UPSC Prelims Research: Environment 2024

1. The Organisms “Cicada, Froghopper and Pond Skater” are :

(a) Birds

(b) Fish

(c) Insects

(d) Reptiles

Answer: (c) Insects

Notes:

• Insects are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes, and a pair of antennae.
  • Insects have no internal skeleton, instead they are covered in an external shell (exoskeleton) that protects their soft internal organs.
  • No insect has more than three pairs of legs, except for some immature forms such as caterpillars that have prolegs. These are appendages that serve the purpose of legs.
  • The typical insect mouth has a pair of lower jaws (maxillae) and upper jaws (mandibles) which are designed to bite. There are many variations to this structure, as many moths and butterflies have tubular sucking mouthparts, many bugs and other blood-sucking insects have sucking stabbing mouthparts and some adult insects simply don’t have functional mouthparts.
  • Insects have one pair of antennae located on the head
  • Most insects have one or two pairs of wings although some insects such as lice, fleas, bristletails and silverfish are completely wingless.
    • Insects are the only invertebrates (animals without backbones) with wings.
• Modern insect classification divides the Insecta into 29 orders, many of which have common names. Some of the more common orders are:
  • Mantodea – praying mantids
  • Blattodea – cockroaches
  • Isoptera – termites
  • Siphonaptera – fleas
  • Odonata – dragonflies and damselflies
  • Dermaptera – earwigs
  • Diptera – flies
  • Lepidoptera – butterflies and moths
  • Orthoptera – grasshoppers, katydids, crickets
  • Coleoptera – beetles
  • Hymenoptera – wasps, bees, ants, sawflies
• All of the Cicada, Froghopper and Pond Skater belong to insects. 
  • The cicadas are a superfamily of insects in the order Hemiptera (true bugs).
  • The froghoppers, or the superfamily Cercopoidea, are a group of hemipteran insects in the suborder Auchenorrhyncha.
  • Pond Skater are a family of insects in the order Hemiptera.

Cicada:

• Order: Hemiptera
• Suborder: Auchenorrhyncha
• Family: Cicadidae
• Description: Cicadas are known for their loud, distinctive mating calls produced by males. They have prominent eyes set wide apart, short antennae, and membranous front wings. Cicadas are found worldwide and are particularly abundant in tropical and temperate regions.
• Lifecycle: Cicadas have a unique lifecycle, with some species (like the periodical cicadas) having very long developmental periods of up to 17 years, mostly spent underground as nymphs.

Froghopper:

• Order: Hemiptera
• Suborder: Auchenorrhyncha
• Family: Cercopidae
• Description: Froghoppers, also known as spittlebugs, are small insects that are known for their ability to jump long distances, similar to frogs, hence the name. They are called spittlebugs because their nymphs produce frothy masses of spittle on plants for protection.
• Habitat: Froghoppers are found on a variety of plants and are distributed across many regions of the world.

Pond Skater (Water Strider):

• Order: Hemiptera
• Suborder: Heteroptera
• Family: Gerridae
• Description: Pond skaters, also known as water striders, are insects that can walk on the surface of water due to the surface tension and their hydrophobic legs. They have long, slender legs that distribute their weight evenly and allow them to move quickly across the water surface.
• Habitat: Pond skaters are typically found in calm waters such as ponds, lakes, and slow-moving streams.

2. Consider the following statements :

Statement-I: Many chewing gums found in the market are considered a source of environmental pollution.

Statement-II: Many chewing gums contain plastic as gum base.

Which pone of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

(c) Statement-I is correct, but Statement-II is incorrect

(d) Statement-I is incorrect, but Statement-II is correct

Answer: (a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

Notes:

• Commercially, chewing gum is produced based on synthetic gum base, which is non-biodegradable. Accordingly, chewing gum residue can be considered as a dangerous environmental pollutant.
• Chewing gum does contain plastic. The ingredient known as “gum base” in the list of ingredients in chewing gum is largely made of polyvinyl acetate.
  • This plastic is non-biodegradable and remains in the environment for a long time. Thus, chewing gum residue can be considered as a dangerous environmental pollutant.

