Community ecology

competition

interaction thats negative for both species (-/-) , competing over resources and food

predation

interaction that benefits one species but negative to another (+ / -)

parasitism

positive for one species but negative for another (+ / -) usually a long term interaction and are not always lethal.

herbivory

comsumtion of plant material, beneficial for one organism and negative for another (+ / -)

mutualism

interaction thats positive or beneficial for both species (+/+)

commensalism

interaction thats positive for one organsism and neutral for another organism (+/0)

amensalism

interaction thats negative for one organism and neutral for the other (-/0)

interspecific competition

competition between individuals of different species

intraspecific competition

competition between organisms of the same species

competitive exclusion principle

species with the same niche cannot inhabit the same area. Overlapping is possible but not identical niches can coexist

resource partitioning

differentiation of niches across time and space

character displacement

tendency for two species to diverge in morphology in order to use a resource in a different way

fundamental niche

broad niche a species has when theres no competition present

realized niche

niche a species has when competition is present. The niche is smaller and more specific since competition makes the broad niche impossible.

chemical defense

Organisms can protect themselves from predators by releasing chemicals as a defense to ward off predators, lots of these species display bright colors as a warning sign of their chemical nature

camoflauge

organisms blend into their environment to avoid being seen by predators

intimidation

way that organisms may ward off predators, includes mimicrys, antlers, etc

Mullerian mimicry

two or more toxic species start to look more like each other to emphasize their toxicity and make their defense more effective

batesian mimicry

nontoxic species evolves to look like a toxic one to trick predators to stay away

top-down control

predators control the number of species

bottom up control

availability of food and quality of food control species populations

community richness

the number of species present in a given area

community diversity

takes both the species richness and relative abundance of the species present. More diverse communities not only have more different species but also a more even distribution of the species

relative abundance

frequency of occurrence of a species within an area

intermediate disturbance hypothesis

the highest species diversity is achieved with an intermediate amount of disturbances.

what types of species would benefit from very frequent disturbances

r-selected

what types of species would benefit from nonfrequent disturbances

k-selected

primary succession

change in species composition on a newly exposed site with no previous biological legacy. examples include melting glaciers or volcanic eruption. Not really happening much anymore, takes a long time

secondary succession

chenge in species composition on a site that has previously supported life but underwent. adisturbance like a natural disaster. This is quicker than primary succession since htere was already species present in the area

facilitation

each colonizing species makes the local environment a little different so it is more suitable for other species. The process goes until the most dominant and competitive species have colonized

inhibition

early colonists prevents the colonization of other species. Common if resources or space are limited

tolerance

any species can start the succession and there are no changes to the environment by other species. CLimax is met in a calm and orderly manner. Species that cant tolerate competition thrive early and species who can tolerate competition thrive later and show up later near climax

diversity stability hypothesis

the more species present, the more stable the community is

what are the big two factors that affect the diversity of an island

the size of an island, the bigger the island, the more species that can be supported

the distance of the island from the mainland, the closer the island is, the higher the immigration rates are

Immigration and extinction rates are highly important as well.