Chapter 45 (part 2): Community Ecology
Terms in this set (34)
Know the difference between the four types of species interactions: competition, Give examples of each.
Occurs when organisms use same resource
Lower fitness for both (-/-)
Know the difference between the four types of species interactions: consumption, Give examples of each.
one organism eats another
increasing consumers fitness/decreasing victims (+/-)
Know the difference between the four types of species interactions: mutualism, Give examples of each.
Two species benefit from interaction (+/+)
Know the difference between the four types of species interactions: commensalism. Give examples of each.
One species benefits, the other is unaffected (+/0)
What is the difference between intraspecific and interspecific competition.
Intraspecific: b/n members of same sp.
Intensifies as population density increases
Interspecific: Members of different spp.
What happens to intraspecific competition as the population density increases?
Intensifies as population density increases
What is the niche model of speciation.
predicts that the competition between species is limited because species that live in a similar area tend to use different resources
What is the competitive exclusion principle.
states that two species competing for the same resources cannot coexist if other ecological factors are constant
What is the difference between asymmetric and symmetric competition?
Asymmetric competition: One species suffers much greater fitness decline, and Competitive exclusion
Symmetric Competition: Each species suffers equal decrease in fitness
What is the difference between a fundamental and a realized niche?
fundamental niche: Resources a sp. can tolerate in absence of competition
realized niche: Resources a sp. can tolerate in presence of competition
The niche differentiation hypothesis suggests that natural selection favors what?
favors individuals that do not compete
List three types of consumption.
Parasitism: small amounts of tissue
What are some defenses against consumption?
avoidance, poison, schooling behavior, fighting back
What is the purpose of mimicry?
Resemblance to a dangerous prey, but aren't
What in the world is pseudocopulation mimicry?
describes behaviors similar to copulation that serve a reproductive function for one or both participants but do not involve actual sexual union between the individuals
Be able to explain the coevolutionary arms race.
occurs when a pair of species influences each others evolution
What traits do predators tend to evolve?
traits that make them faster, stronger and more fierce; increase the efficiency of predation
What traits do prey tend to evolve?
What is the difference between top-down vs. bottom-up hypothesis of herbirvore control?
top down: predation(disease) limit herbivores
bottom up: plants nutrition determines herbivore abundance
What are some examples of mutualisms?
Flowers and pollinators
Ants and acacia trees
Mycorrhizal fungi & plants
Cleaner shrimp and fish
What is an ecological disturbance?
Event that removes biomass from a community
What is a disturbance regime?
A characteristic type of disturbance common to an
What factors affect a disturbance regime?
Type of disturbance
Frequency of disturbance
Severity of disturbance
What is ecological succession?
Recovery of communities following severe
What is difference between primary and secondary succession?
primary- When disturbance removes soil and its organisms
e.g. avalanche, volcanism
secondary- When disturbance removes some or all organisms but leaves soil in tact
e.g. wildfire, windstorm
What do early successional communities composed of?
r-selected species or pioneer species
What characteristics do r-selected species share?
Short lived and small size
Disperse seed long distance
aka pioneer species
What adaptations do r-selected species have?
Most E to reproduction
Little E to competitive ability
Tolerate severe abiotic conditions
What characteristics to K-selected species share?
Long lived and large size
aka climax species
What adaptations to K-selected species have?
Good competitors for resources
High E storage in seeds
What is a climax community?
that following a disturbance ecological communities followed a series of predicatable stages of r-selected species through k-selected species
What did Clements hypothesize about climax communities?
biological communities progress through predictable stages
What predictions do the theory of island biogeography propose?
that the number of species found on a undisturbed island is determined by immigration and extinction.
Predicted species richness
(# of spp.) is higher on:
Larger islands than
Nearshore islands than
more likely with fewer
more likely with more
Clements hypothesized: climax community
Pioneering species consisted on weedy species, then replaced by herbaceous species which was the early sucessional community, then replaced by shrubs and short lived trees which was the mid-sucessional community, replaced by long lived trees that mature which is the climax community