Class | Subject | Book | Chapter | Session | Questions covered |
|---|---|---|---|---|---|
XI | Geography | Fundamentals of Physical Geography (NCERT) | 14 – Biodiversity and Conservation | 2026-27 | 12 of 12 |
Chapter at a glance
Topic | Key points |
|---|---|
Biodiversity | Variety of life forms in an area; result of 2.5–3.5 billion years of evolution |
Levels | Genetic, species, ecosystem diversity |
Importance | Ecological, economic and scientific roles |
Loss | Habitat loss, over-exploitation, pollution, exotic species, natural calamities; IUCN categories: endangered, vulnerable, rare, etc. |
Hotspots | Regions with very high species richness and endemism under threat; e.g. Himalaya, Western Ghats–Sri Lanka, Indo-Burma, Sundaland |
Conservation | Earth Summit, Rio de Janeiro (1992); Environment Protection Act (1986); national parks, sanctuaries, biosphere reserves |
Exercise Questions
Question 1 (i)
Conservation of biodiversity is important for:
(a) Animals (b) Animals and plants (c) Plants (d) All organisms
Answer
- All organisms
Question 1 (ii)
Threatened species are those which:
(a) threaten others (b) Lion and tiger (c) are abundant in number (d) are suffering from the danger of extinction
Answer
- are suffering from the danger of extinction
Question 1 (iii)
National parks and sanctuaries are established for the purpose of:
(a) Recreation (b) Hunting (c) Pets (d) Conservation
Answer
- Conservation
Question 1 (iv)
Biodiversity is richer in:
(a) Tropical Regions (b) Polar Regions (c) Temperate Regions (d) Oceans
Answer
- Tropical Regions
Question 1 (v)
In which one of the following countries, the ‘Earth Summit’ was held?
(a) the UK (b) Mexico (c) Brazil (d) China
Answer
The Earth Summit was held at Rio de Janeiro, Brazil, in June 1992.
- Brazil
Question 2 (i)
What is biodiversity?
Answer
Biodiversity is the number and variety of organisms — plants, animals and micro-organisms — found within a specified geographic region, including the genes they contain and the ecosystems they form. It is the result of billions of years of evolution.
The variety of all living organisms — their genes, species and ecosystems — in an area.
Question 2 (ii)
What are the different levels of biodiversity?
Answer
- Genetic diversity — variation of genes within a species (e.g. different varieties of rice).
- Species diversity — variety of species in an area; measured by species richness and abundance.
- Ecosystem diversity — variety of habitats and ecological processes, e.g. forests, deserts, wetlands, oceans.
Genetic, species and ecosystem diversity.
Question 2 (iii)
What do you understand by ‘hotspots’?
Answer
Hotspots are regions with very high species richness and a high degree of endemism (species found nowhere else) that are also under severe threat from human activity. Conservation International identified them to prioritise conservation. Examples in India: the Himalaya, Western Ghats and Sri Lanka, Indo-Burma and Sundaland (Nicobar Islands).
Areas with very high biodiversity and endemic species that are under serious threat, e.g. the Western Ghats, Himalaya and Indo-Burma.
Question 2 (iv)
Discuss briefly the importance of animals to human kind.
Answer
Animals provide food (milk, meat, eggs, fish), raw materials (wool, leather, silk), draught power and transport, and manure. They help in pollination and seed dispersal, control pests, and maintain ecological balance in food chains. Animals are used in medical research and have cultural, aesthetic and recreational value.
They give food, raw materials, draught power and manure, aid pollination and ecological balance, and have medical, cultural and recreational value.
Question 2 (v)
What do you understand by ‘exotic species’?
Answer
Exotic species are species that are not native to a habitat but are introduced there, intentionally or accidentally, from elsewhere. They often spread fast and harm native species by competition, predation or disease (e.g. Lantana, water hyacinth and Parthenium in India).
Species introduced into a habitat where they are not native, often harming native species (e.g. Lantana, water hyacinth).
Question 3 (i)
What are the roles played by biodiversity in the shaping of nature?
Answer
1. Ecological role
- Each species has a specific function in the ecosystem — capturing and storing energy, producing and decomposing organic matter, cycling water and nutrients, fixing atmospheric gases, regulating climate.
- More diverse ecosystems are more stable and productive and better able to withstand stresses like drought.
- Biodiversity supports essential services: pollination, soil formation, pest control and purification of air and water.
2. Economic role
- Biodiversity is a source of food crops, livestock, fish, timber, fibres, dyes, resins and medicines (many drugs come from plants).
- It supports industries, tourism and livelihoods.
3. Scientific role
- Each species gives clues about the origin and evolution of life; genetic resources help develop new crop varieties and medicines.
- It helps us understand how ecosystems work.
Thus biodiversity shapes nature by maintaining ecological balance and sustaining all life, including humans.
Ecologically it keeps ecosystems stable and productive (energy flow, nutrient cycling, climate regulation); economically it provides food, timber, fibres and medicines; scientifically it explains evolution and provides genetic resources.
Question 3 (ii)
What are the major factors that are responsible for the loss of biodiversity? What steps are needed to prevent them?
Answer
Factors responsible
- Habitat loss and fragmentation due to deforestation, agriculture, urbanisation, mining and dams.
- Over-exploitation — over-hunting, poaching, over-fishing and collection of plants.
- Pollution of air, water and soil, including pesticides.
- Exotic (invasive) species that out-compete native species.
- Natural calamities — earthquakes, floods, volcanic eruptions, forest fires, droughts — and climate change.
- Population growth and rising consumption.
Steps to prevent loss
- Protect habitats through national parks, wildlife sanctuaries, biosphere reserves (in-situ conservation); protect hotspots.
- Ex-situ conservation — zoos, botanical gardens, seed and gene banks.
- Enforce laws like the Wildlife Protection Act (1972) and Environment Protection Act (1986); ban poaching and trade in endangered species.
- Sustainable use of resources; promote eco-friendly agriculture and reduce pesticides.
- Control invasive species and pollution.
- Involve local communities and spread awareness; follow international agreements (Convention on Biological Diversity, 1992).
Causes: habitat loss, over-exploitation, pollution, invasive species, calamities and climate change. Remedies: protected areas and hotspot conservation, ex-situ conservation, strict laws, sustainable use, pollution and invasive-species control, community participation and international cooperation.
Topic checklist
- Meaning and levels of biodiversity
- Importance of biodiversity
- Loss of biodiversity; IUCN categories
- Hotspots
- Conservation of biodiversity