This MCQ module is based on: Biodiversity, Conservation and Human Impact
TOPIC 45 OF 50
Biodiversity, Conservation and Human Impact
🎓 Class 8
Science
CBSE
Theory
Ch 12 — Sound
⏱ ~30 min
🌐 Language: [gtranslate]
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[myaischool_lt_science_assessment grade_level="class_8" science_domain="physics" difficulty="basic"]
Probe and Ponder — The Lost Dodo and the Returning Cheetah
On the island of Mauritius, just off our western neighbour Madagascar, a plump flightless bird called the dodo once walked fearlessly through the forests. Within 80 years of humans reaching the island, the dodo was extinct — gone forever. Meanwhile, in India, the majestic cheetah went locally extinct in 1952. In 2022, after seven decades, cheetahs were brought back from Africa and released into Kuno National Park in Madhya Pradesh. One species lost, another returning — both stories remind us how fragile, and how precious, life on Earth is.
- Why is it so important to have many kinds of living things?
- Why is India one of the world's richest countries in terms of life-forms?
- How do ancient Indian traditions help us take care of nature?
- What can a Class 8 student actually do to help save biodiversity?
12.12 Biodiversity — The Variety of Life
Biodiversity is short for biological diversity — the sheer variety of life. It includes the number of different species, the genetic variety within each species, and the variety of ecosystems across the planet. A patch of mixed forest with oak, teak, bamboo, mongoose, barking deer, 40 species of birds and hundreds of insects is more biodiverse than a plantation with only eucalyptus trees.
Three Levels of Biodiversity
Genetic Diversity
Differences within one species — e.g. India has hundreds of varieties of rice and mango.
Species Diversity
Number of different species in an area — a rainforest has far more than a cold desert.
Ecosystem Diversity
Variety of ecosystems — forests, wetlands, mangroves, coral reefs, deserts.
12.13 India — A Megadiverse Nation
India has only 2.4% of the world's land area but shelters nearly 8% of all known species. That's why India is called a megadiverse country. From snow leopards in the Himalayas to sea turtles on Odisha's Gahirmatha beach, and from one-horned rhinos in Kaziranga to flamingos in the Rann of Kutch — the stage is astonishingly crowded.
Two Treasure-Chests — Western Ghats & Sundarbans
The Western Ghats — running from Gujarat down to Kerala — is one of the planet's great biodiversity hotspots. A UNESCO World Heritage Site, it hosts lion-tailed macaques, Nilgiri tahrs, king cobras, dancing frogs and thousands of flowering plants found nowhere else.
The Sundarbans on the Bay of Bengal is the world's largest mangrove forest, shared by India and Bangladesh. It is the only home of Royal Bengal tigers that can swim between salty islands. Its tangled mangrove roots shelter fish, crabs, crocodiles and migratory birds, and also protect Kolkata from cyclone storm surges.
12.14 How Humans Are Hurting Biodiversity
Nature has survived many storms, but the pressures of the last century are unlike any before. Here are the main culprits:
Deforestation
Forests are cleared for farms, mines, dams and cities. India has lost millions of hectares of forest in the past 50 years.
Habitat Fragmentation
Roads and railways slice forests into small islands, breaking elephant corridors and isolating tiger populations.
Hunting & Poaching
Illegal trade in rhino horns, elephant tusks and pangolin scales has pushed many species near extinction.
Pollution
Pesticides, plastic waste and untreated sewage enter soil, rivers and oceans — killing plankton, fish and birds alike.
Climate Change
Rising temperatures shift where species can live. Coral reefs bleach, glaciers melt, and monsoons become unreliable.
Invasive Species
Outsiders like water hyacinth and lantana out-compete native plants and starve local animals of their food.
Extinction — Forever Gone
Extinction means that every individual of a species has died. The dodo, the great auk, and the Indian cheetah (locally) are tragic examples. Today the Great Indian Bustard, the Gangetic dolphin, and many frogs of the Western Ghats are critically endangered — teetering on the edge.
