CYCLING IN THE ECOSYSTEM

1
CYCLING IN THE ECOSYSTEM

• pp. 371-374

2
DEFINITIONS

• Ecosystem an environment where the living
  (biotic) and non-living (abiotic) things affect
  one another
• Biogeochemical process circulation of substances
  through living organisms and the environment

3
WATER CYCLE
4

• Evaporation water vapor enters the atmosphere
• Transpiration evaporation of water through the
  leaves of plants
• Precipitation water vapor that leaves the
  atmosphere

5
CARBON CYCLE
6

• Photosynthesis converting light energy into
  organic compounds
• Cellular respiration breaking down organic
  compounds to release energy
• Combustion burning of fossil fuels for energy
  releases CO2

7
NITROGEN CYCLE
8

• nitrogen fixation bacteria convert nitrogen gas
  to usable form (ammonia)
• ammonification decomposers break down
  proteins/nucleic acids to ammonia
• nitrification bacteria convert ammonia to
  nitrates (fertilizers)
• assimilation plants take up nitrates to make
  proteins
• denitrification bacteria return nitrogen to
  atmosphere

9
PHOSPHORUS CYCLE
10

• Weathering Erosion of rocks
• Decomposition breaking down organic compounds
• Absorption Plants absorb phosphates from soil
  and water
• Runoff Phosphates from fertilizers or soaps
  washes from land into water bodies