Veterinary Epidemiology and Zoonosis

ECOLOGICAL PYRAMIDS

• The different modes of nutrition that are found in animals occupying different trophic levels can be illustrated by constructing ecological pyramids.
• There are three types of pyramids
  • Pyramid of numbers
  • Pyramid of energy
  • Pyramid of biomass

Pyramid of numbers

• This was first proposed by Charles Elton (1927). This illustrates the population density relationships within and between trophic levels.
• The number of individuals decreased at each trophic level due to differences in population growth and also due to predation.

Pyramid of energy

• Here there is relationship between energy available between different trophic levels.

Pyramid of biomass

• Biomass means total amount of living material.