Final Exam Class 4 Community Ecology Flashcards
what is a community?
consists of all the species living in the same place at the same time
what is community ecology
explores how species interact with one another
what are the 4 types of species interaction?
- competition
- commenalism
- consumption
- mutualism
competition
-/-
consumption
+/-
commensalism
+/0
mutualism
+/+
what is a niche
the range of resources a species is able to use or tolerate
partial niche overlap
when two species flourish in different areas but they do compete in some areas
competition occurs when
the niches of two species overlap
compatition can be
intraspecific or interspecific
what is competitive exclusion?
the principle that two species cannot occupy the same niche
assymmetric competetion occurs
when one species is a better copetitior than the other
a weaker competitor will ither
evolve to live in a new niche or go extinct
what is a realized niche
if overlap is not complete, tehe weaker competitor may be forced to live in this narrower niche
the realizd niche is always equal to or smaller than the
fundamental niche
example of intraspecific competition
squirrels steling nuts
example of intraspecific competition
squirrels steling nutswhat is character displacement?
occurs when the traits of similar competitors changes so that competition is reduced
character displacement
what is an example of character displacement?
birds evolving larger beaks than another species so that they can exploit larger seeds as a food resource
what is niche differentiation
evolutionary change in resource use caused by competiton
niche differentiation is facilitated by
character displacement
consumption occurs when
one organisms eats something else
3 types of consumption
predation
herbivory
parasitism
consumption favors the evolution of
prey defenses
what are some examples of prey defenses?
cryptic coloration
escape behavior
toxins
armor of weapons
herds, schooling or flocking
defenses can either be
constituted or inducible
constitutive defense are
always present even when predators are absent
inducible defenses are
only present when predators are present
mimicry is an example of
constitutive defense
what are the two types of mimicry
batesian mimicry
mullerian mimicry
what is batesian mimicry?
when a nonhazardous animal mimics a hazardous
(only one species benefits)
what is mullerian mimicry?
two poisonous species imitate each other
both species benefit
the impact of consumption is
coevolution and evolutionary arms races
-evolution of traits that increase defense in prey species leads to evolution of traits that increase predation in predators (coevolution)
why dont herbivores eat everything?
top down and pottom up control
top down control
organisms at upper trophic levels control lower trophic levels ex.) predators reduce herbivores which increase plant numbers
bottom up control
organisms at lower trophic levels control upper trophic levels ex.) plant defenses reduce herbivore numbers which reduces predator numbers
what is parasitism
when a parasite feeds off of a host for an extended period of time
what are the two types of parasitism?
exo and endo parasitism
what is commensalism?
occurs when one species benefits and the other is unaffected
what is mutualism?
occurs when both species benefit from one another and each have higher fitness together
- the are not being nice
all mutualism is is reciprocal parasitism
