What Shapes an Ecosystem?

Biotic vs. Abiotic Biotic Factors: biological influences on organisms Abiotic Factors: physical or nonliving climate Determines an organism’s survival & growth productivity of the ecosystem

Habitat vs. Niche Habitat: area in which the organism lives biotic & abiotic factors house Niche: the way an organism uses abiotic and biotic factors how it gets food & what it eats predators job

Community Interactions Competition: organisms try to use the same resource (necessity of life) Predation: one organism catches & eats another

Community Interactions Symbiosis - two species live closely together Mutualims - both benefit; lichen, flower/bees Commensalism - one benefits and one is not helped nor harmed; barnacles on a whale Parasitism - one organism live on or inside another and harms it; parasite/host; tapeworms, fleas, ticks, lice

Ecological Succession Ecosystems constantly change in response to natural and human disturbances older inhabitants gradually die out new organisms move in further change Ecological Succession – a series of predictable changes that occur in a community over time slow change in the physical environment sudden natural disturbance; clearing forest

Primary Succession Occurs on land where no soil exists islands formed from volcanic eruptions bare rocks exposed from glaciers melting pioneer species:1st to populate the area Lichen: add organic matter to soil when they die

Secondary Succession Changes to existing community without removing the soil cleared and plowed land for farming wildfires burn woodlands

Climax Community mature, stable community that doesn’t undergo further succession old-growth forest in Pacific Northwest and Louisiana, and Arkansas