Biology 101 / 102
April 17, 2002
Abiotic Factors of the Biosphere
Habitat – A characteristic community of organisms and the environmental situation in which they live.
Patchiness –
Local and global scale
Based on differences in abiotic factors
Limiting factors
Abiotic factor – Those non-living components of a system
Sunlight
Water
Temperature
Wind
Rocks and Salt
Periodic disturbance
Sunlight
Source of power for most systems
Affects growth and distribution of autotrophs (photosynthesizers / producers)
Limiting factor in aquatic systems
Less so in terrestrial
Ground level competition for light
e.g., felled tree – open
Water
Solute concentration
Drying
(Adaptations to manage)
Waterproofing protein (our skin)
Concentrate urine in kidneys – extract water
Insects
Temperature
Effect on metabolism
(Cellular processes)
General range from 32oF – 122oF
Extremist adaptations
“Spring peepers”
Extremophiles (chemical, temperature, and pressure)
Wind
Blow nutrients
Disperse pollen and seeds
Damage creates openings in concentrates openings in concentrated areas
(Create patchiness)
Water loss and evaporation (evaporative cooling)
Growth patterns
17B
Rocks and soil
Structure and composition
Affect distribution of plants
Water chemistry
Points of attachment
Materials for structures
Disturbance
Fire, hurricanes, tornadoes, volcanoes
Some organisms have evolutionary adaptations
Climate patterns
Sunlight – powering up the cycling of water
Sunlight – powers the system
Water – Amount and movement / cycling
Temperature – Speed of cycles
Rate of evaporation / transpiration
Wind – Movement
Chemistry
Also….Movement in space
Uneven heating
Latitude
Angle of strike – perpendicular or oblique
“Concentration of energy”
Uneven heating drives air movement and water currents
Global
Seasons – Result from tilt of Earth as it orbits the sun
Orientation changes throughout the year
Northern / Southern hemisphere
Tipped toward or away from the sun
Circulation of air (Winds and currents)
Uneven heating
Air warms > Rises > absorbs moisture > cools > falls > loses moisture
Winds
Doldrums
Trade winds
Prevailing winds
Jet stream
Doldrums – Tropics
Air rises and falls
Influence of direct sun
“Column of calm”
Trade winds
Lose moisture over equator
Spread dry air to higher latitudes
Deserts (Sahara and Arabian)
Dry air descends, moves back toward equator
Tropics
Picks up moisture and lifts again
Prevailing winds
Result from rising and falling air masses and Earth’s rotation
Milder climates
Pick up moisture, cool and drop at higher altitudes
Wet or rainy
What about high latitude deserts?
Results from mountain ranges cutting off the flow of moist air
Northern Hemisphere
Trade winds blow from the NE
Temperate zone – Westerlies (Northern H)
Easterlies (Southern H)
Ocean currents
Prevailing winds
Planet rotation
Unequal heating
Continents (shape and location)
Effect on regional climates
Main currents
Gulf stream
Japan
Labrador
Humbolt – Cools western South America, Eastern Australia, South of Asia and East of Africa
Temperate area
Tropical
Local climate
Proximity to large bodies of water and the presence of landforms – Moderate climate by absorbing heat and
releasing heat
Mountains
Cooler with altitude (6oC / 1000 meter increase in altitude)
Block airflow
Microclimate
Shading
Wind
Buffers
Mosaic of scale differences
Rotting log – Forest – region