Tuesday, 30 June 2015

Evergreen Books for Prelims and Mains examination of UPSC Civil Services

UPSC offers a diverse and distinctive questions from various areas in the prelims and mains examination. However there are certain books are must be relied upon in any case as they are very important for conceptual understanding of the subjects. As UPSC is moving towards more basics and opinion based upon those things, it is necessary to follow these books.

For Modern Indian History
1. India's Struggle for Independence by Bipin Chandra (Click here)
2. Modern Indian history by Bipin Chandra (Click here)
3. Indian Since independence by Bipin Chandra (Click here)

For Indian Culture
1. Indian Culture by Spectrum/ NCERT (Click here)

For Polity
1. Indian Polity by Laxmikant (Click here)
2. Indian Polity by Sriram IAS Academy

For Economics
1. Indian Economy by Ramesh Singh (Click here)
2. Indian Economy by Sriram IAS Academy

For Geography
1. NCERT 11th and 12th (Click here)
2. Certificate Physical and Human Geograhy by Goh Cheng Leong (Click here)
There are various books on ecology and environment and are of much importance looking into the fact that Indian Forest Service exam is same as that of Civil Service. So, there is a need for special emphasis on that.

For Environment and Ecology
1. Shankar IAS notes- As Recommended by many
2. Majid Hussain (Click Here)
3. PD Sharma (CLick Here)

For Science
1. NCERT/ S. Chand of Class X

P.S. : The list of in-comprehensive and is not exhaustive. It is based upon my experience with books. Readers can take guidance from other sources as well.

Friday, 26 June 2015

Environment and Ecology: Part 2


In ecosystems flow of nutrients is cyclical. The nutrients cycle from dead remains of organisms released back into the soil by detrivores which are absorbed again i.e. nutrient absorbed from soil by the root of green plants are passed on to herbivores and then carnivores.

This recycling of the nutrients is called biogeochemical or nutrient cycle (Bio = living, geo = rock, chemical = element). The transfer of matter involves biological, geological and chemical processes; hence the name. These cycles facilitate the transfer of matter from one form to another and from one location to another on planet earth. 

It is a circuit or pathway by which a chemical element (or molecule) moves through both biotic and abiotic compartments of an ecosystem. Abiotic factors - water (hydrosphere), land (lithosphere), and air (atmosphere); the living factors of the planet can be referred to collectively as the biosphere. All chemical elements occurring in organisms are part of biogeochemical cycles.

It thus provides a clear demonstration of the harmonious interactions between organisms and their environment, both biotically and abiotically.
The entire earth or biosphere is a closed system i.e. nutrients are neither imported nor exported from the biosphere. There are two important components of a biogeochemical cycle

(1) Reservoir pool

Though components of the biogeochemical cycle are not completely lost, they can be held for long periods of time in one place. This place, called a reservoir is a place or region or location where a biogeochemical element is in its highest concentration.  Eg) Coal deposits that are storing carbon for a long period of time, atmosphere/rocks which stores large amounts of nutrients.

Influx : difference between the amount of elements entering a reservoir and the amount leaving the reservoir.

(2) Cycling pool /exchange pool/ compartments of cycle

They are relatively short storages of carbon in the form of plants and animals. Eg) plants and animals, which temporarily use carbon in their systems and release it back into a particular reservoir. Carbon is held for a relatively short time in plants and animals when compared to coal deposits. The amount of time that a chemical is held in one place is called its residence time.

Note: Generally, reservoirs are abiotic factors while exchange pools are biotic factors

Elements transported in the biogeochemical cycles are categorized as:

Micro elements - elements required by living organisms in smaller amounts. Eg) boron used mainly by green plants, copper used by some enzymes and molybdenum used by nitrogen-fixing bacteria.
Macro elements - elements required by living organisms in larger amounts. Eg) carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur

Importance of biogeochemical cycles

1. They enable the transformation of matter from one form to another. This transformation enables the utilization of matter in a form specific to particular organisms.

Eg) Nitrogen (N2), despite its abundance in the atmosphere, often is the most limiting nutrient for plant growth, as most plants can only take up nitrogen in two solid forms: ammonium ion (NH4+) and the ion nitrate (NO3-). So, biogeochemical cycles enable the provision of elements to organisms in utilizable forms.

