UNIT I – COMPONENTS OF ENVIRONMENT

1. Define Environment:
Environment is defined as the holistic view of the world as it functions at a given point of time, with a multitude of spatial, elemental and socio-economic systems, distinguished by quality of space, and the mode of behaviour of the various abiotic and biotic forms.

2. Write down the elements of environment
The elements of environment can be broadly divided into two;
1. Abiotic
It consists of physical environment consisting of air, water and soil or sediment. The abiotic components are further divided into three;
• Lithosphere (sphere of rocks / soil / sediment)
• Hydrosphere (sphere of water)
• Atmosphere (sphere of gases)
2. Biotic
The biotic or biological environment consists of flora, fauna and micro-organisms. The biotic component consists of,
• Producers (green plants)
• Consumers
a. Primary Consumer
b. Secondary Consumer
c. Tertiary Consumer
• Decomposers (bacteria and fungi)

3. What is abiotic environment?
Abiotic environment is composed of external physical factors like temperature, humidity, water, minerals and gases etc.

4. What are biotic environment?
Biotic environment is composed of all the living components-plants, animals and micro-organisms.

5. What is autecology?
It is concerned with the ecology of an individual species and its population. While studying the autecology of a particular species, an ecologist studies its behavior and adaptation to the environmental condition at every stage of that individual’s life cycle. Autecology is also called species ecology.

6. Why are plants called as producers?
The green plants have chlorophyll with the help of which they trap solar energy and change it into chemical energy of carbohydrates using simple inorganic compounds namely water and carbondioxide.As the green plants manufacture their own food they are known as Autotrpohs.

7. Write the classification of biological environment.
1. Floral/Plant Environment
2. Faunal /Animal Environment
3. Microbial environment

8. Write notes on troposphere
This layer is composed of water vapour, clouds and precipitation. It occupies 80% of the mass of atmosphere. At mid-latitudes it extends upto 10 to 12 km from earth’s surface. At the poles it ranges about 5 to 6 km and at equator it is about 18 km height. In this layer the temperature decreases at 5 to 7 0C as we go up. It is due to the wet adiabatic lapse rate. Troposphere is a very turbulent place ie. there are strong vertical air movements that lead to rapid and complex mixing. Mixing is good for air quality since it rapidly disperse pollutants.

9. Write notes on stratosphere
Stratosphere is a stable layer of dry air. Since there are no strong vertical movements, the pollutants remain suspended for a long time. They can drift back to troposphere where they are diluted and removed by rainfall or settling. Stratosphere contains ozone which absorbs the short wavelength ultraviolet energy, causing the air to heat up. The resulting temperature inversion makes the stratosphere stable. Both troposphere and stratosphere together account for 99.9 % of mass of the atmosphere. It extends upto 50 km above the surface of earth.

10. Define Ecology and Ecosystem:
Ecology is defined as the study of relationships between organisms and their environment.
An Ecosystem is defined as a natural functional ecological unit comprising of living organisms (biotic community) and their non-living (abiotic or physiochemical) environment that interact to form a stable self-supporting system.


11. Write short notes on photosynthesis.
The process by which chlorophyll bearing plants use energy from the sun to convert carbon dioxide and water into sugars is called photosynthesis. The generalized equation for photosynthesis is,


12. Explain energy flow and write down the laws governing that.
The behaviour of energy in an ecosystem can be termed as energy flow.
The flow of energy through the ecosystem is unidirectional and non-cyclic. This one way flow of energy is governed by laws of thermodynamics which state that;
I) Energy can neither be created nor destroyed, but can only be transformed from one form to another. This is known as the ‘first law of thermodynamics’.
II) Energy transfer is always accomplished be dispersion of energy into unavailable heat (ie. entropy). This law is known as the ‘second law of thermodynamics’ or ‘the law of entropy’.

13. Explain food chain and food web.
Food chain:
In a food chain each organism eats the smaller organism and is eaten by the larger one. All these organisms which are interlinked with each other through food together constitute a food chain.
The different species in a food chain are called trophic levels. Each food chain has three major trophic levels – Producers, Consumers and Decomposers.
Sunlight  Producer  Primary  Secondary  Tertiary  Quartenary
Consumer Consumer Consumer Consumer
(Plants) (Herbivores) (Primary (Secondary (Omnivores)
Carnivores) Carnivores)
Grass Rabbit Fox Wolf Man



Death


Inorganic Decomposers
Substances (Bacteria, Fungi)

Fig.: Basic nutritional links in an ecosystem.

