Q. 1. A pesticide which is a chlorinated hydrocarbon is sprayed on a food crop. The food
chain is: Food crop – Rat – Snake – Hawk. In this food chain, the highest concentration of
the pesticide would accumulate in which one of the following?
(a) Food crop
(b)Rat
(c)Snake
(d) Hawk
Ans. (d)
Explanation:
Biomagnification refers to the tendency of pollutants to concentrate as they
move from one trophic level to another.
The toxic compound passes up a food chain, usually as a result of food intake.
In this case, the concentration of the compound will increase with increasing the tropic level.
Biomagnifying pollutants which increase in concentration from producers
Primary consumers > Secondary consumers > Tertiary consumers
Top consumer.
Hawk is the top consumer so the pesticide concentration will be highest in Hawk.
Q. 2. From the point of view of evolution of living organisms, which one of the following is the
correct sequence of evolution?
(a) Otter – Tortoise – Shark
(b) Shark – Tortoise – Otter
(c) Tortoise – Shark – Otter
(d) Shark – Otter – Tortoise
Ans. (b)
Explanation:
Shark – Scientists believe that sharks came into existence around
400 million years ago. It is believed that they descended from a small leaf shaped fish that
had no eyes, bones on fins.
These fish then evolved into two main groups of fish that are found
Today.
Bony fish and cartilagindus fish which include shark and Chimaira
Sharks are on the top of the marine food chain and are the only huge
marine reptiles that exist today.
Tortoise is believed to have existed for 250 million years.
They belong to the reptile species of the family Testudinidae.
Tortoise has a hard shell to protect from the outside environment. They
are believed to have evolved from very large body sizes of around 100
kgs. They are among the longest-living land animals in the world.
Otters are believed to have existed on earth for the past 23 million years.
They have evolved significantly and have gone through many adaptations to survive till this
time.
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Q. 3. Consider the following statements:
1. On the planet Earth, the fresh water available for use amounts to about less than 1% of
the total water found.
2. Of the total fresh water found on the planet Earth 95% is bound up in polar ice caps and
glaciers.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Ans. (a)
Explanation:
As we know, humans can use only fresh water for consumption. Approx. 99.
99.2% of the total water goes into saline water and ice and glaciers, so the
Fresh water available for use amounts to about less than 1% of the total water
found. Hence, statement 1 is correct
The ice caps and glaciers account for approx. 68-69% of the total
Fresh water. Hence, statement 2 is incorrect.
Q. 4. Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in
the environment. Why is mercury used in the manufacture of these lamps?
(a) A mercury coating on the inside of the lamp makes the light bright white
(b) When the lamp is switched on, the mercury in the lamp causes the emission of
ultra-violet radiations
(c) When the lamp is switched on, it is the mercury which converts the ultra- violet energy
into visible light
(d) None of the statement given above is correct about the use of mercury in the
manufacture of fluorescent lamps
Ans. (b)
Explanation:
Recently researchers have found that despite a decrease in seawater
concentration of methylmercury, the amount of mercury found in fish is
different among different species.
Joint research conducted by the Indian Institute of Technology,
Hyderabad (IIT-H), Harvard University, and Fisheries and Oceans Canada (a Canadian
government agency) has found that though there
has been a decrease in the levels of mercury emission, the concentration of mercury in fish
varies across different species.
Some species of fish have less mercury than before, while others have a
very high concentration of mercury (tuna, salmon, and swordfish).
The researchers warn that human exposure to the toxin (methylmercury) through fish
consumption is bound to increase as a result of climate change.
Q. 5. Due to their extensive rice cultivation, some regions may be contributing to global
warming. To what possible reason/reasons is this attributable?
1. The anaerobic conditions associated with rice cultivation cause the emission of methane.
2. When nitrogen based fertilizers are used, nitrous oxide is emitted from the cultivated soil.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Ans. (c)
Explanation:
Methane and Nitrous Oxide are the two green house gases emitted from rice field.
Due to flood conditions, the oxygene supply is obstructed from the atmosphere that results
anaerobic reactions which results in the emmition od Methane and Nitrogene.
Q. 6. King Cobra is the only snake that makes its own nest. Why does it make its nest?
(a) It is a snake-eater and the nest helps attract other snakes
(b) It is a viviparous snake and needs a nest to give birth of offspring
(c) It is an oviparous snake and lays its eggs in the nest and guards the nest until they are
hatched
(d) It is a large, cold blooded animal and needs a nest to hibernate in the cold season
Ans. (c)
Explanation:
King Cobra snakelets are called hatchlings because they hatch from eggs, Cobra
hatchlings’initial size depends on their species, but the average hatchling is about 16 to 18
inches long.
