NEET 2022 | Class 12

NEET Important Chapter - Biodiversity and Conservation

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Biodiversity and Conservation Notes and Important Questions

Biodiversity and Conservation Notes and Important Questions

This document has been designed for the students who are preparing for NEET and want a synopsis of the chapter as per the NEET examination. Biodiversity and Conservation is a very crucial part of NEET and thus needs to be studied thoroughly to gain the maximum.

Biodiversity and Conservation notes for neet covers all the major part of the chapter including what is biodiversity, its levels, patterns of biodiversity, loss of biodiversity, types of extinction, causes of biodiversity loss, and biodiversity extinction.

Important Topics of Biodiversity and Conservation

  • Biodiversity

  • Loss of Biodiversity

  • Biodiversity Conservation

  • Hotspots of biodiversity

  • Patterns of biodiversity

Important Concepts of the Chapter

Edward Wilson, a sociobiologist, coined the term "biodiversity" to characterise the cumulative diversity at all levels of biological organisation.

The most crucial of these are:

(i) Genetic Diversity: Over the course of a species' distributional range, a single species may exhibit substantial genetic variety. The intensity and concentration of the active chemical (reserpine) produced by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges may be affected by genetic diversity. India has around 50,000 genetically distinct rice strains and 1,000 mango kinds.

(ii) Species Diversity: At the species level, there is a lot of diversity. The Western Ghats,  for instance, contain a greater diversity of amphibian species than the Eastern Ghats.

(iii) Ecological Diversity: India, for example, has more ecological diversity than a Scandinavian country like Norway, due to its deserts, mangroves, rain forests, marshes, estuaries, coral reefs, and alpine meadows.

Patterns of Biodiversity

Latitudinal Gradients

  • The diversity is not consistent; instead, it is distributed in an unequal manner. 

  • A latitudinal gradient pattern is seen in the majority of groups and animals. As we travel away from the equator and closer to the poles, the diversity of species generally diminishes. 

  • As a result, the tropics have more species than polar or temperate regions. Colombia has roughly 1400 species near the equator whereas New York contains 105 species at 41 degrees north and Greenland includes 56 species at 71 degrees north.

Species - Area Relationships

Plants and animals of various species can be found in each location. It's worth noting that the relationship between species richness and area for a wide range of taxa (birds, plants, freshwater fishes, and bats) is a rectangular hyperbola.

It's important to keep in mind that the relationship turns linear on the log scale and is given by the equation:

Log S = Log C + Z log A


S = Species richness

A = Area

Z = slope of the line (regression coefficient)

C = Y - intercept

Species - Area Relationships

Importance of Biodiversity

  • Biodiversity is vital because it aids in the prevention of species extinction. 

  • It enables organisms to adapt to their surroundings and provides a greater variety of material and nourishment for existence. 

  • Biodiversity offers extensive genetic pools that aid in the preservation of life on the planet.

  • Rain forests cover roughly half of the Earth's surface. These forests' animal and plant species, as well as their biodiversity, contribute to regulating the Earth's weather patterns. 

  • Biodiversity protects the soil from erosion and drought while also regulating its chemical makeup. It aids in the determination of animal reproductive seasons as well as plant development cycles.

  • Biodiversity is important for preserving environmental balance and defining how various organisms communicate with one another. 

  • It contributes to ecological balance by recycling and storing nutrients, moderating climate, forming and safeguarding soil, battling pollution, and so on. 

Role of Biodiversity

  • Biodiversity and Food - Twenty types of plants provide around 8% of our food, yet we use about 40,000 species for clothing, food, and shelter. Biodiversity is what allows us to eat a wide variety of foods.

  • Biodiversity and Culture - Biodiversity encourages outdoor activities such as hiking, bird viewing, and fishing. It also motivates musicians and painters.

  • Biodiversity and Human Health - Biodiversity is crucial in the development of new pharmaceuticals and medical resources. Natural medicines comprise 80% of all prescriptions in the Earth's population.

  • Biodiversity and Industry - Biodiversity aids in the production of a variety of industrial commodities. Fibres, colours, rubber, oil, food, paper, and timber are all included.

Loss of Biodiversity

According to Edward Wilson, HIPPO is the major cause of destruction. HIPPO stands for “Habitat destruction, Climate change, Invasive species, Pollution, Human overpopulation and Over-harvesting.”

