What do the arrows indicate? What’s going on here? What do the arrows indicate?

Food Chain Simple model Shows how energy flows through an ecosystem Energy flows form the sun, to autotrophs, and then to heterotrophs

Food Chains 3-4 links in a food chain

Trophic Levels Each organism in a food chain represents a feeding step/trophic level Each level represents a link in a food chain

1st Trophic Level- Autotrophs/Producers 4th Trophic Level Consumers 3rd Trophic Level 2nd Trophic Level- “Herbivores” 1st Trophic Level- Autotrophs/Producers

First trophic Level Composed of Autotrophs “Producers” Photosynthetic organisms Ex: grasses, trees, aquatic phytoplanton

2nd Trophic: First-order Heterotrophs Composed of Herbivores Consume autotrophs “Primary Consumers” EX: Mouse

3rd Trophic level: Second-order Heterotrophs Carnivores Can be omnivores “Secondary Consumers” EX: Snake consumes mouse

4th Level: third- Order Heterotrophs Top Predators “Tertiary Consumers” Carnivores EX: Great Horned Owl

FOOD WEBS More realistic A network of interconnected food chains Expresses all of the possible feeding relationships at each trophic level Most organisms depend on more than one species to obtain energy and nutrients

Food Webs TROPHIC LEVEL 3/4 Text Text TROPHIC LEVEL 2 TROPHIC LEVEL 1

ARROWS MUST POINT WHERE THE FOOD ENERGY IS GOING!

Where would decomposers go on a food web?

Decomposers Decomposers will recycle nutrients back into the ground