2. They enable the transfer of molecules from one locality to another.
Eg) Some elements like N2 are highly concentrated in the atmosphere, but some of the atmospheric N2 is transferred to soil through the N2 cycle

3. These cycles facilitate the storage of elements. Elements carried through the biogeochemical cycles are stored in their natural reservoirs, and are released to organisms in small consumable amounts.
Eg) Through N2 cycle and with the help of N2 fixing bacteria, green plants utilize N2 in bits though it is abundant in the atmosphere.

4. They assist in functioning of ecosystems, ie proper functioning in a state of equilibrium. Whenever any imbalances occur, the ecosystem through the biogeochemical cycles restores to the equilibrium state. The adjustment is such that the disturbing factor is eliminated.

5. Biogeochemical cycles link living organisms with living organisms, living organisms with the non-living entities and non-living entities with non-living entities. This is because all organisms depend on one another and, the biotic and abiotic component of the ecosystem are linked by flow on nutrients engineered by the biogeochemical cycles.

6. They regulate the flow of substances. As the biogeochemical cycles pass through different spheres, the flow of elements is regulated since each sphere has a particular medium and the rate at which elements flow is determined by the viscosity and density of the medium. Therefore elements in the biogeochemical cycles flow at differing rates within the cycle and this regulates the flow of the elements in those cycles.

Lifespan And Rate Of Biogeochemical Cycles

It is the time a particular element or molecule of a substance being carried in the biogeochemical cycle takes to make one complete cycle. It may range from several days to millions of years.
Eg) water droplet of average size may stay in the atmosphere for about ten days before precipitation, carbon atoms may reside in the earth crust for the age of the Earth.

The speed of the cycles depends on the medium in which the molecule being cycled is and the surrounding conditions. So, climatic conditions have a significant impact on the biogeochemical cycles.

Cycles that involve molecules or ions in a gaseous state are generally shorter than cycles that involve solid or liquid state transfer because of the slow rate at which molecules move through the lithosphere.

Some of the important Biogeochemical cycles :


Nitrogen is a very important element in that it is part of both proteins (present in the composition of the amino acids that make those proteins) & nucleic acids, such as DNA and RNA (present in nitrogenous bases). Our atmosphere contains nearly 79% of nitrogen but it can’t be used directly by the majority of living organisms.

Nitrogen cycles from gaseous phase to solid phase then back to gaseous phase through the activity of a wide variety of organisms. Cycling of nitrogen is vitally important for all living organisms. There are five main processes :

NITROGEN FIXATION : Nitrates can then be used by plants or animals Involves conversion of gaseous nitrogen into Ammonia, a form in which it can be used by plants. Atmospheric nitrogen can be fixed by the following three methods

Atmospheric fixation: Lightening, combustion and volcanic activity help in the fixation of nitrogen.

Industrial fixation: At high temperature (400°C) and high pressure (200 atm.), molecular nitrogen is broken into atomic nitrogen which then combines with hydrogen to form ammonia (Haber-Bosch process)

Bacterial fixation: There are two types of bacteria-
  • Symbiotic bacteria e.g. Rhizobium in the root nodules of leguminous plants.
  • Free-living or symbiotic e.g. Nostoc, Azobacter, Cyanobacteria 

can combine atmospheric or dissolved nitrogen with hydrogen to form ammonia.

NITRIFICATION: The conversion of ammonia to nitrate is performed primarily by soil-living bacteria and other nitrifying bacteria.
In the primary stage of nitrification, the oxidation of ammonium (NH4+) to nitrites (NO2-), is performed by ammonium oxidizing bacteria (AOB) represented by the "Nitrosomonas" species.
The second reaction is oxidation of nitrite (NO2-) to nitrate (NO3-) by nitrite-oxidizing bacteria (NOB), represented by the “Nitrobacter” species. It is important for ammonia to be converted to nitrates or nitrites because ammonia gas is toxic to plants.

ASSIMILATION: In this process nitrogen fixed by plants is converted into organic molecules such as proteins, DNA, RNA etc. These molecules make the plant and animal tissue.

