UPSC CSE Prelims
Biodiversity and Conservation Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 4 — II and III

Simple Explanation:

Statement I — Incorrect. It is NOT a crustacean — it's a spider (arachnid), specifically a tarantula. Crustaceans (like crabs/shrimp) are a completely different animal group.

Statement II — Correct. Its habitat is restricted to certain forest areas in India, specifically the Eastern Ghats.

Statement III — Correct. It is arboreal — meaning it lives in trees and tree crevices/hollows, not on the ground.

📝 Short Notes: Peacock Tarantula / Gooty Tarantula

Detailed Explanation:

Answer: Option 1 — 1 and 2 only

This question tests knowledge about the behavioral characteristics of big cats, particularly lions, cheetahs, and leopards. Understanding territorial marking, breeding patterns, and vocal capabilities of these species is important for wildlife ecology.

✅ Statement 1 – Correct: Lions do not have a strictly defined breeding season and can breed throughout the year, though some seasonal peaks may occur depending on environmental conditions like prey availability and rainfall.

✅ Statement 2 – Correct: Cheetahs lack the specialized larynx structure (hyoid bone apparatus) that allows other big cats to roar; instead, they produce chirps, purrs, and high-pitched calls similar to birds.

❌ Statement 3 – Incorrect: Male leopards, like male lions, actively use scent marking (urine spraying, scraping, and fecal deposits) to proclaim and defend their territories; this statement incorrectly suggests leopards do not engage in territorial scent marking.

📝 Short Notes: Big Cats - Behavioral Characteristics

• Roaring mechanism: Lions, tigers, leopards, and jaguars belong to genus Panthera with a flexible hyoid bone that enables roaring.
• Cheetah distinction: Belongs to genus Acinonyx; has a fixed hyoid bone, preventing roaring but allowing continuous purring.
• Territorial behavior: All big cats use scent marking (urine, feces, gland secretions) and visual cues (scratch marks) to establish territories.
• Breeding patterns: Most big cats can breed year-round, but environmental factors (prey density, climate) influence peak breeding times.

Detailed Explanation:

Answer: Option 3 — All three

All three groups mentioned in the question—butterflies, fish, and frogs—have poisonous species among them. Butterflies like the Monarch sequester toxins from their larval diet of milkweed, making them poisonous to predators. Many fish species such as pufferfish, lionfish, and stonefish possess deadly venom or toxins. Poison dart frogs are classic examples of amphibians that secrete potent toxins through their skin as a defense mechanism.

📝 Short Notes: Poisonous Species in Different Animal Groups

• Poisonous Butterflies: Monarch butterflies accumulate cardiac glycosides from milkweed plants during their caterpillar stage, making them toxic to birds and other predators. Other examples include the Pipevine Swallowtail.
• Poisonous Fish: Pufferfish contain tetrodotoxin, a neurotoxin deadly to humans. Lionfish and stonefish have venomous spines. Stingrays possess venomous barbs on their tails.
• Poisonous Frogs: Poison dart frogs (family Dendrobatidae) of Central and South America secrete alkaloid toxins through their skin. The Golden Poison Frog is one of the most toxic vertebrates on Earth.
• Mechanism of Toxicity: Some species produce toxins endogenously (within their bodies), while others sequester them from their diet (like Monarch butterflies and poison dart frogs).
• Purpose of Poison: These toxins serve primarily as defense mechanisms against predators, advertised through warning coloration (aposematism) in many cases.

Detailed Explanation:

Answer: Option 3 — Insects

All three organisms—Cicada, Froghopper, and Pond Skater—are classified as insects belonging to different families within the class Insecta. Cicadas are known for their loud mating calls, froghoppers (spittlebugs) are famous for the foam they produce as nymphs, and pond skaters use surface tension to walk on water.

