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 organism 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

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