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Energy in an Ecosystem. Get out your HW and grab your ecosystems…. Quiz: Get out a pencil and answer the question. Make sure to put your name/date on the paper given to you. If you start with 1000kg of biomass of primary producers, how much biomass would you have of… Primary Consumers?
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Quiz: Get out a pencil and answer the question. Make sure to put your name/date on the paper given to you. • If you start with 1000kg of biomass of primary producers, how much biomass would you have of… • Primary Consumers? • Secondary Consumers? • Tertiary Consumers • Why does a biomass diagram form a pyramid? • What is biomass?
Where does the Energy come from? • All the energy in an ecosystem comes from the sun. • 1 - 2 % of the sun’s energy that strikes the earth is absorbed by plants • The rest is absorbed by abiotic objects or deflected to space • Plants use that energy through photosynthesis to produce sugar (glucose) which can then be converted to the biomass of the plant.
Biomass • Biomass – This is the mass of all matter at any level in a food chain • The amount of biomass in a food chain creates a pyramid (diagram).
Pyramid of Biomass • Approximately 10% of biomass at one level becomes biomass at the next level. • The other 90% is uneaten, undigested (this energy is available to decomposers) or given off as heat from the activities of the organism.
Decrease in Biomass • Biomass decreases with each additional step upward in a food chain. • Energy is lost as heat (and cannot be reused) in each step of the food chain (diagram on next slide)
Pyramid of Numbers • This is a pyramid showing that a large number of organisms (see primary productivity) is required at the base of the food chain (there are exceptions) to support a small number of organisms at the top.
Biomass Pyramid Video • http://www.youtube.com/watch?v=NJplkrliUEg
Answer these questions… • The number of organisms at the highest level in a food chain is directly related to the number of levels in the chain. How can more organisms be supported in an ecosystem? • What is the difference between a pyramid of biomass and a pyramid of numbers?