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Nutrient Cycles
Water cycleCarbon cycleNitrogen cycle
Phosphorus cycle
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Water cycle
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• All living things need water because the cytoplasm in cells is composed mostly of water.
• The chemical reactions that support life must take place in water
• The electrical impulses produced by nerves are transmitted through water.
Water cycle
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How does water move through the environment?
• Precipitation – water falls from the sky as rain, snow or sleet
• Evaporation – water returns to the atmosphere as a gas
• Waste – animals release liquid waste• Respiration – water is product of cellular
respiration• Runoff and streams carry water from place
to place in the environment.
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Why is carbon Important?
• All of the macromolecules contain carbon.• Carbon is used to make sugars which
provide living things with energy. • The carbon containing macromolecules
are the building blocks of all life.
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How does carbon move through the environment?
• Photosynthesis – pulls CO2 from the air and uses it to make sugars.
• Consumption – one organism eats another and gets its carbon.
• Respiration – cellular respiration releases CO2 back to the air as it breaks down sugars
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How does carbon move through the environment?
• Decomposition – as dead organisms are broken down, the carbon is released to the soil or back to the air.
• Deposition – the remains of dead organisms can be converted to fossil fuels
• Burning – releases CO2 back to the air when organisms or fossil fuels are burned.
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Why is Nitrogen important?
• Nitrogen is an element that is found in amino acids.
• Amino acids join together to form proteins• Proteins help living things carry out life
processes.
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How does Nitrogen move through the environment?
• Nitrogen gas makes up most of our air but organisms can’t use it in this form.
• Nitrogen fixation – bacteria, lightning and fertilizer factories take Nitrogen from tha air and convert it into forms organisms can use
• Plants take in nitrates from the soil to make amino acids
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How does Nitrogen move through the environment?
• Consumption – organisms eat each other and obtain their nitrogen
• Decomposition and waste return nitrates to the soil.
• Denitrification – bacteria return nitrogen back to the air.
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Why is phosphorus important?
• Phosphorus is found in nucleotides.• Nucleotides join together to form nucleic
acids• Nucleic acids control cell functions
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How does phosphorus move through the environment?
• Consumption – organisms eat each other and obtain phosphorus
• Decomposition and waste return it to the soil
• Plants acquire P from the soil• Weathering – rain breaks down rocks and
release the phosphorus they contain.