Day-547 | Daily MCQs | UPSC Prelims | ENVIRONMENT

Answer: A
Explanation:
Statement 1 is incorrect: Sea butterfly is a type of planktonic marine snail belonging to the family Thecosomata, and its scientific name is Limacina helicina. They fall under pelagic sea snails.
● They are basically transparent. However, they have an orange red coloured head, a tail, and a gut to easily notice them in the ocean.
● Instead of regular wings, they have a set of developed parapodia or lobes. These act as their wings. Using the developed parapodia or lobes, they swim through the ocean water and heavy currents under the sea.

Statement 2 is incorrect: Sea butterfly is a herbivore whose diet comprises of algae, zooplankton, and chalinid sponges. Sea butterflies have a special gland to capture the food or the tiny plankton. The gland has a mucous web like a net that helps them to take the plankton as food.
● The mucous membrane they use to capture the plankton is 5 cm, which is bigger than the body itself.
● The predators posing threats to sea butterfly include other bigger fish, birds, jellyfish, sea turtles, and whales.
Statement 3 is correct: Ocean acidification is more dangerous for shelled, smaller sea butterflies which can impact entire ocean food web. As the sea absorbs an increasing quantity of carbon dioxide (CO2) that turns the water more acidic, the thin outer casing, or the ‘homes’ of these small sea butterflies, dissolve. This leaves them exposed, making it difficult for these delicate species to survive.
● The ocean is the most acidic in winter because cooler water absorbs more CO2. This means, the winter months are the most dangerous for the shelled sea butterflies.
● Their reduced population also impacts larger pteropods and other oceanic creatures that feed on them. The entire underwater food chain of the seas surrounding Antarctica may suffer as a ripple effect.
Additional Information:
● Distribution: Sea butterflies are abundant worldwide in all open seas and oceans. They are widely available from the western coast of America to the North Atlantic Ocean.
● Behaviour Pattern: Social creatures and they often form groups called swarms.
● Conservation Status: Least Concern (LC).
● Reproduction: Sea butterflies are hermaphrodites. That means sea butterflies, irrespective of male and female; they possess both reproductive organs. During the early stage, sea butterflies remain as males and develop a male reproductive organ. Even when they mate, the sperms are contained until the male reproductive organ vanishes and turn out like females to lay eggs.

Answer: A
Explanation:
Recently, a study was published in the journal Nature which elaborately discussed the role of oceans in release of short-lived halogens.
Statements 1 and 2 are incorrect- Short-lived halogens from oceans reduces warming by depleting ozone. Its cooling effect was found to be -0.24 ± 0.02 Watts per square metre (W m−2).
Short-lived halogens have a lifetime of less than six months in the atmosphere and are naturally produced by the oceans. Examples of such halogens include such as chlorine, bromine and iodine. Currently, these halogens contribute 8-10 percent of cooling (and not global warming). This cooling could increase to 18-31 per cent by 2100, the study published in Nature projected.
Human activities have amplified their release into the atmosphere. Human activities cause pollutants such as ozone to deposit on the ocean, which then convert the soluble short-lived halogens into insoluble ones, forcing them out of the sea water and into the atmosphere.
Statement 3 is correct- However, their effect on methane is opposite. Short-lived halogens increase methane’s lifetime in the atmosphere by destroying hydroxyl radicals (OH). OH is a sink as it is known to break down this greenhouse gas.
Additional information:
● These short-lived halogens increased global methane burden by 14 per cent and 9 per cent for pre-industrial and present-day conditions, respectively. This leads to a warming effect of 0.09 ± 0.01 W m−2 of warming.
● Similarly, these halogens increase the levels of water vapour, a greenhouse gas, in the atmosphere, causing a warming effect of 0.011 ± 0.001 W m−2.
● These short-lived halogens reduce the formation of cooling aerosols, which are minute particles suspended in the atmosphere that reflect sunlight. It causes a small warming of 0.03 ± 0.01 W m−2.
● Though these halogens drive an increase in warming by influencing methane, water vapour and aerosols, they compensate this by destroying ozone, which exerts a cooling effect. Overall, the net cooling effect was found to be −0.13 ± 0.03 W m−2.

