Feeding Relationships

Energy flows in one direction from sun or inorganic molecules to autotrophs to heterotrophs

Food Chains Series of steps in which organisms transfer energy by eating and being eaten

Arrows show the flow of energy

Food Chain in an Antarctic Ecosystem

Food Webs Interconnected food chains within an ecosystem

Each step of a food web or food chain is a trophic level. Consumers depend on the trophic level below for their energy. 2nd and higher levels – consumers 1st trophic level – producers

Trophic Relationships 4th Level Consumers (top predators) 3rd Level Consumers 2nd Level Consumers 1st Level Consumers (herbivores) Autotrophs

Producers

Ecological Pyramids

Ecological Pyramids Show relative amounts of energy or matter within trophic levels of food chains and food webs

Energy Pyramids shows amount of available energy at each level most energy is consumed at each level for biological processes or lost as heat only about 10% of energy is transferred to next level 0.01% 0.1% 1% 10% 100%

0.01% 0.1% 1% 10% 100%

Heat Heat Heat 100% 10% 1% Autotrophs Herbivores Carnivores Consumed

Biomass Pyramid represents available food (organic matter)

Pyramids of Numbers represents the number of individuals at each trophic level

Review How does energy flow through an ecosystem? Draw a food chain with at least 3 consumers. What do the arrows indicate? To show all of the feeding relationships in an ecosystems, biologist use a/(an) __ __. How much energy is transferred from one organism to the other? What happens to the energy that is not transferred? What is biomass? What information is found in a biomass pyramid? What is represented by a pyramid of numbers?