Energy Flow in Ecosystems Food Chains & Food Webs
3 Roles • Producer – Makes its own food • usually plants or one-celled organisms • Algae • Phytoplankton, tiny organisms that live in the ocean • Some types of bacteria • Consumer – Obtains energy from eating other organism • Omnivore, herbivore, carnivore, scavenger • Decomposer – Break down wastes and dead organisms and return the raw materials to the environment • fungi and bacteria
Organisms that depend on others for food are consumers. • Herbivores - plant eaters
Organisms that break down wastes and dead organisms & return the raw materials to the environment are decomposers.
Food Chain • A series of events in which 1 organism eats another and obtains energy • Shows 1 possible path along which energy can move
Food Chain • Arrows point in the direction of the organism that is eating the other. It means “Is eaten by” • http://www.woodlands-junior.kent.sch.uk/Homework/fooodchains.htm • Arrows also show the direction of energy flow.
Food Chain • 1st organism always a producer • 2nd organism is a primary consumer that eats the producer – 1st level consumer (primary consumer) • 2nd level (secondary) consumer eats the 1st level consumer • 3rd level consumer (tertiary) feed on secondary consumers
Food Chain • Position in the food chain is related to size. • Larger organisms are normally further up the food chain than smaller organisms
Food Web • A more realistic way to show energy flow in an ecosystem • Shows many overlapping food chainsin an ecosystem
Energy Pyramid • A diagram that shows the amount of energy that moves from 1 feeding level to another in a food web • At each level Energy is lost • Only about 10% of the energy in 1 level is transferred to the next level Where does the energy go?
http://teach.fcps.net/trt2/links/foodchain.htm 2nd level consumer carnivores and omnivores 1st level consumer herbivores plants producers
Energy Pyramid • MOST ENERGY IS AVAILABLE AT THE PRODUCER LEVEL • AT EACH LEVEL THERE IS LESS AVAILABLE ENERGY THAN AT THE LEVEL BELOW
Energy loss from Food Chain/Web • Organisms use the energy they get to survive: • Movement • Body heat • Reproduce • Carry out Chemical Reactions • Energy passed on is from growth. • The bigger the organism eaten, the more energy the next organism gets.