3. Consider the following pairs :

	Country	Animal found in its natural habitat
1.	Brazil	Indri
2.	Indonesia	Elk
3.	Madagascar	Bonobo

How many of the pairs given above are correctly matched?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (d) None

Indri (Indri indri): 

• Indris are the largest lemurs in the world. It has a black and white coat and maintains an upright posture when climbing or clinging.
• It is monogamous and lives in small family groups, moving through the canopy, and is herbivorous, feeding mainly on leaves but also seeds, fruits, and flowers.
• The groups are quite vocal, communicating with other groups by singing, roaring and other vocalisations. Besides humans, it is the only mammal found that can use rhythm.
• Size: Largest living lemur, 64-72 cm in body length, 6-9.5 kg in weight.
• Appearance: Black-and-white coat, large expressive eyes, minimal tail, long legs for leaping.
• Habitat:
  • Location: Endemic to Madagascar, specifically eastern rainforests.
  • Environment: Tropical moist lowland and montane forests, arboreal lifestyle.
• Behavior and Diet:
  • Social Structure: Lives in small family groups (monogamous pairs and offspring).
  • Communication: Loud, distinctive calls for territorial communication.
  • Diet: Primarily folivorous (leaves), also consumes fruits, flowers, and seeds.
• Reproduction:
  • Breeding: Low reproductive rate, single offspring every 2-3 years.
  • Gestation: Approximately 4-5 months.
  • Parental Care: Mother carries infant on abdomen initially, then on back as it grows.
• Conservation Status:
  • IUCN Status: Critically endangered.
  • Threats: Habitat destruction (slash-and-burn agriculture, logging), human encroachment, hunting.
• Conservation Efforts: Protected areas, reforestation, ecotourism, awareness campaigns.
• Cultural Significance:
• Folklore: Holds special place in Malagasy culture, often considered taboo to hunt due to ancestral beliefs.

Elk (Cervus canadensis):

• The elk or wapiti, is the second largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia.
• Size: Large deer species, with males (bulls) weighing 320-330 kg (700-730 lbs) and females (cows) weighing 225-240 kg (495-530 lbs).
• Appearance: Tan or light brown body with a dark brown head, neck, and legs. Males have large, branched antlers that are shed and regrown annually.
• Habitat:
  • Location: Native to North America and northeastern Asia.
  • Environment: Inhabits forests, meadows, and grasslands, often found in mountainous regions.
• Behavior and Diet:
  • Social Structure: Lives in herds, with separate groups for males and females outside the breeding season.
  • Communication: Vocalizations include bugling by males during the rut (mating season) and various calls by females and calves.
  • Diet: Herbivorous, feeding on grasses, leaves, bark, and plants.
• Reproduction:
  • Breeding Season: Rut occurs in the fall (September to October).
  • Gestation: Approximately 8.5 months.
  • Calves: Typically one calf is born in late spring to early summer.
• Conservation Status:
  • IUCN Status: Least concern, but some subspecies are threatened.
  • Threats: Habitat loss, hunting, and competition with livestock.

Bonobo (Pan paniscus):

• Size: Smaller and more slender than common chimpanzees, with males weighing around 39 kg (85 lbs) and females around 31 kg (68 lbs).
• Appearance: Black fur, pink lips, a prominent brow ridge, and long legs. They have a more gracile build compared to chimpanzees.
• Habitat:
  • Location: Endemic to the Democratic Republic of Congo in central Africa.
  • Environment: Inhabits tropical and subtropical forests, particularly dense, lowland rainforests.
• Behavior and Diet:
  • Social Structure: Live in matriarchal societies with strong female bonds; known for their peaceful and cooperative social interactions.
  • Communication: Uses a complex system of vocalizations, facial expressions, and gestures.
  • Diet: Omnivorous, primarily consuming fruits, leaves, seeds, flowers, and small animals.
• Reproduction:
  • Breeding: No specific breeding season; females give birth approximately every 4-5 years.
  • Gestation: Around 8 months.
  • Offspring: Typically one infant per birth; infants are closely cared for by their mothers.
• Conservation Status:
  • IUCN Status: Endangered.
  • Threats: Habitat destruction, poaching, and the bushmeat trade.
• Conservation Efforts: Focus on habitat preservation, anti-poaching measures, and awareness campaigns.

4. Which one of the following shows a unique relationship with an insect that has coevolved with it and that is the only insect that can pollinate this tree?