AMMONIFICATION: Living organisms produce nitrogenous waste products such as urea and uric acid. These waste products as well as dead remains of organisms are converted back into inorganic ammonia by the bacteria. This process is called ammonification. Ammonifying bacteria help in this process.

DENITRIFICATION: Reduction of nitrates back into the largely inert nitrogen gas (N2), completing the nitrogen cycle. This process is performed by bacterial species such as Pseudomonas and Clostridium in anaerobic conditions (in oxygen free medium), eg) waterlogged soils. 
The denitrifying bacteria use nitrates in the soil to carry out respiration and consequently produce nitrogen gas- inert and unavailable to plants. Denitrification is reverse of nitrogen fixation.

Human influences on the nitrogen cycle

Huge increase in transfer of nitrogen into biologically available forms – Due to extensive cultivation of legumes, growing use of the Haber–Bosch process in the creation of chemical fertilizers, and pollution emitted by vehicles and industrial plants

Transfer of nitrogen trace gases from Earth to the atmosphere and from the land to aquatic systems.

Nitrous oxide (N2O) has risen in the atmosphere due to agricultural fertilization, biomass burning, cattle and feedlots, and industrial sources. N2O in the stratosphere breaks down and acts as a catalyst in the destruction of atmospheric ozone.

Nitrous oxide is also a greenhouse gas (GHG) and is currently the third largest contributor to global warming, after carbon dioxide and methane. It is 300 times more potent in its ability to warm the planet, than carbon dioxide.

Ammonia (NH3) in the atmosphere (increasing due to human activities) acts as an aerosol, decreasing air quality and clinging to water droplets, eventually resulting in nitric acid (HNO3) that causes acid rain. Atmospheric ammonia and nitric acid also damage respiratory systems.

The very-high temperature of lightning naturally produces small amounts of NOx, NH3, and HNO3, but high-temperature combustion has contributed to a 6 or 7 fold increase in the flux of NOx to the atmosphere. The higher the temperature, the more NOx is produced. 

Ammonia and nitrous oxides are precursors of tropospheric (lower atmosphere) ozone production, which contributes to smog and acid rain, damages plants and increases nitrogen inputs to ecosystems.

Decrease in biodiversity can also result if higher nitrogen availability increases nitrogen-demanding grasses, causing a degradation of nitrogen-poor species.

Onsite sewage facilities release large amounts of nitrogen into the environment. Microbial activity consumes the nitrogen and other contaminants in the wastewater. But in certain areas, microbial activity is unable to process all the contaminants and wastewater with the contaminants, enters the aquifers.

One health risk associated with drinking water (with >10 ppm nitrate) is the development of methemoglobinemia or blue baby syndrome.  

Additional risks of increased availability of inorganic nitrogen in aquatic ecosystems are water acidification, eutrophication of fresh and saltwater systems and toxicity issues for animals. Eutrophication often leads to lower dissolved oxygen levels in the water column, including hypoxic and anoxic conditions, which can cause death of aquatic fauna.  


Thursday, 25 June 2015

Sociology: A Discipline Part 3/3


The relationship between sociology and common sense is that of relationship between positivist and non-positivist or anti positivists. The relationship between sociology and common sense was marked by three phases

  • Convergence (When scientific methods were not developed)
  • Divergence (Period of glorification of science and its method which are objective)
  • Convergence (The period when there is development of non-positivists and anti-positivists who consider than society and human mind is dynamic and study there action which cannot be quantified)

Now, discussing about common sense, any speculative knowledge, cultural prescription or other presumption is said to be common sense. This means that any knowledge that does not require logic as a proof is common sense.
Therefore common sense is not person specific rather it is culture specific. It is transmitted to individual through the process of socialization through which people internalize and use this knowledge in different social situations.
Early philosophers were explaining material and social world based on common sense knowledge which was questioned by scholars evolving during renaissance. Galileo rejected to common sense knowledge about the interface between earth and sun, common sense understanding about the origin of earth was questioned by scientists of time.
Therefore post renaissance scholars believed that theological presumptions, assumptions and cultural explanation need to be replaced by scientific explanation of truth. They went for use of scientific methods. Thus completely rejecting common sense, they indicated that human behaviour can be quantified and brought into pieces. Further it is static and thus can be studied for everyone with proper procedures.
However, Common sense is not authentic. It is not subject to verifiability. It is a product of faith. Therefore science must be replacing to common sense knowledge. Common sense offers a guide to human behavior and at the same time it explains the social world surrounding man.