Why worry about extinction? Every species is a unique thread in the ecosystem's fabric. Pull out enough threads and the whole cloth unravels. We also lose possible medicines, foods and natural pest-controllers we may not have even discovered yet.
12.15 Conservation — Protecting What We Have
Conservation is the science and practice of protecting living things and their habitats. India has many conservation tools:
| Tool | What It Does | Example |
|---|---|---|
| National Park | Large protected area where hunting and farming are banned. | Jim Corbett NP (Uttarakhand), Kaziranga NP (Assam) |
| Wildlife Sanctuary | Protects one or more species; limited human activity allowed. | Periyar WLS (Kerala), Chilika (Odisha) |
| Biosphere Reserve | Protects whole ecosystems plus surrounding lived-in buffer zones. | Nilgiri, Nanda Devi |
| Project Tiger | Flagship programme (1973) to save Bengal tigers. | 50+ tiger reserves; population rose from ~1,800 (1972) to ~3,600+ (2022). |
| Project Elephant | Protects elephant populations and their corridors. | Over 30 Elephant Reserves across India. |
| Zoological & Botanical Gardens | Captive breeding of rare species. | National Zoological Park, Delhi. |
The Elephant Corridor Story Revisited
Remember the herd from Part 1? Conservationists identify and protect elephant corridors — narrow forest strips linking bigger habitats. India has officially recognised over 100 such corridors. Where corridors cross roads, special wildlife overpasses and underpasses let elephants, leopards and tigers cross safely. NH-44 near Pench and NH-37 through Kaziranga are good examples.
12.16 Indigenous & Tribal Wisdom
Long before modern science named the idea of conservation, Indian communities were living it.
- Sacred groves in Meghalaya, Maharashtra and Kerala are patches of forest worshipped and protected for centuries. Not a single twig is taken from them.
- The Bishnoi community of Rajasthan follows 29 rules set by Guru Jambheshwar in the 15th century — among them, never cutting a living tree nor harming an animal. In 1730, 363 Bishnois led by Amrita Devi gave their lives to save khejri trees — a world-first non-violent environmental movement.
- The Chipko Movement of the 1970s in Uttarakhand, led by Sunderlal Bahuguna and Gaura Devi, saw villagers hug trees to stop loggers.
- Tribal societies across India have traditional rules about which tree to cut, when to fish, and how much honey to collect — all gentle ways of preventing overuse.
Science meets Tradition: Modern ecologists now study sacred groves to understand "reference forests" — patches that show what undisturbed nature looks like. Traditional wisdom and modern science are partners, not rivals.
12.17 Sustainable Living — Small Steps, Big Change
Sustainable living means meeting our needs today without making it harder for tomorrow's children to meet theirs. You, as a Class 8 student, can already do plenty:
Save Energy
Switch off lights and fans when leaving a room; use LED bulbs; choose the staircase over the lift for short floors.
Save Water
Close the tap while brushing; fix leaks; use a bucket for bathing instead of a shower; save rainwater at home.
Reduce & Reuse
Carry a cloth bag; refuse single-use plastic; donate old clothes and books instead of dumping them.
Grow & Compost
Plant even one sapling; compost kitchen waste at home — it cuts garbage and feeds plants.
Eat Wisely
Choose local, seasonal, home-cooked food over packaged imports; don't waste food on your plate.
Travel Smart
Walk, cycle or car-pool for short distances. Use public transport when possible.
🌿 Activity 12.3 — A One-Week Biodiversity Diary
You will need: a small notebook, a pen, a pair of sharp eyes, optionally a smartphone camera.
- For seven days, spend 15 minutes each evening in a park, garden or balcony. List every kind of living thing you see — birds, insects, plants, lizards, stray animals, even mushrooms.
- Note the date, time and weather next to each sighting.
- At the end of the week, count how many different species you met.
- Compare with classmates' diaries. Mark any "special" species — rare birds, native trees, medicinal herbs.
