Diversity in the Living World – Class 6 Science Chapter 2 Notes & NCERT PDF

Class 6ScienceChapter 2NCERT book: Curiosity - Science Class 6

Notes and a simple summary of Chapter 2 of the NCERT Class 6 Science book, with the official chapter PDF, flashcards, an MCQ quiz and an AI tutor for your doubts.

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Chapter 2: Diversity in the Living World

Introduction

The chapter opens with a Sanskrit subhashita:

छायामन्यस्य कुर्वन्ति तिष्ठन्ति स्वयमातपे । फलान्यपि परार्थाय वृक्षाः सत्पुरुषा इव ॥

Trees stand in the Sun and give shade to others. Their fruits are also for others. Likewise, good people bear all hardships and bring welfare to others.

On a pleasant morning after rain, Madam Sulekha (the science teacher) invites Dr Raghu (a scientist from a nearby research laboratory) and Maniram chacha (an elderly man from the community who is an expert at mimicking bird calls and identifying plants and animals) for a nature walk. The students observe grasses, bushes, trees, birds, butterflies and monkeys. They learn that each bird has its own unique chirp, which is an example of diversity in nature. They also learn to respect living creatures and to observe them without disturbing them.

Key Concepts

2.1 Diversity in Plants and Animals Around Us

Plants differ in their stems (tall/short, hard/soft), leaves (shape and arrangement) and flowers (colour, shape, scent).

- Grass: soft, thin stem; a single leaf grows alternately from different points

- Tulsi: hard, thin stem; leaves in opposite pairs

- Hibiscus (gudhal): hard stem, pinkish-purple flowers

- Neem: hard, thick stem

Animals differ in where they live, what they eat and how they move. A crow lives on a tree, eats insects, flies and walks. An ant nests in the soil and has six legs. A cow eats grass and leaves.

The variety of plants and animals in a region is its biodiversity. Each member has a role. Trees give food and shelter, and animals spread seeds after eating fruits, so plants and animals depend on each other.

2.2 How to Group Plants and Animals?

Grouping means arranging things based on their similarities and differences. It makes plants and animals easier to study. Different groups of students may choose different bases for grouping (height, flowers, eating habits, habitat).

#### 2.2.1 Grouping plants

By height and stem:

Trees: tall, with hard, thick, brown, woody stems; branches start high up on the stem (e.g., mango)

Shrubs: medium height, with many hard, brown, woody stems that branch close to the ground and are thinner than a tree trunk (e.g., rose)

Herbs: small, with soft, green stems (e.g., tomato)

Climbers: weak stems that need support to climb

Creepers: creep along the ground

By leaf venation (the pattern of veins on a leaf):

Reticulate venation: net-like veins on both sides of a thick middle vein (e.g., hibiscus)

Parallel venation: veins run parallel (e.g., banana, grass)

By roots:

Taproot: one main root with small side roots (e.g., mustard, hibiscus)

Fibrous roots: a bunch of similar-sized thin roots from the base of the stem (e.g., grass)

By seeds (cotyledons):

Dicots: seeds with two cotyledons (e.g., chickpea)

Monocots: seeds with one cotyledon (e.g., maize)

Key relationship: Dicots → reticulate venation + taproot. Monocots → parallel venation + fibrous roots.

Examples: chickpea and sadabahar (dicot); wheat and lemongrass (monocot).

#### 2.2.2 Grouping animals

Animals move in different ways: they fly, run, crawl, walk, hop or jump. They use different body parts. An ant uses legs, a goat walks and jumps with legs, a pigeon and a housefly walk and fly with legs and wings, and a fish uses fins. Movement, shape, size and colour can all be bases for grouping animals.

2.3 Plants and Animals in Different Surroundings

Fish have streamlined bodies and fins for water; goats move on grassy land with legs.

Cactus (Rajasthan desert): thick, fleshy stems store water.

Deodar (Himalayas): conical shape and sloping branches let snow slide off.

Camels:

- Hot desert (Rajasthan): long legs and wide hooves to walk on sand without sinking; one hump

- Cold desert (Ladakh): shorter legs for mountains; two humps that shrink in late winter; long hair from head to neck

- Camels excrete little urine, have dry dung and do not sweat, so they lose little water.

Rhododendrons are short with smaller leaves on windy Nilgiri mountain tops, but taller in Sikkim.

Adaptations are special features that enable plants and animals to survive in a particular region.

Habitat is the place where plants and animals live. It provides food, water, air and shelter.

Terrestrial habitats: forests, deserts, grasslands, mountains

Aquatic habitats: ponds, lakes, rivers, oceans

Amphibians (e.g., frogs) live both on land and in water.

Protecting Biodiversity

Damage to habitats causes loss of biodiversity. The Bengal Tiger, Cheetah and Great Indian Bustard declined because of habitat loss.

Project Tiger (1973), Cheetah Reintroduction Project (2022), and protected areas for the Great Indian Bustard (Gujarat, Rajasthan, Maharashtra)

Sacred groves: undisturbed forest patches protected by local communities

Save Silent Valley movement (Palakkad, Kerala): people stopped a hydroelectric dam on the Kunthipuzha river after a 10-year struggle.