(a) Fig

(b) Mahua

(c) Sandalwood

(d) Silk cotton

Answer: (a) Fig

Fig

• The fig is the edible fruit of Ficus carica, a species of small shrub in the flowering plant family Moraceae, native to the Mediterranean region, together with western and southern Asia.
• It has been cultivated since ancient times and is now widely grown throughout the world.
• A fig plant is a small deciduous tree or large shrub growing up to 7–10 m (23–33 ft) tall, with smooth white bark.
• They have a unique coevolutionary relationship with fig wasps. This relationship is a classic example of mutualism where both the plant and the insect benefit:
  • Fig Trees: They rely on specific species of fig wasps for pollination. Each species of fig tree is typically pollinated by its own unique species of wasp.
  • Fig Wasps: These wasps lay their eggs inside the fig flowers. The larvae develop within the fig, and in return, the wasps pollinate the flowers.
  • This highly specialized relationship means that fig trees can not reproduce without their respective fig wasps, making it a unique example of coevolution and mutual dependency.
• Figs can be eaten fresh or dried, or processed into jam, rolls, biscuits and other types of desserts. Since ripe fruit does not transport and keep well, most commercial production is in dried and processed forms.
  • Raw figs contain roughly 80% water and 20% carbohydrates, with negligible protein, fat and micronutrient content. They are a moderate source of dietary fiber.

5. Consider the following :

1. Butterflies
2. Fish
3. Frogs

How many of the above have poisonous species among them?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (c) All three

Notes:

• Butterflies: There are indeed poisonous species among butterflies. For example, the Monarch butterfly (Danaus plexippus) is poisonous due to the toxic chemicals it ingests from milkweed plants during its larval stage. Hence, butterflies have poisonous species.
• Fish: There are many species of fish that are poisonous. For example, the Pufferfish (Tetraodontidae family) contains tetrodotoxin, a potent neurotoxin. Hence, fish have poisonous species.
• Frogs: Certain species of frogs are poisonous. The most notable are the Poison Dart Frogs (Dendrobatidae family), which have toxic skin secretions used by indigenous people to poison their blowgun darts. Hence, frogs have poisonous species.

6. Consider the following :

1. Cashew
2. Papaya
3. Red sanders

How many of the above trees are actually native to India?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (a) Only one

Notes:

• Cashew: The cashew tree (Anacardium occidentale) is native to northeastern Brazil. It was introduced to India by Portuguese colonists. Hence, the cashew tree is not native to India. 
• Papaya: The papaya tree (Carica papaya) is native to the tropical regions of the Americas, particularly southern Mexico and Central America. It was introduced to India and is now widely cultivated, but it is not native to India.
• Red sanders: The Red Sanders tree (Pterocarpus santalinus) is native to the southern parts of India, particularly in the state of Andhra Pradesh. It is valued for its rich red-colored wood.

Red Sanders:

• The species, Pterocarpus santalinus, is an Indian endemic tree species, with a restricted geographical range in the Eastern Ghats.
• The species is endemic to a distinct tract of forests in Andhra Pradesh.
• Red Sanders usually grow in the rocky, degraded and fallow lands with Red Soil and hot and dry climate.
• Threats:
  • Illicit felling for smuggling, forest fires, cattle grazing and other anthropogenic threats.
  • Red Sanders, known for their rich hue and therapeutic properties, are high in demand across Asia, particularly in China and Japan, for use in cosmetics and medicinal products as well as for making furniture, woodcraft and musical instruments.
• Protection Status:
  • IUCN Red List: Endangered.

7. With reference to “water vapour”, which of the following statements is/are correct?

1. It is a gas, the amount of which decreases with altitude.
2. Its percentage is maximum at the poles

Select the answer using the code given below :

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (a) 1 only

Notes:

• Water vapor is a gas, and its amount decreases with altitude.
• The amount of water vapor generally decreases with altitude. This is because most of the water vapor originates from evaporation at the Earth’s surface, especially from oceans, seas, lakes, and other water bodies.
• As you move higher in the atmosphere, the temperature decreases, and the capacity of air to hold water vapor also decreases. 
• The percentage of water vapor is not maximum at the poles; it is minimum there.
  • Water Vapor Concentration: The concentration of water vapor is typically higher in warmer regions near the equator, where evaporation rates are highest due to higher temperatures. Conversely, polar regions, which are much colder, have lower evaporation rates and thus lower concentrations of water vapor.
  • Maximum Percentage: The percentage of water vapor is not maximum at the poles; it is actually minimum due to the cold temperatures and limited evaporation.

