or both partners depend on the other for survival and reproduction, may be obligate for one partner facultative for another

facultative mutualism

partners benefit from interaction but do not require each other for survival or reproduction

Dispersal mutualism

birds/bats and seeds

defensive mutualism

ant-herbivore, anemone and fish

trophic mutualism

partners specialized in complementary to obtain energy and nutrients

ex. zooxanthellae and coral

How can either the plant or animal cheat in plant-pollinator systems?

pollination by deception: flowers with appearance and scent of potential mate- but no reward

nectar robbers: cut hole in base of flower to get nectar without collecting pollen- no transfer

Non-native species

a species found outside its natural range, usually either deliberately or accidentally introduced through human activity

ex. by boat

invasive species

species introduced by humans, accidentally or intentionally, outside their native range that have negative impacts on native biodiversity

enemy release hypothesis

absence of natural enemies invaded environment allows introduced population to attain greater abundances

propagule pressure hypothesis

species introduced in larger numbers or more frequently are more likely to succeed in new habitat and become invasive

evolution of increased competitive ability hypothesis

(extension of enemy release) loss of natural enemies allows invasive to devote more resources to competition and less to defense

biotic resistance hypothesis

species-rich communities are more resistant to invasion b/c there more potential for a native to out compete

invasional meltdown hypothesis

once a community is invaded by one species, it is more vulnerable to other invasive species

ex. christmas island mats