Niches and Community Interactions 4.2 Niches and Community Interactions

Niche = range of physical and biological conditions in which a species lives and the way the species obtains resources Competitive exclusion principle = no two species can occupy the same niche at the same time

Species Interactions 1. Predator-Prey  predator hunts, kills, eats prey

2. Herbivore-Plant  herbivores affect size and distribution of plant populations 3. Keystone species  change in its population dramatically changes community

Symbiosis: 3 main classes - Mutualism  both species benefit - Parasitism  one species (parasite) lives in/on another (host) causing harm - Commensalism  one species benefits, other is unaffected