Transcript Cycle
Cycling of Matter 1. 2. 3. 4. 4.3 WATER CARBON-OXYGEN NITROGEN PHOSPHORUS 1 WATER CYCLE • The continual movement of H20 from the Earth’s surface and oceans to the atmosphere and back to the surface and oceans again. • Powered by the sun (solar energy) which causes evaporation & transpiration. • Cells: 70-90% water…Earth: 75% water …water is a KEY factor in terrestrial ecosystems!! 2 KEY TERMS • • • • • • • precipitation (forms: rain, snow, sleet, hail, fog) transpiration (aka evapotranspiration) evaporation runoff water vapor percolation (water into soil) ground water (water in soil) 3 Sources/Causes • Heat (sun ) causes water to evaporate from bodies of water into water vapor in the atmosphere (90%). • Little H2O transpires from stomata of plant leaves (10%). • Animals exhale (respire) a very small percentage. • Water in the atmosphere encounters temperature and pressure changes and precipitates. • Precipitation either becomes runoff or ground water and again cycles by evaporation and/or transpiration. 4 http://www.education.noaa.gov/Freshwater/Water_Cycle.html 5 DRAW IT!! FoldNotes…BLUE ARROWS 6 CARBON-OXYGEN CYCLE • Driven by photosynthesis and cellular respiration. Which types of organisms do which process(es)? • Remember the chemical equations? • Carbon is an essential component of proteins, carbohydrates, nucleic acids, and lipids…the 4 biomolecules found in living things! 7 • Cycle: CO2 to plants photosynthesis (requires sunlight and H20 also!) carbohydrates to consumers (AND PLANTS!) respiration back to CO2 and biomass. • PHOTOSYNTHESIS stores solar energy in the form of C-C bonds in organic compounds. • RESPIRATION releases chemical bond energy and makes it available (“usable”) to cells…cells need energy to grow, develop, reproduce, respond, maintain homeostasis, etc. • Sources (where does “it” come from?): all organisms (including decomposers), natural burning, power plant / factory / vehicle 8 emissions. Rate of Carbon Cycling • Man impacts the RATE of C-cycling by: *burning fossil fuels *construction *deforestation *composting http://www.epa.gov/epaoswer/non-hw/composting/basic.htm *agriculture *use of pesticides and herbicides • Cars: 1/3 of CO2 emissions (overall total 6 billion metric tons)!!! 9 10 DRAW IT!! FoldNotes…BLACK ARROWS – Photosynthesis – Cellular respiration – Decomposition (CR): bacteria & fungi in soil – Combustion – Food chain (consumers…part of CR) – CO2 (CARBON cycle), O2, H20, Sun 11 NITROGEN CYCLE • Air contains ~78% N2 gas • N2 gas must be converted into other compounds (nitrates) before it can be used by living things called nitrogen fixation (done by bacteria). 12 Nitrogen Fixing Bacteria • Convert N2 to ammonia (NH3) which quickly dissolves in H20 to produce ammonium ions…called ammonification. • Special kinds of bacteria convert the ammonium ions to nitrates that can then be absorbed by the roots of plants…called nitrification. • Plants use the nitrogen compounds they absorb (through a process called assimilation) to make amino acids, proteins, and other important substances. Animals get the nitrogen they need by consuming plants or organisms that consume plants. 13 Others! • Another group of bacteria converts some of the ammonia and nitrates into free N2 gas back into atmosphere…this is called denitrification. • Decomposers play an important role by breaking down N-containing animal wastes and the remains of dead organisms. --this breakdown releases ammonia which dissolves to produce ammonium ions (called ammonification) taken up by roots of plants etc. 14 15 DRAW IT!! FoldNotes…GREEN ARROWS • Ammonia • N2, H20 • • • • • • • • • Nitrification Ammonification Denitrification Nitrogen-fixing bacteria Nitrates Assimilation Denitrifying bacteria Decomposers Death/waste 16 PHOSPHORUS CYCLE • P is a component of ATP (energy storing compound used by cells) and DNA (genetic code) • Found in soil and rock as calcium phosphate which dissolves in H20 to form phosphate plants absorb through their roots animals eat plants (P is transferred) animals and plants die phosphorus is returned to soil. 17 http://phos-cyclenc.tripod.com/ 18 DRAW IT!! • FoldNotes: RED ARROWS 19