Ecosystem Structure

Passing of Energy

All Energy starts from the sun Photosynthetic plants convert

energy from the sun into food The energy moves through the

ecosystem as one organism eats another

Autotrophs / Producers

An organism that converts the sun’s energy (or inorganic substances) into food

Heterotrophs / Consumers

Organisms that obtain energy by eating other organisms

Can eat plants or animals

Food Chains

A model of the flow of energy through organisms in a community

Flow of energy is shown by arrows

Transferred Energy

At each step in the food chain only 10% energy is passed to the organism

90% of the energy is lost in the form of HEAT

90%HEAT

90%HEAT

90%HEAT

Trophic Levels

Each step in the transfer of energy

Producers are 1st trophic level… they form the base of all food chains

Primary Consumers / Herbivores

Feed directly on producers

Make up the 2nd trophic level

Secondary & Tertiary Consumers / Carnivores

Eat only meat

Feed on primary & secondary consumers

Make up the 3rd and 4th trophic levels

Omnivores

Eat both producers and consumers

Scavengers

Consumer that feeds on the tissue of dead animals

Decomposers (recyclers)

Feed on wastes and dead organic matter from all trophic levels

Ecological Pyramid

Shows the relationship between producers & consumers in 3 ways: Biomass Energy # of organisms

Biomass

Total mass of all organisms in a food chain or ecological community

Biomass Pyramid

There is less biomass as you move up trophic levels

Energy Pyramid & 10% Law

Only 10% of energy is passed to next level

1st trophic level is important in determining the rest of the levels

# of organism pyramid

Population of each trophic level decreases as you move up the trophic levels

Food Web

Shows the interconnected food chains in a community or ecosystem

A lot of food chains together