Summary ECOLOGY, ENVIRONMENT AND DISASTER MANAGEMENT

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ECOLOGY, ENVIRONMENT AND
DISASTER MANAGEMENT

1. BIOSPHERE AND WORKING OF ECOSYSTEMS 1-16
2. BIODIVERSITY 17-32
3. PLANT COMMUNITIES AND MAJOR VEGETATION 33-55
4. WETLANDS 56-66
5. ENVIRONMENTAL CHANGE: CLIMATE CHANGE AND POLLUTION 67-97
6. NATIONAL AND INTERNATIONAL CONVENTIONS 98-115
7. POST 2015 DEVELOPMENT FRAMEWORK-SUSTAINABLE
DEVELOPMENT GOALS 116-126
8. NATURAL HAZARDS, DISASTERS AND THEIR MANAGEMENT 117-145
9. GM CROPS 146-151
10. SUSTAINABLE HABITAT GREEN BUILDING NORMS IN INDIA 152-155




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BIOSPHERE AND WORKING OF ECOSYSTEMS
Table of Contents

1. BIOSPHERE AND WORKING OF ECOSYSTEMS .................................................................................................... 2
1.1. Biosphere................................................................................................................................................... 2
1.2. Ecology ...................................................................................................................................................... 2
1.3. Ecosystem .................................................................................................................................................. 2
1.3.1. Components of Ecosystem .................................................................................................................. 2
1.3.2. Types of Ecosystem ............................................................................................................................. 3
1.3.3. Energy Flow in Ecosystem.................................................................................................................... 3
1.3.4. Productivity ......................................................................................................................................... 6
1.3.5. Ecological Niche................................................................................................................................... 6
1.3.6. Habitat ................................................................................................................................................ 6
1.3.7. Species structure ................................................................................................................................. 7
1.3.8. Decomposition .................................................................................................................................... 7
1.3.9. Biomagnification ................................................................................................................................. 7
1.4. Nutrient Cycles........................................................................................................................................... 8
1.5. Succession................................................................................................................................................ 11
1.5.1. Sere................................................................................................................................................... 11
1.5.2. Climax ............................................................................................................................................... 11
1.6. Biotic Potential......................................................................................................................................... 12
1.7. Carrying Capacity ..................................................................................................................................... 12
1.8. Ecosystem Services .................................................................................................................................. 12
1.9. Ecotone.................................................................................................................................................... 13
1.9.1. Edge Effect ........................................................................................................................................ 13
1.9.2. Home Range...................................................................................................................................... 13
1.9.3. Other Important terms: ..................................................................................................................... 13
1.10. UPSC QUESTIONS RELATED TO ABOVE TOPICS ....................................................................................... 14
1.11. PRELIMS QUESTIONS .............................................................................................................................. 14




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,1. BIOSPHERE AND WORKING OF ECOSYSTEMS
1.1. BIOSPHERE
Biosphere is that part of lithosphere, hydrosphere and atmosphere
where plants and human beings live. Biosphere contains all life
forms on earth.

The biosphere consists of all the living organisms (the biotic
component), energy and physical environment (the abiotic
component) and there are continuous interactions between living
organisms and physical environment and among the living
organisms themselves.

 The biosphere consists of two major systems viz. (i) terrestrial
biomes systems and (ii) aquatic biomes systems. Figure 1: BIOSPHERE
 The terrestrial biomes systems are further comprised of three
subsystems viz., (i) plant system, (ii) animal system and (iii) soil system. These subsystems are intimately
interrelated among themselves through the cyclic pathways of movements and transfer of energy and
materials.
 The aquatic biomes systems are also composed of three sub-systems viz. : (i) Plant system, (ii) Animal
system, and (iii) Nutrients. These three sub-systems of aquatic biomes system of the biosphere are also
intimately interrelated through cyclic pathways of movements of energy and matter among themselves.
 Man depends on biosphere to fulfill many of his needs like food, drugs, clothes, housing, paper and tourism
and environment.
1.2. ECOLOGY
Ecology can be defined as a scientific study of the interactions of organisms with their physical environment and
with each other.

The term ecology is derived from the Greek word ‘oikos’ meaning ‘house’, combined with the word ‘logy’
meaning the ‘science of’ or ‘the study of ’. Literally, ecology is the study of the earth as a ‘household’, of plants,
human beings, animals and micro-organisms. They all live together as interdependent components.

A German zoologist Ernst Haeckel, who used the term as ‘oekologie’ in 1869, became the first person to use the
term ‘ecology’. The study of interactions between life forms
(biotic) and the physical environment (abiotic) is the science of
ecology.

1.3. ECOSYSTEM
An ecosystem is a functional unit of nature, where living
organisms interact among themselves and also with the
surrounding physical environment.

1.3.1. COMPONENTS OF ECOSYSTEM
There are four basic components of an ecosystem.

1. The abiotic part, which is the non-living environment.
2. The producers or autotrophs, the green plants capable of
producing their own food by using the energy of sunlight to
make carbohydrates from water and carbon dioxide; this Figure 2: Ecosystem and its components
process is called photosynthesis.
3. There are the consumers or heterotrophs. These are animals which obtain their food by eating plants or
other animals. The heterotrophs in any ecosystem can be divided into groups by their feeding habits:
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, o herbivores eat only living plant material;
o Detritivores feed on dead plant and animal material;
o Carnivores eat other animals;
o Omnivores eat both plant and animal material.
4. Decomposers, such as the bacteria and fungi that promote decay.




Figure 3: Structure and Functions of Ecosystem

1.3.2. TYPES OF ECOSYSTEM
Ecosystem varies greatly in size from a small pond to a large forest or a sea. Many ecologists regard the entire
biosphere as a global ecosystem, as a composite of all local ecosystems on Earth. Since this system is too much
big and complex to be studied at one time, it is convenient to divide it into two basic categories, namely the
terrestrial and the aquatic.

 Terrestrial Ecosystem
o The ecosystem which is found only on landforms is known as the terrestrial ecosystem.
o The main factor which differentiates the terrestrial ecosystems from the aquatic ecosystems is the
relative shortage of water in the terrestrial ecosystems and as a result the importance that water attains
in these ecosystems due to its limited availability.
o Another factor is the better availability of light in these ecosystems as the environment is a lot cleaner in
land than it is in water.
o The main types of terrestrial ecosystems are the forest ecosystems, the desert ecosystems, the grassland
ecosystems and the mountain ecosystems.
 Aquatic Ecosystem
o An ecosystem which exists in a body of water is known as an aquatic ecosystem.
o The aquatic ecosystems are mainly of two types, the freshwater ecosystems and the marine ecosystems.

1.3.3. ENERGY FLOW IN ECOSYSTEM
Sun is the primary source of energy for all ecosystems on Earth. Of the incident solar radiation less than 50 per
cent of it is photosynthetically active radiation (PAR). Photosynthetically active radiation, often
abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that
photosynthetic organisms are able to use in the process of photosynthesis.




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