📝 Short Notes: Classification of Common Insects

• Cicada: Order Hemiptera; known for their distinctive loud buzzing sounds produced by males during mating season; have a long lifecycle with some species emerging every 13-17 years.
• Froghopper (Spittlebug): Order Hemiptera; small jumping insects; nymphs produce foam (cuckoo spit) on plants for protection; adults are powerful jumpers.
• Pond Skater (Water Strider): Order Hemiptera, family Gerridae; use surface tension and hydrophobic legs to walk on water; predators of small aquatic organisms.
• Common Feature: All three belong to Order Hemiptera (true bugs), characterized by piercing-sucking mouthparts and incomplete metamorphosis.
• Ecological Role: These insects play important roles as herbivores, predators, and prey in their respective ecosystems.

Detailed Explanation:

Answer: Option 4 — None

None of the given country-animal pairs are correctly matched. Each animal mentioned is native to a completely different geographical region than the country paired with it.

❌ Pair 1 – Incorrect: Indri is a lemur species endemic only to Madagascar, not Brazil.
❌ Pair 2 – Incorrect: Elk (Cervus canadensis) are found in North America and parts of Asia, not in Indonesia.
❌ Pair 3 – Incorrect: Bonobo (Pan paniscus) is a great ape found exclusively in the Democratic Republic of Congo, not Madagascar.

📝 Short Notes: Endemic Species and Their Natural Habitats

• Endemic species: Species found exclusively in one geographic location and nowhere else naturally in the world
• Madagascar biodiversity: Island isolation for ~88 million years has led to extraordinary endemic biodiversity, especially lemurs, chameleons, and unique flora
• Conservation importance: Understanding natural habitats is crucial for wildlife conservation and preventing extinction of endemic species

Detailed Explanation:

Answer: Option 1 — Only one

Among the three trees mentioned, only Red Sanders is native to India, specifically endemic to the Eastern Ghats of Andhra Pradesh. Both Cashew and Papaya are exotic species that were introduced to India from the Americas by European traders during the colonial period.

✅ Red Sanders – Native to India: Endemic to the Eastern Ghats, particularly Andhra Pradesh, known for its valuable reddish wood.
❌ Cashew – Not native: Originally from Brazil, introduced to India by Portuguese traders in the 16th century.
❌ Papaya – Not native: Originated in southern Mexico and Central America, brought to India during colonial times.

📝 Short Notes: Native vs. Exotic Trees of India

• Red Sanders (Pterocarpus santalinus): Endemic to India, found exclusively in the Eastern Ghats of Andhra Pradesh and parts of Karnataka. It is listed in CITES Appendix II due to illegal logging and trade. The tree produces valuable red heartwood used in furniture, musical instruments, and traditional medicine.
• Cashew (Anacardium occidentale): Native to Brazil, introduced to Goa by Portuguese colonizers in the 16th century. India is now the world's largest producer and exporter of cashew nuts, with major cultivation in Kerala, Karnataka, Goa, and Maharashtra.
• Papaya (Carica papaya): Originated in tropical Americas (southern Mexico and Central America). Brought to India by Portuguese and Spanish traders. India is now one of the largest producers of papaya globally, cultivated throughout tropical and subtropical regions.
• Other Native Indian Trees: Neem (Azadirachta indica), Banyan (Ficus benghalensis), Peepal (Ficus religiosa), Sal (Shorea robusta), Teak (Tectona grandis), and Sandalwood (Santalum album).
• Other Exotic Trees in India: Eucalyptus (Australia), Pine (temperate regions), Rubber (Brazil), Coffee (Ethiopia), and Tea (China).
• Conservation Concern: Red Sanders is classified as 'Endangered' on the IUCN Red List due to overexploitation for its valuable timber, leading to strict protection measures and anti-smuggling operations.

Detailed Explanation:

Answer: Option 2 — Only two

The question tests knowledge about the behavioral ecology of Indian squirrels. Out of the three statements, two are correct (statements 2 and 3), while statement 1 is incorrect as Indian squirrels are primarily arboreal and build tree nests rather than ground burrows.

❌ Statement 1 – Incorrect: Indian squirrels like the Indian Palm Squirrel (Funambulus) and Malabar Giant Squirrel (Ratufa indica) are arboreal species that build nests (dreys) in tree branches, hollows, or crevices using twigs and leaves, not ground burrows.

