Class 12 Biology Ch 13 Biodiversity Conservation Formula Sheet

Q: How does the species-area equation predict extinction from habitat loss?

From \( S = C A^z \), a small fractional loss in area \( \Delta A / A \) produces a fractional species loss \( \Delta S / S \approx z \cdot \Delta A / A \). With z = 1.0 (large continent), losing 30% of area predicts losing 30% of species; with z = 0.15 (small biome), the same loss predicts only ~ 4.5%. This is why large contiguous protected areas matter more than scattered fragments.

The 2026-27 NCERT keeps Class 12 Biology Chapter 13 Biodiversity and Conservation intact as the closing unit of the Ecology block. This Collegedunia formula sheet collapses every numerical fact, species-area equation, extinction rate, hotspot count and conservation-network number from Sections 13.1 and 13.2 into one revision page tuned for NEET and the CBSE Board.

12 formula and number boxes

34 hotspots indexed

2 NCERT sections

7 printable pages

CBSE Weightage: 4 to 6 marks
NEET Weightage: 2 to 4 questions per year
AIIMS / entrance overlap: 1 to 2 statement-based questions per paper

Chapter 13 Biodiversity and Conservation Formula Sheet PDF

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Biodiversity And Conservation Formula Sheet - Class 12 Biology

Student Pulse: Chapter 13 Biodiversity and Conservation Difficulty Read from a Recent Class 12 Biology Survey

In a recent independent survey of 10,800 Class 12 Biology students conducted before the 2026 boards, 72% rated the species-area curve numerical (log S = log C + Z log A) as the hardest sub-topic in the chapter, even though it routinely carries the highest single-question marks in CBSE and NEET papers.

The same survey gave us the breakdown below, which a Class 12 student should look at before deciding how to allocate revision time across biodiversity and conservation class 12 biology formula sheet topics.

What 10,800 students told us about the Chapter 13 Biodiversity and Conservation Formula Sheet journey:

72% of students surveyed marked the species-area curve numerical (log S = log C + Z log A) as the hardest sub-topic.
61% reported losing 1-2 marks on matching IUCN categories (EX, EW, CR, EN, VU, NT, LC), even when the rest of their answer was correct.
4 out of 5 students said the world biodiversity-hotspot map was the most-skipped figure in their answer sheet.
Average student took 4.8 hours for the first read of the chapter, and 2.0 hours for a focused revision pass before the board exam.
Of the 10,800 students surveyed, only 41% attempted all 9 NCERT exercise questions; the rest stopped earlier. Toppers, however, reported attempting every question and revisiting wrong attempts within 24 hours.

Source: 2025-26 Class 12 Biology student survey. Sample of 10,800 students from CBSE-affiliated schools across 18 states.

This formula sheet is curated by Collegedunia subject experts, mapped to the 2026-27 NCERT, and refined against the last five years of CBSE Board and NEET papers.

Also Check:

Biodiversity and Conservation Class 12 Biology Notes
Biodiversity and Conservation Class 12 Biology NCERT Solutions
CBSE Class 12 Biology Syllabus 2026-27

Biodiversity and Conservation Video Walkthrough

Source: Magnet Brains on YouTube

Biodiversity and Conservation Master Quantitative Reference for Class 12 Biology

The canonical master table indexes every NEET-testable number against its NCERT sub-section. Over 70 percent of NEET 1-mark MCQs from this chapter plug a value from one of the rows below.

Parameter	Value / Range	NCERT Ref
Described species (IUCN 2004) / Robert May estimate	> 1.5 million / ~ 7 million	13.1.1
Animals share of described species	> 70 percent (insects > 70% of animals)	13.1.1
Indian plants / animals (approx)	~ 45,000 / ~ 90,000 species	13.1.1
Mega-diversity countries	12 (India is one)	13.1.1
Species-area slope z (small / large)	0.1 to 0.2 / 0.6 to 1.2 (Whittaker)	13.1.2
Equation S = C A^z on log-log	log S = log C + z log A	13.1.2
Present vs background extinction	100 to 1000 times higher	13.1.4
Species recently extinct	~ 700 species	13.1.4
Threatened species globally / India	> 15,500 / > 650	13.1.4
Costanza ecosystem services valuation	~ 33 trillion US dollars per year	13.1.5
Amazon O₂ share	~ 20 percent of atmospheric O₂	13.1.5
Global biodiversity hotspots	34 (3 in India)	13.2
Hotspot protection extinction relief	~ 30 percent of mass extinctions averted	13.2
India biosphere reserves / NPs / sanctuaries	14 / 90 / 448	13.2
Earth Summit Rio 1992 signatories	190 nations (Convention on Biological Diversity)	13.2

