Basic Ecology I
• Energy• Types of Ecosystems• Productivity• Energy Flow• Trophic levels• Food webs/chains
Energy: the ability to do work
• Moving matter over a distance/ a heat transfer between two objects• Kinetic energy: energy contained in moving objects• Potential energy: stored energy• Heat: energy transferred between objects• High and Low quality energy: concentrated versus diffused• Ie, wind compared to oil
Thermodynamics
• 1st law: energy is conserved
• 2nd law: with energy transfer, less energy becomes available
Potential and kinetic energy
Energy and EcosystemsChemosynthesis
Ecosystems
Productivity
• Limits to Primary production
• Light• Nutrients• Water• Temperature
Energy Source for Ecosystem
• Energy flows through ecosystem
• Not recycled like matter
• Continuous supply• Solar energy
• Enters ecosystem through photosynthesis
Equations for production
• Biomass 1 = biomass 2 – NP (net production)• Three currencies of energy flow: biomass,
energy content, carbon content
Trophic levels
• Autotrophs (Producers)
• Heterotrophs (Consumers)
• Detritivores (Decomposers)
Trophic levels
• Autotrophs (Producers)
• Heterotrophs (Consumers)
• Detritivores (Decomposers)
Chemosynthetic
Light is not the source of energy
Energy & Biomass
Energy and Biomass
Food Chains/Webs
Aquatic Food webs
Limits to Food Chain Length
• Energetic Hypothesis
• Inefficiency of energy transfer
• 10% rule
• Dynamic stability hypothesis (length of chain)
Applications
Human trophic Level
Dependent of where weEat in the food chain.
Should Humans eat lower on theFood Chain?
Biomagnification
Toxic materials: DDT, Hg, Pb
Summary
• Energy determines the limits of the food supply
• Energy is fixed by autotrophs
• Energy flow between levels depends on the efficiency of energy transfer