Cycles Water Carbon Nitrogen Biological Cycles repeating events
Cycles (Water, Carbon, Nitrogen) Biological Cycles: repeating events that are needed for life to survive • Water Cycle • Carbon • Nitrogen There are others important cycles as well that effect life • Phosphorus cycle, nutrient cycle, rock cycle, weather cycles
Learning Objectives: • Know all the basic steps of the Water, Carbon, & Nitrogen Cycles • Recognize what drives the Water Cycle and where fresh water comes from • Recognize what drives the Carbon Cycle and how it can be effected by human activities • Recognize the “weak points” in the Carbon & Nitrogen Cycles
Essential Question: • What specific problems for humans can come for EACH of these 3 cycles if they are disrupted? (should be a different answer for each cycle) Focus questions: • What powers the Water Cycle? • Where is the “bottle neck” in the Carbon Cycle? • What is the “bottle neck” in the Nitrogen Cycle
THE WATER CYCLE Pg 53 Solar energy Cloud movement by wind Precipitation over ocean Evaporation from ocean Evaporation & Transpiration from land Transport over land Precipitation over land Percolation through soil Runoff and groundwater
Water Cycle: • All water moves in a global cycle (it keeps a steady, but small, supply of fresh water available for human use) • powered by solar energy
– Evaporation: liquid H 20 �� water vapor (needs sunlight to the heat water)
– Transpiration: loss of H 20 by plant leaves as photosynthesis occurs (liquid �� vapor)
Where does most rainwater come from in the world?
Water Cycle allows freshwater supplies on earth to be refilled
Water Cycle allows freshwater supplies on earth to be refilled
THE WATER CYCLE Pg 53 Solar energy Cloud movement by wind Precipitation over ocean Evaporation from ocean Evaporation & Transpiration from land Transport over land Precipitation over land Percolation through soil Runoff and groundwater
THE CARBON CYCLE Pg 55 CO 2 in atmosphere Photosynthesis Cellular respiration Burning of fossil fuels and wood Higher-level Primary consumers Carbon compounds in water Decomposition
Carbon Cycle: • Reflects the reciprocal processes of photosynthesis and cellular respiration (metabolism) • Autotrophs/Producers get the carbon they need to make their food (photosynthesis) and to grow bigger in size from CO 2 in the air, NOT the soil (nutrients and water only) • Heterotrophs/Consumers get the carbon they need to grow from their food, but also they release CO 2 for respiration (cellular respiration)
Carbon Cycle: • CO 2 is a known greenhouse gas: (traps heat from the sun) • The burning of fossil fuels (oil/coal) adds more CO 2 to the atmosphere (so it is thought more heat will get trapped) • Note: the Greenhouse effect is a natural process that keeps the earth from cooling off to much • Global warming is thought to be the result of adding to much CO 2 into the atmosphere, greatly increasing the greenhouse effect
THE CARBON CYCLE Pg 55 CO 2 in atmosphere Photosynthesis Cellular respiration Burning of fossil fuels and wood Higher-level Primary consumers Carbon compounds in water Decomposition
Greenhouse Effect and side effects https: //www. youtube. com/watch? v=y. U 3 Gw. Ju_y. NA Particle/Carbon pollution https: //www. youtube. com/watch? v=mob. U 0 j 331 DY https: //www. youtube. com/watch? v=2 n. FZa. Sbkf 0 U
THE NITROGEN CYCLE Pg 56 N 2 in atmosphere (use-less) Nitrogen-fixing bacteria in root nodules of legumes Assimilation NO 3 Decomposers Nitrification Ammonification NH 3 Nitrogen-fixing soil bacteria NH 4+ − Nitrifying bacteria NO 2 − Nitrifying bacteria Denitrifying bacteria
The Nitrogen Cycle Nitrogen fixation - Only a few types of bacteria (that live in the roots of plants called Legumes) can make Useless N 2 In the atmosphere Legumes Useful ammonia NH 3 In the soil
• Consumers get the Nitrogen they need from eating plants (or animals that eat plants) after plants absorb nitrogen from the soil/oceans • Consumers return nitrogen to soil/oceans with wastes like urine (urea is a molecule with nitrogen) and when organisms bodies decay in the soil • Nitrogen in the soil may be returned to the atmosphere after denitrification (another bacteria does this) Urea
• Nitrogen based-molecules (like ammonia) are also used a lot in fertilizers to increase the size and growth rate of plants
Red Tides: Naturally occurring, but made more Extreme by nutrient (nitrogen) runoff https: //www. youtube. com/watch? v=Fs. Yu. U-4 q. RBM
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