what is the carbon cycle? -...
TRANSCRIPT
What is the Carbon Cycle?
The Carbon Cycle is a complex series of processes through which all of the carbon atoms in
the world are recycled. The same carbon atoms in your body today have been used in countless
other molecules since time began. The wood burned just a few decades ago could have produced
carbon dioxide which through photosynthesis became part of a plant. When you eat that plant, the
same carbon from the wood which was burnt can become part of you. The carbon cycle is the great
natural recycler of carbon atoms. Unfortunately, its importance is rarely stressed enough. Without the
proper functioning of the carbon cycle, life as you know it would not exist. You and every other living
thing on this planet are based upon carbon—you are a carbon-based life form. Without carbon you
would not be alive. We believe that it's vital to understand how the carbon cycle works in order to see
the danger of it not working. Therefore, let's look at a sample carbon cycle and explore how carbon
atoms move through our natural world.
Plants, animals, and soil interact to make up the basic cycles of nature. In the carbon cycle,
plants, producers—organisms that make their own energy—absorb carbon dioxide from the
atmosphere and use it, combined with water they get from the soil, to make the substances they need
for growth. Photosynthesis is the process that plants use to take carbon dioxide (CO2 ) from the air
and water from the soil to produce energy for themselves. The process of photosynthesis
incorporates the carbon atoms from carbon dioxide into sugars. Animals—who are consumers since
they must eat other organisms to get energy—such as rabbits, eat plants and use the carbon to build
their own tissues through a process called respiration. Other animals, such as a fox, eat the rabbit
and then use the carbon for their own needs, again through the process of respiration. These animals
return carbon dioxide into the air when they breathe, and when they die, they return carbon to the soil
as their bodies are decomposed by organisms such as fungi and bacteria. The fungi and bacteria are
known as decomposers since they decompose—breakdown—the bodies of dead organisms. The
carbon atoms returned to the soil may then be used in a new plant or small microorganisms.
Ultimately, the same carbon atom can move through many organisms and even end in the same
place where it began. Herein lies the fascination of the carbon cycle; the same atoms can be recycled
for millennia—millions of years!
When animals die, such at the dinosaurs did millions of years ago, their decomposing bodies
put large amounts of carbon in the ground. As their bodies break down and return carbon to the
Earth, the carbon is recycled in the form of fossil fuels—oil, gasoline, diesel, kerosene, natural gas,
etc.—that humans burn to produce energy. This burning of fossil fuels by humans to produce energy
is called combustion.
Answer the following questions using the information you have read: 1. Define photosynthesis. 2. Define respiration. 3. Define combustion. 4. Define decomposition. 5. Define decomposers. 6. Define producers. 7. Define consumers. 8. Give 2 examples of decomposers. 9. Give an example of a consumer.
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5 5
10. Give an example of a producer. 11. Define fossil fuels. 12. List 3 examples of fossil fuels. 13. What gas do animals release to the atmosphere as they undergo respiration? 14. What gas do plants take from the atmosphere as they undergo photosynthesis? 15. What cycle is pictured above? 16. What is happening in the picture at number 5? 17. Identify the fox, rabbit, cow, and trees as a consumer, producer, or decomposer. 18. Where do fossil fuels come from? 19. What is the source of carbon in fossil fuels? 20. Where is the carbon in the carbon cycle eventually returning? (Hint: Look at where the arrows are
pointing.)
21. Think further: What is all of the carbon that is returned to the atmosphere as carbon dioxide doing to Earth?
Source: http://library.thinkquest.org/11226/why.htm and Mrs. Morris’ brain