Trophic Levels Ecology - The Flow of Energy

A trophic level is basically an organisms position in the food chain. There are four levels of a trophic level:

Producers

Producers are photosynthetic organisms who make their own energy using the sun. See photosynthesis. (organisms that make their own food from sunlight and/or chemical energy from deep sea vents) are the base of every food chain - these organisms are called autotrophs. 

Primary Consumers

Primary consumers are animals that eat primary producers; they are also called herbivores (plant-eaters). They survive on leaves, grass, or roots. Some examples are insects, cows, rabbits, deer, pigs, hippos and pigs. 

Secondary Consumers

An animal that feeds on smaller plant-eating animals in the food chain. Animals that are secondary consumers include bears, dogs, cats, and snakes. 

Tertiary Consumers 

A Carnivore is at the top level of the food chain that feeds on other carnivores; an animal that typically only feeds on secondary consumers. 

Energy is lost as you move up the chain - example - the owl has to eat a lot of mice to fuel it's energy needs