12abiotic - - temperate sunlight more spread out,...

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BIO 20 ABIOTIC 1 ABIOTIC FACTORS 1. PHYSICAL ENVIRONMENT homeostasis - maintaining a stable internal environment - resist changes in external environment - temperature - environment 0-40°C law of minimum - distribution-abundance controlled by a limited resource - temp, light, food, water, space, soil law of tolerance - distribution-abundance also retarded if a resource is excessive light - provides for heat, photosynthesis - 25% reflected by atmo - 25% absorbed by atmo - 5% reflected by surface - 45% absorbed by surface greenhouse effect - surface absorbs high-energy light - surface re-radiates low-energy light absolute humidity - amount of moisture in atmosphere - more humid if warmer, at lower elev. 3. PERIODICITY periods - daily circadian, 2x daily tidal, monthly lunar, annual seasons - earth tilted 23.5° from axis of rotation - tropics direct sunlight
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Unformatted text preview: - temperate sunlight more spread out, cooler-fluctuates more than tropics- northern & southern seasons opposite BIO 20 ABIOTIC 2 4. SOIL soil - reservoir for nutrients (incl. P & S)- formed from weathering of rocks textures - % diff size of soil particles- clay small, silt medium, sand large, gravel largest- loam balances clay-silt-sand 5. GEOGRAPHY microclimate- local weather in immed surroundings vegetation - cooler if more plants topography - valleys more humid- south-facing slopes sunny & warmer- north-facing slope shady & cooler- warmer nearer to ground rain shadow - upslope cools & rains- downslope warms & absorbs water 6. URBAN ENVIRONMENTS absorbs more sunlight- more if concrete, less if haze/smog radiates more heat - 6-8 warmer- more people, autos, bldgs, heaters lower relative humidity - less plants less evaporation - water drains away more fog - condenses around smog...
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This note was uploaded on 08/12/2010 for the course BIO 20 taught by Professor Hom during the Spring '08 term at City College of San Francisco.

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12abiotic - - temperate sunlight more spread out,...

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