Download my carbon cycle

The
carbon
Cycle
The carbon cycle
• The carbon cycle shows how carbon atoms are recycled in
the atmosphere
• Carbon is typically recycled by the exchange of carbon
dioxide into and out of the atmosphere
What is carbon dioxide?
• In the atmosphere, carbon dioxide is a greenhouse gas.
• We use carbon dioxide to make drinks fizzy and keep foods
fresh.
• Although CO2 makes up less than 1% of the atmosphere, for
the past 100 or so years, carbon dioxide has been added to
the atmosphere more quickly than it is removed.
• The extra carbon dioxide contributes towards global
warming.
• What process releases carbon dioxide into the atmosphere?
• Combustion also add carbon dioxide to the atmosphere.
• Respiration returns carbon dioxide to the atmosphere.
• Animals and plants do this.
• Decomposers also respire which returns carbon dioxide to
the atmosphere.
• What process takes away carbon dioxide from the
atmosphere?
• Plants carry out photosynthesis and remove carbon dioxide
from the atmosphere
Write down the word equation
Photosynthesis:
Respiration:
The Carbon Cycle
Photosynthesis
Combustion
Respiration
Respiration
Death and
decay
Decay/
decomposition
Fossils
Decomposers
Progress check
Carbon sinks
• The main natural carbon sinks are plants, the ocean and soil.
Plants grab carbon dioxide from the atmosphere to use in
photosynthesis.
• The oceans are a major carbon storage system for carbon
dioxide.
• Marine animals also take up the gas for photosynthesis,
while some carbon dioxide simply dissolves in the seawater.
Exam question: Describe how carbon dioxide levels change in our
atmosphere (6 marks)
1. CO2 is taken in by plants for photosynthesis and turned into glucose
2. Plants release CO2 through respiration
3. The carbon taken in by plants is then eaten by animals and the
animals that eat them
4. Animals release CO2 through respiration
5. Animals (and plants) die and their remains are fed on by microbes
6. These microbes also release CO2 through respiration
7. Burning fossil fuels also releases CO2
Answer these questions in your book.
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What happens to the plants and animals after they have died?
What is meant by the word decomposer?
What living things help break down dead plants and animals?
What process do they carry out, releasing Carbon Dioxide back
into the atmosphere?
What is a fossil? What is a fossil fuel?
How is the carbon stored in fossil fuels released back into the
atmosphere?
How does carbon found in the plants get passed on to the
animals?
Why does deforestation lead to a rise in CO2 in the
atmosphere?
• What happens to the plants and animals after they have died?
They decompose
• What is meant by the word decomposer?
An organism that breaks down living matter/stuff
• What living things help break down dead plants and animals?
Bacteria
• What process do these living things carry out, releasing Carbon Dioxide back into
the atmosphere? Respiration
• What is a fossil? Remains of dead plants and animals trapped in layers of rock
• What is a fossil fuel? When we take these fossils and burn them to release the
energy
• How is the carbon stored in fossil fuels released back into the atmosphere?
combustion
• How does carbon found in the plants get passed on to the animals? eaten
• Why does deforestation lead to a rise in CO2 in the atmosphere? Trees use it for
photosynthesis. Deforestation is removal of trees.
c/w
Do now: Answer these exam questions in your book.
c/w
Answering exam questions about the carbon cycle
Answer these questions in your book.
What letter shows Photosynthesis?
What letter(s) show Respiration?
What letter shows Combustion?
What 2 processes add Carbon Dioxide to the atmosphere?
What process removes Carbon Dioxide from the atmosphere?
Challenge question: What effect would the industrial revolution have had on the
carbon cycle? What about deforestation?
B
A and D
Eating