Dibrugarh University| B.A | Environmental Studies| Solved Paper - (July) - 2021| 2nd Semester
2021
(July)
ENVIRONMENTAL STUDIES
(Common Paper)
Marks: 75
Time: 3 hours
The figures in the margin indicate full marks for the questions
PART-A
(Short
answer-type)
Answer all questions: 1.5×10=15
1. Define environment.
Ans:- The environment can be defined as the sum of
all living (biotic) and non-living (abiotic) elements and their effects that
affect human life. Living elements include animals, plants, and forests, while
non-living elements include water, land, sunlight, rocks, and air.
2. Mention three main causes of deforestation in
North-East India.
Ans:- The three main causes of deforestation in northeast
India are:-
(i) Shifting
cultivation (Jhum farming)
(ii) Expansion
of agricultural land
(iii) Wood
harvesting and clearance
3. What are biodiversity hot spots? Give one example.
Ans:- Biodiversity hotspots are areas with high
levels of species diversity, many endemic species (species that are found
nowhere else), and a significant number of threatened or endangered species.
Example: California Floristic Province in the United States.
4. What are endemic species? Give one example.
Ans:- Endemic species are plants, animals, fungi, or
other organisms that are native to a specific geographic region and found only
within it. Example: The ring-tailed lemur (Lemur catta) is endemic to
Madagascar.
5. What are ozone holes?
Ans:- Ozone holes are regions of the stratosphere,
particularly over Antarctica, where the concentration of ozone has fallen below
220 Dobson units due to human activities, particularly the release of
chlorofluorocarbons (CFCs) and other ozone-depleting substances.
6. Mention three main sources of soil pollution.
Ans:- The three main sources of soil pollution are:-
(i) Use of
chemical fertilizers and pesticides
(ii) Industrial
waste disposal
(iii) Dumping of
domestic and municipal waste
7. What is disaster management?
Ans:- Disaster management is the systematic and
coordinated effort to address the negative consequences of disasters. It
includes preparedness, response, and recovery phases aimed at minimizing harm
to people, property, and the environment.
8. What is population explosion?
Ans:- Population explosion refers to a rapid and
dramatic increase in population size, often caused by high birth rates and
declining death rates, resulting in an increase in the number of individuals in
a specific area.
9. What is environmental ethics?
Ans:- Environmental ethics is the branch of
philosophy that studies the ethical relationship of humans with the environment
and its non-human contents.
10. Expand the following acronyms:
(a) CFC
Ans:- Chlorofluorocarbon
(b) CPCB
Ans:- Central
Pollution Control Board
(c) NWDB
Ans:- National
Wastelands Development Board
PART-B
(Long answer-type)
Answer any five questions: 4x5=20
11. Describe natural resources. 4
Ans:- Natural resources are substances and components
found in nature that are used by humans with little alteration. They include
sunlight, air, water, land, minerals, vegetation and wildlife. These resources
are the basis of commercial, industrial, aesthetic, scientific and cultural
value. Natural resources may be renewable, such as forests and water, or
non-renewable, such as minerals and fossil fuels. They are essential for human
survival and development, and their management is important for sustainability.
12. Mention two causes and two effects of soil erosion.
2+2=4
Ans:- Two causes and two effects of soil erosion are:-
Causes:-
(i) Heavy
rainfall and flooding: Intense rain storms break up soil and carry it away
into rivers and streams.
(ii)
Deforestation and agricultural activities: Clearing trees and ploughing
land for cultivation exposes soil, making it more vulnerable to erosion.
Effects:
(i) Loss of
arable land: Fertile topsoil is removed, reducing soil fertility and crop
productivity.
(ii) Blocking
of waterways: Soil erosion occurs in rivers and lakes, causing pollution
and increasing the risk of flooding.
13. Distinguish between in situ and ex situ method of
biodiversity conservation. 4
Ans:- Distinguish between in situ and ex situ methods of
biodiversity conservation:-
In situ
conservation:-
(i) In situ
conservation refers to the protection and conservation of species within their
natural habitats.
(ii) This
method maintains the natural ecosystem and allows species to interact, evolve
and adapt in their native environment.
(iii) Examples
include national parks, wildlife sanctuaries, biosphere reserves and sacred
groves.
(iv) It helps
to conserve not only the targeted species but also the entire ecosystem,
supporting ecological balance and natural evolutionary processes.
(v) In situ
conservation is generally more cost-effective and relies on the cooperation of
local communities.
Ex situ
conservation:-
(i) Ex situ
conservation involves the conservation and maintenance of species outside their
natural habitats in controlled or artificial environments.
(ii) This
method is used when species are at high risk of extinction in the wild or
require special care that cannot be provided in their natural habitat.
(iii) Examples
include zoos, botanical gardens, aquariums, seed banks and gene banks.
(iv) Ex situ
conservation allows captive breeding, storage of genetic material, and
research, but cannot replicate the complexities of natural habitats.
(v) It is
generally more expensive and requires significant technical and financial
resources.
14. Write briefly on 'pyramid of biomass'. 4
Ans:- The pyramid of biomass is a graphical
representation that shows the total mass of living organisms at each trophic
level in an ecosystem. The base of the pyramid consists of producers (plants),
followed by herbivores (primary consumers) and then carnivores (secondary and
tertiary consumers) at the top. Biomass is usually measured as dry weight per
unit area. The pyramid of biomass shows the flow of energy and the decrease of
biomass at higher trophic levels – only about 10% of the energy is transferred
from one level to another. In terrestrial ecosystems, the pyramid is usually
upright, but in some aquatic ecosystems, it may be inverted due to the rapid
change of producers such as phytoplankton.
15. Distinguish between primary and secondary pollutants.
What are the impacts of air pollution? 2+2=4
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