quiz 5 Ch 13 Flashcards
modes of resource competition
exploitative
interference
exploitative
differential ability to acquire resources.
don’t interact directly
use resources available to others
interference
direct aggressive interaction between individuals
types of interference
intraspecific or interspecific
competition for resources ___ at higher population densities
increases
plant growth rate and weight ___ in low density populations
increases
self thinning
intense competition causes mortality among competing plants causing
intraspecific
competition between two spp doesn’t not affect a 3rd party
interspecific
competition between two spp affects a 3rd party
case study: alfalfa density v. dry weight
~ 3 units increase in plants weight with each 2 unit decrease in population density
case study: infraspecific competition among planthoppers
hypothesis
they aggregate, rapid growth, and unstable food supply
wanted to see how their density affects body length, survivorship, and development
case study: infraspecific competition among planthoppers
result
high densities lead to small body length, low survival. and short developmental time
niches
all environmental factors that influence growth, survival, and reproduction
Hutchinson’s definition of niche
n -dimensional hype volume
fundamental niche- hypervolume
realized niche
Gause: principle of competitive exclusion
hypothesis
2 spp. with identical niches cannot coexist and the better competitor will eventually exclude the other
Gause: principle of competitive exclusion
result
when grown alone there was intraspecific competition.
when grown together P. caudatum declines due to reduced resource supplies
fundamental niche can be changed by
strong and persuasive interaction lead to evolutionary response
character displacement
interspecific competition cause two species to differ more from each other in geographic areas where they occur together and distributions do not overlap
allopatric character displacement
two spp occur apart leading to similar charcteristics (overlap)
sympatric character displacement
two spp occur together leading to directional selection (no overlap)
lotka - volterra model of competition
effect of interspecific competition on population growth of each spp.
alpha competition coefficient
effect of one spp on the other
isocline
anywhere along line there in no population growth
below isocline pop. is decreasing.
above line the population. is increasing
