Table of contents |
|
Ecosystems |
|
Pyramids of Ecosystem |
|
Productivity |
|
Some Information |
|
As much as the food web is complex the ecosystem is more permanent or stable. Such a type of ecosystem is not destroyed naturally and continues for a long time. This ecosystem is not affected by the loss of any organism of any particular tropic level. Those ecosystems which have a simple food web are not very stable it means that they can be finished at any time if there is a change in any particular tropic level.
The science of self-control as (homeostasis) in an ecosystem is called cybernetics.
Pyramids are of Three Types:
In this type of pyramid, the number of the individual organisms in various tropic levels is shown. These pyramids are mostly upright because the number of producers [T1] is maximum and No. of herbivores and carnivores decrease towards the apex or at successive tropic levels, such as Grassland ecosystem and aquatic ecosystem. But in a tree ecosystem, the pyramid of numbers is inverted. This is called a parasitic ecosystem because birds (herbivores) depend on the tree (producer) and parasites (consumer) depend on birds, therefore with an increase in the number of tropic levels, the number of the organisms increases sequentially.
Note:
Maximum number of producers are present in aquatic ecosystem. The number of organisms at any tropic level depends upon the availability of organism which are used as food on lower level so availability of food is the main factor.
Pyramid of number shows biotic potential of a ecosystem. The number of members of any particular species in favourable conditions is called their biotic potential. When the number of the members of any species increases then it is called population explosion. Because of this, existence of the species comes in danger. Human population is also near this condition at present.
Pyramids of biomass represent the total amount of biomass of each tropic level of the ecosystem, mostly these pyramids are also upright (erect) e.g. (tree ecosystem), forest ecosystem.Pyramids of biomass in an aquatic ecosystem are inverted because in it producers are micro-organisms and their biomass is very less.
Note: Pyramid of lake on the basis of biomass:
Limitations of Ecological Pyramids
Some Special Points related to Biomass
Note: The pyramids of biomass show the standing crop of ecosystem.
It represents amount of energy at different tropic levels, energy pyramids are always upright or erect because there is a gradual decrease in energy at successive tropic levels. According to the 10% law of Lindemann, the 90% part of obtained energy of each organism is utilized in their various metabolic activities and heat and only 10% energy is transferred to the next tropic level. So 90% energy is lost at each tropic level, therefore top consumers like lion etc. are ecologically weakest but physically they are strong.
Note: Pyramids of energy represent the productivity of ecosystem as well as transfer of production in ecosystem.
Some Information: The respiration cost also increases along successive higher tropic levels normally on an average respiration of producers consume about 20% of its gross productivity. Herbivores consume about 30% and 60% consumed by carnivores in respiration.
There are two types of productivity present:
![]() |
Download the notes
Ecosystems & Ecological Pyramids
|
Download as PDF |
Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (g/m2/yr) or energy (Kcal m–2). The rate of biomass production is called productivity. It is expressed in terms of g–2yr–1 or (Kcal m–2) yr–1 to compare the productivity of the different ecosystems. It can be divided into GPP and NPP.
It is again divided into two types:
Secondary productivity is the rate of formation of new organic matter by consumers.
Net community productivity or Net productivity – The rate of storage of organic matter not used by the heterotrophs.
NCP = N.P.P. – HR (HR = Energy used by Heterotrophs or consumers)
78 videos|280 docs|174 tests
|
1. What is an ecosystem? | ![]() |
2. What are ecological pyramids? | ![]() |
3. How are ecological pyramids useful in understanding ecosystems? | ![]() |
4. What is productivity in an ecosystem? | ![]() |
5. How can the concept of productivity be applied to real-world scenarios? | ![]() |