Biodiversity and Conservation, Class 11 Geography: Notes and Hotspot Map Work

What Biodiversity and Conservation is about

Key concepts

Meaning and levels of biodiversity

NCERT section Biodiversity and Conservation

Meaning: the number and variety of organisms in a specified region: plants, animals and micro-organisms, their genes and the ecosystems they form, including variability within and between species and ecosystems. It is our living wealth, the product of hundreds of millions of years of evolution.

Distribution: not even; richer in the tropics; towards the poles, larger populations of fewer species. Basic cause of variation: inputs of solar energy and water, which also govern the depth of the weathering mantle and vegetation diversity.

Numbers: species estimates 2 million to 100 million (best estimate 10 million); many not yet classified (about 40 per cent of South American freshwater fishes); average half-life of a species 1-4 million years; 99 per cent of all species that ever lived are extinct. Before humans, the earth supported more biodiversity than at any time; since then it has declined rapidly.

Level	Meaning	Example
Genetic	Variation of genes within a species; essential for healthy breeding	Humans (Homo sapiens) differ in height, colour, appearance
Species	Variety and number of species in an area, measured by richness, abundance and types	Species-rich areas are hotspots
Ecosystem	Differences between ecosystem types and the diversity of habitats and processes within each; boundaries are hard to draw	Grasslands and sholas, Indira Gandhi National Park, Annamalai (Western Ghats)

Worked example

Why is genetic diversity important for a species? (2 marks)

Try it first, then show the solutionSolution

1. Genetic diversity is the variation of genes within a species, seen for example in the different heights and colours of humans.
2. It is essential for healthy breeding of a population, helping it survive and adapt.

Answer: It keeps breeding populations healthy and adaptable.

Roles of biodiversity

NCERT section Biodiversity and Conservation

Biodiversity has shaped human culture, and humans have shaped biodiversity at genetic, species and ecological levels.

Ecological role: every organism takes what it needs and also contributes something to others. Species capture and store energy, produce and decompose organic matter, cycle water and nutrients, fix atmospheric gases and help regulate climate. The more diverse an ecosystem, the better its species survive adversity and the more productive and stable it is; losing species weakens its ability to maintain itself.

Economic role: a resource in daily life. Crop diversity (agro-biodiversity) is a key part. Biodiversity is a reservoir for food, pharmaceutical and cosmetic products; this view of it as a resource also drives its deterioration and creates conflicts over sharing natural resources. Commodities: food crops, livestock, forests, fish, medicinal resources.

Scientific role: each species gives clues to how life evolved and will evolve, and how ecosystems function.

Ethical view: every species has an intrinsic right to exist; causing extinction voluntarily is morally wrong. The level of biodiversity indicates the state of our relationship with other species.

Worked example

Why is a species-rich ecosystem more stable than a species-poor one? (2 marks)

Try it first, then show the solutionSolution

1. In a diverse ecosystem many species share functions (energy capture, nutrient cycling, decomposition).
2. So it can survive adversities and attacks and adapt to environmental change; losing species reduces this ability.

Answer: More species give more ways to keep functions going under stress.

Loss of biodiversity and IUCN categories

NCERT section Loss of Biodiversity

Causes of loss:

• Population growth and consumption: tropical regions occupy about one-fourth of the world's area but hold about three-fourths of its people; over-exploitation and deforestation are rampant. Tropical rainforests contain about 50 per cent of species, so their destruction is disastrous for the biosphere.
• Natural calamities: earthquakes, floods, volcanic eruptions, forest fires, droughts.
• Pesticides and pollutants (hydrocarbons, toxic heavy metals) destroy weak, sensitive species.
• Exotic species: species introduced into a habitat where they are not natural inhabitants can damage native communities.
• Poaching: tigers, elephants, rhinoceros, crocodiles, minks and birds hunted for horns, tusks and hides, making some endangered.

