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Slide 1

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Ecological Pyramids
Biology (Unit 4) AQA…read more

Slide 2

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Order of Pyramids
· Tertiary consumers
· Secondary consumers
· Primary consumers
· Producers
· It is unusual to have more than 5 trophic levels due to poor
energy transfer at each stage.
· The area of the block shows the size of the population of that
trophic level.
· Types of pyramid = Number, Biomass and Energy…read more

Slide 3

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Number Pyramids
· Show the number of organisms at each trophic level
· No account taken for size of organism
· So pyramids can become inverted
· The number may be too big to represent accurately…read more

Slide 4

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Pyramids of Biomass
· Show amount of biomass in (gm)^-2 or (gm)^-3
· At a single moment in time
· Nearly always pyramid shaped (except plankton)
· More reliable than number pyramids
· Does not account for different seasons
· Unethical as requires organisms to be dead (dry mass)…read more

Slide 5

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Pyramids of Energy
· Measures energy stored in organisms
· Most accurate representation
· Data is collected in a given area for a set period of time
· Measured in KJm^-2year^-1
· Fat stores more energy than carbohydrates
· Unethical to take samples?…read more


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