✅ Statement 2 – Correct: Indian squirrels exhibit scatter hoarding behavior, burying nuts and seeds in shallow ground locations for later retrieval, which also aids in seed dispersal and forest regeneration.

✅ Statement 3 – Correct: Squirrels are opportunistic omnivores; while their primary diet includes seeds, nuts, fruits, and fungi, they also consume insects, caterpillars, bird eggs, and occasionally small vertebrates.

📝 Short Notes: Indian Squirrels - Ecology & Behavior

• Common Species: Indian Palm Squirrel (Funambulus palmarum), Three-striped Palm Squirrel (F. tristis), Malabar Giant Squirrel (Ratufa indica), and Indian Giant Squirrel (Ratufa macroura)
• Habitat: Predominantly arboreal (tree-dwelling); found in forests, urban parks, gardens, and agricultural landscapes
• Nesting: Build dreys (leaf and twig nests) in tree branches or use tree hollows; do not make ground burrows unlike ground squirrels found in other regions
• Food Storage: Practice scatter hoarding - bury food items in multiple scattered locations rather than one central cache; excellent spatial memory for retrieval
• Diet: Omnivorous - primarily herbivorous (nuts, seeds, fruits, flowers, bark) but also consume insects, bird eggs, and occasionally small animals
• Ecological Role: Important seed dispersers for many tree species; forgotten caches germinate into new plants, aiding forest regeneration
• Conservation Status: Most species are Least Concern, but habitat specialists like the Malabar Giant Squirrel face threats from habitat fragmentation

Detailed Explanation:

Answer: Option 1 — Only one

Among the three fauna listed, only the Malabar Civet is a nocturnal animal, being primarily active during the night. The Lion-tailed Macaque is a diurnal species, active during the day, while the Sambar Deer is crepuscular, most active during dawn and dusk rather than after sunset.

Analysis of Each Species:
🦁 Lion-tailed Macaque: Diurnal primate found in Western Ghats, active during daylight hours.
🐆 Malabar Civet: Nocturnal carnivore endemic to Western Ghats, most active after sunset. ✅
🦌 Sambar Deer: Crepuscular herbivore, most active at dawn and dusk, not strictly nocturnal.

📝 Short Notes: Activity Patterns in Animals

Detailed Explanation:

Answer: Option 2 — Orangutan

Orangutans are highly intelligent great apes known for their remarkable tool-use capabilities. They have been extensively observed using sticks to scrape and extract insects from holes in trees and logs, probe for honey, and even fashion leaves into gloves or napkins. This behavior demonstrates their advanced cognitive abilities and problem-solving skills, making them one of the most tool-proficient non-human primates.

📝 Short Notes: Tool Use in Animals

• Orangutans: Use sticks to extract insects, honey, and seeds; use leaves as umbrellas, gloves, and napkins; found in Borneo and Sumatra.
• Chimpanzees: Use sticks to fish for termites, stones to crack nuts, and leaves as sponges for drinking water.
• Crows: Craft hooked tools from twigs to extract insects; demonstrate advanced problem-solving abilities.
• Sea Otters: Use rocks as anvils to crack open shellfish while floating on their backs.
• Elephants: Use branches to swat flies, scratch themselves, and modify sticks to reach food.
• Dolphins: Use marine sponges to protect their rostrums while foraging on the seabed.

Detailed Explanation:

Answer: Option 3 — Statement-I is correct but Statement-II is incorrect

This question tests knowledge about the biogeographical distribution of marsupials and their ecological adaptations. Statement I correctly identifies that marsupials are not naturally found in India, while Statement II incorrectly restricts their habitat requirements.

✅ Statement I – Correct: Marsupials are indeed not naturally found in India. They are primarily native to Australia (kangaroos, koalas, wombats), the Americas (opossums), and Papua New Guinea. India falls outside the natural distribution range of marsupials.