8. With reference to perfluoroalkyl and Polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements :

1. PFAS are found to be widespread in drinking water, food and food packaging material.
2. PFAS are not easily degraded in the environment.
3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (d) 1, 2 and 3

PFAS

• Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals used in various consumer and industrial products for their resistance to heat, water, and grease.
• PFAS are not easily degraded in the environment. Due to their persistent nature and widespread use, they have become increasingly prevalent in the environment and human blood.
• Concerns have been raised about their potential health effects, including reproductive harm, developmental problems, and certain types of cancer.
• Uses and Potential Sources:
  • Due to their unique properties, including surfactant qualities, heat and stain resistance, and amphiphilic nature, PFAS are used widely by a number of industries, including carpet, textile and leather production, chromium plating, photography, photolithography, paper products, semi-conductor manufacturing, coating additives, and cleaning products.
  • Sources to the environment include primary manufacturing facilities, where PFAS is produced, and secondary manufacturing facilities, where PFAS is incorporated into products.
  • PFAS are found in a variety of consumer products including food paper and packaging, furnishings, waterproof clothing, and cosmetics.
    • The presence of PFAS in consumer products has created an urban background concentration in stormwater, wastewater treatment plant influent, and landfill leachate.

9. Consider the following :

1. Carabid beetles
2. Centipedes
3. Flies
4. Termites
5. Wasps

Parasitoid species are found in how many of the above kind of organisms?

(a) Only two
(b) Only three
(c) Only four
(d) All five

Answer: (b) Only three

Parasitoid Species:

• Parasitoids are organisms, typically insects, that spend their immature stages within or on another organism (the host), eventually killing it.
• They are distinct from predators because they rely on a single host for development and reproduction, and unlike parasites, they ultimately kill the host.
• Most parasitoids are wasps or flies, but some beetles, moths, and other insects also fall into this category.
• Examples of Parasitoid Species:
  • Wasps:
    • Many wasp species are parasitoids, including Ichneumonid wasps, Encyrtid wasps, Trichogramma wasps (egg parasitoids), and Aphelinid wasps.
  • Flies:
    • Tachinid flies are a notable example of parasitoid flies.
  • Beetles:
    • Some beetles, like the larval parasitoid Netelia producta (Orange caterpillar parasite), are also parasitoids.
  • Other insects:
    • While less common, some species of butterflies, moths, lacewings, and even caterpillars can also be parasitoids.

10. Consider the following statements :

Statement-I : The Indian Flying Fox is placed under the “vermin” category in the Wild Life (Protection) Act, 1972.

Statement-II : The Indian Flying Fox feeds on the blood of other animals.

Which one of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

(c) Statement-I is correct, but Statement-II is incorrect

(d) Statement-I is incorrect, but Statement-II is correct

Answer: (c) Statement-I is correct, but Statement-II is incorrect

Indian flying fox

• The Indian flying fox (Pteropus medius), also known as the greater Indian fruit bat, is a species of flying fox native to the Indian subcontinent.
• It is a keystone species causing seed dispersals of many plants in tropical systems.
• Appearance:
  • Indian flying fox is characterized by its large size and fox-like facial features.
  • Usually displays a dark brown, gray, or black body, often with a distinct yellowish mantle (typical of Pteropus genus).
  • Males are generally larger than females.
• Geographic Range:
  • Indian flying fox occurs in tropical regions of South Central Asia, from Pakistan to China, and as far south as the Maldive Islands.
• Habitat:
  • These animals can be found in forests and swamps. Large groups of individuals roost in trees such as banyan, fig, and tamarind. Roosting trees are usually in the vicinity of a body of water.
• Conservation Status:
  • Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES): Appendix II
  • Wildlife (Protection) Act, 1972: Schedule II
• Negative Impact:
  • Indian flying foxes considered as vermin cause extensive damage to fruit orchards, and are therefore considered pests in many regions. They may also be responsible for spreading disease, particularly the Nipah virus, which causes illness and death in humans.
• Diet: 
  • They maintain a frugivorous diet, supplementing it with insects as well as flowers, containing juice and nectar.
• Threat: 
  • Being external roosters, the flying fox is exposed to predators and disturbances apart from environmental indicators such as heat and light.

11. Consider the following materials :

1. Agricultural residues
2. Corn grain
3. Wastewater treatment sludge
4. Wood mill waste

Which of the above can be used as feedstock for producing Sustainable Aviation Fuel?

