Energy in Ecosystems Food Chains and Webs Note

Energy in Ecosystems Food Chains and Webs Note: Organisms interact in order to obtain energy and resources necessary to stay alive.

Energy Flow • Energy flows thru an ecosystem in one direction: sun autotroph heterotroph

Autotrophs • Organisms that use solar energy to make their own food. • Auto = self • Also called Producers

Heterotrophs • Organisms that depend on other organisms for food and energy. • Hetero = other • Also called consumers

5 Types of Heterotrophs

Herbivores • Eat only plants

Carnivores • Eat other heterotrophs or eat meat

Scavengers • Eat organisms that are already dead

Omnivores • Eat both animals and plants • omni = all

Decomposers • Absorb nutrients from dead organisms • Fungi, Bacteria

Quick Review

• What do you call an organism that can make its own food? autotroph • What direction does energy flow thru an ecosystem? Producer consumer • What do you call an organism that eats both animals and plants? omnivore • What do you call an organism that absorbs nutrients from dead organisms? detrivore

Food Chain • A model that shows how matter and energy move through an ecosystem. It has arrows that show the direction that energy is being transferred.

FOOD CHAIN

Trophic Level • A feeding step in a food chain that represents each organism.

Can you name the trophic levels below? ? Producer Primary consumer Secondary consumer Tertiary consumer

Food Web • Shows all the possible feeding relationships at each trophic level in a community.

Energy pyramids • Diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. • 3 types

Pyramid of energy Heat Pa dec rasit lev omp es, s el. ose cav rs eng fee ers da , a t e nd ach 0. 1% Consumers • Only about 10% of energy available 10% within one trophic Consumers level is transferred to organisms at the next trophic 100% Producers level 1% Consumers

Pyramid of numbers Pyramid of Numbers Fox (1) Birds (10) Grasshoppers (100) Grasses (1000) • Based on the number of individual organisms at each trophic level

Pyramid of Biomass • The total amount of living tissue within a given trophic level is called biomass. • A pyramid of biomass represents the amount of potential food available for each trophic level in an ecosystem.