Question map
Consider the following statements : 1. Some species of turtles are herbivores. 2. Some species of fish are herbivores. 3. Some species of marine mammals are herbivores. 4. Some species of snakes are viviparous. Which of the statements given above are correct?
Explanation
The correct answer is option D because all four statements are correct.
**Statement 1 is correct:** Green sea turtles are unique among sea turtles in that they are primarily herbivores, eating mostly seagrasses and algae.[1]
**Statement 2 is correct:** While not explicitly covered in the provided sources, it is well-established scientific knowledge that several fish species (such as parrotfish, surgeonfish, and rabbitfish) are herbivorous, feeding on algae and plant matter.
**Statement 3 is correct:** Dugong and manatees are herbivorous marine mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine[2] waters. Additionally, Dugong, a mammal-dependent resident of sea grass for food, is also on the verge of extinction.[3]
**Statement 4 is correct:** Sea Kraits are one of the few sea snakes that go to land to lay their eggs, while most others, like the Olive sea snake will give birth in the water.[4] This confirms that some snake species are viviparous (giving live birth) rather than oviparous (laying eggs).
Therefore, all four statements (1, 2, 3, and 4) are correct, making option D the right answer.
Sources- [1] https://www.fisheries.noaa.gov/feature-story/10-tremendous-turtle-facts
- [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 12: Animal Diversity of India > r:2..2.2, Herbivorous Marine Mammals > p. 189
- [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > Bo you know? > p. 209
- [4] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > Do you know? > p. 207
PROVENANCE & STUDY PATTERN
Full viewThis question looks like a biology bouncer but is actually a logic test wrapped in standard static GK. Statements 3 and 4 are direct lifts from Shankar IAS 'Do You Know' boxes. Statements 1 and 2 rely on the 'Power of Some'—in vast taxonomic groups like fish and turtles, finding one exception makes the statement true. Trust the 'Some' keyword in biodiversity questions.
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Explicitly states a sea turtle species is primarily herbivorous.
- Names the species (green sea turtle) and specifies plant foods (seagrasses and algae).
- Explicitly calls the green sea turtle the only herbivorous sea turtle.
- Clarifies that adults switch to an exclusively plant-based diet (algae, seaweed, seagrasses), supporting that at least one turtle species is herbivorous.
Gives a categorical difference: land-dwelling 'tortoises' are described as herbivorous while 'turtles' are called omnivorous.
A student could use this rule to check whether some taxa labelled 'tortoise' (land) are herbivorous and whether any aquatic 'turtle' groups deviate from the stated omnivory (e.g., specialized feeders).
Mentions seagrass and lists 'Green turtle' among sea turtles nesting on Indian coasts, linking that species to seagrass habitat.
Knowing seagrass is a plant, a student could investigate whether species associated with seagrass (e.g., Green turtle) feed on it and thus are herbivorous.
Lists the Green and other named sea turtles found in Indian waters, providing specific species to examine for diet differences.
A student could take the named species (Green, Olive ridley, Hawksbill) and look up or test diet differences to see which are plant-eaters.
Defines the 'grazing food chain' and that herbivores are primary consumers eating plant material.
Combine this trophic concept with species-habitat links (e.g., turtle species found on seagrass beds) to infer possible herbivory and then verify with species-specific diet data.
Gives general examples and definition of herbivores/omnivores vs carnivores, establishing the classification framework for animal diets.
Use this classification framework to categorize turtles/tortoises by observed diets or by known habitats (land vs aquatic) to hypothesize which are herbivores.
Describes an aquatic grazing food chain: phytoplankton (producers) → zooplankton → fishes, showing fishes occupy consumer roles in aquatic chains.
A student could note that if fishes occupy distinct consumer levels, some might feed lower (on plants/phytoplankton) rather than only on zooplankton or other animals, and then check examples or ranges of fish diets on a species list.
States zooplankton transfer organic matter from primary producers to secondary consumers like fishes, highlighting the existence of multiple trophic links in aquatic systems.
One could infer that aquatic food webs include direct links from producers to consumers and then look for fish taxa that feed directly on algae or plants (primary consumers) versus those feeding on zooplankton.
Notes marine flora includes algae and seaweeds — abundant plant/plant-like resources in aquatic environments.
A student could combine this with knowledge of fish mouthparts/feeding behavior (from external sources) to identify species adapted to grazing on algae/seaweed.
Explains food webs provide multiple alternative food links and that herbivores may serve multiple predators, emphasizing dietary diversity and shifts.
Use this rule to expect dietary variation among fish — some species may specialize on plant material while others shift seasonally — and then search species-specific diet data.
Mentions major diversification of fishes in the Devonian ('age of the fishes'), implying evolutionary diversification in form and likely in feeding strategies.
A student can reasonably infer that among diversified fish lineages some evolved herbivorous feeding modes, and then verify with modern taxonomic/dietary records.
- Explicit heading identifies 'Herbivorous Marine Mammals' and lists dugong and manatees.
- Places these species in swamps, estuaries and coastal marine waters, confirming marine habitat.
- Specifies dugong as a mammal that depends on seagrass for food, directly demonstrating herbivory.
- Highlights conservation concern for seagrass, linking habitat and dietary dependence.
- Lists Dugong (Sea Cow) among marine mammals, reinforcing identity of a herbivorous marine mammal.
- Associates dugong with the Indian Ocean region, situating the species within marine fauna.
- Explicitly contrasts sea kraits (egg-laying) with Olive sea snake which "will give birth in the water".
