Q.In a given habitat we have 20 plant species and 20 animal species. Should we call this as 'diversity' or 'biodiversity'? Justify your answer.
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Biodiversity: The Web of Life Around You
Imagine walking into a kitchen garden. You see a few tomato plants, some mint, maybe a rose bush. Now imagine walking into a forest — hundreds of tree species, birds calling from every direction, insects crawling under leaves, fungi on the bark, and a stream with tiny fish. That staggering variety of living things — from the tallest tree to the invisible bacteria in the soil — is what we call biodiversity.
The Simple Intuition
Biodiversity is short for biological diversity. Think of it as the "variety of life" on Earth. Just as a library with only one kind of book is boring and limited, an ecosystem with only one kind of plant or animal is fragile and poor. Biodiversity is nature's library — the more species, the richer and more stable the system.
The Precise Meaning
The NCERT textbook defines biodiversity as:
The variety of living organisms present on Earth, including the different plants, animals, fungi, and microorganisms, their genes, and the ecosystems they form.
This definition has three layers, and each matters:
- Genetic diversity — variation within a species. For example, all humans are one species, but we have different eye colours, heights, and resistance to diseases. In crops, genetic diversity means some wheat varieties resist drought while others resist pests.
- Species diversity — the number of different species in a region. A tropical rainforest has thousands of species; a cold desert has very few.
- Ecological diversity — the variety of habitats, ecosystems, and communities. A forest, a grassland, a coral reef, and a pond are all different ecosystems.
Biodiversity is not just about counting species. It includes the genes inside each species and the ecosystems they create together. Lose one layer, and the others suffer.
Why Does Biodiversity Matter?
For a commerce or humanities student, the question is natural: why should I care about how many beetles live in a forest? The answer is that biodiversity is the foundation of everything we use and consume.
Direct economic value — We depend on biodiversity for food (crops, fish, livestock), medicine (many drugs come from plants and fungi), raw materials (timber, cotton, rubber), and tourism (wildlife sanctuaries, national parks).
Indirect value — This is harder to see but more critical. Forests clean the air, wetlands purify water, bees pollinate crops, and soil microbes recycle nutrients. These are called ecosystem services. If biodiversity collapses, these services stop — and no technology can replace them at scale.
Ethical and cultural value — Every species has a right to exist, regardless of its usefulness to humans. Many cultures, especially in India, revere certain trees, animals, and rivers as sacred. Biodiversity is also a source of beauty, inspiration, and knowledge.
The NCERT textbook emphasises that biodiversity is our life insurance. It gives us resilience — when one species fails due to disease or climate change, another can take its place. A system with low biodiversity (like a wheat monoculture) is one disease away from collapse.
A Quick Look at India's Biodiversity
India is one of the world's mega-diverse countries. Though it has only 2.4% of the world's land area, it contains about 8% of all known species. This includes:
- Over 45,000 plant species
- More than 90,000 animal species
- 10 biogeographic zones — from the Himalayas to the Western Ghats to the Andaman Islands
This richness is not accidental. India's varied climate, geography, and ancient landmass have allowed many species to evolve and survive here.
The Threat: Why We Talk About It …
This should be called biodiversity, not simply diversity.
- Biodiversity refers specifically to the number and variety of organisms found in a given area — plants and animals together.
- Since the habitat here has both 20 plant species and 20 animal species, it is describing the richness of living organisms as a whole across both major groups. …
A habitat containing 20 plant species and 20 animal species together is an example of biodiversity, the term specific to the richness of living organisms in an area.
Biodiversity is defined as the number and variety of organisms found within a given area or region. It is not restricted to plants alone or animals alone — it takes in the full range of living organisms present.
- In this scenario, the habitat contains 20 different plant species and 20 different animal species, adding up to a combined richness of living organisms in that one area.
- Because this figure spans both plants and animals together, it precisely matches what biodiversity is meant to describe, rather than a narrower or more general use of the word 'diversity'. …
Showing the 12 most recent of 14 on this concept.
