Pyramids Numbers Biomass Productivity FOOD CHAINS AND PYRAMIDS
Pyramids Numbers, Biomass, & Productivity
FOOD CHAINS AND PYRAMIDS n Pyramid diagrams give information about the organisms in a food chain: n n numbers of organisms biomass of organisms energy stored in organisms productivity of organisms
Pyramid diagrams n n are drawn to scale the width of each rectangle is proportional to: n n n the number of organisms per square meter or the biomass in grams per square meter or the productivity in joules per square meter per month/year
Pyramid of Numbers n The information collected for each trophic level is the total number of organisms in the area, which depends on: n n n Problem is each organism is counted equally. n n n the size of individual organisms the standing crop at the trophic level 1000 kg tree = 1 gram grass plant Units = organisms Number pyramid diagrams may be: n n upright pyramids inverted pyramids
Pyramid of Biomass n Takes the total biomass of all organisms at each trophic level in the area , and depends on: n n n the energy available at each trophic level the standing crop at each trophic level Problem it is a measure in one instant of time Unit = grams Biomass pyramid diagrams may be: n n upright pyramids inverted pyramids
Pyramid of Productivity n These show productivity of organisms at different trophic levels, which depends on: n n the energy available from the previous trophic level the efficiency of the organisms Unit = joules Designed to eliminate the inverted pyramid
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