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 CO2 to the atmosphere through:–Burning fossil fuels.–Clearing vegetation faster than it is

replaced.

Nitrogen CycleWhy is Nitrogen important to life?

Used to make proteins and DNALife 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)