Ecological efficiency : The relationship between the amount of energy accumulated, and the amount of energy utilized within one trophic level of food chain has an important bearing on how much energy on trophic level passes to the next trophic level in the food chain. The ratio of output energy to input of energy is referred to a s ecological efficiency.

Food Web : The collection of connecting feeding patterns in a biotic community tends to look more like a web than a chin and is called a food web.

Standing Crop : Amount of living material present in an ecosystem at any time.