All entries above are retained in the 2026-27 syllabus. Biggest 1-mark trap: India shares THREE hotspots, not two; the slope z increases with area, not decreases.

How will Collegedunia's Biodiversity and Conservation Formula Sheet Help You?

2026-27 NCERT alignment: Every number and equation matches the current print of Sections 13.1 and 13.2.
Quantitative slant: Species-area equation, extinction rate (100 to 1000 times), Costanza valuation (~ 33 trillion USD) are the recall-based NEET facts.
Quick-lookup format: Biodiversity levels, patterns, loss, importance and conservation blocks each get a colour-coded box.

Exam Hook: The highest-frequency 1-mark trap is in-situ vs ex-situ. In-situ = natural habitat (biosphere reserves, parks, sanctuaries, sacred groves); Ex-situ = away from habitat (zoos, botanical gardens, seed banks, cryopreservation, IVF, tissue culture). NEET swaps the two in distractor options every cycle.

Species-area power law S = cA^z formula breakdown with z slope ranges for Class 12 Biology Chapter 13

Species-Area Equation and Slope Card for NEET Class 12 Biology

Section 13.1.2 carries almost all of the chapter's algebra. The card below packages the must-know species-area mathematics.

Quantity	Equation / Range
Power-law relation	S = C A^z ; rectangular hyperbola on linear axes
Log-log linearisation	log S = log C + z log A ; slope = z, intercept = log C
z for small areas (within a biome)	0.1 to 0.2
z for very large areas (continents)	0.6 to 1.2 (Whittaker, frugivorous birds and mammals)
Reverse argument (area loss)	Δ S / S ≈ z · Δ A / A for small fractional loss
Extinction-rate amplification	Present rate is 100 to 1000 times the background

NEET swaps z = 0.1 to 0.2 with z = 0.6 to 1.2 every other paper. Lock both: gentle slope inside a biome, steep slope across continents.

Evil Quartet and Loss-of-Biodiversity Snapshot for 12th Biology

Section 13.1.4 is built around one acronym (Evil Quartet) and one ratio (present-to-background rate). Edward Wilson named the four causes: habitat loss and fragmentation, over-exploitation, alien invasions, co-extinctions. Present rate is 100 to 1000 times the background; about 700 species have recently gone extinct and over 15,500 are threatened (650+ in India).

Concept: Habitat loss is the prime cause, not over-exploitation. Examples for each Evil Quartet member: habitat loss = Amazon deforestation; over-exploitation = Steller's sea cow, passenger pigeon; alien species = Nile perch wiped out 200 cichlids in Lake Victoria, water hyacinth in India, African catfish, Parthenium; co-extinction = obligate host-parasite pairs.

Conservation Network Snapshot for 12th Biology

India's legal network is one of the cleanest 1-mark facts on the chapter: 14 biosphere reserves, 90 national parks, 448 wildlife sanctuaries. Globally there are 34 hotspots; three extend into India (Western Ghats - Sri Lanka, Himalaya, Indo-Burma). Strict protection of all 34 could avert ~ 30 percent of mass extinctions.

NEET has tested the 3 Indian hotspots as a 1-mark match in 4 of the last 5 papers. Sacred groves (Khasi-Jaintia Hills, Aravallis, Western Ghats of Karnataka and Maharashtra, Sarguja-Chanda-Bastar in MP) are the community-protected counterpart.

In-situ vs ex-situ conservation side-by-side comparison for Class 12 Biology Chapter 13

In-Situ vs Ex-Situ Toolkit for Class 12 Biology

Section 13.2 splits cleanly into two columns. The compact card below pairs each tool with its protection mode.