Answer: D
Explanation:
Statement 1 is incorrect- In India, the National Lighting Code (NLC) published by the Bureau of Indian Standard (BIS) regulates the light pollution. No separate legislative measure on the lines of the Air (Prevention and Control of Pollution) Act, 1981 has been taken, as of now. The umbrella legislation for regulation of the environmental stresses such as pollution, degradation of environmental quality etc. is the Environment (Protection) Act, 1986.
● The National Lighting Code (NLC) has been formulated for the purpose of setting out in a convenient form the requirements for responsible social, commercial and engineering conduct for the designers, manufacturers and suppliers of lighting.
● The intent of this code is to encourage good lighting practices and systems which would minimize light pollution, glare, light trespass and conserve energy while maintaining safety, security, utility and productivity.
● This National Lighting Code is applicable to the lighting systems in large varieties of interior and exterior installations including special areas like hospitals, utilities, sports complex, metro railway etc. under the control of qualified persons.
● The code, however, does not specify the additional requirements to be considered while designing lightening system for certain areas such as marine, railway rolling stock, theatre, television and photography etc.
● The code also does not cover the requirements and methods of test applicable to light sources and luminaries for which separate Indian Standards exists.
Statement 2 is correct- Marine organisms that evolved over millions of years to adapt to natural light now face an ever-increasing flood of light from anthropogenic sources along the coasts. Artificial light can easily wash out the glow of moonlight and starlight, which are important cues for marine organisms. This disrupts their hormonal cycles, inter-species behaviour and reproduction, noted the findings of the study published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems.
Compared to prior technologies, LEDs often emit more short-wavelength light and can pierce deep into the water.
Additional information:
Impacts Of Light Pollution in a Nutshell:
● Light pollution interrupts wildlife patterns and harms biodiversity: Migratory birds rely on natural light to guide them, and interruptions can lead to collisions and incorrect navigations on their long-distance journeys.
● Risks to human health: Artificial light can wreak havoc on natural body rhythms in both humans and animals. Nocturnal light interrupts sleep and confuses the circadian rhythm—the internal, twenty-four-hour clock that guides day and night activities and affects physiological processes in nearly all living organisms. One of these processes is the production of the hormone melatonin, which is released when it is dark and is inhibited when there is light present. An increased amount of light at night lowers melatonin production, which results in sleep deprivation, fatigue, headaches, stress, anxiety, and other health problems.
● Impact on astronomy: Artificial light in the sky causes ‘sky glow’ which tends to reduce visibility of stars and interferes with the astronomical studies.

Answer: C
Explanation- Option C is the correct answer.
Slender Lorris:

● Habitat and Distribution: Commonly found in the tropical scrub and deciduous forests as well as the dense hedgerow plantations bordering farmlands of Southern India and Sri Lanka, the Slender Loris is a small, nocturnal primate. It prefers to inhabit thick, thorny bushes and bamboo clumps where it can evade predators and also find insects, which is the main diet.
● Physical traits: These animals are about 25 cm long and have long, thin arms. They weigh around 275 grams. They have a small, vestigial tail. Their most prominent feature is the pair of two large, closely set, brown eyes.
● Behaviour: Being arboreal, they spend most of their life on the trees. Though their movements are slow, they can climb up fast to the tree top when threatened. They either hunt on their own or in pairs. They are known to be very social at dusk and dawn, interacting with others of their own.
● Reproduction: Their mating season is twice a year, from April to May as well as October to November. Gestation is 166-169 days. The females give birth to normally one and rarely two infants at one time. The mother carries the infants constantly during the first few weeks after birth. They live between 12-15 years.
● Diet: (Omnivores): Apart from insects they are also known to eat leaves, flowers, slugs and sometimes eggs of birds.
● Uniqueness: Among the strange habits they have is the urine washing of their face and limbs, which is thought to soothe or defend against the sting of the toxic insects they prefer to eat.
● Threats: These animals face a threat from poachers due to the misplaced belief that these animals have magical and medicinal powers. This hunting, along with destruction of their habitat, is their major threat.
● Conservation status: IUCN has listed them as ‘Endangered’, whereas they are listed under the Schedule I of the Wildlife (Protection) Act of India, 1972, according them the highest level of legal protection.
About other species given in the options:
Himalayan Musk Deer
● Distribution:The Himalayas from central Kashmir through Himachal Pradesh up to Sikkim.
● Habitat: Subalpine oak and rhododendron forests ( 3000-4300 m) medium to high elevation coniferous forest in the Western Himalayas below the tree line ( 2500-4400 m) in Sikkim, thick bamboo forests below alpine zone ( 2600-300 m.
● Unique Behaviour: Communication is chiefly by olfaction. The deer scent is marked by defecation and secretion of caudal, musk and inter digital glands.
● Solitary, except when female is with young.
● IUCN status: Endangered (EN); Schedule 1 of Wildlife (Protection) Act, 1972.

