Essential Question: How is Earth's climate connected to its geological, biological and cultural systems?
ENGAGE
Carbon Chemistry--It's Organic!
With all the news and information about greenhouse gas-induced climate change, you might be surprised to learn that today carbon dioxide is a trace gas in Earth's atmosphere, measured at less than 0.04% of all the gases.
And the total amount of carbon that occurs in any form on the planet is a tiny fraction of far less than 1% of the planet's total mass. A little bit goes a long way. It has to.
Because carbon is the basis for life on this planet, it's biological chemistry has evolved into elaborate, interconnected, opposite, but complementary cycles of synthesis and recycling--the carbon cycle.
Even if you didn't specialize in organic chemistry in college, you certainly learned in high school biology that carbon is the fundamental element central to all the molecules that make up all life that has ever existed on Earth.
You also learned that when we consume carbon compounds like sugars, proteins and fats, we break down these complex carbon compounds, releasing their stores of chemical energy for our growth and maintenance, and in turn we release the spent exhaust of our metabolism as oxidized carbon, or carbon dioxide, with each exhalation.
Chemically speaking, this is no different than what occurs in the combustion chambers of our furnaces, factories and cars; Complex carbon molecules are oxidized, releasing energy, water vapor and carbon dioxide as a product. Same-same.
It wouldn't take long for us to deplete our sources of complex carbon molecules were it not for another extraordinary chemical cycle that takes up life's waste carbon dioxide and uses it to re-synthesize the carbon compounds and create the oxygen we need. This process is, of course, photosynthesis--the daily work of plants. Had these finely-tuned dual processes not evolved along with our planet, we would not have evolved along with our planet.
EXPLORE
Teachers' Domain
There are good reasons why Carbon became the fundamental building block for life, not the least of which is its unique four-bond geometry and stable reactivity. This TD video explores some of the reasons why Carbon is center stage, in Ingredients for Life: Carbon.
Ingredients for Life: Carbon. This NOVA TD video, Energy Flow in the Coral Reef Ecosystem serves as an excellent example of a tightly coupled Carbon cycle, with inputs of Solar energy and Carbon Dioxide and outputs of complex Carbon compounds, Oxygen and ultimately energy for life throughout the foodweb.
Energy Flow in the Coral Reef EcosystemNow, take a look at this TD resource illustrating these various aspects in this Carbon Cycle Diagram.
Carbon Cycle DiagramEXPLAIN
- Why is carbon the basis for life?
- What biological processes involve carbon?
- What is the role of oxygen in the carbon cycle?
- How does our technology fit into the carbon cycle?
- Why did photosynthesis and cellular respiration processes evolve together?
- How does knowledge of the carbon cycle influence your perspective of life and technology?