Mode	Tool / Key Number
In-situ (natural habitat)	14 biosphere reserves, 90 national parks, 448 wildlife sanctuaries, sacred groves
In-situ - hotspot strategy	34 hotspots globally; 3 in India; ~ 30% mass-extinction relief
Ex-situ - housing	Zoological parks, botanical gardens, wildlife safari parks
Ex-situ - reproductive techniques	Gamete cryopreservation, in vitro fertilisation, tissue culture propagation
Ex-situ - long-term storage	Seed banks for commercially important crop genetic strains
Global framework	Earth Summit Rio 1992 (CBD, 190 nations); Johannesburg WSSD 2002

Watch out: NCERT explicitly lists 448 wildlife sanctuaries; some textbooks round to 450. NEET 2024's answer key accepted both, but stick to 448 to match the official NCERT phrasing.

Importance and Ecosystem Services Card for Class 12 Biology

Section 13.1.5 splits reasons-to-conserve into three buckets. The split table below pairs each with its NEET-quoted example.

Argument	Examples / Numbers
Narrowly utilitarian	Food, fibre, firewood, pharmaceuticals (25%+ from plants), industrial products
Broadly utilitarian (ecosystem services)	Pollination, pest control, climate moderation, flood control, O₂ (Amazon ~ 20% of atmospheric O₂)
Costanza valuation (ecosystem services)	~ 33 trillion USD per year, ~ twice global GNP at the time
Ethical	Moral duty to leave biodiversity intact for the next generation

Memory Hook: HOAC rolls up the Evil Quartet: Habitat loss and fragmentation, Over-exploitation, Alien invasions, Co-extinctions. SAB-MEM rolls up the global numbers: Species described 1.5M, Animals > 70%, Biggest insects 70%, May's estimate 7M, Extinction 100 to 1000x, Mega-diversity 12.

One-Shot Revision Tips for Class 12 Biology Biodiversity and Conservation

Three Indian hotspots: Western Ghats - Sri Lanka, Himalaya, Indo-Burma. Never two.
z values: 0.1 to 0.2 small area, 0.6 to 1.2 large area; slope rises with scale.
Evil Quartet (Wilson): habitat loss first, then over-exploitation, alien invasion, co-extinction.
Conservation modes: in-situ = habitat; ex-situ = zoo, garden, seed bank, cryopreservation.
Robert May vs IUCN: IUCN counts 1.5 million described; May estimates ~ 7 million total.
Extinction rate: present is 100 to 1000 times background; 700 lost; 15,500+ threatened.

Top NEET Recall Hits and Recent PYQ Pattern for Biodiversity and Conservation

NEET 2025 lifted the 34-hotspot count and the species-area slope range; NEET 2024 went after the Rivet Popper hypothesis and the sacred-grove regions; CBSE 2025 set a 3-mark long-answer on hotspots and a 2-marker on the Evil Quartet; CBSE 2024 ran in-situ vs ex-situ as a 5-marker. NEET 2023 plugged the latitudinal-gradient three-hypothesis list into an MCQ.

Full topic-by-topic explanation: Biodiversity and Conservation Notes | Full year-wise PYQ map: Biodiversity and Conservation NCERT Solutions

Related Links:

More Biodiversity and Conservation Biology Class 12 Resources

Formula Sheet for Class 12 Biology: All Chapters

The table below links every other Class 12 Biology chapter's formula sheet.

Chapter	Resource
Chapter 1	Sexual Reproduction in Flowering Plants
Chapter 2	Human Reproduction
Chapter 3	Reproductive Health
Chapter 4	Principles of Inheritance and Variation
Chapter 5	Molecular Basis of Inheritance
Chapter 6	Evolution
Chapter 7	Human Health and Disease
Chapter 8	Microbes in Human Welfare
Chapter 9	Biotechnology Principles and Processes
Chapter 10	Biotechnology and Its Applications
Chapter 11	Organisms and Populations
Chapter 12	Ecosystem

Biodiversity and Conservation Class 12 Biology Formula Sheet FAQs

Ques. What does the Biodiversity and Conservation Class 12 Biology formula sheet cover?

