Biodiversity and Conservation for NEET: Chapter 13 Guide

Biodiversity and Conservation for NEET: Chapter 13 Guide

Biodiversity and conservation is Chapter 13 of NCERT Class 12 Biology, the last chapter of the book, and for NEET it is the third bullet of Unit 10, Ecology and Environment. It is not deleted. It covers the three levels of biodiversity, how many species exist, the patterns of diversity, why species are lost and how we protect them. This guide maps biodiversity and conservation to the NMC syllabus line by line and lists the traps that cost marks.

What is biodiversity and conservation in NEET?

Biodiversity and conservation in NEET is the study of the variety of life at every level of biological organisation and of the methods used to protect it, as NCERT Class 12 Biology Chapter 13 teaches it. Questions test the levels of diversity, species numbers, the latitudinal gradient, the species-area relationship, causes of loss and in situ versus ex situ conservation.

The NCERT Chapter 13 PDF is short: two sections, three figures and a summary. Most of it is examples and numbers, and that is exactly how NTA builds one-line options. A question rarely asks you to explain biodiversity. It asks which country is mega diverse, which slope value is right, or which pair of species is an example of co-extinction.

So the method for biodiversity and conservation is simple. Learn every example with its group, learn every number with its unit, and keep NCERT's wording for the definitions.

Is biodiversity and conservation deleted for NEET?

No. Biodiversity and conservation is in the current NEET syllabus. The NMC syllabus for NEET (UG) 2026, dated 22 December 2025, lists "Biodiversity and its conservation" as the third bullet of Unit 10, Ecology and Environment, next to organisms and environment and the ecosystem.

The confusion comes from the old Environmental Issues chapter. The rationalised NCERT Class 12 book (reprint 2026-27) now ends at Chapter 13, Biodiversity and Conservation, with no Environmental Issues chapter, and pollution topics do not appear in Unit 10 at all. Students hear "an ecology chapter was deleted" and assume it was this one. It wasn't. Our NEET 2027 deleted syllabus explainer lists what actually went out.

One caution for the next cycle. NTA had not published a NEET (UG) 2027 bulletin or syllabus on neet.nta.nic.in by 14 November 2026. Until it does, the 2026 syllabus is the latest official version, and this guide follows it.

Syllabus phrase (Unit 10, third bullet)	Where NCERT teaches it	What questions ask
Concept of Biodiversity	13.1	Three levels, who popularised the term
Patterns of Biodiversity	13.1.2	Latitudinal gradient, species-area relationship, Z values
Importance of Biodiversity	13.1.3	Tilman's plots, rivet popper hypothesis
Loss of Biodiversity	13.1.4	Extinction numbers, the evil quartet, examples
Biodiversity conservation	13.2.1 and 13.2.2	Three reasons to conserve, in situ and ex situ
Hotspots	13.2.2	34 worldwide, three covering India
Endangered organisms, extinction	13.1.4 and 13.2.2	Threatened shares by group, recent extinctions
Red Data Book	Not named in the chapter	Recognise the term (see below)
Biosphere reserves, National parks and sanctuaries, Sacred Groves	13.2.2	14, 90 and 448; where sacred groves are

Biodiversity and conservation also ties into the rest of Unit 10, and its first lines on taxonomy echo Class 11. If you want the whole Biology picture first, our NEET Biology syllabus guide puts Unit 10 next to the other nine units.

What are the three levels of biodiversity?

The three levels of biodiversity are genetic diversity, species diversity and ecological diversity. NCERT says biodiversity is the combined diversity at all levels of biological organisation, from macromolecules to biomes, and credits the sociobiologist Edward Wilson with popularising the term. Each level has one fixed NCERT example.

Level	What it means	NCERT example
Genetic diversity	Variation within one species across its range	Rauwolfia vomitoria in different Himalayan ranges differs in reserpine; India has more than 50,000 strains of rice and 1,000 varieties of mango
Species diversity	Variety of species in an area	Western Ghats have more amphibian species than the Eastern Ghats
Ecological diversity	Variety of ecosystems	India (deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, alpine meadows) beats Norway

The trap here is the plant. In biodiversity and conservation MCQs, Rauwolfia is the genetic diversity example, and the chemical is reserpine. NTA can swap either word.

How many species are there on earth and in India?

According to NCERT, the IUCN (2004) put the number of described plant and animal species at slightly more than 1.5 million. Robert May's conservative estimate of global species diversity is about 7 million, while extreme estimates run from 20 to 50 million. India has 2.4% of the world's land area but 8.1% of its species diversity.

Those two percentages make India one of the 12 mega diversity countries in NCERT's list, a line that biodiversity and conservation questions quote almost word for word. India has nearly 45,000 recorded plant species and twice as many animals. If May is right, only 22% of species have been recorded so far, so India may still hold more than 1,00,000 undescribed plant species and more than 3,00,000 animal species.

