Rucete ✏ Biology In a Nutshell
1. Hydrologic Cycle (Water Cycle)
Reservoirs: oceans, air, groundwater, glaciers
Assimilation: plants absorb water from soil; animals drink water or eat organisms with water
Release: plants transpire; animals and plants decompose
Additional Processes: transpiration, evaporation, precipitation, runoff
2. Carbon Cycle
Reservoirs: atmosphere (CO₂), fossil fuels (coal, oil), peat, cellulose
Assimilation: plants absorb CO₂ in photosynthesis; animals consume plants
Release: CO₂ released through respiration by plants and animals, decomposition, burning fossil fuels
3. Nitrogen Cycle
Reservoirs: atmosphere (N₂), soil compounds (NH₄⁺, NH₃, NO₂⁻, NO₃⁻)
Assimilation:
- Nitrogen fixation: N₂ → NH₄⁺ by nitrogen-fixing prokaryotes
- N₂ → NO₃⁻ by lightning and UV
- Nitrification: NH₄⁺ → NO₂⁻ → NO₃⁻ by nitrifying bacteria
- Release:
- Denitrification: NO₃⁻ → N₂ by denitrifying bacteria
- Ammonification: organic matter → NH₄⁺ by decomposers
- NH₄⁺ (or NH₃), urea, uric acid excreted as waste
4. Phosphorus Cycle
Reservoirs: rocks and ocean sediments
Assimilation: plants absorb phosphate from soil; animals consume plants
Release: decomposition of organisms returns phosphate to soil or sediment