UPSC 2011 Prelims Questions with Answers

Explanation

Biodiversity Hotspot are regions with high species richness and a high degree of endemism. In 1988, the British bi-ologist Norman Myers coined the term "biodiversity hotspot" as a biogeographic region characterized both by exceptional levels of plant endemism and by serious levels of habitat loss and provided certain qualifications for a hotspot. Options 1, 3 and 5 are correct: In 1989, Conservation Inter-national (CI) adopted Myers’ hotspots as its institutional model. Western Ghats-Sri Lanka and Indo-Burma Region meets the Myers’ criterion to qualify as Biodiversity Hotspot:

Species richness and endemism is one of the major criteria which must contain at least 1,500 species of vascular plants (> 0.5% of the world’s total) as endemics. ‘Degree of Threat’ is also a major criteria for the recognition of biological hotspots. It has to have lost at least 70% of its original habitat. (It must have 30% or less of its original natural vegetation). In other words, it must be threatened. Options 2, 4 and 6 are incorrect: Vegetation density, ethno-bo-tanical importance and adaptation of flora and fauna to warm and humid conditions are not part of the criteria for the recognition of Biodiversity Hotspots.

Explanation

The diversity of plants and animals varies widely over the world. The tropics are home to more species than temperate or polar regions.

Statement 1 is correct: Species diversity decreases as we move away from the equator towards the pole. This is due to several reasons:

Lower latitudes experience warmer temperatures and more stable climates, which support a greater variety of life forms. The equatorial regions receive more consistent and intense sunlight throughout the year, leading to higher primary productivity (photosynthesis) and thus more diverse ecosystems. Tropical regions, such as rainforests, have complex habitats with multiple layers (canopy, understory, forest floor) which support a wide range of species. Tropical regions have remained relatively stable over geological time, allowing species to diversify over millions of years.

Statement 2 is correct: Elevational diversity gradient (EDG) is an ecological pattern where biodiversity changes with elevation. The EDG states that species richness tends to increase as elevation increases, up to a certain point, creating a "diversity bulge" at middle elevations, after which it decreases with altitude. Therefore, it is true that along the mountain gradients, biodiversity is normally greater in the lower altitudes as compared to the higher altitudes.

Explanation

Biodiversity provides a number of natural services for human beings which are listed in the table below:

Ecosystem Services Protection of water resources Soil formation and protection Nutrient storage and recycling Pollution breakdown and absorption Contribution to climate stability Maintenance of ecosystems Recovery from unpredictable events Biological Services Food Medicinal resources and pharmaceutical drugs Wood products Ornamental plants Pollination of crops Breeding stocks Diversity in genes, species and ecosystems Social Services Research, education and monitoring Recreation and tourism Cultural values

Explanation

Statement 1 is correct: The primary reason the westerlies in the Southern Hemisphere are stronger and more persistent than in the Northern Hemisphere is because the Southern Hemisphere has significantly less landmass (about 20% land and 80% water), whereas the Northern Hemisphere has 40% land and 60% water. The vast oceans in the Southern Hemisphere allow westerly winds to move with minimal obstruction, making them stronger and more persistent. In contrast, larger landmasses in the Northern Hemisphere create friction and disrupt wind flow.

Statement 2 is incorrect: The Coriolis force acts equally in both hemispheres at the same latitude as it depends on the Earth’s rotation and the latitude. It does not make the westerlies stronger in one hemisphere over the other. The main reason for the difference is the land-sea distribution. The Coriolis force is stronger near the poles and weaker at the equator, but it does not explain the difference in strength of the westerlies between the two hemispheres.

Explanation

Being a confluence of different biogeographical zones Himalayan Range is very rich in species diversity. The Himalayas act as a natural transition zone between several major bio-geographical regions, leading to high species diversity and endemism. There are ten biogeographic zones in India:

1. Trans-Himalayan zone. 2. Himalayan zone

3. Desert zone. 4. Semi Arid zone.

5. Western ghat zone. 6. Deccan plateau zone.

7. Gangetic plain zone. 8. North east zone.

9. Coastal zone 10. Islands

Explanation

Statement 1 is correct: The African and Eurasian desert belt (Sahara, Arabian, Thar, Gobi) lies in the sub-tropical high-pres-sure zone (20°-30° latitudes). In this region, descending dry air from the Hadley Cell suppresses cloud formation and rainfall, creating arid conditions. This becomes the main reason for the formation of these deserts.

Statement 2 is incorrect: Warm ocean currents increase evaporation followed by humidity, leading to higher rainfall in coastal areas rather than desert formation. Deserts are mainly found near cold ocean currents (e.g., the Atacama Desert near the Peru Current, the Namib Desert near the Benguela Current), which cool the air and reduce its moisture-holding capacity, causing dry conditions. Moreover, many deserts in this belt are landlocked, far from direct oceanic influence.

Explanation

Statement 1 is correct: The lower stratosphere is mostly free from clouds and water vapor, as most weather phenomena occur in the troposphere below. This impacts the clear air conditions, making it ideal for jet aircraft to fly smoothly.

Statement 2 is correct: The stratosphere is a stable layer with no vertical air movements like convection currents. In contrast, the troposphere experiences turbulence due to rising and falling air masses. The absence of vertical winds in the lower stratosphere ensures a steady flight for jet aircraft.

Explanation

Mangroves function as a safety hedge due to their extensive root systems. These roots act as a natural barrier, protecting coastlines from erosion and the impact of strong waves during storms, cyclones, and tsunamis. The dense network of roots helps to dissipate the energy of waves, reducing their im-pact on the shoreline.

Explanation

Any substance that can inhibit the formation of unstable molecules known as free radicals, which harm DNA, cell membranes, and other components of cells, is referred to as an "antioxidant." Free radicals grab electrons from other molecules in order to complete their electron complement, which causes those molecules to suffer damage. Regular consumption of fresh fruits and vegetables is recommended because they are rich sources of antioxidants. Antioxidants play a crucial role in maintaining health and promoting longevity by neutralizing free radicals produced during metabolism. Free radicals are unstable molecules that can damage cells, proteins, and DNA, contributing to ageing and various diseases. By donating electrons, antioxidants stabilize free radicals, thereby preventing cellular damage and supporting overall health.

Explanation

Statement 1 is correct: The Kheda Satyagraha (1918) was a protest against the British government’s tax demands on Gujarat farmers whose crops had failed due to drought. Despite the revenue code allowing remission, the government insisted on full payment, threatening to seize property. Led by Sardar Vallabhbhai Patel and others, Gandhi encouraged farmers to resist paying taxes peacefully. The government eventually agreed to return confiscated property and suspend tax collection for the year.

Statement 2 is incorrect: Permanent Settlement was introduced by Lord Cornwallis in 1793 and it was confined in the areas of Bengal, Bihar, Orissa, Varanasi (United Provinces), Northern Karnataka. It was never introduced in Gujarat.