Expert: Dana Krempels, Ph.D. - 9/24/2007

Question
why is the energy pyramis so complicated as for the trophic level

Answer
Dear Darlene,

Your question is not worded very clearly.  Are you asking why the trophic levels are so complicated?  I am not sure if you also asking about energy pyramids, so please write back and ask a bit more clearly if I'm not getting this right.

Trophic levels are complex because most organisms eat more than one type of food.  Humans, for example, can be top carnivores, secondary consumers, or even herbivores, depending on what they're eating at the moment.  

Because more organisms can be supported if they eat organisms lower on the energy pyramid, that means that an individual's "place" on the energy pyramid also depends on what it's eating.  If a human is a vegetarian, that means that about 10% of the energy in the plants eaten will be made into the biomass of the human.  But if a human eats steak, that means that only about 1% of the energy in the plants (eaten by the cow that was eaten by the human) will be converted into the human's biomass.

So by eating "lower on the food web" we can support more humans than if we eat higher on the web, as we do when we eat meat.

Hope that helps.

Dana