Ecological Pyramids : An ecosystem is represented graphically by means of pyramids which are called as ecological pyramids. First time (Elton 1927) represent ecological pyramid.
Various modes of relationships in an ecosystem can be shown through graphic diagrams known as ecological pyramids.
Ecological pyramids are the sketches of-
(i) the number of individuals
(ii) energy level
(iii) the quantity of biomass in different trophic levels.
The first tropic level or the producer level constitutes the base of the pyramid and successive levels. Based upon the relationships which exist among organisms at different trophic levels in the ecosystem.
Types of Ecological Pyramids : Following three types below:
- Pyramid of numbers
- Pyramid of energy
- Pyramid of biomass
In grassland and crop ecosystem the pyramid may be upright (where producers are maximum in number) and primary, secondary and tertiary consumers constitute the successive decrees in number and top these are least in number. In a tree ecosystem the pyramid is inverted, i.e, one single tree which is primary producer has got a large number of birds on it (Primary consumers) which also have a large number of insects outside their body (Secondary consumers). Levels are given in diagram below
Pyramid of Biomass: The total fresh or dry weight of all living organisms in a certain unit area is called biomass. The amount of new biomass produced in a single growing season is called yield. The pyramid of biomass may be upright (terrestrial ecosystem) or inverted (aquatic ecosystem). In terrestrial ecosystem (forest) the biomass of primary producers is maximum and biomass of top carnivorous is minimum. In aquatic ecosystem the biomass of consumer may be even more than that of primary producers.
3. Pyramid of Energy: This type of pyramid shows energy accumulation pattern at different trophic levels. Such a pyramid of all ecosystems is upright. Primary producers are characterized by maximum value and at each.
Successive decrees of consumers (starting from herbivores ending to top carnivorous). The energy value per square meter per year is decreased by approximately 1/10. Thus there is noted a gradual decrease in the energy content at successive trophic level from producers to consumers. The amount of energy content in plants is measured by bomb calorimeter.
Functions of Ecosystem: The ecosystem is functional unit of ecological studies. In this biotic and abiotic components inter-reaction together make balance in themselves.
The main function of ecosystem are:
- By knowing the amount of energy flow through an ecosystem we may know the increase in dry matter of living beings and the rate of photosynthesis and respiration.
- By the help of study of ecosystem we understand the cycling of materials in living and nonliving components.
No comments:
Post a Comment