IUCN categories of threatened species:

Category	Meaning
Endangered	In danger of extinction; listed in the IUCN Red List of threatened species (e.g. the red panda)
Vulnerable	Likely to become endangered in the near future if threats continue; populations greatly reduced
Rare	Very small world populations, confined to limited areas or thinly scattered (e.g. *Humboldtia decurrens*, a rare endemic tree of the southern Western Ghats)

Worked example

What are exotic species, and why can they harm biodiversity? (2 marks)

Try it first, then show the solutionSolution

1. Exotic species are species introduced into a habitat where they are not natural inhabitants.
2. They can cause extensive damage to the natural biotic community of the ecosystem (as on Hawaii, where introduced species threaten unique plants and animals).

Answer: Introduced, non-native species that can damage native communities.

Conservation, mega diversity centres and hotspots

NCERT section Conservation of Biodiversity

Why conserve: all life forms are interlinked; disturbing one unbalances others, and endangered species degrade the environment, which may threaten human existence itself.

Steps (world conservation strategy):
1. Preserve endangered species.
2. Plan and manage to prevent extinction.
3. Preserve varieties of food crops, forage plants, timber trees, livestock and their wild relatives.
4. Each country should identify and protect habitats of wild relatives.
5. Protect habitats where species feed, breed, rest and nurse young.
6. Regulate international trade in wild plants and animals.

India: the Wild Life (Protection) Act, 1972 set up national parks, sanctuaries and biosphere reserves. India and 155 other nations signed the Convention on Biodiversity at the Earth Summit, Rio de Janeiro, Brazil, June 1992.

Mega diversity centres: 12 countries, mostly tropical, holding a large share of species: Mexico, Colombia, Ecuador, Peru, Brazil, Democratic Republic of Congo, Madagascar, China, India, Malaysia, Indonesia, Australia.

Hotspots: identified by the IUCN to concentrate resources on the most vulnerable areas; defined by vegetation, because plants determine an ecosystem's primary productivity. Most depend on species-rich ecosystems for food, firewood, cropland and timber income. In Madagascar about 85 per cent of plants and animals are found nowhere else. Hotspots in wealthy countries face other pressures: Hawaii has unique species threatened by introduced species and land development.

People's role: conservation with sustainable use needs local communities, environment-friendly practices and local institutions; the key is continuing the process of conservation.

Worked example

Why are hotspots defined by their vegetation? (2 marks)

Try it first, then show the solutionSolution

1. Plants determine the primary productivity of an ecosystem: they capture the energy on which other life depends.
2. So areas with rich, unique plant life support rich animal life and are the right focus for conservation.

Answer: Because plants set primary productivity and support all other life.

Biodiversity and Conservation in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Loss of Biodiversity, IUCN Categories, Conservation Measures and Biodiversity Hotspots
• Biodiversity: Meaning, Distribution, Three Levels and Ecological, Economic and Scientific Roles

Biodiversity and Conservation: key facts

Species estimates

2 million to 100 million; best estimate 10 million

99% of all species ever are extinct.

Levels

Genetic	within species
species	variety in area
ecosystem	types and habitats

Species-rich areas = hotspots.

Roles

$Ecological+economic+scientific(+ethical)$

Agro-biodiversity is part of the economic role.

Tropics

About 1/4 of world area, about 3/4 of people; rainforests hold about 50% of species

Why tropical loss is so serious.

IUCN categories

$Endangered|vulnerable|rare$

Red List of threatened species.

Milestones

Wild Life (Protection) Act 1972; Earth Summit, Rio, June 1992 (India + 155 nations)

Convention on Biodiversity.

Hotspot map list

Eastern Himalaya, Western Ghats, Indonesia, Eastern Madagascar, Upper Guinean forests, Atlantic forest (Brazil), Tropical Andes

Only this map work is in the theory paper.

Biodiversity and Conservation: map work

The places on the official CBSE map list for this chapter. Find each one on an outline map of India and practise marking it.

Tricks to remember Biodiversity and Conservation

Short memory aids. Say each one aloud once, then use it on a question the same day.

• Hotspot list

  'East West Indo, East Mada, Upper Guinea, Atlantic, Andes': Eastern Himalaya, Western Ghats, Indonesia, Eastern Madagascar, Upper Guinean forests, Atlantic forest, Tropical Andes.