Three ratios are tested again and again:

• More than 70% of recorded species are animals, and plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) are no more than 22%.
• Insects are more than 70% of all animals, so 7 of every 10 animals are insects.
• Fungi have more species than fishes, amphibians, reptiles and mammals combined.

Prokaryotes are left out of these estimates. NCERT's reason: classical taxonomy can't identify most microbial species, and many cannot be grown in the lab.

What patterns does biodiversity follow?

Biodiversity follows two main patterns in NCERT. First, the latitudinal gradient: species diversity falls as you move from the equator towards the poles. Second, the species-area relationship: species richness rises with the area explored, but only up to a limit, and the curve is a rectangular hyperbola.

Latitudinal gradient. Tropics (23.5° N to 23.5° S) hold more species. NCERT's bird numbers are a common question: Colombia has nearly 1,400 species, New York at 41° N has 105 and Greenland at 71° N only 56. India has more than 1,200. The Amazon rain forest has the greatest biodiversity on earth: more than 40,000 plant species, 3,000 fishes, 1,300 birds, 427 mammals, 427 amphibians, 378 reptiles and more than 1,25,000 invertebrates.

Why the tropics? NCERT gives three hypotheses. Speciation is a function of time, and the tropics escaped frequent glaciations, so they had longer to diversify. Tropical environments are less seasonal and more predictable, which favours niche specialisation. And more solar energy means higher productivity, which may indirectly support more species.

Species-area relationship. Alexander von Humboldt saw it in South American jungles. On a log scale the curve becomes a straight line:

log S = log C + Z log A

Here S is species richness, A is area, Z is the slope (regression coefficient) and C is the Y-intercept. For most regions, Z lies between 0.1 and 0.2, whatever the group. For very large areas such as whole continents, the slope is steeper, with Z between 0.6 and 1.2. Frugivorous birds and mammals in tropical forests across continents give a slope of 1.15.

Why does species diversity matter to an ecosystem?

Species diversity matters because richer communities tend to be more stable. David Tilman's long-term outdoor plot experiments showed that plots with more species had less year-to-year variation in total biomass, and that higher diversity also raised productivity. NCERT adds that ecologists still lack a definitive answer, so learn the experiment rather than a rule.

Paul Ehrlich's "rivet popper hypothesis" is the analogy NCERT uses. The airplane is the ecosystem and the rivets are species. Popping a few rivets may not crash the plane at first, but each loss weakens it. And losing a rivet on the wing (a key species) matters far more than one on a seat.

What causes the loss of biodiversity?

Biodiversity loss today is driven by human activities, and NCERT groups the causes into the "evil quartet": habitat loss and fragmentation, over-exploitation, alien species invasions and co-extinctions. Habitat loss is the most important of the four. Current extinction rates are estimated at 100 to 1,000 times faster than in pre-human times.

Cause	NCERT example
Habitat loss and fragmentation	Tropical rain forests fell from more than 14% of earth's land surface to no more than 6%; the Amazon is cleared for soya beans and cattle
Over-exploitation	Steller's sea cow and the passenger pigeon
Alien species invasions	Nile perch in Lake Victoria wiped out more than 200 cichlid fish species; Parthenium, Lantana and water hyacinth (Eicchornia); illegal African catfish Clarias gariepinus
Co-extinctions	A host fish and its parasites; a plant and its coevolved pollinator

The numbers behind the loss, all from section 13.1.4. The IUCN Red List (2004) records 784 extinctions in the last 500 years: 338 vertebrates, 359 invertebrates and 87 plants. Colonisation of the tropical Pacific Islands led to the extinction of more than 2,000 native bird species. Recent losses include the dodo, quagga, thylacine, Steller's sea cow and three tiger subspecies (Bali, Javan, Caspian). The last twenty years alone saw 27 species disappear. There have been five mass extinctions before; the "Sixth Extinction" differs because of its rate.

More than 15,500 species worldwide face extinction. The share differs a lot by group, and NEET likes this comparison.

In biodiversity and conservation terms, loss of biodiversity in a region can mean lower plant production, weaker resistance to disturbances such as drought, and more variability in processes like productivity, water use and pest and disease cycles.

Why should we conserve biodiversity?

NCERT gives three groups of reasons to conserve biodiversity: narrowly utilitarian, broadly utilitarian and ethical. Narrowly utilitarian means direct products such as food, fibre and medicines. Broadly utilitarian means ecosystem services such as oxygen and pollination. Ethical means every species has intrinsic value, and we owe its care to future generations.

