UPSC Static Quiz – Environment : 25 June 2024

Solution: b)

Statement 2 is incorrect.

The mechanisms used by most mammals to regulate their body temperature are similar to the ones that we humans use. We maintain a constant body temperature of 37 degree C. In summer, when outside

temperature is more than our body temperature, we sweat profusely.

The resulting evaporative cooling, similar to what happens with a desert cooler in operation, brings down the body temperature. In winter when the temperature is much lower than 37 degree C, we start to

shiver, a kind of exercise which produces heat and raises the body temperature. Plants, on the other hand, do not have such mechanisms to maintain internal temperatures.

Thermoregulation is energetically expensive for many organisms. This is particularly true for small animals like shrews and humming birds. Heat loss or heat gain is a function of surface area. Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; then they have to expend much energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions.

Solution: b)

Statement 1 is incorrect.

Phosphorous cycle is mainly terrestrial. The main storage for phosphorus is in the earth’s crust. On land phosphorus is usually found in the form of phosphates.

It occurs in large amounts as a mineral in phosphate rocks and enters the cycle from erosion and mining activities.

By the process of weathering and erosion phosphates enter rivers and streams that transport them to the ocean.

Being an important nutrient, phosphorous promotes eutrophication in lakes. Along with nitrogen related compounds it leads to undesirable situations like algal bloom.

Solution: c)

• Exotic species introduced to new environments often reset the ecological conditions in that new habitat, threatening the species that exist there; this is the reason that they are also termed invasive species.
• Invasive species that are closely related to rare native species have the potential to hybridize with the native species; harmful effects of hybridization have led to a decline and even extinction of native species.
• Invasive species can change the food web in an ecosystem by destroying or replacing native food sources. The invasive species may provide little to no food value for wildlife.
• Lakes and islands are particularly vulnerable to extinction threats from introduced species.

Solution: c)

The Chipko movement (1973) in Uttarakhand and the Silent Valley movement (the late 1970s) in Kerala are two of the most well-known modern-day people’s movements for environmental protection in India that inspired several other environmental movements during the last five decades.

The Chipko movement gave rise to many similar resistance groups in India, including Appiko in Karnataka.

The Jungle Bachao Andolan took shape in the early 1980s when the government proposed to replace the natural sal forest of Singhbhum District, Bihar, with commercial teak plantations.

Solution: c)

The Ramsar Convention on Wetlands defines wetlands as “areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters”.