- AP EAPCET 2026Set ap-2026-05-19-FN1 markMCQQ.Study the following and pick up the correct statements: I. Beta diversity is measured by counting the number of taxa within a particular area. II. In tropical regions, biodiversity is more. III. Tilman stated that increased diversity contributed to higher productivity. IV. Cryopreservation is a type of in-situ conservation. (A) I, II (B) II, III (C) III, IV (D) II, IV
›Reveal solutionSolution
This tests recall of core biodiversity concepts (alpha vs beta diversity, latitudinal gradient, Tilman's productivity-diversity link, and ex-situ vs in-situ conservation). The correct statements are II and III.
Concept and Intuition
Ecologists describe biodiversity at three scales: alpha (within one community/habitat), beta (turnover of species composition between habitats along a gradient), and gamma (over a whole landscape/region). Species richness patterns also follow a latitudinal gradient — species diversity is consistently higher near the equator and falls as you move towards the poles. Separately, ecologist David Tilman's long-term grassland plot experiments in Minnesota showed that plots with more species were more productive and showed less year-to-year variation in productivity — diversity is not just a passenger of ecosystem function, it drives it. Conservation strategies are split into in-situ (protecting species in their natural habitat, e.g., national parks, biosphere reserves) and ex-situ (protecting components of biodiversity outside their natural habitat, e.g., zoos, botanical gardens, seed banks, cryopreservation of gametes/embryos/DNA).
Step-by-Step Solution
- Statement I says beta diversity is "measured by counting the number of taxa within a particular area" — that description is actually alpha diversity. Beta diversity instead measures the difference/turnover in species composition between two habitats/communities. So I is false.
- Statement II — tropical regions do show markedly higher biodiversity than temperate or polar regions, a well-established ecological generalisation. True. …
- AP EAPCET 2026Set ap-2026-05-19-AN1 markMCQQ.Study the following and pick up the incorrect statements: I. Amazon rain forests are the lungs of our planet earth. II. Invasion of alien species lead to the extinction of Steller's sea cow. III. Anticancer drug vinblastin is extracted from the plant Digitalis. IV. Red Data Book is published by IUCN. (A) I, II (B) II, IV (C) I, III (D) II, III
›Reveal solutionSolution
Steller's sea cow went extinct from human overhunting (not alien-species invasion), and vinblastine comes from Catharanthus roseus (not Digitalis) — these are the two incorrect statements. Answer: (D) II, III.
Concept and Intuition
Biodiversity/conservation questions often test precise cause-effect and source-product pairings that are easy to conflate with superficially similar, more famous examples. The textbook example of extinction driven by "invasion of an alien species" is the introduction of the predatory Nile perch into Lake Victoria, which wiped out over 200 endemic cichlid fish species — Steller's sea cow, by contrast, was hunted to extinction by sailors within about 27 years of its discovery, a case of direct overexploitation, not species invasion. Similarly, in pharmacognosy, vincristine and vinblastine (important anticancer alkaloids) are extracted from Catharanthus roseus (Madagascar periwinkle/Vinca), while Digitalis (foxglove) is the classic source of cardiac glycosides (digoxin/digitoxin) used for heart conditions, not cancer.
Step-by-Step Solution
- Statement I: "Amazon rain forests are the lungs of our planet" — a commonly accepted description of the Amazon's role in oxygen production/carbon cycling. Taken as correct.
- Statement II: "Invasion of alien species led to extinction of Steller's sea cow" — false; Steller's sea cow was hunted to extinction directly by humans, not displaced by an invasive species. INCORRECT. …
- AP EAPCET 2026Set ap-2026-05-20-AN1 markMCQQ.Identify the major threats to Biodiversity, that is, the evil quartette from the following: I. Invasion of local species II. Over exploitation III. Introduction of alien species IV. Sanctuaries V. Habitat loss VI. Long photoperiod VII. Co-extinction (A) I, III, VI, VII (B) I, II, V, VII (C) II, III, V, VII (D) III, IV, VI, VII
›Reveal solutionSolution
This tests the "evil quartet" of biodiversity loss — habitat loss,
over-exploitation, alien-species invasion, and co-extinctions — correctly matched
to II, III, V, VII.
