Ecosystem I
• What is an
ecosystem?
• Types of Ecosystems
• Productivity
• Energy Flow
• Trophic levels
• Food webs/chains
What is an ecosystem?
• Ecosystem =
• Community + abiotic
component
• Energy Flow
• Chemical cycling
• No discrete boudaries
Types of Ecosystems
Ecosystem productivity
Energy Source for Ecosystem
• Energy flows through
ecosystem
• Not recycled like
matter
• Continuous supply
• Solar energy
Primary Productivity
Energy Enters ecosystem through
photosynthesis
Productivity
• Limits to Primary
production
•
•
•
•
Light
Nutrients
Water
Temperature
Limitations
Energy Flow
Trophic levels
• Autotrophs
(Producers)
• Heterotrophs
(Consumers)
• Detritivores
(Decomposers)
Energy & Biomass
Food webs/chains
Limits to Food Chain Length
• Energetic Hypothesis
• Inefficiency of energy
transfer
• 10% rule
• Dynamic stability
hypothesis (length of
chain)
Applications
Biomagnification
Toxic materials: DDT, Hg, Pb
Human trophic Level
Dependent of where we
Eat in the food chain.