Energy pyramids show energy flow per unit area per unit time. Each bar represents the energy available at one trophic level, so the diagram can be used to compare producers and consumers and to consider organisms that feed across levels.
Ecologists sometimes display data from an ecosystem using a diagram called a pyramid of energy. Describe what is shown in pyramids of energy.
pyramid of energy shows the flow of energy from one trophic level to the next (in a community);
units of pyramids of energy are energy per unit area per unit time /kJm−2yr−1;
bar width is proportional to the energy stored (in the biomass) in that trophic level;
the first/lowest trophic level is producers;
second level is primary consumers/herbivores;
third level of secondary consumers/carnivores;
only a small amount (10 to 20 % ) of energy of one level is passed to the next;
bar width/energy stored in the trophic level decreases (proportionally) as you go up each level;
pyramid shows that there is a limit to the length of food chains;
Award any of the above marking points to a correctly drawn and clearly labelled pyramid.