Concept and Intuition
Ecologists commonly summarise the four dominant causes of accelerating species loss
as the "evil quartet":
- Habitat loss and fragmentation — the single most important cause (e.g. deforestation of tropical rainforests).
- Over-exploitation — harvesting a species faster than it can replenish itself (e.g. Steller's sea cow, passenger pigeon driven extinct this way).
- Invasion by alien (exotic) species — non-native species introduced deliberately or accidentally that outcompete, prey on, or bring disease to native species (e.g. Nile perch in Lake Victoria).
- Co-extinctions — when an obligately dependent species (a specific host-specific parasite, a pollinator, etc.) goes extinct because the species it depended on went extinct first.
Step-by-Step Solution
- Go through the seven listed items and classify each: I says "Invasion of local species" — this is a misstatement; the real threat is invasion by alien species, not local ones, so I is wrong as worded.
- II "Over exploitation" — matches the evil quartet directly. Correct.
- III "Introduction of alien species" — matches the evil quartet (alien species invasion). Correct.
- IV "Sanctuaries" — sanctuaries are a conservation tool, the opposite of a threat. Wrong. …
- AP EAPCET 2025Set ap-2025-05-19-AN1 markMCQQ.Which factor primarily contributes to greater biodiversity in the tropics ? (A) Large seasonal variations (B) High niche specialization (C) Frequent habitat distrubances (D) Low resource availability
›Reveal solutionSolution
The relatively stable, less-seasonal tropical climate promotes high niche specialisation, and that specialisation is the key ecological driver of the tropics' much greater species diversity.
Concept and Intuition
Ecologists (e.g., in discussions following Odum's and MacArthur's work, as summarised in NCERT's biodiversity chapter) explain the latitudinal diversity gradient (more species near the equator, fewer toward the poles) using several complementary explanations: tropical environments are less seasonal, more constant, and more predictable, which promotes greater species interactions and allows organisms to specialise into narrower ecological niches rather than needing broad tolerances to survive seasonal swings. This niche specialisation, in turn, allows many more species to coexist by dividing up resources finely rather than competing broadly for the same ones.
Step-by-Step Solution
- Rule out (A) "Large seasonal variations" — this is actually characteristic of temperate, not tropical, regions, and large seasonal swings tend to reduce diversity by favouring generalist survivors.
- Rule out (C) "Frequent habitat disturbances" — frequent disturbance generally reduces stable niche differentiation and tends to lower, not raise, long-term diversity. …
- AP EAPCET 2025Set ap-2025-05-19-FN1 markMCQQ.It is not considered an alien species in India (A) Lantana (B) Nile Perch (C) Parthenium (D) Echhornia
›Reveal solutionSolution
This tests recognition of India-specific alien/invasive species; three options are well-known Indian invasives, while Nile Perch is a non-Indian (African) case study.
Concept and Intuition
Alien species are organisms introduced (deliberately or accidentally) outside their native range that often become invasive, outcompeting native species. Indian biology texts list specific invasive alien species established in India as case studies, and separately cite the Nile perch/Lake Victoria case as a classic example of extinction caused by an introduced predator — that event occurred in Africa, not India.
Step-by-Step Solution
- Lantana camara — an ornamental shrub from tropical America, now a widespread invasive weed across Indian forests and grasslands.
- Parthenium hysterophorus ("congress grass") — introduced from the Americas, now a common invasive weed across India, especially wastelands and roadsides.
- Eichhornia crassipes (water hyacinth) — introduced ornamental aquatic plant from South America, now clogs Indian water bodies as an invasive. …
- AP EAPCET 2025Set ap-2025-05-20-AN1 markMCQQ.Find the mismatched pair (A) In-situ conservation - National Park (B) Ex-situ conservation - Botanical garden (C) In-situ conservation - Seed bank (D) Ex-situ conservation - Cryopreservation
›Reveal solutionSolution
Seed banks store germplasm ex-situ, outside the organism's natural habitat, so pairing them with 'in-situ' is the mismatch.
Concept and Intuition
In-situ conservation protects species within their natural habitat (e.g. National Parks, Biosphere Reserves). Ex-situ conservation protects them outside their natural habitat, in controlled facilities — botanical gardens, zoos, cryopreservation facilities, AND seed banks. So 'In-situ conservation – Seed bank' is the mismatched pair; seed banks are an ex-situ method.
