12 Mar 2019 Ecology and Environment Class Notes for UPSC aspirants, IAS aspirants and OAS aspirants.

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CLASS NOTE of 12/03/2019
*Please refer to previous notes for better understanding
Carbon Cycle—
Carbon is a fundamental building block of life. Life on the earth is comprise of carbon based life
forms. The geological carbon cycle (Hadean Phase) take place over 100 million of year and
involve the cycling of carbon through the various layer of the earth.
The biological carbon cycle occur over day, weeks, months, years involve – absorption,
conversion and respiration of carbon by living organism.
It is the mainly conversion of CO2 from the atmosphere through photosynthesis. Such
conversion results production of carbohydrate, glucose that may be converted into other organic
compound (Fat, Protein). The remaining carbohydrate not being utilize by the plant, became
part of plant tissue. (Net primary productivity).
Plant tissue are either being carbon by the herbivores or decompose by the microorganism.
Animal consume carbohydrate and release CO2 through respiration.
The microorganism decomposes the remaining carbohydrate after the animal die and this
carbohydrate oxidized into CO2.
Within the ocean large amount of CO2 sink to the ocean flair to be buried into the crust of the
earth.
Ocean flair CO2 might take 10’s million of years to return to the atmosphere.
The stored CO2 in the form of hydrocarbon and after combustion convert in a form of
atmospheric CO2. Though deforestation and combustion earth crust CO2 rapidly converted into
atmospheric CO2 and this is the primary green house gas responsible for global warming. This
gas enhance the green house effect and could result in change in global climate (Change in
season, higher global temperature, etc.)
– Anthropological activities
Nitrogen Cycle—
Nitrogen is the most abundant element in the atmosphere and it is the major block of protein,
nitric acid such as DNA crucially important component of biological cycle.
Atmospheric Nitrogen is the reservoir pool can’t be used by most plant and only leguminous
plant.
Leguminous plant absorbs N2 in the from of Nitrate N2O and pass through food chain.
Ultimately there are released as ammonia when organic material is decomposed. The Ammonia
is changed back to nitrate by action of bacteria.

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If the Nitrate is not absorb by the plants, Atmospheric Nitrogen through rainfall and by teaching
penetrate into the soil – Shallow marine sediments and consumed by fish – consumed by
pelican birds and dropping of pelican convert into Ammonia.
5 basic process in the Nitrogen Cycle—
1) Nitrogen fixation through leguminous family
2) Nitrification while ammonia can be used by some plant most of the nitrogen take up by
plant is converted by bacteria from ammonia, which is highly toxic to many organism
then nitrate converts in nitrate.
This process is called Nitrification and this bacteria called Nitrifying bacteria.
3) Assimilation – Nitrogen compared an various form (Nitrate, Nitrite, Ammonia,
Ammonium) are taken up from soil by plant which synthesis in the form of animal
protein.
4) Ammonification – When plants and animal dies the nitrogen in the organic matter reenter
into the soil through microorganism decomposition. This decomposition produce
ammonia which is then available for other biological process.
5) Denitrification - Nitrogen make its way back into the atmosphere called denitrification. It
occurs primarily in wet soils where water make its difficulties for microorganism growth,
at here certain organism known as denitrifying bacteria will process nitrate to Oxygen
and free nitrogen gas is a byproduct.
Phosphorus Cycle— It is the major sedimentary cycle phosphates in the soil are taken in the
plant for protein synthesis and pass through food chain.
Plant and animal body and there exerts and phosphorous is released to the soil and its can take
back into plant or washed out in the ocean.
Sulphur Cycle— Sulphur Cycle is a process of collection by which sulphur more into water
including living system.
Steps of the Sulphur Cycle—
Mineralisation or organic sulphur into inorganic sulphur component (H2S)
Oxidisation of Hydrogen sulfite convert it into sulfite.
Ecological Succession— Ecological Succession is a process of change of species structure of
an ecological community over time.
Barren — Simple Fung/Biche — Grasses — Shrub — Bruise — Small tree — Big tree Complex
(Climax tree/Bisme)
– The community begin with relatively few pioneer plant and animal and developed
through increasing complexity as a climax community.
– After forest fire, severe wind volcanic activities Biome Collapse and Succession that
began new habitat and here soil is already developed called Secondary Succession

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(Faster – Visible – Very important for ecosystem). Further autorotation leads to Second
Succession.
Biodiversity—
Bio – Life Diversity – Variation/Variety
Biodiversity depends as temperature, precipitation altitude, soil, geography and the presence of
other species.
Levels of Biodiversity—
1) Genetic – It refers to the variation of gene within the species.
Genetic diversity is essential for a health breeding of population of species.
2) Species diversity – This refers to the variety of species it relates to the numbers of
species in a defined area humorous numbers of individual different species and this
region represent hotspots of biodiversity.
Western Ghats, Eastern Himalaya
3) Ecosystem diversity – The broad different between ecosystem type and diversity of
habitat and the ecological process occurring within each ecosystem constitute
ecosystem diversity.
The boundaries of community and ecosystem are not very rigidly define.
– Species divides + genetic diversity + Topography
Diversity may be measure at different scales.
α – Diversity – It refers to diversity within a particular area/close system / communities / area /
Ecosystem.
β – Diversity – It is a species diversity between ecosystem. This involve the compare of number
taxa that are unique of each ecosystem.
Ex-Hotspot
γ – Diversity – It is the measurement of overall diversity for different ecosystem within a
ecoregion.