1. 4.2-Niches & Community Interactions
-Niche-range of physical & biological conditions in which a species lives & the way the species gets what it needs to survive & reproduce
~environment it lives in
~how it interacts with biotic & abiotic
factors
~resource-what you need to live—water,
nutrients, food, space

2. Tolerance-ability to survive & reproduce under a range of environmental circumstances (every species has some level of tolerance)
Physical Aspects-abiotic factors needed for survival
Biological Aspects-biotic factors needed for survival

3. Competition-when organisms attempt to use the same limited ecological resource in the same place at the same time
Intraspecific competition-same species
Interspecific competition-different
species
**In competition, there is always a winner (lives) & a loser (dies)

4. Competitive Exclusion Principle
No two species can occupy exactly the same niche in exactly the same habitat at the same time.
Predation-interaction where one animal (predator) captures & feeds on another animal (prey)
Herbivory-interaction where one animal (herbivore) feeds on producers (plants)

5. Keystone species-changes in the population of a single species that can cause dramatic changes in the structure of a community.
symbiosis-”living together”--any relationship where two species live closely together.

6. 3 main classes:
1. mutualism-a relationship where both species
benefit (sea anemone & clownfish)
2. parasitism-relationship where an organism
lives inside or on another organism & harms it
(tapeworm) parasite
3. commensalism-relationship where one
organism benefits & the other is not helped
or harmed (barnacles on whale's skin)