The Below-given Diagram Represents the Causes and Consequences of Biodiversity Loss.

Causes and Consequences of Biodiversity Loss

Causes of Biodiversity Loss

  • Habitat loss and fragmentation

  • Over-exploitation

  • Alien-species Invasion

  • Co-extinctions

How Should We Conserve Biodiversity?

Biodiversity conservation is critical as biodiversity offers necessary services and resources supporting life on Earth. Biodiversity has societal benefits as well. One can preserve biodiversity by:

  • Keeping trees from being cut down.

  • Putting an end to animal hunting.

  • The utilisation of natural resources in a cost-effective manner.

  • Protected areas for animals should be created where no human activity is permitted.

In situ (on-site) Conservation

It refers to the methods for conserving all living species in their natural habitats and environments, particularly wild and endangered species. Biosphere reserves, national parks, and wildlife sanctuaries are examples of in-situ biodiversity conservation.

  • Hotspot: The Biodiversity Hotspot is a biogeographical area which is both rich in biodiversity and under threat of extinction. It comprises a group of 25 high-biodiversity locations on the Earth that have lost at least 70% of their native environment.

There are four hotspots in India, namely, the Western Ghats, the Himalayas, the Sundaland, and the Indo-Burma region.

  • Sacred Groves: Sacred Groves are areas of virgin forest which have been left unspoiled by locals and are safeguarded by them because of their culture and religious beliefs. Tribals in this area firmly forbid the practice of deforestation.

Ex-situ (off-site) Conservation

It refers to the ways of preserving all live species in artistic habitats that mirror their natural living environments. Aquariums, botanical gardens, cryopreservation, DNA banks, and zoos are examples of ex-situ biodiversity protection.

  • Cryopreservation techniques - used to preserve gametes of threatened species.

  • Seed banks - Seeds of various genetic strains of commercially valuable plants could be stored in seed banks for long periods of time.

  • All nations were prompted to take suitable actions for biodiversity protection and sustainable use of its benefits during the historic Convention on Biological Diversity ('The Earth Summit') held in Rio de Janeiro in 1992.

  • With the follow up of the same, 190 countries affirmed their resolve to seek a marked decline in the present rate of biodiversity loss at global, regional, and local levels by 2010 at the World Summit on Sustainable Development in Johannesburg, South Africa, in 2002.

The Below diagram shows the Biodiversity Conservation Management System

Biodiversity Conservation Management System

Some Other Major Information

IUCN Red List (2004)

In the last 500 years, 784 species have gone extinct, including 338 vertebrates, 359 invertebrates, and 87 plants.

Quagga (Africa), thylacine (Australia), dodo (Mauritius), tiger subspecies - Bali, Java, and the Caspian, Steller's sea cow (Russia) are the recent extinctions.

The Evil Quartet

Describes the four major causes of biodiversity loss: 

Loss of habitat, over-exploitation, alien species invasions, and co-extinctions.

“Lungs of the planet”

Amazon rainforest

Keystone species

Species that have a large effect on its ecosystem and help in maintaining its structure.

Example - large predator species including sea otters in the kelp forest, Grey wolves in greater Yellowstone, etc.

Alien species

Non-native invasive species introduced in an area, bringing modifications.

For example, The Nile perch led to the extinction of 200 species of cichlid fish in Lake Victoria, and invasive weed species including Lantana, Parthenium, Eicchornia, etc.

Endemic species

Species native to a particular region and are not seen anywhere else.

Example: Nepenthes khasiana, Nilgiri Tahr, Asiatic lion, Pygmy Hog, Glacier bear, etc.

Solved Examples From the Chapter

1. Give three hypotheses for explaining why tropics show the greatest levels of species richness.

Ans: Scientists have offered three main ideas to explain the diversity of organisms in the tropics.

  1. Tropical latitudes absorb higher solar energy than temperate ones, resulting in great productivity and a diverse range of species.

  2. Tropical regions see less seasonal changes and a more or less consistent climate. This encourages niche specialisation and, as a result, significant species diversity.

  3. During the ice age, temperate regions were exposed to glaciations, but tropical regions were unaffected, resulting in an increase in species diversity in this region.

2. The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a:

  1. Rectangular hyperbola

  2. Straight line

  3. Sigmoid curve

  4. Sine curve

Ans: a. Rectangular Hyperbola.

