Ecological Pyramids - Practice Questions & MCQ

• There is some sort of relationship between the numbers, biomass and energy contents of the producers and consumers of different orders in any ecosystem.
• These relationships, when represented in diagrammatic ways, are referred to as ecological pyramids.

Pyramid of Numbers:

• The pyramid of numbers deals with the relationship between the numbers of primary producers and consumers of different orders. 
• In all cases, the base of such a pyramid always represents the numbers of primary producers and the subsequent structures on this base are represented by the number of consumers of successive levels, the top representing the number of top carnivores in that ecosystem. 
• The shape of the pyramid of numbers may be upright or inverted.
• In a cropland ecosystem:
  • the numbers of crop plants shown at the base of the pyramid are very large; 
  • the numbers of grasshoppers are usually less than the numbers of green plants;
  • numbers of frogs is lesser than the number of grasshoppers and 
  • the number of top carnivores is the least in the series of organisms
• But in an inverted pyramid of numbers the number of primary consumers (herbivorous birds feeding upon the tree fruits) is always greater than the number of primary producers (a tree), and the number of parasites living and feeding upon the bird’s body is still greater.