Slides in this set
Pyramids of Number
· Each step of the pyramid
represents the number of
organisms at each trophic
· These have limits as one oak
tree can only harbour so
· Only one oak tree, so it is
· Many insects are on the tree,
· Fewer woodpeckers are
needed to consume the…read more
Pyramids of Biomass
· These show the mass
consumed at each level,
this always decreases as
mass is lost from:
· Uneaten parts, e.g. bones
· A huge amount of clover
will only feed one sparrow
· Energy is passed along the trophic levels.
· It is shown as a transfer of energy along a food chain.
· Energy is passed on up the food chain (when not used at
· Only about 10% of the energy is passed on at each level
of a food chain.
· This limits the number of trophic levels as eventually
there is not enough energy left.
· E.g. light energy is used by plants during photosynthesis.
The plant is eaten so the energy is passed to the next
organism. Etc.…read more