The numbers attached to each are fair game in biodiversity and conservation papers. More than 25% of drugs sold worldwide come from plants, and 25,000 plant species are used in traditional medicine. Exploring diversity for useful products is called bioprospecting. On the broadly utilitarian side, the Amazon forest is estimated to produce 20% of the oxygen in earth's atmosphere through photosynthesis, and pollinators (bees, bumblebees, birds and bats) provide a service we could not easily replace.

What is in situ and ex situ conservation of biodiversity?

In situ conservation protects species in their natural habitat by protecting the whole ecosystem: we save the entire forest to save the tiger. Ex situ conservation takes threatened plants and animals out of their habitat and protects them in special settings such as zoological parks, botanical gardens, wildlife safari parks and seed banks.

	In situ (on site)	Ex situ (off site)
Where	Natural habitat	Outside the habitat, in special settings
Protects	Whole ecosystem, all levels of biodiversity	Individual threatened species
NCERT examples	Biodiversity hotspots, biosphere reserves, national parks, wildlife sanctuaries, sacred groves	Zoological parks, botanical gardens, wildlife safari parks, seed banks
Modern tools	Legal protection of areas	Cryopreservation of gametes, in vitro fertilisation, tissue culture

Hotspots. Hotspots are regions with very high species richness and a high degree of endemism (species found nowhere else). NCERT says 25 were identified first and nine added later, making 34. They cover less than 2% of earth's land area, and strict protection could cut ongoing mass extinctions by almost 30%. Three cover India: Western Ghats and Sri Lanka, Indo-Burma, and Himalaya.

Protected areas. NCERT's text says India has 14 biosphere reserves, 90 national parks and 448 wildlife sanctuaries.

Sacred groves. These are forest tracts protected by religious and cultural tradition. NCERT places them in the Khasi and Jaintia Hills of Meghalaya, the Aravalli Hills of Rajasthan, the Western Ghat regions of Karnataka and Maharashtra, and the Sarguja, Chanda and Bastar areas of Madhya Pradesh. In Meghalaya they are the last refuge of many rare plants.

International effort. The Convention on Biological Diversity was opened for signature on 5 June 1992 at the Rio "Earth Summit" and entered into force on 29 December 1993. NCERT adds the 2002 World Summit on Sustainable Development in Johannesburg, where 190 countries pledged to significantly reduce the rate of biodiversity loss by 2010.

Which numbers should you write: NCERT or the latest data?

Write NCERT's numbers in NEET. NTA sets Biology questions on the NCERT text, and the chapter's figures are what the answer key will expect. Newer official data exists and often differs, so read it as background, not as an answer. Here is how the main figures compare.

Fact	NCERT Chapter 13 (write this)	Newer official source (background only)
Hotspots covering India	3 of 34	4 of 34, adding Sundaland, in India's CBD country profile
India's share of world species	8.1%	"nearly 7-8%" (CBD profile)
Species recorded in India	About 45,000 plants, twice as many animals	Over 91,200 animals and 45,500 plants (CBD profile)
Protected areas	14 biosphere reserves, 90 national parks, 448 sanctuaries	679 protected areas: 102 national parks, 517 sanctuaries (CBD profile, from India's report on the 2020 Aichi targets)
Threatened species worldwide	More than 15,500	49,505 of 175,909 species assessed (IUCN Red List page, read 14 November 2026)

Notice that NCERT is not even consistent with itself. The text says 448 wildlife sanctuaries; the summary says more than 450. The text counts 784 extinctions since 1500; the summary says nearly 700. If an option says "448" or "784", pick it. If a question is built on the summary's wording, the options usually make it obvious.

What is the Red Data Book?

The Red Data Book is a printed record of threatened species with data sheets on each one: its status, distribution, habitat and conservation measures. The NMC syllabus names it, but NCERT Chapter 13 never uses the term. The chapter speaks of the IUCN Red List instead, which is the global list of extinction risk.

The IUCN Red List page explains that the same threatened-species categories are used in Red Data Books and Red Lists. It sorts species into nine categories: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern, Data Deficient and Not Evaluated. Only Vulnerable, Endangered and Critically Endangered count as threatened. For India, the Botanical Survey of India published The Indian plant red data book in 1984, with data sheets on 125 selected plants. That is enough to recognise the term in a statement question.

Ten traps in biodiversity and conservation questions

Most wrong answers in biodiversity and conservation come from the same ten swaps.

1. Biodiversity was popularised by Edward Wilson, not Robert May. May gave the estimate of about 7 million species.
2. Rauwolfia vomitoria is the genetic diversity example, and the chemical is reserpine.
3. Western Ghats beat Eastern Ghats in amphibians, which is species diversity, not ecological diversity.
4. Z is 0.1 to 0.2 for regions and 0.6 to 1.2 for continents. The 1.15 value is frugivorous birds and mammals.
5. The species-area curve is a rectangular hyperbola, and only on a log scale does it become a straight line.
6. Habitat loss is the most important cause of the evil quartet, not over-exploitation.
7. Nile perch and cichlids is an alien species invasion, not co-extinction. Host fish and parasites is co-extinction.
8. Steller's sea cow and the passenger pigeon are over-exploitation examples.
9. Three hotspots cover India in NCERT, and sacred groves are in situ, not ex situ.
10. Seed banks, cryopreservation and tissue culture are ex situ. National parks and biosphere reserves are in situ.

