# numbers of organisms biomass of organisms energy stored in organisms productivity of organisms Pyramid

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```					Pyramids

Numbers, Biomass, & Productivity
FOOD CHAINS AND
PYRAMIDS
   Pyramid diagrams give information
about the organisms in a food chain:
   numbers of organisms
   biomass of organisms
   energy stored in organisms
   productivity of organisms
Pyramid diagrams
   are drawn to scale
   the width of each rectangle is
proportional to:
   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
   The information collected for each trophic level
is the total number of organisms in the area,
which depends on:
   the size of individual organisms
   the standing crop at the trophic level
   Problem is each organism is counted equally.
   1000 kg tree = 1 gram grass plant
   Units = organisms
   Number pyramid diagrams may be:
   upright pyramids
   inverted pyramids
Pyramid of Biomass
   Takes the total biomass of all organisms at
each trophic level in the area , and depends
on:
   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:
   upright pyramids
   inverted pyramids
Pyramid of Productivity
   These show productivity of organisms at
different trophic levels, which depends on:
   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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