Food web:
Various food chains are often interlinked at different trophic levels to form a complex interaction between different species from the point of view of food. This network is called the food web. The following figure shows the food web from grass to hawk.
Grasshopper Lizard

Grass Rabbit Hawk

Mouse Snake
Fig.: Example of food web.
If any of the intermediate stage of the food chain is removed, the succeeding links of the food chain will be affected. The food web provides more than one alternatives of food to most of the organisms in an ecosystem and, therefore, increases their chances of survival.

14. Define Nutrient cycle / Biogeochemical cycle / Material cycle.
The cyclic exchange of nutrient material between the living organisms and their non-living environment is called nutrient / material / biogeochemical cycle. As indicated by the name, the nutrients circulate through life (bio) and through earth (geo) repeatedly (cycle).

15. What all will be included under Edaphic factors?
Soil, pH, topography, minerals etc

16. Name some of the natural impacts on water, air and land:
Natural hazards can be broadly divided into two:
1. Geo Physical
2. Biological
Geo Physical can be again divided into;
i. Climatic and Meteorological
ii. Geologic and Geomorphic
Climatic and Meteorological hazards include;

a) Snow & Ice
b) Droughts
c) Floods
d) Fog
e) Frost
f) Hail
g) Heat waves
h) Tropical cyclones
i) Lightning and Fire
j) Tornadoes

Geologic and Geomorphic hazards include;

a) Avalanches
b) Earthquakes
c) Erosion
d) Land Slides
e) Shifting Sand
f) Tsunamis
g) Volcanic Eruptions


Biological hazards can be divided into,
i. Floral
ii. Faunal
Floral hazards include;
a) Fungal disease
b) Hay fever
c) Poisonous plants
Faunal hazards include;
a) Bacterial and Viral disease
b) Venomous animal bites
c) Infestation

17. Name some of the man-made (Anthropogenic) impacts on environment

1. London smog
2. Mediterranean-a dead sea
3. Nuclear explosions
4. Minamata disease
5. Bhopal disaster
6. Chernobyl disaster
7. Gulf war hazards
8. Acid Rain
9. Global warming and green house effect
10. Ozone layer depletion

18. State the theory of Classical Economics
Adam Smith and Thomas Malthus, in the 1700’s developed the theory of classical economics, according to this view, “as the population grows, the increasing scarcity of the finite resources reduces the quality of life, increases competition and ultimately causes population to fall”.

19. Give two importance of ecological services.
1. Chemical composition of the atmosphere and oceans
2. Water catchments and ground water recharge.
3. Biological diversity balance.

20. What is PEP?
PEP is Preventive Environmental Policy. It involves the adoption of technologies such as
1. Cleaner technologies for production process.
2. Recycle and reuse technologies.
3. Replace non-renewable resource base with renewable resource base.
4. Integrated technologies that minimize cross-media transfer of pollutants, thus minimizing overall pollution- induced risks in all environmental components.

21. What are Heterotrophic components?
Fungi, non-photosynthetic bacteria, other microorganisms and animals are the heterotrophic components of the ecosystem.

22. What are the different types of capital in neoclassical economics?
Economics distinguish several kinds of capital
1. Natural capital
2. Human capital
3. Manufactured capital

23. Define Sustainable Development
The term 'sustainable development' was introduced in a 1987 report by the World Commission on Environment and Development called 'Our Common Future'. According to the report, the term 'sustainable development' can be summarised as 'meeting the needs of the present without compromising the ability of future generations to meet their own needs.'
24. Explain the concept of sustainable development
The concept of sustainable development has the following underlying promises:
1. A symbiotic relationship between the consumer human race and the producer natural system.
2. Compatibility between ecology and economics.

Fig: Concept of sustainable development
The following general constitutional preconditions must be satisfied while working towards the goal of sustainable development:
1) Economic efficiency
2) Ecologic harmony
3) Equality and Social justice
4) Endogenous choices

25. Write notes on carrying-capacity-based developmental agenda for sustainable development.
A carrying-capacity-based developmental agenda for sustainable development ensues, which includes;
a. A preventive environmental policy
b. Structural economic change
c. The enhanced role of environmental management tools like,
Environmental Impact and Risk Assessment (EIRA), Environmental Audit (EA), Life Cycle Assessment (LCA) and Natural Resource Accounting (NRA).