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Explore the concept of energy flow in food chains and the flaws of pyramids of numbers and mass. Discover how pyramids of energy offer a better representation of energy transfer. Learn why food chains usually have fewer than five trophic levels and how to maximize energy intake from your diet. Watch a tutorial on creating your own Ecospheres.
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BiologySeptember 12th 2012 BioBellwork: As energy moves through a food chain 90% is lost. What is that energy used for? What happens to the other 10%?
Pyramids of Numbers • The literal counting of organisms in each trophic level Number of Organisms
Pyramid of Mass • Size of each trophic level is shown by mass not number of organisms.
Both are flawed • Pyramid of Mass • If the producer is something small, that reproduces and if fed upon quickly at any point of time the producers would appear small even thought there has been plenty of producers through out a measure of time. • Pyramid of Numbers • One large tree can feed many insects but in the pyramid it would be visually represented as being a small about of producers.
A better representation of energy flow • Pyramids of Energy • These show the energy transferred from one trophic level to the next.
Why do food chains usually have fewer than 5 trophic levels? • At each trophic level energy is lost as heat to the environment and consumers lose energy in their feces and urine to decomposers which means that there is less for the next trophic level.
Sooooo If we wanted to get more energy from our food what kinds of food should we be eating? Eat the producers don’t waste that 90% in the secondary consumer level.
Vegetarian?! • Even though I don’t think I could do it myself….. Vegetarians get the most value (energy) from what they eat.
Making your Ecospheres • http://www.youtube.com/watch?v=s_WWG9rTUyI