NUTRITION AND ENERGY FLOW

HOW ORGANISMS OBTAIN ENERGY -Producers: AUTOTROPHS make their own food -Consumers: HETEROTROPHS take their food in ready made ◦Carnivores: meat, hawk ◦Herbivores: plants, rabbit ◦Omnivores: meat and plants, bear ◦Scavengers: carrion and refuse, buzzard -Decomposers: breakdown and release nutrients from dead organisms, bacteria and fungi.

MATTER AND ENERGY FLOW IN ECOSYSTEMS Food chain: Model used to show how matter and energy flows through an ecosystem. Autotrophs  Heterotrophs  Decomposers ◦Usually 3-5 links. ◦10% of available energy reaches next link. Because energy is used/lost as heat at each link.

Practice building food chains Click on the link below (or access build food chain activity from the wiki ecology page) and build all the food chains.

FEEDING LEVELS -Trophic level: A feeding step in a food chain. (Animal may occupy more than one trophic level in an ecosystem.) 1st trophic level = green plant = producer 2nd trophic level = herbivore = primary consumer/1st order 3 rd trophic level = carnivore = secondary consumer/2nd order 4th trophic level = carnivore = tertiary consumer/3rd order 5th trophic level = carnivore = quaternary consumer/4th order

What is wrong with this diagram?

Food Web -Model showing all possible feeding relationships at each trophic level in a community. -Network of interlinked food chains.

WRITE 2 FOOD CHAINS IN THIS FOOD WEB

ECOLOGICAL PYRAMIDS Shows how energy flows through an ecosystem. Initial energy source is the sun. Autotrophs/1st trophic level at base of all pyramids. Three types

Pyramid of Numbers -Based on population size at each trophic level. -Populations decrease at each successive trophic level but inversion is possible.

Pyramid of Energy -Based on the amount of energy available at each trophic level. -Only 10% of the energy is past to the next level. Decreases at each level by 90%, this energy is used or lost as heat.

Pyramid of Biomass -Shows mass of living material at each trophic level. -Decreases at each trophic level