ecosystem i - wou homepageguralnl/101ecosysi.pdf · • trophic levels • food webs/chains. what...

Ecosystem I

• What is an ecosystem?

• Types of Ecosystems• Productivity• Energy Flow• Trophic levels• Food webs/chains

What is an ecosystem?

• Ecosystem =

• Community + abioticcomponent

• 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 ProductivityEnergy Enters ecosystem throughphotosynthesis

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 weEat in the food chain.