Flow of Energy and Matter

Ecosystem Recycling Energy and matter flow through an ecosystem Plants get energy from the sun We get energy from what we eat – Metabolism

Ecosystem Recycling Matter must be recycled and reused. A few elements make up most living things CHNOPS These elements move between living and non living things.

CHNOPS CHNOPS cycle through an ecosystem and recombine into different compounds. Compounds important to life: – Carbohydrates: CHO – Lipids: CHO – Proteins: CHNO – Nucleic Acids: CHNOP

Biogeochemical Cycles How do these elements and compounds move through an ecosystem? – Biogeochemical cycles: Movement of elements through the air, water, soil, rock and living things.

Water Cycle Why is water critical to life? – Makes up most of our cells – It’s a place for chemical reactions to take place – Helps to dissolve, break up and transport compounds in rock and soil.

Water Cycle Where is water in the environment? – Atmosphere Water vapor – Bodies of Water Streams, lakes, oceans – Frozen in ice – Groundwater

Water Cycle How does water “cycle” – Evaporation – Transpiration – Condensation – Precipitation – Infiltration – Run off

Water Cycle

Effects of Human Activities on Water Cycle We alter the water cycle by: – Using large amounts of freshwater. – Clearing vegetation and eroding soils. – Polluting surface and underground water. – Contributing to climate change.

Carbon Cycle What make Carbon so great? – Carbon bonds easily with carbon – Carbon makes a skeleton for other atoms – It’s the perfect building block for large molecules like protein and nucleic acids

Carbon Cycle Where is carbon in the environment? – Atmosphere: carbon dioxide – Ocean: marine life, dissolved in water. – Stored in rocks, soil and fossil fuel

Carbon Cycle – Plants use CO₂ and water for photosynthesis and release O₂ – Animals use O₂ for cellular respiration and release CO₂

Carbon Cycle

Effects of Human Activities on Carbon Cycle We alter the carbon cycle by adding excess CO 2 to the atmosphere through: – Burning fossil fuels. – Clearing vegetation faster than it is replaced.

Nitrogen Cycle Why is Nitrogen important to life? Used to make proteins and DNA Life could not go on without it Where do we get nitrogen? 80% of the atmosphere is nitrogen But….living things can not use it in this form.

Nitrogen Cycle Nitrogen fixation - bacteria change N₂ to a usable form NO₃⁻ Decomposers – break down dead things, urine and dung (N₂ to NH₃ ⁻ ) Nitrification – bacteria change NH₃ ⁻ to NO₃ ⁻ Denitrification – bacteria change fixed nitrogen to nitrogen gas. Plants take up nitrogen and animals eat plants or other animals.

Nitrogen Cycle

Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by: – Adding gases that contribute to acid rain. – Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. – Contaminating ground water from nitrate ions in inorganic fertilizers. – Releasing nitrogen into the troposphere through deforestation.

Phosphorus Cycle Why is Phosphorus Important to Life? ATP (that energy molecule created by every living thing) DNA and Bone tissue too. Where is it? -Rocks and soil

Phosphorus Cycle How does it cycle? – Plants absorb it from the soil – Animals get P from eating plants of other animals. – P is returned to the soil by excrement and decomposing organisms – It’s absorbed again or its stored in rocks

Phosphorus Cycle

Effects of Human Activities on the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer. We reduce phosphorous in tropical soils by clearing forests. We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

Rock Cycle Rocks: – Igneous – Sedimentary – Metamorphic Processes that change rock into soil – Weathering (freeze/thaw) – Erosion (removal by wind/water/ice)