Step-by-Step Solution
- National Park is a correct example of in-situ conservation — (A) is a valid pair.
- Botanical garden is a correct example of ex-situ conservation — (B) is a valid pair. …
- AP EAPCET 2025Set ap-2025-05-20-AN1 markMCQQ.The species diversity between two adjacent ecosystems is (A) α-diversity (B) β-diversity (C) γ-diversity (D) δ-diversity
›Reveal solutionSolution
Diversity compared BETWEEN ecosystems (species turnover across habitats) is beta diversity, as distinct from within-habitat (alpha) or regional (gamma) diversity.
Concept and Intuition
α-diversity is the diversity of species within a single community/habitat. β-diversity compares the diversity (species turnover) between two different communities/ecosystems. γ-diversity is the total diversity across a larger landscape or region encompassing multiple ecosystems.
Step-by-Step Solution
- Within one ecosystem → α-diversity.
- Between two adjacent ecosystems → β-diversity.
- Across an entire region/landscape → γ-diversity. …
- AP EAPCET 2024Set ap-2024-05-16-AN1 markMCQQ.Pick up the ex-situ conservation method (A) National Parks (B) Sanctuaries (C) Gene Banks (D) Sacred Groves
›Reveal solutionSolution
Gene banks preserve genetic material outside the organism's natural habitat, making them a textbook ex-situ conservation method, unlike national parks, sanctuaries, and sacred groves, which are all in-situ.
Concept and Intuition
Conservation strategies are broadly divided into in-situ (protecting species within their natural habitat/ecosystem) and ex-situ (protecting species outside their natural habitat, in artificial or controlled settings). National parks and wildlife sanctuaries are protected areas that conserve entire ecosystems and their resident species in place, a classic in-situ method. Sacred groves are community-protected patches of natural vegetation, also conserving biodiversity in its original habitat, again in-situ. Gene banks, by contrast, store seeds, pollen, tissue cultures, or cryopreserved genetic material away from the organism's natural environment, specifically to safeguard genetic diversity for future use, the defining feature of ex-situ conservation.
Step-by-Step Solution
- National Parks protects species/ecosystems in their natural setting -> in-situ.
- Sanctuaries similarly protects wildlife in their natural habitat -> in-situ.
- Gene Banks stores genetic material (seeds, germplasm) outside the natural habitat -> ex-situ. …
- AP EAPCET 2024Set ap-2024-05-17-AN1 markMCQQ."Increased diversity contributed to higher productivity". It was stated by (A) Paul Ehrlich (B) Alexander Von Humboldt (C) Tilman (D) Edward Wilson
›Reveal solutionSolution
Tilman's grassland experiments established the diversity–productivity–stability relationship, showing plots with more species were more productive and more resistant to environmental perturbations.
Concept and Intuition
Ecologists have long asked whether biodiversity affects ecosystem functioning. David Tilman ran multi-year field experiments in Minnesota grassland plots, varying the number of plant species per plot and measuring total biomass production, finding that more diverse plots consistently produced more biomass and recovered better from drought.
Step-by-Step Solution
- Paul Ehrlich is known for the "rivet popper hypothesis" about species loss, not the diversity–productivity link.
- Alexander von Humboldt is known for early descriptions of species-area relationships in different regions.
- Edward Wilson is a key figure in island biogeography and biodiversity conservation broadly, not specifically this productivity experiment. …
- AP EAPCET 2024Set ap-2024-05-17-FN1 markMCQQ.Study the following and identify the incorrect combinations
List-1 List-2 List-3 I Wild life protection society of India Dehradun Preventing the destruction of Indian wild life II Earth summit Rio de Janiero Protecting the diverse living forms III Zoological survey of India Kolkata Preventing the over – exploitation of resources IV World summit South America Sustainable development (A) I, II (B) III, IV (C) II, III (D) I, IV ›Reveal solutionSolution
The question asks to identify which combinations in the table are factually incorrect. By checking each row against known facts, we find that rows III and IV contain errors, so the incorrect combinations are III and IV, corresponding to option (B).
