ECOLOGICAL PYRAMIDS FLOW OF ENERGY IN AN ECOSYSTEM LIMITATIONS OF ECOLOGICAL PYRAMIDS

1. ECOLOGICAL PYRAMIDS
SUBMITTED TO

2. ECOLOGICAL PYRAMID
• A graphical representation of trophic structure and function of an ecosystem,
starting with producers at the base and successive trophic levels forming the
apex.
•Charles Elton (1927) developed the idea of ecological pyramids. Therefore
these are also termed as Eltonian pyramids.
•The trophic level of an organism is the position it occupies in a food web

3. PYRAMID OF NUMBER
 Graphical representation of number of individual organisms
per unit area at each trophic level.
 It can be upright(grassland and aquatic ecosystem)or inverted.

4. PYRAMID OF biomass
 The relationship between biomass and trophic level by quantifying the
biomass present at each trophic level at a particular time.
 Graphical representation of biomass (total amount of living organic matter
in an ecosystem) present in unit area at a particular time in different tropic
levels.
Forest ecosystem(UPRIGHT) Pond Ecosystem(INVERTED)

5.  It represents the amount of energy present at each trophic level.
 Also called as pyramid of productivity.
 Based on Second law of thermodynamics
 Decline in energy at subsequent level is referred to as 10% law.
 It is always upright
PYRAMID OF ENERGY
PYRAMID OF energy

6. LIMITATIONS OF ECOLOGICAL PYRAMID
 Species with more than one mode of nutrition i.e feed
at more than one trophic level
 Saprophytes are not included
 Detritus such as litter are important source of energy
yet not included
 Do not provide any clue to seasonal and diurnal
variation
 Rate of transfer from one trophic level to another is
not reflected