Big Idea u The organism’s niche determines its biotic interaction with other organisms including feeding relationships, competition, and symbiosis

NICHE the role of an organism in its ecosystem

NICHE generalist: broad niche live in different habitats eat different things tolerate wide range of environment factors specialist: narrow niches one type of habitat one type of food narrow range of environment factors

FUNDAMENTAL NICHE: theoretical niche an organism would ideally fill if other organisms weren’t present REALIZED NICHE: niche that organisms actually fill because of competitive relationships with other organisms

No 2 species share the same niche

the reduction or loss of a population due to direct competition with another species

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Space Competition u Sea palm = kelp that takes advantage of the waves u adult kelp drops spores which develop into young sporlings u the young grow on the space competitors (mussels, algae) u young root themselves down around competitors and pull them off the rock with help of the waves u leaves space for the adult

PREDATORS reduce the population of a prey species create more available resources predators can create another niche

KEYSTONE PREDATOR A predator that controls the dynamic of the entire ecosystem

Predation Can Influence the Outcome of Competition prey on best competitor result in the persistence of a species that would be excluded species determining outcome= KEYSTONE PREDATOR

PREDATORS AND PREY Their populations are closely linked. large prey population can support more predators prey population grows or shrinks, the # of predators it can support changes as well

Classic Example: lynx and hare

On average, how often does the lynx population fluctuate?

On average, how often does the hare population fluctuate?

On average, how do the peaks of predator and prey populations compare?(do they happen at the same time?)

SYMBIOSIS A relationship where 2 species live closely together.

SYMBIOSIS 3 TYPES: parasitism commensalism mutualism

PARASITISM relationship where one organism feeds on the tissues or body fluids of another. Parasitism harms one organism and benefits the other. SYMBIOSIS

HOST The organism on which a parasite feeds. SYMBIOSIS: PARASITSM

A parasite may even kill its host. Most do not. SYMBIOSIS: PARASITISM: HOST

COMMENSALISM relationship where one organism benefits and the other is neither benefited nor harmed SYMBIOSIS

MUTUALISM relationship where both species benefit SYMBIOSIS