HELP!! PLEASE!!!! SCIENCE COURSE troubles!?

Question

My professor is offering no help and the book is not helping me much either. The question he is asking is :

The population density of large carnivores is always less than their prey. Using the idea of an engery pyramid and the 10 % rule of energy transfer, why does this occur?

If you could, elaborate or help... Anyhing that can help me further to the correct answer he is looking for.. Thanks in advance!!

Answer 1

i think this is what your looking for:

all energy comes from the sun. as you go up the food chain, energy is lost. the energy comes from chlorophyll i believe. plants directly turn sunlight into energy. first order (herbivores) consume plants, and turn the chlorophyll into energy, but through metabolics, energy is expended and lost, so herbivores have to consume many plants. second order (carnivores, omnivores) consume the first order animals and get their energy from them, which initially came from plants, and started with sunlight. since energy is lost through these transfers, carnivores have to consume a large mass of meat (proportionally larger than the mass of plant matter the first order herbivores consumed).

since energy is lost, higher order predators need to consume a higher mass, and competition for food resources limits their population. for example, a hectare will contain countless plants, maybe a few hundred field mice that eat the plants, tens of snakes that eat the mice, and a few birds of prey that eat the snakes.

my explanation is a little shaky and hard to put into words, but the basics are there.

Answer 2

There always has to be far less carnivores compared to prey. Meat eaters need 10 times as much food as a plant eater to survive. If there were as many, lets say, coyotes as rabbits, then the competition would be to stiff and both animals would die out. With less predators, they can eat some of the prey and some of the prey can live to reproduce.

Answer 3

As the food energy goes up the ladder, toward the carnivore, only 10% is passed on per trophic level. Thus, carnivores must remain in small proportion to prey and prey in small proportion to plants. Simple put.