Nilgiri Tahr
● The Nilgiri Tahr is the only mountain ungulate in southern India amongst the 12 species present in India.
● It is also the state animal of Tamil Nadu.
● The Nilgiri Tahr is a sure-footed ungulate that inhabits the open montane grassland habitats at elevations from 1200 to 2600 m of the South Western Ghats.
● The Nilgiri Tahr, which used to be found along the entire stretch of Western Ghats, is presently found only in small fragmented pockets.
● The Eravikulam National Park in Anamalai hills, Kerala, is home to the largest population of the Nilgiri tahr, with more than 700 individuals.
● It faces several threats such as habitat loss due to rampant deforestation, competition with domestic livestock, hydroelectric projects in Nilgiri tahr habitat, and monoculture plantations and occasional hunting for its meat and skin.
● This endemic species of the Western Ghats is listed as ‘Endangered’ in the IUCN Red List of Threatened Species and is protected under Schedule I of the Wildlife (Protection) Act of India, 1972.

Himalayan serow
● Official state animal of the Indian state of Mizoram.
● Native to the Himalayas where they inhabit hilly forests above an elevation of 300 m (980 ft) but descend to 100 m (330 ft) in winter.
● Himalayan serows are territorial animals that live alone or in small groups.
● They are active during the day (not nocturnal), and have acute vision, smell, and hearing, and are wary of humans.
● They move with ease through the difficult terrain of mountain and hill slopes and also swim well.
● Lifestyle: viviparous and terrestrial
● Himalayan serows are herbivores (folivores) and browse various types of vegetation.
● After the gestation period of 6 to 7 months, females give birth to a single kid; it is fully developed at birth and is able to travel with its mother shortly after birth.
● IUCN status: Vulnerable (VU)

Answer: D
Explanation: Pulsing along on our ocean currents, jellyfish can be found in waters both cold and warm, deep and shallow and along coastlines, too. Jellyfish have been around for millions of years, even before dinosaurs lived on the Earth.
Statement 1 is correct: Even without a central brain, jellyfish can learn from past experiences like humans, mice, and flies. The researchers trained Caribbean box jellyfish (Tripedalia cystophora) to learn to spot and dodge obstacles.
The study published in ‘Current Biology’ has challenged previous notions that advanced learning requires a centralised brain and sheds light on the evolutionary roots of learning and memory. No bigger than a fingernail, these seemingly simple jellies have a complex visual system with 24 eyes embedded in their bell-like body. Scientists demonstrated that the jellies could acquire the ability to avoid obstacles through associative learning, a process through which organisms form mental connections between sensory stimulations and behaviours.
Statement 2 is correct: The jellyfish’s mouth is found in the centre of its body. From this small opening it both eats and discards waste. And it serves another purpose, too – by squirting a jet of water from its mouth, the jellyfish can propel forward. Therefore, the jellyfish is known as a simple or “primitive” animal.
Statement 3 is correct: They aren’t actually fish. They are invertebrates from the phylum Cnidaria and are so varied as a taxonomic group that many scientists have taken to simply referring to them as “gelatinous zooplankton.” Jellyfish do not have scales, gills, or fins like fish. Instead, they swim by opening and closing their “bells.”
Statement 4 is correct: Some jellyfish are clear, but others are vibrant colours of pink, yellow, blue and purple. They can be bioluminescent, too, which means they produce their own light!
Additional information:
● The jellyfish itself provides a tasty meal for other ocean creatures, particularly sea turtles.
● Unlike most marine creatures, jellyfish are thriving in our oceans despite marine heat waves, ocean acidification, overfishing, and various other human influences. While corals, oysters, and any marine organisms that build shells are considered the biggest losers of increasingly acidic oceans, jellyfish don’t seem to be as susceptible to climate change.
● When threatened, a species of jellyfish namely ‘Turritopsis nutricula’ is capable of undergoing cellular transdifferentiation, a process whereby the organism’s cells essentially become new again.