- Write a short plan: how can your family or school help these creatures thrive?
🔍 Predict: Will city gardens show fewer species than village fields? Will the list differ between morning and evening? Why?
Most students discover 20–40 species they had never consciously noticed — from sunbirds and butterflies to lichens on walls. Cities with planted gardens often surprise with more bird species than a plain field. Mornings and evenings reveal different residents — owls and bats are missed if you only look during the day!
This simple diary is exactly how professional ecologists begin: observe, count, compare — then plan action.
🎯 Competency-Based Questions
Meera visits Kaziranga National Park in Assam with her family. She sees one-horned rhinos, wild elephants and Bengal tigers. The guide explains how a highway is planned through a nearby elephant corridor, and how villagers and conservationists are protesting together. He also mentions that tiger numbers in India have more than doubled in the last 50 years thanks to a famous project.
Q1. L1 Remember Name the project started in 1973 that helped tiger populations recover in India, and give the name of any one tiger reserve.
Answer: The project is Project Tiger, launched in 1973. Examples of tiger reserves include Jim Corbett (Uttarakhand), Ranthambore (Rajasthan), Bandhavgarh (Madhya Pradesh), Sundarbans (West Bengal) and Periyar (Kerala).
Q2. L2 Understand Why is Kaziranga considered a biodiversity-rich area, and why is protecting one species (like the rhino) not enough?
Answer: Kaziranga supports many species — rhinos, elephants, tigers, wild buffalo, swamp deer, hundreds of birds — and a mix of grassland, wetland and woodland ecosystems. Protecting only the rhino would fail because rhinos depend on grasslands, which depend on floods, tigers, grazers and many microbes. You must protect the whole ecosystem, not a single species.
Q3. L3 Apply Suggest three practical ideas the highway planners could use to reduce harm to the elephant corridor.
Answer: (i) Build wildlife overpasses or underpasses at known elephant crossings. (ii) Raise the highway on pillars over the sensitive stretch so animals walk freely underneath. (iii) Reduce vehicle speed limits, install warning signs and reflective fences, and ban traffic during nighttime peak movement. Combining these with local community monitoring gives the best outcome.
Q4. L4 Analyse Analyse why the Bishnoi community's 300-year-old practices are now valued as modern conservation.
Answer: The Bishnois ban cutting of living trees and harming of wildlife. In their villages, blackbuck herds and khejri trees thrive even though the surrounding land is semi-desert. Their rules show that sustained community belief is a powerful conservation tool — stronger even than government fences. Modern ecologists now recognise such "community conserved areas" as a cost-effective, culturally rooted form of biodiversity protection.
Q5. L5 Evaluate A friend says, "Since zoos breed tigers in cages, we don't really need tiger reserves." Evaluate this view.
Answer: The view is weak. Zoos can breed a handful of animals but cannot recreate forests, prey, territory and natural behaviour. A tiger born in a zoo does not learn to hunt or raise wild cubs. Moreover, protecting a tiger reserve also protects thousands of other species that share the forest — something a zoo can never do. Zoos have a role in public awareness and emergency breeding, but they are no replacement for real, protected wild habitat.
🔗 Assertion–Reason Questions
Assertion (A): India is called a megadiverse country.
Reason (R): Despite having only 2.4% of the world's land, India hosts close to 8% of all known species.
Answer: A. Being small in area yet home to a huge fraction of global species is precisely what makes India megadiverse.
Assertion (A): Elephant corridors are important even outside national parks.
Reason (R): Elephants travel long distances for food and water, and corridors link separate forest patches so populations do not become isolated.
Answer: A. Isolated populations risk inbreeding and local extinction; corridors keep gene flow and daily movement alive.
Assertion (A): Once a species becomes extinct, we cannot bring it back in the usual sense.
Reason (R): Every extinct species had a unique set of genes built up over millions of years, which cannot be remade.
Answer: A. The irreversible nature of genetic loss is exactly why preventing extinction is so important.
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