fv10 - energy flow
AP Environmental Science: Unit 1 – The Living World: Ecosystems
Topic: 1.10 Energy Flow and the 10% Rule
Page 1: Energy Supply in Ecosystems
Solar Energy as the Primary Source
Solar energy is the foundation for energy supply in ecosystems.
Energy is transformed from solar to chemical energy through photosynthesis.
Energy Transformation
Plants convert light into oxygen and food.
Energy is stored in glucose and transformed into ATP through cellular respiration.
Energy Transfer Efficiency
Energy transfer is not 100% efficient; energy changes into less organized forms.
Ecosystems lose energy to dysfunction and environmental processes.
Page 2: Thermodynamics in Ecology
First Law of Thermodynamics
Energy cannot be created or destroyed, only transformed.
Example: 100 kcal of ice cream should yield 100 kcal of kinetic energy.
Second Law of Thermodynamics
Entropy increases with energy transformations.
Energy transformations result in losses to waste heat.
The 10% Rule
Only 10% of energy from one trophic level is passed to the next.
Example: If producers have 10,000 J, only 1,000 J is passed to primary consumers.
90% of energy is lost as waste heat.
Photosynthesis Efficiency
Photosynthesis captures only about 1% of the sun's energy; 99% is lost.
Page 3: Key Concepts and Principles
Ecological Principle for Large Predators
Large predators like jaguars require extensive territories due to energy needs.
Key Terms to Review
10% Rule: Only about 10% of energy is transferred to the next trophic level.
ATP (Adenosine Triphosphate): Energy currency of cells.
Cellular Respiration: Process of converting glucose into ATP.
Entropy: Measure of disorder in a system.
First Law of Thermodynamics: Energy conservation principle.
Photosynthesis: Process of converting sunlight into glucose and oxygen.
Page 4: Additional Concepts
Primary Consumers
Herbivores that feed directly on producers to obtain energy.
Second Law of Thermodynamics
Total entropy in an isolated system always increases.
Thermal Energy
Total kinetic energy of particles in a substance.
Trophic Pyramid
Visual representation of energy flow through different trophic levels, showing energy decrease from producers to consumers.
Conclusion
Understanding energy flow and the 10% rule is crucial for grasping ecological dynamics and the energy requirements of