Levels of study: organismal, population, community: interactions among
diff. species in an area, ecosystem
Key questions: what reg. pop size? What reg. species number? What reg.
distribution of species?
Types of species interactions: competition (-/-), predation/parasitism (+/-),
mutualism (+/+), commensalism (+/0), facilitation (+ or 0/+)
“effect”=effect on fitness of individuals involved (i.e.: survival, reproduction)
o competition: mutually negative interaction between individuals
resulting from resource limitation (space, niche, food, etc.); very
important type of interaction in ecology, central to evolution by
Why is there leveling off in paramecium population? Carrying
capacity, competition among individuals of SAME species
(intraspecific) or among individuals of different species
(interspecific), as density goes up MORE INTENSE
White rayed pentachaeta (pygmy daisy), highly endangered,
found only on serpentine soils in one county of CA, is this