  Use it when: Map list.

• Levels

  'GSE': Genes, Species, Ecosystems (small to big).

  Use it when: Levels of biodiversity.

• IUCN categories

  'EVR: Endangered now, Vulnerable soon, Rare always few'.

  Use it when: Threat categories.

• Causes of loss

  'People, Pests, Poachers, Pollution, Plants from outside': population/deforestation, pesticides, poaching, pollutants, exotic species (plus calamities).

  Use it when: Loss of biodiversity.

Practice questions on Biodiversity and Conservation

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · Map workExam level

   On an outline map of the world, mark and label the two biodiversity hotspots on the 2026-27 list that lie in India.

   Hint

   One in the north-east, one along the west coast.

   Answer

   Eastern Himalaya (north-east India) and the Western Ghats (along the west coast).

2. Q2 · 1 mark · Map workExam level

   Identify the hotspot described: 'an island off south-east Africa, where about 85 per cent of plants and animals are found nowhere else'. Mark its eastern part.

   Hint

   The chapter gives the 85 per cent figure.

   Answer

   Eastern Madagascar; shade the eastern side of Madagascar.

3. Q3 · 1 mark · Map workExam level

   Which hotspot on the list lies along the Gulf of Guinea coast? Mark it.

   Hint

   West Africa.

   Answer

   Upper Guinean forests: the coastal belt of West Africa north of the Gulf of Guinea.

4. Q4 · 2 marks · Map workHarder exam level

   Two hotspots on the list are in South America. Name them and say how you would distinguish their positions on the map.

   Hint

   One mountain, one coast.

   Answer

   Tropical Andes (mountains along the western side, in the tropics) and the Atlantic forest (along the east coast of Brazil).

5. Q5 · 1 mark · Map workExam level

   A map shows a shaded area of islands between the Indian and Pacific Oceans, south-east of the Malay Peninsula. Which hotspot is it?

   Hint

   An island nation of Asia.

   Answer

   Indonesia (Asia).

6. Q6 · 2 marks · Map workHOTS / competency

   Suppose you must mark all seven hotspots on one world map. Which continent has the most, and why do you think most hotspots lie in or near the tropics? (2 marks)

   Hint

   Count by continent; recall where biodiversity is richest.

   Answer

   Asia (Eastern Himalaya, Western Ghats, Indonesia) has three; Africa and South America have two each. Most lie in or near the tropics because biodiversity is consistently richer there, where inputs of solar energy and water are high.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.What is the best estimate of the number of species?Show answer

   About 10 million (range 2-100 million).

2. 2.What share of species do tropical rainforests contain?Show answer

   About 50 per cent.

3. 3.Who publishes the Red List of threatened species?Show answer

   The IUCN.

4. 4.When was India's Wild Life (Protection) Act passed?Show answer

   1972.

5. 5.Where and when was the Earth Summit held?Show answer

   Rio de Janeiro, Brazil, June 1992.

6. 6.How many mega diversity countries are there?Show answer

   12.

7. 7.What share of Madagascar's plants and animals are found nowhere else?Show answer

   About 85 per cent.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Theory paper: only hotspot map work; the rest is a project.
• ☐Hotspots: Eastern Himalaya, Western Ghats, Indonesia, Eastern Madagascar, Upper Guinean forests, Atlantic forest (Brazil), Tropical Andes.
• ☐Biodiversity: variety of genes, species and ecosystems; richest in the tropics.
• ☐10 million species (best estimate); 99% of all species ever are extinct.
• ☐Roles: ecological (stability), economic (food, medicine, agro-biodiversity), scientific, ethical.
• ☐Loss: deforestation (rainforests hold 50% of species), calamities, pollutants, exotic species, poaching.
• ☐IUCN: endangered, vulnerable, rare; Red List.
• ☐Wild Life (Protection) Act 1972; Earth Summit Rio 1992; 12 mega diversity countries; IUCN hotspots defined by vegetation.

Biodiversity and Conservation: frequently asked questions