Read this article to learn about the processes, operation and energy flow in eco-system!
Processes in Eco-System:
The processes are the operations in the eco-system which describe the pathways of energy and material flow within the biotic and abiotic components of eco-system.
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The different processes taking place within the eco-systems may be categorised as under:
(a) Metabolic Process:
The metabolic processes are assimilation, respiration, growth, production uptake of nutrients and water, transpiration, fixation of nitrogen, litter decomposition and mineralisation. Such processes operate in biotic component of environment. The importance of metabolic process in an ecosystem is the addition of biomass, storing of energy in the form of food and maintenance of orneriness of the system by pumping out the disorders.
(b) Energy Flow:
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The process of energy flow involves transfer of energy from autotrophs to various components of heterotrophs and help in maintaining diversity and order within eco-system.
(c) Bio-geochemical Cycling:
The process of bio-geochemical cycling operates continuously circulating minerals and water in between biotic and abiotic components of eco-system.
Operations in Ecosystem:
The different steps involved in the operation of eco-system are outlined as below:
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Step-I:
Trapping of solar energy by the producers.
Step-II:
Synthesis of organic materials (carbohydrate) from inorganic ones (H20 and C02) by the producers.
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Step-III:
Consumption of producers and carbohydrate by consumers.
Step-IV:
After the death of producers and consumers, the complex organic compounds are degraded by the decomposers into smaller organic molecules.
Step-V:
The smaller organic molecules are finally converted into inorganic forms by transformers which may be suitable for reuse by the producers.
Energy Flow in Eco-System:
The transformation of energy in between the different components of ecosystem is known as energy flow. It is unidirectional in nature and based on two fundamental laws of thermodynamics.
(a) First Law of Thermodynamics:
Energy can neither be created nor be destroyed but can be converted from one form to other. Hence, total amount of energy of the universe is constant other. Hence, total amount of energy of the universe is constant.
(b) Second Law of Thermodynamics:
It may be stated as the processes involving energy transformation will not take place spontaneously unless there is a degradation of energy from a non- random to a random form” or “Non-random energy (mechanical, chemical, radiant energy) cannot be transformed without some degradation into heat energy.” From the above concept, it is clear that after transformation, the capacity to perform work is decreased. Thus, energy flows from higher to lower level.
The unit of energy is Erg (work done in lifting one gram of weight to a height of one cm. against the force of gravity).
107 erg = 1 joul: 1 calorie = 4.184 jouls
In order to have a clear-cut understanding about energy flow, the following points are to be focused:
(i) The quantity of solar energy reaching an eco-system per unit area per unit time.
(ii) The efficiency of producer in solar energy trapping and its bio-conversion into chemical energy.
(iii) The use of this converted chemical form of energy by the consumer.
(iv) The total input of energy in the form of food and its efficiency of assimilation.
(v) The loss through respiration, heat, excretion, etc.
(vi) The gross net production.
Living organisms can use energy mainly in two forms:
Radiant Energy:
It is the light energy coming from the sun.
Fixed Energy:
It is the potential energy stored in various organic substances which can be broken down in order to release their energy content.
The unidirectional energy flow in eco-system takes place in the following manner:
The green plants trap solar energy through chlorophyll and convert the same to chemical energy which is stored in carbohydrates and other organic molecules. Such a process of conversion of solar energy into chemical energy along with the simultaneous production of organic molecules from inorganic sources is known as primary production.
The total quantity of solar energy converted into chemical energy by green plant is known as Gross Primary Production (Pg). A portion of gross production is used by the producers for their various metabolic activities (Pm).
The remainder of energy after utilization is called Net Primary Production (Pn). Thus, Pg = Pn + Pm. In case, the gross production becomes equal to energy required for metabolic activities, then there shall be no change in energy content.
But if the gross production is lesser than energy required for metabolic activities, the bio-mass will undergo degradation. However, if the gross production is more than energy required for metabolic activities, there will be accumulation of biomass.
When the herbivore consume plants (autotroph or producers) as food and convert chemical energy accumulated in plants into kinetic energy, degradation of energy will take place through its conversion into heat. The production of organic matter by the animals or other heterotrophic organism is known as Secondary Production. The total quantity of plant material ingested and stored in the body of the herbivore is known as Gross Secondary Production.
Out of the total energy stored in plants, a part is utilized for various metabolic activities and the remainder of the assimilated energy is known as the Net Secondary Production. When herbivores are consumed by carnivores of the first order (secondary consumers), further degradation of energy will occur. Similarly, when primary carnivores are consumed by top carnivores, again energy will be degraded.
Thus, at each level of the system (producer, consumer etc.) some energy is transformed. The decomposer will get food and energy from the dead remains (organic molecules) in the process of decomposition of degradation of dead organisms of all the trophic levels. Energy flow through various levels in an eco-system is represented in Fig- 3.5, 3.6 and 3.7.
