APES Review 1. First Law of Thermodynamics: energy is neither created nor destroyed, may be converted from one form to another. 2. Second Law of Thermodynamics: when energy is changed from one form to another, some useful energy is degraded into lower quality energy (usually heat) Entropy is increased. 3. High quality energy: organized and concentrated, able to perform useful work (ex: oil and nuclear) 4. Low quality energy: disorganized dispersed (ex: heat) 5. Units of energy” joules, calories, kilocalories, BTU’s, kilowatt-hours 6. Power: the rate of doing work. Units of power: watts and kilowatts. 7. Electromagnetic radiation: form of energy, travel as waves-radio waves, IR, visible light, UV, gamma rays 8. Ionizing radiation: has enough energy to knock electrons from atoms, forming ions and capable of doing damage to DNA. (Gamma rays, X-rays, UV) 9. Radioactive decay: unstable radioisotopes decay releasing gamma rays, alpha and beta particles. 10. Half-life: time it takes for ½ of the mass of a radioisotope to decay 11. Estimate of how long a radioisotope must be stored until it has decayed to a safe level: 10 half lives. 12. Nuclear fission: nuclei of isotopes are split apart into smaller nuclei; used in nuclear reactors. 13. Nuclear fusion: 2 isotopes of light elements are forced together at high temperatures; not technologically available now. 14. Parts of hydrologic (water) cycle: evaporation (transpiration), condensation, precipitation 15. Fate of precipitation: runoff or infiltration, percolation. 16. Aquifer: underground water bearing layer Water table- upper surface of groundwater. 17. Cone of depression: lowering of water table around a pumping well. 18. Salt water intrusion: over pumping of groundwater near coast causes salt water to move into aquifer. 19. Ways to conserve water. Agriculture- drip irrigation, industry- recycling, home use- fix leaks, use gray water, low flow fixtures. 20. Distribution of water on Earth: 97% seawater, 2% in icecaps and glaciers, <1% in ground water, surface, organism, and atmosphere. 21. Carbon: component of all organic molecules. 22. Largest reservoir of carbon: sedimentary rocks, then ocean. 23. Photosynthesis: process by which plants convert CO2 to carbohydrates, removes C from the atmosphere. 24. Cellular respiration: organisms break down carbohydrates; releases energy, returns C to atmosphere. 25. Processes that releaser C back into the atmosphere: cellular respiration and decomposition, fires, burning fossil fuels, volcanoes. 26. Carbon-silicate cycle: very slow, geological cycle, C in oceans used by marine organisms, end up in ocean sediments and are subducted into Earth’s crust, eventually returned through volcanic venting. 27. Nitrogen: component of proteins and amino acids 28. Largest reservoir of nitrogen: the atmosphere (78% N2). Producers cannot use nitrogen gas. 29. Nitrogen fixation: N2 is converted to ammonia NH3. Bacteria do this (esp. Rhizopbium in legumes) 30. Nitrification: ammonia is converted to nitrite (NO2) to nitrate (NO3). 31. Assimilation: plants incorporate ammonia and nitrate ions into organic molecules (nucleic acids, amino acids). 32. Ammonification: decomposer bacteria break down organic compounds into ammonia. 33. Denitrification: specialized bacteria convert nitrogen compounds into N2 and N2O which is released into the atmosphere. 34. Phosphorous: component of nucleic acids. 35. P cycles more slowly: no gaseous phase, mostly found in rocks as PO4, released by weathering. 36. P: major limiting factor for plant growth. 37. Too much P in aquatic ecosystems: from animal wastes, fertilizers, sewage can cause eutrophication. 38. Major macronutrients: CHNOPS. Micronutrients and trace elements: needed in small amounts.