The key here is to recall basic environmental and institutional facts. Each row pairs an organization/event (List-1) with its location (List-2) and its primary purpose (List-3). We need to spot mismatches.
-
Row I: Wildlife Protection Society of India – Dehradun – Preventing the destruction of Indian wildlife
The Wildlife Protection Society of India (WPSI) is indeed headquartered in Dehradun, and its mission is to protect Indian wildlife, especially from poaching and habitat loss. This combination is correct.
-
Row II: Earth Summit – Rio de Janeiro – Protecting the diverse living forms
The Earth Summit (1992) was held in Rio de Janeiro, Brazil. Its main outcomes included the Convention on Biological Diversity, which aims to protect biodiversity (“diverse living forms”). This combination is correct.
-
Row III: Zoological Survey of India – Kolkata – Preventing the over-exploitation of resources
The Zoological Survey of India (ZSI) is headquartered in Kolkata, but its purpose is to survey, study, and document the fauna of India, not to prevent over-exploitation of resources. Preventing over-exploitation is more the role of organizations like the Forest Department or the Ministry of Environment. So this combination is incorrect.
-
Row IV: World Summit – South America – Sustainable development …
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- AP EAPCET 2023Set ap-2023-05-22-AN1 markMCQQ.Choose the incorrect pair among the following A. Biosphere reserve – Indo Burma region B. Aravalli Hills – Rajasthan and Gujarat. C. Koringa sanctuary - Uttarakhand. D. Biodiversity hotspot – Himalayan region. (A) B, C (B) A, C (C) A, D (D) B, D
›Reveal solutionSolution
A wrongly labels Indo-Burma (a biodiversity hotspot) as a "Biosphere reserve," and C wrongly places Koringa Sanctuary in Uttarakhand instead of Andhra Pradesh — these are the two incorrect pairs.
Concept and Intuition
This question tests precise recall of India's protected-area/biodiversity geography: distinguishing the "biodiversity hotspot" designation (a global conservation-priority category, e.g. Indo-Burma, Himalaya, Western Ghats, Sundaland) from specific named biosphere reserves, and knowing the correct state locations of specific named sanctuaries.
Step-by-Step Solution
- A: "Biosphere reserve – Indo Burma region" — Indo-Burma is internationally recognised as a biodiversity hotspot, not the name of a designated biosphere reserve — this pairing is incorrect.
- B: "Aravalli Hills – Rajasthan and Gujarat" — the Aravalli range genuinely runs through Rajasthan and Gujarat (extending further into Haryana/Delhi) — this pairing is correct.
- C: "Koringa sanctuary - Uttarakhand" — Koringa Wildlife Sanctuary is actually located in Andhra Pradesh (East Godavari district, a mangrove sanctuary), not Uttarakhand — this pairing is incorrect. …
- AP EAPCET 2023Set ap-2023-05-23-AN1 markMCQQ.Punishable offence under Wildlife Act of 1972 is (A) Reduction in rate of loss of biodiversity (B) Protection of wild life in natural habitats (C) Publishing Red Data Book (D) Trading wild life products
›Reveal solutionSolution
The Wildlife Protection Act, 1972 exists to prevent harm to wildlife — so among the options, only trading in wildlife products is an actual punishable offence; the rest are conservation objectives.
Concept and Intuition
The Wildlife (Protection) Act, 1972 is Indian legislation enacted to protect wild animals and plants, regulate hunting, and control trade in wildlife-derived products. Its provisions criminalise activities like poaching, hunting of protected species, and trade in animal skins, horns, ivory, and other wildlife products. Reducing the rate of biodiversity loss, protecting wildlife in natural habitats, and publishing the Red Data Book are all conservation goals/tools the Act (and related bodies like IUCN) works towards — they are not offences; rather, they describe what the Act aims to achieve or the documentation it uses.
Step-by-Step Solution
- Recognise the Act's purpose: to prevent harm to wildlife, not merely to describe conservation goals.
- Eliminate (A) 'Reduction in rate of loss of biodiversity' — this is an aim, not an offence. …
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