The young cobra has enough venom, fully developed fangs, and poison delivery system
sufficient enough to kill an adult person or cause serious health risks.
The cobra venom is neurotoxic. The striking distance between the snake and the human
body can be a
few centimeters, with its agility, the young snake could strike at any angle with lightning
speed.
Cobra is one of the four venomous snakes that account for most of the snakebite deaths in
the country.
Russell’s viper, Saw-scaled viper, and Common krait are the other members of the lethal
league.
Snakes hatched towards the end of the summer months and the chance of encountering
them was higher during the monsoon period.
Also Read:Solved UPSC Prelims 2018 Questions : Environment and Ecology Subject
Q. 7. Biodiversity Consider the following statements:
1. The Taxus tree naturally found in the Himalayas.
2. The Taxus tree is listed in the Red Data Book.
3. A drug called “taxol” is obtained from Taxus tree is effective against Parkinson’s disease.
Which of the statements given above is/are correct?
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3
Ans. (b)
Explanation:
A rare tree whose extracts are used for an anti-cancer drug is being felled illegally the
Himalayan yew (Taxus wallichiana), a rare tree found in the Himalayan foothills, is fast
disappearing because of largescale illegal felling for an anti-cancer drug made from its
leaves and bark. The tree parts are allegedly smuggled to laboratories in the us, Germany
and other Western countries involved in research on taxol, a resinous substance extracted
from Taxus.
For decades, Indian drug manufacturers have been using Taxus parts in various Ayurvedic
preparations. “In Gulmarg as Taxus baccata (old nomenclature) is on the verge of extinction,
the state authorities should think of its local cultivation,” says S D Swatantra, chief
conservator of forests, Jammu & Kashmir (j&k) .
Q. 8. Biodiversity Other than Jatropha curcas, why is Pongamia pinnata also considered a
good option for the production of bio-diesel in India?
1. Pongamia pinnata grows naturally in most of the arid regions of India.
2. The seeds of Pongamia pinnata are rich in lipid content
Which of the statements given above is/are correct?
(a)1 only
(b)2 only
(c)Both 1 and 2
(d) Neither 1 nor 2
Ans. (c)
Explanation:
Both the statements are self explanatory.
Algae-based biofuels are technically and economically viable and cost competitive, require
no additional lands, require minimal water use, and mitigate atmospheric CO2. However,
commercial production of microalgae biodiesel is still not feasible due to the low biomass
concentration and costly downstream processes. The viability of microalgae biodiesel
production can be achieved by designing advanced photobioreactors, developing low cost
technologies for biomass harvesting, drying, and oil extraction.
Q. 9. India is a party to the Ramsar Convention and has declared many areas as Ramsar
Sites.
Which of the following statements best describes as to how we should maintain these sites
in the context of this Convention?
(a) Keep all the sites completely inaccessible to man so that they will not be exploited
(b) Conserve all the sites through ecosystem approach and permit tourism and recreation
only
(c) Conserve all the sites through ecosystem approach for a period without any exploitation,
with specific criteria and specific period for each site, and then allow sustainable use of then
by future generations.
(d)Conserve all the sites through ecosystem approach and allow their simultaneous
sustainable use
Ans. (d)
Explanation:
The Ramsar Convention (The Convention on Wetlands of International Importance,
especially as Waterfowl habitat), named after the town of Ramsar in lran, is an international
treaty for the conservation and sustainable utilisation of wetlands, i.e. to stem the
progressive encroachment on and loss of wetlands now and in the future, recognising the
fundamental ecological functions of wetlands and their economic, cultural, scientific, and
recreational value.
Q. 10. The United Nations Framework Convention on Climate Change (UNFCCC) is an
international treaty drawn at
(a) United Nations Conference on the Human Environment, Stockholm, 1972
(b) UN Conference on Environment and Development, Rio de Janeiro, 1992
(c)World Summit on Sustainable Development, Johannesburg, 2002 (d) UN Climate Change
Conference, Copenhagen, 2009
Ans. (b)
Explanation:
The United Nations Conference on Environment and Development (UNCED), also known as
the ‘Earth Summit’, was held in Rio de Janeiro, Brazil, from 3-14 June 1992. This global
conference, held on the occasion of the 20th anniversary of the first Human Environment
Conference in Stockholm, Sweden, in 1972, brought together political leaders, diplomats,
scientists, representatives of the media and non-governmental organizations (NGOs) from
179 countries.
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