Presentation1 eco
- 2. Graphic representation of the trophic structure and function of an ecosystem with special reference to the number of individual organisms, biomass and energy level
- 3. The concept of ecological pyramid was first advanced by British ecologist CHARLES ELTON ( 1972) The model proposed by him is called Eltonian pyramid
- 4. Three types of ecological pyramids Pyramid of Energy Pyramid of Biomass Pyramid of Numbers
- 5. Pyramid of Energy Graphic representation of the energy level & energy flow in the different trophic levels of ecosystem Gives general picture of functional state of communities , energy content of each trophic level & loss of energy from each trophic level
- 6. Energy Pyramid Organisms USE energy which means there is less available the higher levels
- 7. The 10% Rule – Energy losses. Energy transfers are never 100 percent efficient. 10% of all energy once available at a trophic level may transfer to the next trophic level. Some energy is lost at each step. Limits the number of trophic levels in an ecosystem.
- 8. • Most of the energy available to the community is in the 1st trophic level. • Only 10-20% of the energy is available to the next trophic level (≈ 90% lost)
- 9. Progressive decrease in energy content of successive trophic level Pyramid of energy is always UPRIGHT Maximum amount of energy is available for producers
- 11. Pyramid of Number Graphic illustration of the numerical relationship between different trophic levels of a food chain. It indicates the total number of individual organisms in the trophic levels of an ecosystem Number pyramid diagrams may be: upright pyramids inverted pyramids
- 12. Upright in case of predatory food chain
- 13. Inverted pyramid of number of parasitic food chain reveals that a single host may harbour several parasites and each parasite may harbour several hyperparasites
- 14. Pyramid of Biomass Biomass represent the total dry weight of individual organisms. These show the total biomass of organisms at different trophic levels, which depends on: the energy available at each trophic level the standing crop at each trophic level Biomass pyramid diagrams may be: upright pyramids inverted pyramids
- 16. In terrestrial ecosystem there is a progressive decrease in biomass from lower to higher trophic levels.so the pyramid of biomass is upright.
- 17. In pond or lake ecosystem there is progressive increase in biomass from lower to higher trophic levels & so the pyramid of biomass is inverted. Reason : producers small sized with low biomass, whereas the consumers are large sized with high biomass.
- 18. Short comings of ecological pyramids Do not provide any clue regarding seasonal and daily variations in the number of individuals, biomass and energy level Omnivores feed on members of different trophic levels , thus belongs to different trophic levels cannot be properly represented in ecological pyramids