Biology UNIT 8

Carbon Cycle

What is the biochemical equation for Photosynthesis in words and symbols? Is energy being stored or released?

Water + Carbon Dioxide (light)→ Sugar (w/ energy) + Oxygen

6O2 + 6H2O (light)→ C6H12O6 + 6O2

Storing energy!

What is the biochemical equation for Cellular Respiration in words and symbols? Is energy being stored or released? 

Sugar (w/ energy) + Oxygen (light)→ Carbon Dioxide + Water

C6H12O6 + 6O2 (light)→ 6O2 + 6H2O

Releasing energy!

Which organisms on earth are able to photosynthesize? Which organisms on earth are able to do cellular respiration?  of the above processes?  

Photosynthesis: Plants, algae, and cyanobacteria

Cellular Respiration: Animals, plants, fungi, protists, and various bacteria

Define a  “tipping point”

The point in which an ecosystem can no longer cope with environmental change

Be able to discuss each of these approaches to carbon sequestration: 

• Afforestation

• Forest Regeneration

• Restoration of peat-forming wetlands

Sequestration: trapping carbon

• Afforestation: Planting trees where there currently are none

• Forest Regeneration: New tree seedlings establish themselves after a disturbance

• Restoration of peat-forming wetlands: Re-establishing the natural hydrology of peat

How have atmospheric carbon dioxide concentrations changed over human history? 

They have increased significantly, especially due to burning fossil fuels

How has data for changing CO2 concentrations been collected?

Through atmospheric measurements and analysis of historical air samples trapped in ice cores

What is the difference between correlation and causation?

Correlation: The relationship between two variables where the changes in one variable is associated with the changes in the other

Causation: One variable directly influences or changes another

What evidence do we have that human (anthropogenic) effects have increased global temperature?

Sea levels rising, temperatures rising, melting ice sheets and glaciers, increased natural disasters, etc.

How is decrease in deep ocean upwelling a positive feedback cycle?

The combination of enhanced upwelling and reduced CO2 uptake

How is decrease in snow a positive feedback cycle?

Warmer temperatures cause ice to melt, including polar ice caps. Less ice results in more water, and water absorbs energy. The more energy there is in the water, the warmer the water is.

How is decomposition of peat a positive feedback cycle?

Increased decomposition of peatlands releases stored carbon, which leads to further warming and accelerating decomposition and a reinforcing loop

How is melting permafrost a positive feedback cycle?

Warmer temperatures cause permafrost to thaw, which releases methane and increases greenhouse gases

How are droughts positive feedback cycles?

Drought conditions such as dry, warm land further worsen droughts

How are forest fires positive feedback cycles?

Fire releases CO2, which causes more greenhouse gases. Excessive greenhouse gases result in warmer temps and trees are more likely to burn