Food Chains and Webs Principles of Ecology Students

Food Chains and Webs Principles of Ecology

Students will be able to… o o Explain food chains and webs Understand what a food web and food chain are.

Interesting Fact “Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90, 000 frogs, that must consume 27 million grasshoppers that live off of 1, 000 tons of grass. ” —G. Tyler Miller, Jr. , American Chemist (1971)

Ecosystems o Discrete unit that consists of living and non-living parts that interact to form a (relatively) stable system. n Community + abiotic factors interact to form stable system

Ecosystems o Depends on: n One-way flow of energy o Energy input from sun n Cycling of materials o Nutrient inputs

“Biogeochemical” cycles o o Recycles chemicals n Carbon cycle n Phosphorous cycle n Nitrogen cycle Life on earth depends on these cycles & photosynthesis

Producers o o Base of the ecosystem All plants & algae—green organisms n Convert sunlight energy to chemical energy n Construct organic compounds from inorganic raw materials

Producers o o Photosynthesis a very fundamental process !! n Chlorophyll Producer = autotroph = plants & algae (green organisms)

Consumers o o Organisms that eat other living plants, animals or microbes Get energy from preformed organic molecules heterotrophs- can not fix carbon and uses organic carbon to grow

3 Types of Consumers o o o Primary consumers n Herbivores Secondary n Carnivores that eat herbivores Tertiary n Carnivores that eat the primary carnivores eats it all

Detrivores o Organisms that eat detritus n Detritus- Dead plants, animals, & microbes & fecal wastes of animals n Get energy from preformed organic molecules n Decomposers- live on detritus n Examples o Fungi and bacteria

Food chains & webs o o Food chain n Pathways of feeding relationships o Producer-consumer relationships o Parasite-host relationships Food web n Complex pattern of interconnected food chains

N ut rie nt s A food chain

A food chain Identify the following sources: n Energy o n n Sun Producer o Secondary Consumer o n Grass Primary Consumer o n Third Consumer o n Grasshopper Fish Tertiary Consumer o n Frog Bear Decomposer o Fungus

Nutrient s A food web

Assignment o o You will draw your own food web. (Not the picture, your own ideas) You will need to have all the sources on it: n n n n Energy Producer Primary Consumer Secondary Consumer Third Consumer Tertiary Consumer Decomposer

Assignment o o You will need arrows to every animal to see its source Then on a different piece of paper you need to explain your food web in detail. n n How does it work What are the producers, consumers, ect

Example of a Food Web Energy Source N ut rie nt s Decomposer 4 th Consumer Primary Consumer Producer Secondary Consumer Third Consumer

o My food web works by the sun giving the grass energy to grow. Then the grass becomes a producer for the other animals. The grasshopper eats the grass making it the primary consumer because it eat the producer. Then the frog eats the grasshopper making it the secondary consumer. The fish eats the frog making the tertiary (3 rd) consumer. Finally the bear eats the fish making it the 4 th consumer. Then the bear goes to the bathroom and then the feces becomes the decomposer or fungi.