Carbon Cycle
318-1 illustrate the cycling of matter
through biotic and abiotic
components of an ecosystem by
tracking carbon, nitrogen and oxygen
Where do trees get the material
they need to grow?
• Plants and trees make carbohydrates (simple
sugars) during photosynthesis.
6CO2 + 6H20 + Energy = C6H1206 + 602
Based on this equation, what three things
does a tree need to make carbohydrates?
1. Energy from sun
2. Carbon dioxide
3. Water
Photosynthesis, Cellular
Respiration and the Atmosphere
• Photosynthesis is one stage of the carbon
cycle. During photosynthesis, plants
capture carbon dioxide and combine it with
water to make carbohydrates. Some
carbon is used by plants to build other
carbon-containing compounds, such as fats
and proteins.
Then, consumers eat the plants and the
carbon compounds are broken down and
recombined to build animal tissue. In this
way, carbon moves through food chains,
from species to species.
Time to Think …
• Carbon dioxide only makes up 0.03% of
Earth’s atmosphere. If plants are always
using carbon dioxide, why is there still
carbon dioxide left in the atmosphere?
… Cellular Respiration
• All living cells carry out cellular respiration.
C6H1206 + 602 = 6CO2 + 6H20 + energy
• How is this equation similar to
photosynthesis?
• Cellular respiration breaks apart
carbohydrate molecules and releases
carbon, as carbon dioxide, back into the air.
Disrupting the Carbon Cycle
• Over the years, carbon dioxide produced by
cellular respiration has tended to equal the
amount of carbon dioxide absorbed by
photosynthesis.
• However, the balance can be changed if
large amounts of carbon are removed from
or added to parts of the carbon cycle.
The Carbon Cycle and Climate
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Read p. 304 & 305
P. 308
#12 & 13
P. 311
#3, #4, #5, #6, #7, #8, #12, #13, #14