Therefore, the main focus should be on a common pattern to understand common sense which is: 
  • Introduction
  • Positivists (August Comte, Durkheim)- Rejection of Common sense
  • Non positivists (Weber)- Every action is making of history and culture for which a human is part and thus it creates a base of ideas which we call common sense
  • Interactional (C.H. Cooley and G.H. Mead) -  In an action situation, how two actors interact. Concept of ‘I and me’ can be included as well
  • Reflexive (Husserl and Schultz) which talk abut full flexibity and freedom to the researcher
  • Phenomenology – Every phenomenon is interpreted by every person separately ( A common example is that of a fruit like tomato- some consider it as salad, others as vegetable, still others use it as a tool to throw on people they don’t like and many others use it for fun like tomatina festival in spain.)
  • Conclusion.

Therefore a researcher must have to liberate himself from the bondage of mechanical theories and models while explaining human behavior. Therefore social researcher must give importance on knowledge procured through culture and that knowledge is used to define relationship and understand truth surrounding man. It is to be remembered that animal behavior starts and ends with common sense but human behavior starts with common sense, question to common sense, replaces to common sense, brings forward new common sense by rationality. Hence human behavior and life is dynamic in character that cannot ignore the role of common sense which is a strong guide to everyday life of an individual.

Saturday, 20 June 2015

Environment and Ecology : Part 1

Environment : Surroundings or conditions in which an organism lives or operates.

Ecosystem : An ecosystem is a functional unit of nature encompassing complex interaction between its biotic (living) and abiotic (non-living) components.

I.   Abiotic components :

They can be grouped into following three categories :

1. Physical factors: Sun light, temperature, rainfall, humidity and pressure. They sustain
and limit the growth of organisms in an ecosystem.

  • Light – Sunlight provides energy. Green plants utilize it for synthesizing food for themselves & other living organisms, through photosynthesis
  • Rainfall –Water is essential for all living beings. Majority of biochemical reactions take place in an aqueous medium. Water helps to regulate body temperature. Water bodies form the habitat for many aquatic plants & animals.
  • Temperature– Temperature is a critical factor of the environment which greatly influences survival of organisms. Organisms can tolerate only a certain range of temperature & humidity

2. Inorganic substances: Carbon dioxide, nitrogen, oxygen, phosphorus, sulphur, water,
rock, soil and other minerals.
  • Atmosphere - The earth’s atmosphere is made of 21% oxygen, 78% nitrogen & 0.038% carbon dioxide. Rest are inert gases (0.93% Argon, Neon etc).
  • Substratum- Organisms may be terrestrial or aquatic. Land is covered by soil & a wide variety of microbes, protozoa, fungi & small animals (invertebrates) thrive in it. Roots of plants pierce through the soil to tap water & nutrients. Terrestrial animals live on land. Aquatic plants, animals & microbes live in fresh water as well as in the sea. Some microbes live even in hot water vents under the sea.

3. Organic compounds: Carbohydrates, proteins, lipids and humic substances. They are the building blocks of living systems and therefore, make a link between the biotic and abiotic components.

II. Biotic components

1. Producers: The green plants manufacture food for the entire ecosystem and are called autotrophs, as they absorb water and nutrients from the soil, carbon dioxide from the air, and capture solar energy for this process

2. Consumers: They are heterotrophs and they consume food synthesized by the autotrophs.
Based on food preferences they can be grouped into Herbivores (feed directly on plants), carnivores (animals which eat other animals) and omnivores (organisms feeding upon both plants and animals)

3. Decomposers: Also called saprotrophs. These are mostly bacteria and fungi that feed on dead decomposed and the dead organic matter of plants and animals by secreting enzymes outside their body on the decaying matter. They play a very important role in recycling of nutrients. They are also called detrivores or detritus feeders

Living organisms, therefore, need both abiotic & biotic components of the environment for survival. A delicately balanced relationship between living organisms & their environment is critically important for their survival.


