Biogeochemical Cycles

Unit 6-2 NotesMr. Hefti - Pulaski Biology

You’ve seen this before – what does it mean?

Earth has a finite supply of resources

*Bio = life

*Geo = earth

*Chemical = having to do w/ atoms

Layers of Earth

• Lithosphere: Rocks / soils • Hydrosphere: Water• Atmosphere: Air• Biosphere: Any place there is life

Phosphorus Cycle

• P released from weathered rocks and decaying organisms

• Why is it important?– P holds DNA molecule together– Used to make ATP

The

Phos

phor

us C

ycle

Soil decomposers

Rot

Water Cycle

• H2O supply replenishes itself through:– Evaporation (and transpiration) – Condensation – Precipitation – Runoff

• Why is it important?– Earth would dry out without the water cycle

Condensation

Precipitation

Runoff

Evaporation

Ground water

LakeSoil

Ocean

The Water Cycle

Carbon Cycle

• C gets transformed through:– Photosynthesis– Respiration– Burning of fossil fuels

• Why is it important?– Needed to make glucose

CO2 in the atmosphere

Used to make glucose during photosynthesis

Plants eaten by animals

Decaying plants make

C in rotting tissue

C in fossil fuels

CO2 released to atmosphere during

respiration

CO2 released to atmosphere when

fossil fuels are burned

The Carbon Cycle

Nitrogen Cycle

• Life requires N-compounds but atmospheric nitrogen (N2) unusable to most living things

• Nitrogen-fixing bacteria important!

• Why is it important?– Needed to make proteins

Nitrogen in atmosphere

Nitrogen in animal proteins

Nitrogen in plant proteins

The

Nitr

ogen

Cyc

le

Nitrogen in decaying tissues

Soil bacteria “fix” nitrogen for use by plants

Oxygen Cycle

• Living things need O2

• Needed for release of energy

• Why is it important?– Cellular respiration

At night, plants take in O2 and give off CO2

During day, plants take in CO2 and give off O2

Animals take in O2 and give off CO2

The Oxygen Cycle

The Water Cycle The Water Cycle

The Carbon Cycle The Carbon Cycle

The Nitrogen Cycle The Nitrogen Cycle

The Oxygen Cycle The Oxygen Cycle

The Phosphorus Cycle The Phosphorus Cycle