❌ Statement II – Incorrect: This statement is factually wrong on multiple counts. Marsupials do not require montane grasslands exclusively and can thrive in diverse habitats including forests, deserts, savannas, wetlands, and even urban areas. They also coexist with various predators in their natural habitats (e.g., dingoes in Australia). The claim that they can thrive "only" in montane grasslands with no predators is completely false.

📝 Short Notes: Marsupials - Distribution and Ecology

• Definition: Marsupials are mammals characterized by giving birth to relatively undeveloped young that continue development in a pouch (marsupium).
• Primary Distribution: Australia (~70% of all marsupial species), Americas (opossums), Papua New Guinea, and nearby islands.
• Habitat Diversity: Marsupials occupy varied habitats - rainforests (tree kangaroos), deserts (bilbies), grasslands (kangaroos), forests (koalas), and wetlands (water opossums).
• Examples: Kangaroos, wallabies, koalas, wombats, Tasmanian devils, possums, and opossums.
• Evolutionary Significance: Marsupials represent an ancient mammalian lineage that thrived in Gondwanaland before continental drift isolated populations.
• Indian Context: No native marsupials exist in India due to biogeographical separation and different evolutionary pathways in the Indian subcontinent.

Detailed Explanation:

Answer: Option 3 — Honeybees

The waggle dance is a unique form of communication performed by worker honeybees to inform other members of the colony about the direction and distance to food sources. This remarkable behavior was decoded by Austrian scientist Karl von Frisch, who won the Nobel Prize for this discovery. The direction of the dance relative to the vertical indicates the angle to the food source in relation to the sun, while the duration of the waggle portion indicates the distance.

📝 Short Notes: Honeybee Waggle Dance

• Discovered by: Karl von Frisch (Austrian ethologist, Nobel Prize 1973)
• Purpose: Communication among worker bees about food source location (nectar, pollen, water)
• Direction indication: Angle of the waggle run relative to vertical = angle to food source relative to the sun's position
• Distance indication: Duration and number of waggles indicate distance to the source (longer dance = farther distance)
• Round dance: Performed for food sources very close to the hive (within 50-100 meters)
• Significance: Demonstrates complex social communication in insects and symbolic language in non-human species

Detailed Explanation:

Answer: Option 1 — Golden Mahseer

The Golden Mahseer (Tor putitora) is a species of large freshwater fish, not a bird. Often referred to as the 'Tiger of the Water', it is native to the Himalayan region and inhabits the rapid streams and rivers of the Indus, Ganga, and Brahmaputra basins. It is recognized by its large golden scales and is currently listed as Endangered on the IUCN Red List.

✅ Option 2 – Indian Nightjar: A nocturnal bird species found across the Indian subcontinent, belonging to the Caprimulgidae family.
✅ Option 3 – Spoonbill: A wading bird characterized by its distinctive spoon-shaped bill, found in wetlands and marshes.
✅ Option 4 – White Ibis: A wading bird with white plumage, commonly found in wetlands and coastal regions.

📝 Short Notes: Indian Wildlife Species

• Golden Mahseer (Tor putitora): Large freshwater fish found in Himalayan rivers; known as 'Tiger of the Water'; IUCN status: Endangered; threatened by overfishing, habitat degradation, and dam construction.
• Indian Nightjar: Nocturnal insectivorous bird; cryptic plumage provides excellent camouflage; found in dry scrublands and open forests.
• Spoonbill: Includes species like Eurasian Spoonbill; feeds by sweeping its spatulate bill through water; inhabits wetlands and shallow water bodies.
• White Ibis: Includes Black-headed Ibis (Threskiornis melanocephalus); wading bird found in wetlands; feeds on aquatic invertebrates and small fish.
• Conservation Significance: All these species are indicators of ecosystem health; wetland birds indicate water quality while mahseer indicates river health.

Detailed Explanation:

Answer: Option 1 — Ant

Certain ant species, particularly leaf-cutter ants and others in the tribe Attini, are well-known for cultivating fungi. These ants practice sophisticated agriculture by cutting plant material, using it as substrate to grow specific fungus species in underground gardens, which then serve as their primary food source. This remarkable mutualistic relationship represents one of the most advanced examples of non-human agriculture in nature.