- Names a specific snake (Olive sea snake) that gives live birth, demonstrating viviparity in snakes.
- Shows reproductive variation within sea snakes (some oviparous, some viviparous).
- States that some animals lay eggs while others directly give birth, establishing the general biological categories oviparity vs viviparity.
- Provides a general reproductive framework that supports interpreting snake exceptions as possible live-bearing.
- [THE VERDICT]: Logical Sitter. Statements 3 and 4 are directly in Shankar IAS (Chapter: Marine Organisms). Statements 1 and 2 are safe bets based on biological diversity.
- [THE CONCEPTUAL TRIGGER]: Functional roles in Ecosystems (Grazers vs Predators) and Reproductive anomalies (Oviparous vs Viviparous).
- [THE HORIZONTAL EXPANSION]: Memorize these specific biological exceptions: 1. Herbivorous Marine Mammals: Dugong (Sea Cow), Manatee. 2. Viviparous Reptiles: Sea Snakes (e.g., Olive Sea Snake), Vipers, Boas. 3. Herbivorous Turtles: Green Sea Turtle (adults eat seagrass). 4. Egg-laying Mammals: Platypus, Echidna. 5. Herbivorous Fish: Parrotfish, Surgeonfish (crucial for coral health).
- [THE STRATEGIC METACOGNITION]: Do not memorize lists of 10,000 species. Instead, memorize the *rule breakers*. If the standard rule is 'Reptiles lay eggs', specifically hunt for reptiles that give live birth. If the rule is 'Mammals give birth', hunt for those that lay eggs. UPSC targets the exceptions.
Tortoises are land-dwelling and herbivorous, while turtles are water-dwelling and described as omnivorous.
High-yield for ecology and biodiversity questions: distinguishes similar reptiles by habitat and trophic role, useful for conservation and species classification questions. Helps answer questions comparing terrestrial and aquatic adaptations and diets.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 12: Animal Diversity of India > Do ycu know? > p. 188
Herbivores consume plants and occupy the primary consumer level in grazing food chains.
Core ecology concept frequently tested in UPSC: explains energy flow, trophic levels and food web interactions. Mastery allows quick elimination in MCQs about producers/consumers and supports answers on ecosystem functions and food chain examples.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 1: Ecology > Herbivores are primary consumers which feed > p. 7
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > i) Grazing food chain > p. 12
Several named sea turtle species (Green, Olive ridley, Hawksbill, Leatherback) are listed with habitat and conservation notes.
Important for environment and biodiversity syllabi: links species identification to conservation status, threats and policy (Wildlife Protection Act). Useful in policy, biodiversity and coastal ecology questions.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.9. SEA TURTTE PROJECT > p. 242
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 11: Schedule Animals of WPA 1972 > i\,/^] 'Jr-14 EhrutR# * ,EH?", > p. 183
The aquatic grazing food chain runs from phytoplankton to zooplankton to fish, which frames the question of whether fish consume primary producers directly.
High-yield for ecology questions: understanding this chain clarifies trophic transfers in marine and freshwater systems, underpins discussions of fisheries and energy flow, and helps answer questions about trophic roles and food-web impacts.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > i) Grazing food chain > p. 12
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > 14.3. ZOOPLANKTON > p. 209
Algae and seaweeds form the base of marine food webs as primary producers, providing the plant material that would be consumed by herbivores.
Important for questions on marine ecology and resource management: knowing what constitutes primary production explains productivity, supports arguments about ecosystem services and fisheries, and links to nutrient cycling and habitat value.
- Exploring Society:India and Beyond. Social Science-Class VI . NCERT(Revised ed 2025) > Chapter 2: Oceans and Continents > Oceans > p. 31
Herbivores are defined as primary consumers feeding on plants, while carnivores feed on consumers; this classification applies across terrestrial and aquatic ecosystems.
Core ecological concept frequently tested: mastering trophic classifications aids in answering questions on food chains, ecological pyramids, energy flow, and human impacts on ecosystems; it connects ecology to conservation and resource-use topics.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > i) Grazing food chain > p. 12
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 1: Ecology > Herbivores are primary consumers which feed > p. 7
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Producers and Consumers > p. 30
Dugong and manatee are concrete examples of marine mammals that feed on aquatic plants.
High-yield for biodiversity and conservation questions: knowing flagship herbivorous marine mammals helps answer questions on species diets, habitat-specific threats, and protection priorities. Connects to topics on marine biodiversity, species lists, and conservation policy.
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 12: Animal Diversity of India > r:2..2.2, Herbivorous Marine Mammals > p. 189
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > Bo you know? > p. 209
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > x) not evaluated (ne) > p. 16
The same Shankar IAS page contrasting Sea Snakes (viviparous) mentions 'Sea Kraits'. The Shadow Fact: Sea Kraits are amphibious and come to land to lay eggs (Oviparous), unlike true Sea Snakes which never leave water. Also, look out for 'Sea Horses'—where the male carries the eggs.
The 'Impossibility Test'. For statement 2 ('Some fish are herbivores') to be false, EVERY fish species in the ocean must be a carnivore. Given the sheer size of the ocean, this is logically improbable. In biodiversity, 'Some' is almost always True; 'All' or 'None' is almost always False.
Link Herbivorous Fish/Turtles to GS-3 Environment (Coral Reefs). Herbivores (like Parrotfish) are 'Algal Grazers'. If they are overfished, algae overgrow and kill corals (Phase Shift). This connects biodiversity directly to Climate Resilience and the Blue Economy.