Species richness rose with decreasing investigated area, according to AV Humboldt, a German scientist, inside a region (only up to a limit). As a result, for a wide range of taxa, the relationship between species richness and area appears to be a rectangular hyperbola.

Key Point to remember: On a logarithmic scale, the connection represents a straight line, as indicated by the equation log S = log C + Z log A.

3. Which one of the following is not included under in situ conservation?

  1. Sanctuary

  2. Botanical Garden

  3. Biosphere reserve

  4. National Park 

Ans: b. Botanical Garden.

Ex-situ conservation occurs in botanical gardens because the plants are preserved away from their natural habitat.

Key Point to Remember: A botanical garden is a space dedicated to the collecting, cultivation, preservation, and presentation of botanically named plants.

4. The total number of biodiversity hotspots in the world are:

  1. 72

  2. 34

  3. 52

  4. 24

Ans: b. 34.

Key Point to Remember: A biodiversity hotspot can be described as a biogeographic region with high biodiversity that is endangered by human presence.

Solved Problems of Previous Year Question from the Chapter

1. According to Robert May, the global species diversity is about:

  1. 20 Million

  2. 50 Million

  3. 7 Million

  4. 1.5 Million

Ans: c. 7 Million.

2. In the following, in each set, a conservation approach and an example of a method of conservation are given

  1. In situ conservation - Biosphere Reserve

  2. Ex situ conservation - Sacred Groves 

  3. In situ conservation - Seed Bank

  4. Ex situ conservation - Cryopreservation

Select the option with the correct match of approach and method:

  1. (a) and (c)

  2. (a) and (d)

  3. (b) and (d)

  4. (a) and (b)

Ans: 2. (a) and (d).

Sacred groves are the example of in-situ conservation whereas the seed banks are the example of ex-situ conservation.

Key Point to Remember: In-situ conservation refers to the preservation of all living species in their natural habitats and environments, particularly wild and endangered species. Ex-situ conservation refers to the preservation of all living species in artificial / artistic settings that are similar to their natural habitats.

3. Which of the following regions of the globe exhibits the highest species diversity?

  1. Madagascar

  2. Himalayas

  3. Amazon forests

  4. Western Ghats of India

Ans: c. Amazon forests. 

With an approximate 390 billion individual trees separated into 16,000 species, the Amazon represents over half of the world's surviving rainforests and is the world's largest and therefore most biodiverse tropical rainforest.

Key Point to Remember: The Amazon rainforest is home to the world's most biologically varied ecosystem and is popular for carrying 10% of all known species on the planet.

Practice Questions

1. The Earth Summit was held in Rio de Janeiro in:

  1. 1987

  2. 1990

  3. 1992

  4. 2002

Ans: c. 1992.

Seeing the poor condition of the environment and socio-economic development, the Earth Summit was held in Rio de Janeiro in 1992. It was to address biodiversity conservation and sustainable utilisation of resources. 

2. The exotic species, introduced in India for its flower and leaf, is:

  1. Lantana

  2. Water Hyacinth (Eicchornia)

  3. Parthenium

  4. All are correct

Ans: b. Water Hyacinth (Eicchornia).

Water hyacinth is regarded as invasive all across the world due to its quick growth and ability to produce thick layers on the surface of the water.

3. Alexander von Humbolt described for the first time

  1. Ecological biodiversity

  2. Law of limiting factor

  3. Species area relationships

  4. Population growth equation

Ans: c. species area relationships.


These biodiversity and conservation notes can be highly beneficial to the students who are looking for the last minute revision notes. This article carries the sample questions that one can practise before an exam and have a clear understanding of the kind of questions that appear in the NEET examination.

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FAQs on NEET Important Chapter - Biodiversity and Conservation


1. How many questions from the previous year's exam papers are likely to be repeated in NEET?

Although an exact number cannot be determined, it is estimated that 10 to 15 questions would be repeated in a modified form. A student can review past year's questions, learn the pattern and types of questions asked in the NEET Exam, and improve the preparations. The certainty of the questions asked in the exam can not be determined but can only be expected. 

2. What is the average number of questions appearing in NEET from the chapter Biodiversity and Conservation?

The average number of questions appearing in NEET from the chapter Biodiversity and Conservation is 2-3. 

3. What is the weightage of the unit Ecology and Environment in NEET?

The unit Ecology and Environment, on the whole, comprises 4 chapters and makes a total weightage of 19%.