(a) 1 and 2 only
(b) 3 and 4 only
(c) 1, 2, 3 and 4
(d) 1, 3 and 4 only

Answer: (c) 1, 2, 3 and 4

Sustainable Aviation Fuel: 

• Sustainable Aviation Fuel (SAF) is also known as bio-jet fuel.
• It is made from renewable biomass and waste resources have the potential to deliver the performance of petroleum-based jet fuel. 
• It is a “drop-in” fuel that can be blended up to 50% with traditional jet fuel.
• Itis a liquid fuel currently used in commercial aviation which reduces CO2 emissions by up to 80%.
• Production: It can be produced from a number of sources (feedstock) including waste oil and fats, green and municipal waste and non-food crops.
  • It can be produced from various sources, including palm stearin, sapium oil, palm fatty acid distillates, algae oil, karanja, and jatropha.
  • It can also be produced synthetically via a process that captures carbon directly from the air.
• Significance:
  • Its carbon footprint is significantly lower than aviation turbine fuel (ATF).
  • It is ‘sustainable’ because the raw feedstock does not compete with food crops or water supplies, or is responsible for forest degradation. 
  • It remains the major mature and viable pathway to decarbonise the aviation sector. At the same time, SAF only accounts for 0.3% of the current fuel use for aviation.
  • In contrast to fossil fuels, which release carbon that was previously locked up, SAF recycles the CO2 that has been absorbed throughout the course of the life of the biomass utilized as the feedstock.
  • It can be used in existing aircraft engines without modifications and can be blended with conventional jet fuel, making it relatively easy to integrate into existing aviation infrastructure.
• Challenges associated:
  • Four times more expensive than traditional fossil jet fuel.
  • Scarcity of waste based feedstock.
  • Lower energy density than traditional jet fuel.

12. Consider the following statements :

1. Lions do not have a particular breeding season.
2. Unlike most other big cats, cheetahs do not roar.
3. Unlike male lions, male leopards do not proclaim their territory by scent marking.

Which of the statements given above are correct 2

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 2

Answer: (a) 1 and 2 only

Notes:

• Lions can mate and breed throughout the year. Their breeding is not restricted to a specific season, and females can come into estrus at any time.
• Cheetahs are indeed unique among big cats in that they cannot roar. Instead, they produce a variety of other vocalizations, including purring, chirping, and growling.
• Male leopards, like many other big cats, do use scent marking to proclaim their territory. They use urine, feces, and secretions from scent glands to mark their boundaries.

13. Consider the following plants :

1. Groundnut
2. Horse-gram
3. Soybean

How many of the above belong to the pea family?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (c) All three

Notes:

• The Fabaceae family, also known as the Leguminosae or pea family, is a large and economically important family of flowering plants.
• It includes trees, shrubs, and herbaceous plants, and is recognized for its ability to fix nitrogen through a symbiotic relationship with Rhizobium bacteria in root nodules.
• Groundnut (Arachis hypogaea)
  • Family: Fabaceae
  • Description: Groundnuts, also known as peanuts, are herbaceous plants that grow annually. The plant produces yellow flowers that, after fertilization, turn downward and burrow into the soil to form pods containing seeds (peanuts).
  • Significance: Groundnuts are rich in protein and oil, making them a crucial crop for human consumption and oil production. They also play a role in improving soil fertility through nitrogen fixation.
• Horse-gram (Macrotyloma uniflorum)
  • Family: Fabaceae
  • Description: Horse-gram is a drought-tolerant legume that is widely cultivated in India and other parts of Asia. The plant has trifoliate leaves, small flowers, and produces small, hard seeds.
  • Significance: Horse-gram is a nutritious legume high in protein, iron, and calcium. It is used in traditional dishes and as fodder for livestock. Like other legumes, it helps in nitrogen fixation, enhancing soil fertility.
• Soybean (Glycine max)
  • Family: Fabaceae
  • Description: Soybean plants are annual legumes with hairy stems and leaves. They produce clusters of small, purple or white flowers, followed by pods containing seeds (soybeans).
  • Significance: Soybeans are one of the most important leguminous crops globally, used for their protein-rich seeds in food products, animal feed, and oil extraction. Soybeans contribute significantly to soil health through nitrogen fixation.
• Key Characteristics of the Fabaceae Family:
  • Flowers: Typically have five petals arranged in a unique “butterfly” shape (papilionaceous) with one large petal (standard), two lateral petals (wings), and two lower petals fused together (keel).
  • Leaves: Usually compound, often with stipules, and can be pinnate or trifoliate.
  • Fruit: A legume or pod that splits open on two sides to release seeds.
  • Nitrogen Fixation: Many members of this family form symbiotic relationships with Rhizobium bacteria, which fix atmospheric nitrogen into a form usable by the plant, improving soil fertility.