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Cycles of Matter In all ecosystems, materials cycle between living things and the environment.

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Presentation on theme: "Cycles of Matter In all ecosystems, materials cycle between living things and the environment."— Presentation transcript:

1 Cycles of Matter In all ecosystems, materials cycle between living things and the environment

2 Cycling Materials Living things incorporate substances –by eating –during respiration and photosynthesis When they die, they are broken down by decomposers and the materials are returned to the environment Materials also return to environment through excreted wastes such as feces, and urine, and the gases given off during respiration and photosynthesis

3 The Water Cycle

4 Water Cycle Water cycles from the surface of the earth to the atmosphere and back again –Evaporation: from bodies of water to become water vapor –Transpiration: giving off water vapor by plants through their leaves –Precipitation: (rainfall) gaseous water condenses to liquid form –Respiration: water is a waste product of cellular respiration

5 Nitrogen Cycle Nitrogen is an element necessary to form amino acids and proteins as well as nucleic acids like DNA and RNA

6 So How Does Nitrogen Get to Living Things? Green plants need nitrogen to synthesize plant proteins Animals get nitrogen by eating plants or other animals that eat plants

7 80% of Atmosphere is nitrogen gas (N 2 ) Most organisms can’t use elemental nitrogen (N 2 ) directly from the air It needs to get “fixed” into usable compound by bacteria

8 The Role of Bacteria Nitrogen Fixing Bacteria: –Convert N 2 in air to ammonia (NH 3 ) –Often live in symbiotic relationship with certain plant root nodules –Ex: Legumes: (peas, bean, clover) have nodules on roots containing nitrogen fixing bacteria

9 Bacteria of Decay: (Decomposers) –convert nitrogenous wastes into ammonia (NH 3 ) Nitrifying Bacteria: –convert ammonia (NH 3 ) to nitrates (NO 3 ) which can then be used by plants –Note: most plant fertilizers contain nitrates. Denitrifying Bacteria: –convert nitrates (NO 3 ) and ammonia (NH 3 ) back into N 2 gas Nitrogen cycle short clip: afe=active

10 Carbon, Hydrogen and Oxygen Cycles Cycled through the processes of Photosynthesis and Cellular Respiration –The products of one process are reactants of the other.

11 Photosynthesis (carbon fixation): takes in CO 2 from air and “fixes” it into high energy organic compounds like sugar Cellular Respiration: returns CO 2 to the air as carbon compounds get broken down into CO 2 and water Video: The Carbon Cycle

12 Animals eat plants and other animals and thus take in carbon compounds. Dead animals get broken down by decomposers which release CO 2 to atmosphere through respiration. Thus: The level of CO 2 in the atmosphere remains fairly constant.

13 Burning of fossil fuels (oil, coal, gasoline) has increased the amounts of CO 2 in the atmosphere drastically since the 1800’s Global Warming

14 The Greenhouse Effect –The CO 2 in the atmosphere retains heat reflected by the earths surface trapping it –Gradually this warms the earth –Ice caps gradually melt –Raises ocean levels –

15 Tiny Biosphere

16 Artificial Human Biosphere Biosphere 2 Biomes: OrZXs&safe=active OrZXs&safe=active Making Your Own Biosphere: 30CB4&safe=active 30CB4&safe=active 1Fu4Bv1qg&safe=active 1Fu4Bv1qg&safe=active

17 Carbon Cycling

18 Nutrient Limitation If ample sunlight and water are available, the primary productivity of an ecosystem may be limited by the availability of nutrients. (Like phosphorus and nitrogen)

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