Expert: Walter Hintz - 3/23/2010

Question
QUESTION: I'm trying to find out what the conversion ratio might be if, hypothetically, I wanted to grow bears using pig meat.  It relates to nitrogen needed to grow corn, convert corn to pig biomass (4:1), and then pig biomass to bear biomass.  Can you help???
Thanks, Mike

ANSWER: I am not quite sure what you are asking here . Are you asking about an energy pyramid

---------- FOLLOW-UP ----------

QUESTION: I don't think I'm looking for a food pyramid at this point (maybe I am?).  I'm just trying out to find how much herbivore mass an animal like a bear needs to eat to put on a pound, during early growth.  I will follow up with the short essay I'm writing, which I would very much like to get reviewed.  It deals with converting nitrogen that's killing our oceans into fish bi0mass via ecologically engineered marine nursery habitats, with a "by-product" of crystal clear water.

thanks, Mike

Answer
OK I know what you are thinking about. Let me remind you about the second Law or the Law of entropy which tells us that with any change of energy from form to another there is a loss of useful energy. So when an animal converts the chemical if food to heat energy through the digestive processes and glycolysis energy is lost. Lets assume a food chain where a bear eats fish. It takes ten Kg of algae to make one Kg of little fish and ten Kg of little fish to make one Kg of big fish. Ten it takes 10 Kg of fish to make one pound of bear. In other words about 90% of the mass of fish eaten is not converted to bear mass. This is often referred to as the pyramid of protoplasm. Look at what happens with this food chain where it takes 1000 Kg of the produces {algae) to make one Kg of bear
This is a generalization. In some cases maybe the loss would be slightly less then 90%