With negative marking at minus one for every wrong answer, two confusable options are where a guess costs most; our NEET negative marking guide shows when guessing pays.

How should you revise biodiversity and conservation?

Revise biodiversity and conservation in two focused days: section 13.1 on the first day, section 13.2 and the number table on the second. The chapter has few concepts and many facts, so the work is active recall of examples and figures, followed by timed questions. NTA does not publish chapter-wise question counts, so plan by syllabus coverage, not by a rumoured number.

1. Day 1, section 13.1. Read it once. Write the three levels with their examples from memory. Write the species numbers (1.5 million, 7 million, 2.4%, 8.1%, 45,000) and the bird gradient (1,400, 105, 56). Draw Figure 13.2 and label S, A, Z and C.
2. Day 1, evening. Write the evil quartet table without looking and add the extinction figures (784, 338, 359, 87). Check against the book and mark every miss.
3. Day 2, section 13.2. Write the three reasons to conserve, then the in situ and ex situ table. List the three hotspots, the 14, 90 and 448, and the sacred grove regions.
4. Day 2, test. Do 30 to 40 timed MCQs on biodiversity and conservation and log every wrong answer against the ten traps above.

Biology is half the paper. In the NEET (UG) 2026 information bulletin, it carries 90 of the 180 questions and 360 of the 720 marks, with plus four for a correct answer and minus one for a wrong one. A fact-heavy chapter like biodiversity and conservation is one of the cheapest places to collect those marks. Keep it fresh with steady NEET Biology MCQ practice, and check Figures 13.1 and 13.2 in our NEET Biology diagrams guide. The classification side of diversity sits in our plant kingdom guide, and the timescale behind extinctions in our evolution class 12 guide.

For the bigger picture, the NEET 2027 chapter-wise weightage guide on futureMBBS shows where Ecology stands next to the other Biology units. Its NEET syllabus overview puts all three subjects on one page, and its explainer what is an NCERT book helps if you are deciding how far beyond the textbook to read.

If biodiversity and conservation is where easy Biology marks keep slipping, NEETsheet's chapter-wise practice and timed mocks show whether the gap is the Z values, the evil quartet or the in situ list, so your next hour goes to the right place. Start at neetsheet.in.

Sources

All links were checked on 14 November 2026.

• National Medical Commission (UGMEB), Syllabus for NEET (UG) 2026, public notice of 22 December 2025 (Biology Unit 10, Ecology and Environment, third bullet: concept, patterns, importance and loss of biodiversity, biodiversity conservation, hotspots, endangered organisms, extinction, Red Data Book, biosphere reserves, national parks and sanctuaries, sacred groves): https://cdnbbsr.s3waas.gov.in/s37bc1ec1d9c3426357e69acd5bf320061/uploads/2026/01/202601081066816297.pdf
• National Testing Agency, Information Bulletin NEET (UG) 2026 (pattern: Biology 90 questions and 360 of 720 marks; plus four, minus one and zero marking): https://cdnbbsr.s3waas.gov.in/s37bc1ec1d9c3426357e69acd5bf320061/uploads/2026/02/202602231394640855.pdf
• National Testing Agency, NEET (UG) website (no NEET (UG) 2027 notice as of 14 November 2026): https://neet.nta.nic.in/
• NCERT, Biology Class 12, Chapter 13 Biodiversity and Conservation, reprint 2026-27 (sections 13.1 and 13.2, Figures 13.1 and 13.2, Summary and Exercises): https://ncert.nic.in/textbook/pdf/lebo113.pdf
• Convention on Biological Diversity, History of the Convention (opened for signature 5 June 1992, in force 29 December 1993): https://www.cbd.int/history
• Convention on Biological Diversity, Country Profile: India (4 of 34 hotspots, nearly 7-8% of recorded species, 91,200 animal and 45,500 plant species, 679 protected areas including 102 national parks and 517 wildlife sanctuaries): https://www.cbd.int/countries/profile?country=in
• International Union for Conservation of Nature, The IUCN Red List of Threatened Species (175,909 species assessed, 49,505 threatened, nine categories, categories used in Red Data Books and Red Lists): https://iucn.org/resources/conservation-tool/iucn-red-list-threatened-species
• IUCN Library record, S. K. Jain and A. R. K. Sastry, The Indian plant red data book, Botanical Survey of India, 1984 (data sheets on 125 selected plants): https://portals.iucn.org/library/node/16746