Scientists: Janaki Ammal (botanist, Save Silent Valley, head of the Botanical Survey of India); Salim Ali, the Birdman of India (Keoladeo and Ranganathittu, Padma Vibhushan 1976)

Activities in the Chapter

2.1 Nature walk: observe and record stems, leaves and flowers (Table 2.1) and animals' homes, food and movement (Table 2.2). Do not pluck leaves or flowers.

2.2 Let us appreciate: each student draws one plant and one animal. Conclusion: the variety is huge (biodiversity).

2.3 Grouping cards: group pictures by common features. Conclusion: the basis of grouping can differ.

2.4 Height and stem table: classify plants as trees, shrubs or herbs.

2.5 Leaves: observe reticulate and parallel venation.

2.6 Roots: dig out herbs with a khurpi, wash the roots, observe taproot vs fibrous roots, then replant.

2.7 Relate: check saplings (lemongrass, marigold, sadabahar). Venation and root type are linked.

2.8 Seeds: soak chickpea and maize. Chickpea splits into 2 cotyledons (dicot); maize has 1 (monocot).

2.9 Movement table: animals, their type of movement and the body parts used

2.10 Surroundings table: plants and animals of desert, mountain, ocean and forest

Key Terms

Biodiversity (जैव विविधता): the variety of plants and animals in a region

Grouping (समूहीकरण): arranging things by common features

Herb / Shrub / Tree (शाक / झाड़ी / वृक्ष): plant groups by height and stem

Climber / Creeper (आरोही / विसर्पी लता): weak-stemmed plants that climb or spread on the ground

Venation (शिराविन्यास): the pattern of veins on a leaf

Reticulate / Parallel venation (जालिकावत् / समानांतर शिराविन्यास)

Taproot / Fibrous root (मूसला जड़ / झकड़ा जड़)

Cotyledon (बीजपत्र): a part of the seed

Dicot / Monocot (द्विबीजपत्री / एकबीजपत्री)

Adaptation (अनुकूलन): a special feature that helps survival in a region

Habitat (आवास): the place where an organism lives

Terrestrial / Aquatic (स्थलीय / जलीय)

Amphibian (उभयचर): lives both on land and in water

Sacred grove (पवित्र उपवन): a community-protected forest patch

Real-life Connections

Radish and carrot are swollen taproots; onion and garlic plants show fibrous roots.

Wheat, rice and maize are monocots; pulses such as chana, rajma and moong are dicots.

Protecting local trees, ponds and sacred groves protects biodiversity near you.

Common Misconceptions

"All tall plants are trees." Classification also depends on the stem type and where the branches start.

"A rose plant is a small tree." It is a shrub, with woody stems branching close to the ground.

"All camels have one hump." Camels of the cold desert (Ladakh) have two humps.

"Frogs are fish because they swim." Frogs are amphibians. They live on land and in water.

"Grouping has only one correct answer." Different bases can give different, equally valid groups.

Keep the Curiosity Alive (Exercise Hints)

Wheat vs kidney beans: wheat is a monocot (fibrous roots, parallel venation); kidney bean is a dicot (taproot, reticulate venation).

Habitat sorting: aquatic: dolphin, whale; terrestrial: horse, sheep, squirrel, earthworm, pigeon; both: frog, crocodile, tortoise.

Radish: a taproot, so expect reticulate venation in its leaves.

Duck: webbed feet help it swim.

Gudhal: ask about its height, stem hardness and where the branches start.

💡 Key Learning Points

✓Biodiversity is the variety of plants and animals in a region; its members depend on each other (trees give shelter, animals spread seeds).
✓Plants can be grouped as herbs, shrubs and trees by height, stem type and branching; climbers need support and creepers spread on the ground.
✓Dicots (two cotyledons) have reticulate venation and taproots; monocots (one cotyledon) have parallel venation and fibrous roots.
✓Adaptations are special features for survival: the cactus's fleshy stem, the deodar's conical shape, the camel's hooves and humps, the fish's fins and streamlined body.
✓Habitats can be terrestrial or aquatic; habitat loss reduces biodiversity, which projects like Project Tiger and community sacred groves try to protect.

👨‍🏫 Teaching Tips

→Conduct a real nature walk in the school campus with a nature journal; insist on the 'observe, don't disturb, don't pluck' rule from the chapter.
→Soak chickpea and maize seeds two days before class so every group can split them and count the cotyledons themselves.
→Uproot a small weed and a grass tuft (then replant) to compare taproot and fibrous roots side by side.
→Make a 'Monocot or Dicot?' sorting game with real leaves: students predict the root type from the venation, then check.
→Use the two camel pictures (Rajasthan vs Ladakh) for a 'spot the differences and explain why' pair activity.
→Invite a grandparent or gardener (like Maniram chacha) to talk about local plants and birds that were common earlier but are rare now.
→Build a class biodiversity register and a scrapbook of fallen leaves and flowers across the term.
→Tell the Save Silent Valley story and hold a short class debate on development versus conservation.

📋 Assessment Questions

Can the student classify given plants (mango, rose, tomato, money plant, pumpkin) as tree, shrub, herb, climber or creeper with reasons?
Given a leaf's venation, can the student predict its root type and seed type?
Can the student explain at least two adaptations each of the camel and the deodar tree?
Can the student sort animals into terrestrial, aquatic and amphibian groups?
Can the student suggest two ways of protecting biodiversity in their own area?

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