Ecosystems are complex dynamic system. They perform certain functions

  1. Energy flow through food chain
  2. Nutrient cycling (biogeochemical cycles)
  3. Ecological succession or ecosystem development
  4. Homeostasis (or cybernetic) or feedback control mechanisms

FUNCTION 1 : Energy flow through food chain

Food Chain : Transfer of food energy from green plants (producers) through a series of organisms with repeated eating and being eaten.

Each step in the food chain is called trophic level. During this transfer of energy, some energy is lost into the system as heat energy and is not available to the next trophic level. So the number of steps are limited in a chain to 4 or 5. 

Following trophic levels can be identified in a food chain :

Autotrophs : They are largely green plants and convert inorganic material in the presence of solar energy by the process of photosynthesis into the chemical energy (food).

The total rate at which the radiant energy is stored by the process of photosynthesis in the green plants is called Gross Primary Production (GPP) or total photosynthesis or total assimilation. From the gross primary productivity a part is utilized by the plants for its own metabolism. The remaining amount is stored by the plant as Net Primary Production (NPP) which is available to consumers.

Herbivores : The animals which eat the plants directly are primary consumers or  herbivores e.g. insects, birds, rodents and ruminants.

Carnivores: They are secondary consumers if they feed on herbivores and tertiary consumers if they use carnivores as their food. e.g. frog, dog, cat and tiger.

Omnivores: Animals that eat both plant and animals e.g. pig, bear and man

Decomposers: They take care of the dead remains of organisms at each trophic level and help in recycling of the nutrients e.g. bacteria and fungi.

There are two types of food chains: Grazing food chain & Detritus food chain

Food web: A network interconnected food chains existing in an ecosystem. Trophic levels in an ecosystem are not linear rather they are interconnected and make a food web. One animal may be a member of several different food chains.

The quantity of energy flowing through the successive trophic levels decreases as shown by the reduced sizes of boxes in the figure here. At every step in a food chain or web the energy received by the organism is used to sustain itself and the left over is passed on to the next trophic level.

Ecological pyramids

Graphic representations of trophic levels in an ecosystem. They are pyramidal in shape; the producers make the base of the pyramid and the subsequent tiers of the pyramid represent herbivore, carnivore and top carnivore levels. They are of three types:

Pyramid of number: This represents the number of organisms at each trophic level. It may be upright or inverted.

Pyramid of biomass: This represents the total standing crop biomass at each trophic level. Standing crop biomass is the amount of the living matter at any given time. It is expressed as gm/unit area or kilo cal/unit area

In most of the terrestrial ecosystems the pyramid of biomass is upright. However, in case of aquatic ecosystems the pyramid of biomass may be inverted e.g. in a pond phytoplankton are the main producers, they have very short life cycles and a rapid turn over rate (i.e. they are rapidly replaced by new plants). Therefore, their total biomass at any given time is less than the biomass of herbivores supported by them.  

Pyramid of energy: This pyramid represents the total amount of energy at each trophic level. Energy pyramids are never inverted.

ECOLOGICAL EFFICIENCY: Ratio between the amount of energy acquired from the lower trophic level and the amount of energy transferred from higher trophic level

10% rule : Proposed by Lindman. If autotrophs produce 100 cal, herbivores will be able to store 10 cal. (10% of 100 cal.) and carnivores 1 cal. (10% of 10 cal.)
There may be slight variations in different ecosystems and ecological efficiencies may range from 5 to 35%. Ecological efficiency (also called Lindman’s efficiency) can be represented as


Increase in concentration of a pollutant from the environment to an organism in a food chain (every organism is part of atleast one food chain). It occurs within a trophic level, and is the increase in concentration of a substance in certain tissues of organisms' bodies due to absorption from food and the environment.

The affected organism has a higher concentration of the substance than the concentration in the organism's surrounding environment. The toxic substances are very slowly metabolized or excreted so if the organism keeps on consuming prey or food contaminated with toxic substances, the concentration of the substance will further increase in its body, hence, bioaccumulation results. 

Bio-concentration : Occurs when uptake from the water is greater than excretion


Increase in concentration of a pollutant from one link in a food chain to another. It is the increase in concentration of a substance in a food chain, not an organism.

