Carbon, Nitrogen, and Oxygen Cycles

​How much energy moves to the next trophic level?

Explain how the flow of energy within
food webs is interconnected with the

cycling of matter (including water,

nitrogen, carbon dioxide and oxygen).

TODAY’S LEARNING TARGET

On Earth, organisms (including
humans) are constantly using

matter from our environment, such
as carbon, nitrogen, and water.

Why doesn’t planet Earth ever run
out of these materials? What do
you think happens to the matter

after you consume or use it?

The Cycling of Matter in Ecosystems

● The Earth constantly receives

energy from the sun

● The amount of matter does

not change, just its form

● Matter is recycled from

organisms to the
environment and back again

● There are three

main cycles:
○ Carbon
○ Nitrogen
○ Water

THE CARBON CYCLE

• Carbon moves among the air, the ground, and the plants/animals

• Carbon is found in all living organisms, the atmosphere, gasoline

and many rocks

• Carbon stored in organisms can not be reused until the organism

is eaten or decomposed.

• Decomposition

– Bacteria or other decomposers break down dead organisms
– Carbon dioxide is released into the atmosphere in this

process

• Combustion (burning) of wood or other organic material

produces large amounts of CO2 released into the atmosphere.

Carbon Cycle Take Aways

• ​THE SUN IS A DIRECT PART OF THIS CYCLE!

• Carbon is the building block of all life.

• Photosynthesis (producers) and cellular respiration (consumers) are a huge part of this cycle.

• All carbon is recycled!

Multiple Choice

Which of the following add carbon dioxide to the atmosphere?

• volcanoes

• combustion of fossil fuels

• animal and plant respiration

• all of these

Multiple Choice

How do living organisms return carbon to the atmosphere in the carbon cycle?

• respiration and photosynthesis

•  decomposition and respiration

Multiple Choice

When humans burn fossil fuels, most of the carbon quickly enters the                       as carbon dioxide.

• Water

• Atmosphere

• Sun

• Ground

Multiple Choice

How does carbon in a grass plant get into a lion?

• The lion eats an antelope that ate the grass

• Carbon from grass doesn't end up in a lion.

• The lion absorbs the carbon given off by transpiration

• The lion breathes in carbon given out by the plant

Multiple Choice

Which describes the relationship between plants and animals in the carbon cycle?

• Plants produce and release oxygen that animals need

• Plants produce and release carbon dioxide that animals need

• Animals produce and release oxygen that plants need

• Animals produce oxygen that plants turn into carbon dioxide

THE NITROGEN CYCLE

•The movement of nitrogen through the environment

•Nitrogen is found in many places. Most is in the atmosphere

•All living things use nitrogen to make proteins

•Nitrogen Fixation
– The natural process bacteria use to convert nitrogen from the atmosphere into

forms that are useful to organisms

– Produces compounds such as ammonia and nitrate

•Usually found in animal waste such as urine or fertilizers

•Denitrification
– Takes nitrogen from nitrates and other compounds in soil and

releases it as nitrogen gas

Nitrogen Cycle Take Aways

• THE SUN STILL PLAYS A PART – Plants need the sun to live.

• Nitrogen is a building block for life (Proteins – Amino Acids)

• Most plants and animals can only use “fixed” nitrogen

• Bacteria is the most important part of this cycle

Multiple Choice

Which organism is the most important to the nitrogen cycle?

• Humans

• Plants

• Bacteria

• Bees

Multiple Choice

Why do all organisms need nitrogen?

• To live and grow 

• To build phosphorus

• To make oxygen levels grow

• To help blood circulate better

Multiple Choice

When nitrogen gas is turned in to a form that plants and animals can use is called 

• Combustion

• Photosynthesis

• Decomposition

• Nitrogen Fixation

Multiple Choice

How do  animals get nitrogen?

• the atmosphere 

• eating other organisms

• bacteria

• lightning 

Multiple Choice

Building proteins and DNA is the reason organisms need what substance?

• Water

• Carbon

• Nitrogen

• Calcium

Compare and Contrast

How are the
carbon and

nitrogen cycles

similar?

How are they

different?

THE WATER CYCLE

•Water Cycle

–The continuous movement of water between Earth’s surface and its
atmosphere.

–Water changes from one form to another

–The sun is the source of energy for this process

•Evaporation

–Process where liquid changes to gas

•Transpiration

–Water vapor is released through tiny openings in plant leaves

–Animals also add water vapor to the atmosphere through breathing

•Condensation

–The process by which gas changes to a liquid

•Precipitation

–Water that falls to the Earth’s surface in the form of rain, snow, sleet, or hail

•Groundwater

–Water located below the Earth’s surface

•Runoff

– that flows over the surface of the earth, returning to the oceans.

PAUSE
AND
REFLECT

How is water used in your household?

Include activities that use water, sources of

water, and ways that water leaves your house.

Water Cycle Take Aways

• THE SUN IS THE POWER SOURCE FOR THIS CYCLE

• All life needs water

• Water helps the carbon and nitrogen cycles either directly or indirectly

• All water is recycled

We can run low on freshwater or potable water, but we will never run out until the heat death of the Earth

Multiple Choice

What is the water cycle?

• the 3 forms of water

• the movement of water on, above, or below the surface of the Earth

• when water melts

• when clouds form

Multiple Choice

Which best explains why runoff is important?

• It returns water to other locations on Earth

• It increases the chance of flooding

• It makes evaporation occur faster

• It increases condensation

Multiple Choice

During which stage do clouds form?

• condensation

• evaporation

• precipitation

​Questions?

Multiple Choice

What is the ultimate source of all energy for life and the cycles?

• Sun

• Carbohydrates

• Producers

• Consumers

Multiple Choice

Identify the cycle pictured.

• The Water cycle

• The Carbon cycle

• The Nitrogen cycle

• The Phosphorus cycle

Multiple Choice

What is the role of decomposers in an Ecosystem? 

• They recycle matter and nutrients for reuse or to form fossil fuels.

• They are burn and release as carbon dioxide

• Decomposers are responsible to turn oxygen into carbon dioxide

• They recycle energy back to the sun

Multiple Choice

Identify the cycle pictured.

• The Water cycle

• The Carbon cycle

• The Nitrogen cycle

• The Phosphorus cycle

Multiple Choice

Many food chains connected to each other is known as...

• Fast Food Chain

• Biodiversity

• Food Pyramid

• Food Web