1. ABIOTIC FACTORS
Of Ecosystems

2. *ABIOTIC FACTORS: physical aspects of the environment
*can limit the size of a population
*include: water, carbon, nitrogen, soil, light, and temperature

3. 1. WATER:
*Why important?
*necessary for survival (i.e. metabolism), cells contain 70% - 90% water, acts as home to organisms

5. *also returns to air b/c animals breathe out water vapor/ urinate
*takes place between Earth and atmosphere
*water falls to Earth—plants pull water from ground
*plants lose water through leaves (water back to air) (TRANSPIRATION)
*also returns to air b/c animals breathe out water vapor/ urinate
*also returns to air due to evaporation

6. = water changes from gas to liquid
= rain falls to Earth
=plants lose water through leaves
=water changes from liquid to gas
= water filters through soil– ground water

9. 2. CARBON:
*all living organisms need carbon
*starts w/ autotrophs—photosynthesis—converts CO2 into usable energy (C- based) (takes C out of atmosphere)
*Heterotrophs feed on autotrophs—growth and energy
*as heterotrophs use C (energy), release CO2 back into air (respiration)
*decomposers release CO2 back into atmosphere when they break down organic compounds
*burning of fossil fuels also releases C back to atmosphere
*how fast the cycle goes depends on whether C found in soil, leaves, roots, oil, fossils, etc.

13. *120 billion tons of C exchanged each year

16. 3. NITROGEN
*78% of air = Nitrogen
*bacteria change N to usable form for plants (takes place in soil)
*plants use N to make proteins—animals eat plants and make other proteins
*urination by animals—contains excess N—returns to soil
*also returns to soil when animals decay—plants can then reobtain N
*Soil bacteria also act on dead—puts N back into the atmosphere

17. NITROGEN FIXATION: process of converting N gas to
*NITROGEN FIXATION: process of converting N gas to nitrates (plants can use)
*NITROGEN FIXING BACTERIA: convert N gas to ammonia, then nitrite, then nitrate
*AMMONIFICATION: decomposers break down dead/ wastes and release N as ammonia
*NITRIFICATION: bacteria in soil take up ammonia and oxidize it into nitrites (NO2-) & nitrates (NO3-)
*DENITRIFICATION: anaerobic bacteria break down nitrates and release N gas into atmosphere

20. OTHER ABIOTIC FACTORS:
4. SOIL:
*source of water/ minerals for plants
*home to microorganisms
*HUMUS: decayed remains of organisms that enrich soil
*pH and type affects which plants grow

21. 5. LIGHT:
*source of energy for ecosystems
*amount affects type of plants/ location of plants
*also important for vision, migration patterns, vitamin production
*heat produced by absorption of light contributes to water cycle

22. 6. TEMPERATURE:
*wind, amount of rainfall affect this
*temperature decreases from surface upward and as move away from equator
*varies with time (of day, of year)
*air temperature varies more than water temperature
*signals certain biological processes to start (i.e. blooming, migration)
*organisms have adaptations for changes in temperature (i.e. perspiration)