Ecosystem -modified

 Ecosystem-1:-

                           Ecosystem is a functional unit of nature in which one organism interacts with others and environment. Ecosystem is divided in two categories aquatic and terrestrial.There ae some man made ecosystems as crop field and aquarium.

Ecosystem :- Structure and function

                            Vertical distribution of different species occupyingdifferent levels is known as Stratification.Ecosystem function asa unit in 

1) Productivity

2) Decomposition 

3) Energy flow

4) Nutrient cycle

                             An example which includes all is Pond

                             Pond is a shallow body  in which all the above mentioned four basic components are present of ecosystem in which abiotic component is water in this organic and inorganic substances and soil is at the bottom . Other climatic conditions that regulate the function of pond is Solar input ( Sun-light), temperature cycles and day length etc.

                             The Autotrophic ( Organisms which makes food with the help of sunlight from CO2 and water in the presence of chlorophyll) include phytoplankton, algae and plants in floating and submerged conditions.

                             Consumers are zooplanktons the free swimming and bottom dwelling forms of orgamisms.The decomposers are the fungi, bacteria and flagelletes present in large amount at bottom.this system performs all the functions of any ecosystem and whole biosphere.

eg  Autotrophs which makes the food by conversion of inorganic to organic material with the help of radiant energy or sun-light.Consumption of autotrophs by heterotrophs eg Algae by fish.Decompositon and mineralisation of the dead matter for reuse by autotrophs. And energy flows in unidirection towards higher trophic level and dissipation and loss of heat to environment.

Productivity:-

                            For ecosystem to thrive continues sun-light is required. 

Primary production :-

1.                            The amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis is primary production. Its unit is (weight) gm2 or in terms of energy is kcal m2.
2. The rate of biomass production is productivity that is more mass or energy higher productivity..Its unit is gm2/year or (kcal m2)/year.
3. It has two types GPP and NPP
4. Gross primary productivity which is rate of biomass produced of organic matter during photosynthesis,
5. Net Primary productivity is Gpp minus respiration loss

                NPP = GPP - respiration loss

Secondary productivity:-

1. The rate of formation of new organic matter by consumers is called secondary productivity.
2. The annual net primary productivity of the whole biosphere is approximately 170 billion tons of dry weight organic matter, 
3. Of this although ocean is 70% its productivity is only 55 billion.
4. while land has 115 billion productivity.

Decomposition:-

1. Earthworm is farmers friend because it breaks down complex organic matter and helps in loosening of soil.
2. Similarly Decomposers break down complex organic matter into inorganic substances like CO2, water and nutrients called decomposition.
3. Dead plant remains such as leaves bark, flowers and dead remains of animals, including fecal matter constitute detritus, whch is raw material for decomposition.
4. Detritivours (earthworm like) break down detritus into small particles called fragmentation.
5. By the process of leaching water soluble inorganic nutrients go down in soil and becomes unavailable.
6. Bacteria and fungal enzymes degrade detritus into simple inorganic substances.  This is called as catabolism.
7. Humification and mineralisation occur during decomposition of soil. Humification leads to accumulation of a dark coloured amorphous substance called Humus.
8. Humus is further degraded by some microbes and release inorganic nutrients called Mineralisation.
9. Warm and moist environment favour decomposition whereas low temperature and anaerobic condition inhibit decomposition results in increased organic material,

Energy flow:-

1. Except deep sea hydrothermal ecosystem Sun is only source of energy for all ecosystems on earth Of the incident solar radiation less than 50% of it is photosynthetically active radiation (PAR),
2.  Plants capture 2-10% of the PAR and this small energy sustains entire living world.
3. So energy flow should get studied for knowledge.
4. All organisms are dependent for there food on producers, either directly or indirectly.So thre is unidirectional flow of energy from producers to consumers.
5. Ecosystems are not exempt from the Second law of thermodynamics.Producers are green plants in the ecosystem as they synthesis or produce energy from Sun-light through Photosynthesis. 
6. In a terrestrial ecosystem herbaceous or woody plants are major producers.
7. The chain or web is formed because of interdependencies. Energy could not remain trapped into an organism forever and can't be, although it flows.
8. Producers trap energy which get passed on to a Consumer. Then organism dies which is begining of the Detritus food chain/ Web.
9. Animals are dependent on producers for energy either directly or indirectly therefor they are called as consumers and also heterotrophs.
10. The animals feed on producers or plants they are called Primary consumers.
11. And if animals eat animals which eat producers are known as Secondary consumers.
12. And organisms which thrives on secondary consumers are called as tertiary consumers. And organisms which thrives on secondary consumers are called tertiary consumers. 
13. herbivores are primary consumers example insects Birds mammals in tertiary ecosystem and mollusc in aquatic ecosystem .
14. The consumers which eats herbivores are carnivores or more exactly primary carnivores. 
15. and which survives on primary carnivores are called secondary carnivores. 
16. detritus food chain begins with organisms and made up of decomposers which are heterotrophic organisms mainly bacteria and fungi. 
17. decomposers meets their energy requirements by degrading dead organic matter or detritus. These are known as saprophytes or saprotrophs. 
18. decomposers or saprotrophs secrets digestive enzymes that breakdown dead aur waste material into simple inorganic materials which absorbs by saprotrophs. 

Aquatic ecosystem :-

1. In this ecosystem grazing food chain is major energy flow. 
2. As against in Terrestrial ecosystem a much larger fraction of energy flows through the detritus food chain then through the grazing food chain.
3. At some level grazing food chain is connected with detritus food chain in natural ecosystem. 
4. Detritus food chain organism are pray to food chain animals. 
5. Some organisms are Omnivores like cockroach, crows which feed on dead as well as living organisms.
6. Natural Interconnection of food chains make it a food web. Humans are Omnivores whitch may thrive on animals. 
7. Organisms occupy a place in natural surrounding, based on the source of their nutrition habit in food chain as their trophic level.
8.  The amount of energy decreases at successive trophic levels.
9. each topic level has some mass of living material at a particular time call the standing crop. 
10. standing crop is measured is the mass of Living Organism (Biomass) or number in unit area. 
11.  Biomass is expressed as fresh or dry weight.