Thus, biomagnification is similar to bioaccumulation but is descriptive of higher level biological processes, not individual.

Bioconcentration and bioaccumulation occur within an organism, and biomagnification occurs across trophic (food chain) levels.

Bio-dilution : It is also a process that occurs to all trophic levels in an aquatic environment; it is the opposite of biomagnification, thus a pollutant gets smaller in concentration as it progresses up a food web.

1. NOS material on Environment and Biodiversity
2. Internet

Friday, 19 June 2015

Booklist for Prelims : GEOGRAPHY

  1. NCERT Books for class 11 & 12 (4 books)
  2. Certificate Physical and Human Geography G.C.Leong
  3. Orient Black Swan Atlas

How to prepare?

1. Fundamentals of Physical Geography NCERT class 11 & GC Leong have many common topics.
Basics of geography – The Earth & the Universe may be studied from GC Leong. Landforms may be studied from NCERT.
World climate zones are analysed in depth in GC Leong while NCERT gives comparatively less information. Atleast one time reading of this topic from GC Leong will help.

For other topics, one may compare the content and decide what to be studied, based on his/her needs – time available, depth of knowledge that one wants.
Overall, good understanding of the underlying science behind every concept is very essential to answer questions in CSE.

2. NCERT class 11 India Physical Environment will give a comprehensive idea about India’s physical features, climate, vegetation etc; and it may be studied after studying the basics of Earth’s structure, Climatological concepts for easier understanding.
Environmental aspects of geography like wildlife conservation, pollution etc will be covered under environment & ecology. It is a huge topic to cover but I will mention sources separately in the Environment Section.

3. NCERT class 12 Fundamentals of Human Geography is important for human and economic geography. Data such as population of any random country is not essential. The concepts have to be understood.

4. NCERT class 12 India -People And Economy deals with the Indian aspect of it.
Population and demography has to be studied along with the latest census data – 2011. One should also know the most recent data on important indicators like – Infant Mortality rate (IMR), Maternal Mortality rate (MMR), Total fertility rate (TFR) etc. Clear understanding of what each indicator actually means is required, as the questions are becoming more dynamic.

Tribes in India and areas of their presence may be prepared from Human Geography by Majid Husain (very useful for geography optional), else it may be searched on the internet.

Land, soil, agriculture & water resources have to be studied along with soil & drainage systems (physical geography) for a comprehensive understanding & ease of remembering.
Similarly, minerals & energy resources have to be studied along with manufacturing industries. While preparing about agro-based industries, one has to recollect crop patterns and their geographical coverage.

Under the topic transport & communication, one has to know the important sea-ports, roads like national highways (people generally prepare NH1 to NH10 & other important ones, for eg: NH 223 – cutting through the Jarawa reserve (in news due to Supreme Court order), NH 47A – shortest NH, connecting Cochin city & Willingdon island in Vembanad lake.
Few important gas & oil pipelines must also be known, and may be related to the location of petrochemical & fertiliser industries.

Additional Reading :

1. Linking current issues with geographical concepts and locations.

Eg: Nepal earthquake – Origin of Himalayas? Why Himalayas are geologically unstable? How the mountain system has affected India’s geography, climate etc. Such questions may be anticipated.
Eg: Jarawa tribes - Great Andaman Trunk Road, origin of Andaman islands, location, climate & vegetation in that region.

Any reports released by the Government or any other global institutions regarding sustainable development, conservation, demographics etc maybe prepared alng with relevant topics

Most of these aspects will be studied by us during the course of preparation, but constant revision is needed to recollect them when questions are asked linking 2-3 topics.

2. Census data – recent figures.

Always study along with an atlas. Keep referring whenever needed. Make maps of rivers, mountains, minerals, crops, rainfall etc, for quick revision later.

Compare and study topics that can be. Eg: Compare Himalayan system & Great Plains, Eastern Himalayas Vs Western Himalayas, Himalayan Vs Peninsular rivers, North-east Vs South-west monsoon, Rice Vs wheat cultivation, Andamans Vs Lakshadweep, Eastern Vs Western ghats, and many more. Brainstorm points – it will help you recollect and concise notes will help for CSE mains too.