ENERGY IN ECOSYSTEMS ENERGY
Feb 24, 2016
E N E R GY I N E C O S Y S T E M S
ENERGY
Energy is transferred from one form to another
In any energy conversion, some energy is lost. E goes from high to low qualityHigh Quality is highly organized and compactLow quality is dispersed
2nd Law of Thermodynamics
Everything has a cost
Entropy: Without energy to organize the system, it falls to disorder
Endergonic reaction
Potential E
Potential E
Free E
Free E
H2O + CO2 > C6H12O6 + O2
Free E
Free E
Potential EPotential E
Exergonic reaction
C6H12O6 + O2 > H2O + CO2
Ecosystems depend on the ability of organisms to convert inorganic compounds into food
• Initial energy comes from the sun or chemicals – Autotrophs/producers • Convert inorganic compounds into organic compounds
– Photosynthesis– Chemosynthesis
– Energy is transferred through trophic levels• Producer>primary consumer > secondary > tertiary
Energy flow through an ecosystem
ENERGY in ecosystems Hydrothermal vents
Chemosynthesis • Tubeworms mine for sulfide in the carbonate
substrate with their roots• Bacteria living in the tubeworm metabolizes
the sulfide and produce chemosynthetic energy that sustains them both
• CO2 + H2O + 4H2S + -> CH20 + 4S + 3H2SO4
•
Photosynthesis • 6CO2 + 6H2O > C6H12O6+ 6O2
• 50% of sunlight reaches earth’s surface
• 43 percent of the total radiant energy from the Sun is in the visible parts of the spectrum
• Most of the visible light that plants use is in the 420-680 nm range
• 1 man eats• 300 trout for a year eat• 90,000 frogs that eat• 27,000,000 grasshoppers that
consume• 1,000 tons of grass
Ecological pyramidsBiomass & numbers pyramids
10%
10%
10%90%90%
Producer
SecondaryPrimary Consumer
1,000 lbs100 lbs10 lbsTertiary1 lb
90%
Energy Pyramid
1. 2nd Law of Thermodynamics2. There is a limit to the size of animals. 3. Unusable tissue4. Productivity of producers
Aquatic : Nutrients(P) Terrestrial Nutrients(N), Temp. & Climate
There is a limit to the links in a food chain