Download Carbon Cycle and Nitrogen Cycle Readings

CARBON CYCLE
Carbon is an element found in nature. It’s in the graphite that make up the “lead” of your pencil. It’s found in the shiniest
diamonds and in the gasoline we use to run our cars. It’s one of the most important elements found on earth. Carbon is also
found in all living organisms. In fact, living things are fu ll of carbon. The element carbon is perhaps the single most important element to
life. Virtually every part of our bodies is made with large amounts of this element. The carbon atom is ideal to build big biological molecules. The carbon
atom can be thought of as a basic building block. These building blocks can be attached to each other to form long chains, or they can be attached to other
elements.
Carbon is one of the elements that cycles through nature. The Carbon Cycle is one of the biogeochemical cycles. During
photosynthesis, plants combine carbon dioxide from the air and hydrogen from water to make carbohydrates. Some of these
carbohydrates are stored in the tissues of the plant. Others are used by the plant for energy. When that plant is eaten, the cells
of the animal break down the plant's tissues during digestion. This releases the stored carbon and other nutrients into the animal's system. As the animal breathes
out (exhales), carbon dioxide is released into the air (atmosphere) and the cycle can begin again. This is known as respiration.
Respiration is not the only way carbon makes it into the air (atmosphere). Carbon and/or carbon dioxide is also released when dead plants and animals are
decomposed and when fossil fuels are burned.
NITROGEN CYCLE
We commonly think of the air that we breathe as being mostly oxygen. In fact it’s actually a mix of gasses and nearly 80% of that mix is nitrogen (N2). Nitrogen in
the atmosphere comes in a chemical shape called diatomic, meaning that two nitrogen atoms are bonded together. Nitrogen is
also one of the building blocks of life on this planet. It is one of the major components of amino acids the building blocks of
protein. Without protein our bodies could not make muscle. Nitrogen also helps form nucleic acid a vital component of DNA.
DNA is the genetic code that creates the blueprint to make the many different types of cells our bodies needs to survive. From
the tiniest insect to the largest Blue Whale, DNA guides the formation and growth of these creatures. Without nitrogen life as
we know it couldn't exist.
Free nitrogen – the nitrogen found in the atmosphere, animal wastes, and dead and decaying organisms – is all around. However, only a few organisms can use it
just as it is. These organisms “fix” the nitrogen for all other organisms to use. They are called nitrogen fixing bacteria. In the nitrogen fixation part of the cycle,
nitrogen-fixing bacteria found in the soils and in the roots of certain plants, change (or convert) free nitrogen into substances that other organisms can use. When
the fixing process is finished, free nitrogen is converted into nitrates, nitrites, and ammonia. These substances can be used by plants. As the plants become food,
the nitrogen can be used by animals.
Just as there are nitrogen-fixing bacteria, some bacteria have the job of denitrifying the soil to keep the nitrogen in balance. These bacteria take the nitrogen
compounds and return them to nitrogen gas that is released back into
the atmosphere.
QUESTIONS. Discuss these questions and answer in your journal.
BE SPECIFIC!!!
1.
Starting with CO2, describe the carbon cycle. Where does the
carbon go?
2.
Where do plants get carbon? What do they use it for?
3.
Where do animals get carbon? What do they use it for?
4.
Starting with N2 in the atmosphere, describe the nitrogen cycle.
5.
Where do plants get nitrogen? What do they use it for?
6.
Where do animals get nitrogen? What do they use it for?
7.
Describe the difference in how energy flows through an ecosystem
and how matter cycles through an ecosystem.
8.
Describe why matter could be considered a limiting factor in an
ecosystem. Explain at least 2 possible reasons.