Ans. The sheet collates every numerical fact and named pattern across NCERT Sections 13.1 and 13.2: the three levels of biodiversity, IUCN 1.5 million and Robert May ~ 7 million estimates, the species-area equation S = C A^z with z = 0.1 to 0.2 (small) and 0.6 to 1.2 (large), the present-to-background extinction ratio (100 to 1000 times), the Evil Quartet, Costanza's ~ 33 trillion USD valuation, the 34 hotspots (3 in India), the 14 biosphere reserves / 90 national parks / 448 wildlife sanctuaries network, sacred groves and the 1992 Rio Earth Summit. One printable revision page aligned to the 2026-27 NCERT.

Ques. Is this Class 12 Biology Chapter 13 formula sheet aligned with the 2026-27 NCERT?

Ans. Yes. Every entry matches the current 2026-27 print of NCERT Biology. Sections 13.1 and 13.2 are retained in full, and the sheet flags both the classical numerical facts (z values, hotspots, conservation network) and the NCERT-extension topics (Rivet Popper hypothesis, Amazon O₂ share) exactly as they appear in the latest edition.

Ques. How is this Biodiversity and Conservation formula sheet useful for NEET preparation?

Ans. NEET pulls 2 to 4 questions a year from this chapter, almost all recall-based numericals or named-pattern MCQs: the number of hotspots, the species-area slope range, the India protected network, the present-to-background extinction ratio and the Evil Quartet items. The Collegedunia sheet packages these in quick-lookup tables so a 15-minute final-pass the night before the paper covers nearly every common MCQ.

Ques. What is the species-area relationship and what are the slope values?

Ans. The species-area relationship discovered by Alexander von Humboldt is the power law S = C A^z , which becomes a straight line log S = log C + z log A on log-log axes. The slope z lies between 0.1 and 0.2 for small areas (within a biome) and between 0.6 and 1.2 for very large areas like entire continents (Whittaker). A steeper slope means small fractional area losses cause disproportionately large species losses.

Ques. How many biodiversity hotspots are there and how many lie in India?

Ans. There are 34 biodiversity hotspots globally; three extend into India: the Western Ghats - Sri Lanka, the Himalaya, and Indo-Burma. Strict protection of all 34 hotspots could reduce ongoing mass extinctions by almost 30 percent.

Ques. What is the Evil Quartet according to NCERT Chapter 13?

Ans. The Evil Quartet, named by Edward Wilson, is the four major causes of biodiversity loss: (1) habitat loss and fragmentation (the prime cause), (2) over-exploitation, (3) alien species invasions (water hyacinth, Nile perch, African catfish, Parthenium), and (4) co-extinctions when host species are lost and their dependents follow.

Ques. What is the difference between in-situ and ex-situ conservation in Chapter 13?

Ans. In-situ conservation protects species in their natural habitat: India has 14 biosphere reserves, 90 national parks, 448 wildlife sanctuaries, plus sacred groves and the hotspot strategy. Ex-situ conservation relocates species: zoological parks, botanical gardens, wildlife safari parks, gamete cryopreservation, in vitro fertilisation, tissue culture propagation and seed banks for commercially important crop strains.

Ques. How does the species-area equation predict extinction from habitat loss?

Ans. From S = C A^z , a small fractional loss in area Δ A / A produces a fractional species loss Δ S / S ≈ z · Δ A / A . With z = 1.0 (large continent), losing 30% of area predicts losing 30% of species; with z = 0.15 (small biome), the same loss predicts only ~ 4.5%. This is why large contiguous protected areas matter more than scattered fragments.

Ques. How many marks does Biodiversity and Conservation carry in CBSE Class 12 Biology Boards?

Ans. Chapter 13 contributes around 4 to 6 marks in the CBSE Class 12 Biology board paper, typically split across a 2-mark short-answer on the Evil Quartet or levels of biodiversity and a 3 to 5-mark long-answer on hotspots, in-situ vs ex-situ, or the species-area relationship. NEET tests 2 to 4 questions a year, almost always 1-mark numericals or named-pattern MCQs.