UPSC Static Quiz – Environment : 20 January 2025

Solution: a)

Seaweeds are diverse marine plants and macroalgae found in oceans, lakes, and sometimes rivers. Statement 1 is correct because “seaweed” is a general term for numerous species of marine plants and algae that thrive in various aquatic environments.

Statement 2 is incorrect as seaweeds can grow in various aquatic ecosystems, including flowing waters such as rivers and streams, though they predominantly thrive in saltwater environments like oceans and seas.

Statement 3 is also incorrect because seaweed cultivation is an integral part of aquaculture in India. India has been actively promoting seaweed farming as a sustainable livelihood option for coastal communities. The cultivation of seaweed contributes to the fishing and aquaculture sector, which plays a significant role in India’s economy, contributing about 1.5% to GDP.

Solution: a)

Statement 1 is correct: A heatwave can accelerate the melting of the Antarctic Ice Sheet, leading to a reduction in ice volume. This, in turn, contributes to rising global sea levels, posing a significant threat to coastal regions worldwide.

Statement 2 is correct: The heatwave may disrupt the global ocean circulation system, such as the thermohaline circulation. This system is crucial for distributing heat and regulating climate patterns globally. Disruptions could cause extreme weather events and affect marine ecosystems.

Statement 3 is incorrect: Rather than strengthening the polar vortex, a deep-winter heatwave weakens it. The polar vortex is a large-scale circulation of winds that helps trap cold air near the poles. A weakened polar vortex can result in warmer polar temperatures and altered weather patterns in the mid-latitudes.

Solution: d)

Prokaryotes are simple, single-celled organisms, such as bacteria and archaea, that lack a defined nucleus. They are indispensable to marine ecosystems due to their critical roles in nutrient cycling, primary production, and carbon cycling.

• Option a is incorrect: Prokaryotes are essential for marine ecosystems. Their decline would severely disrupt food chains and biogeochemical cycles.
• Option b is incorrect: While many marine organisms may experience significant biomass loss due to warming oceans, prokaryotes are generally more resilient and may decline less, potentially altering ecosystem dynamics.
• Option c is incorrect: Prokaryotes do not possess complex cell structures or a defined nucleus; these are features of eukaryotic cells.

Option d is correct: Prokaryotes support food chains by breaking down organic matter and cycling nutrients. They also play a vital role in balancing carbon emissions by sequestering carbon dioxide through processes like photosynthesis and decomposition.

Solution: b)

Statement 1 is incorrect: While bio-plastics are derived from renewable resources, not all are biodegradable or compostable. Some bio-plastics, such as certain types of polylactic acid (PLA), can persist in the environment under normal conditions, behaving similarly to conventional plastics.

Statement 2 is correct: Bio-plastics are derived from renewable biomass sources such as corn starch, sugarcane, and other agricultural by-products. These materials are used as alternatives to petroleum-based raw materials.

Statement 3 is correct: By using renewable feedstocks, bio-plastics help reduce dependence on fossil fuels, which are traditionally used in the production of conventional plastics. This shift supports sustainability efforts and decreases greenhouse gas emissions associated with plastic production.

Solution: b)

• Big cats are considered umbrella species because their conservation protects entire ecosystems, including other species that share their habitats (statement 1).
• The loss of apex predators like big cats can lead to an overpopulation of prey species, which causes overgrazing and habitat degradation (statement 3).
• India is home to 75% of the world’s tigers, not 50%, making statement 2 incorrect.
• Statement 4 is also incorrect, as big cats significantly influence the trophic levels within their ecosystems.