Energy Flow in Ecosystems Spring 2018

Question Why are food chains generally limited to three or four levels? ANSWER There is not enough energy at the top of a food chain to support another trophic level.

Energy Flow In Ecosystems Energy flows through an ecosystem in ONE direction From the sun or chemical compounds To autotrophs (aka producers) Then to various heterotrophs (aka consumers)

Food Chains Food chains- Shows how matter and energy move through an ecosystem in a series of steps Shows which organisms transfer energy by eating and being eaten. Each organism in a food chain represents a feeding step or trophic level. The feeding step represents the transfer of matter and energy,

Examples of a Marine Food Chain Zooplankton Phytoplankton Fish Squid Shark

Food webs- models that show all possible feeding relationships. Shows relationships at each trophic level in a community. Links all food chains in an ecosystem together. Ecological pyramid- diagram that shows various amounts of energy or matter at each trophic level. There are 3 different types

Energy Pyramid Snake 10KCal Mice 100 KCal Insects 1,000KCal Producers 10,000 KCal

Biomass Pyramid Human 80 grams Chickens 800 grams 8,000 grams Grain

Pyramid of Numbers 1 Fox 26 Birds 250 Grasshoppers 3000 Grasses