Why other options are incorrect:
• Cockroaches are omnivorous scavengers that do not cultivate fungi
• Crabs are aquatic scavengers or predators without fungal cultivation behavior
• Spiders are predators that capture prey and do not engage in fungal farming

📝 Short Notes: Fungus-Growing Ants

• Primary Species: Leaf-cutter ants (Atta and Acromyrmex genera) and fungus-growing ants (Tribe Attini) cultivate fungi as their primary food source
• Agricultural Process: Worker ants cut fresh plant material, chew it into a pulp, and use it as substrate for fungal cultivation in specialized underground chambers
• Fungal Species: They cultivate specific fungi from the family Lepiotaceae, which cannot survive outside the ant colonies
• Mutualistic Symbiosis: The ants provide the fungus with nutrients and protection, while the fungus provides specialized structures (gongylidia) as food for the ants
• Antibiotic Production: Some fungus-growing ants harbor bacteria (Actinomycetes) on their bodies that produce antibiotics to protect their fungal gardens from parasitic fungi
• Evolutionary Significance: This ant-fungus mutualism evolved approximately 50-60 million years ago and represents convergent evolution with human agriculture

Detailed Explanation:

Answer: Option 4 — 1 and 3

Among the given animals, hedgehogs and pangolins roll up into a tight ball as a defensive mechanism to protect their vulnerable parts from predators. Hedgehogs use their sharp spines, while pangolins use their tough keratin scales for protection. Marmots, on the other hand, do not roll up; they rely on burrows and alarm calls to avoid predators.

✅ Hedgehog – Correct: Rolls into a tight ball with spines covering vulnerable soft belly parts when threatened.
❌ Marmot – Incorrect: Does not roll up; uses burrows and vocal warning calls as primary defense against predators.
✅ Pangolin – Correct: Rolls into a protective ball, using overlapping keratin scales as armor to shield vulnerable underside.

📝 Short Notes: Defensive Mechanisms in Animals

• Hedgehog: Small spiny mammals found in Europe, Asia, and Africa; covered with about 5,000-7,000 spines made of keratin; rolls into a ball when threatened, making it difficult for predators to attack.
• Pangolin: Only mammal covered in scales; found in Asia and Africa; scales made of keratin (same material as human nails); listed as critically endangered due to illegal wildlife trade; all eight species protected under CITES.
• Marmot: Large ground squirrels found in mountainous areas; social animals living in burrows; use sentinel behavior where one individual watches for predators while others forage; emit high-pitched whistles as alarm calls.
• Other Rolling Animals: Armadillos (three-banded armadillo can roll completely), pill millipedes, pill bugs (woodlice), and some species of armored caterpillars also use rolling as defense.
• Types of Defense Mechanisms: Physical barriers (spines, scales, shells), camouflage, warning coloration, chemical defense (toxins), behavioral (fleeing, freezing, rolling), and group defense.

Detailed Explanation:

Answer: Option 3 — Oyster

Oysters are filter feeders that strain suspended matter and food particles from water by passing it over specialized filtering structures called gills. Among the given options, only oysters possess this feeding mechanism, while catfish are bottom feeders, octopuses are predators, and pelicans are visual hunters that catch fish.

📝 Short Notes: Filter Feeders

• Definition: Filter feeders are organisms that feed by straining suspended matter and food particles from water through specialized filtering structures.
• Common Examples: Clams, oysters, mussels, sponges, krill, baleen whales, and certain fish including some sharks.
• Avian Filter Feeders: Flamingos and certain duck species use filter feeding mechanisms.
• Ecological Role: Filter feeders act as ecosystem engineers by clarifying water and removing suspended particles, improving water quality.
• Bioaccumulation: They serve as indicator organisms due to their role in bioaccumulation of pollutants and toxins from water.
• Pearl Production: Oysters and mussels are commercially important for pearl farming, practiced in states like Gujarat, Maharashtra, Kerala, Odisha, and others in India.