Diversity in the Living World

A nature walk reveals differences in plant height, stems, leaf shapes, flowers and scents. Animals differ in where they live, what they eat and how they move. The variety of plants and animals in an area is the starting meaning of biodiversity used in this chapter.

Observation needs a record: note the place, date and feature actually seen. Grass may have alternate leaves while Tulsi has paired, opposite leaves. A crow can fly and walk; an ant moves on six legs. A brief visit shows some local diversity, not a complete inventory.

Grouping brings order to this variety. Choose a feature, compare it consistently, and put organisms with that feature together. A grouping by habitat need not match a grouping by movement or food. There can be more than one useful way to organise the same observations.

Living things also depend on one another. Trees can provide animals with food and shelter, while some animals help disperse seeds. Understanding these relationships matters as much as naming the organisms.

Use stem texture, thickness and branching together with height. Height alone can mislead: a young tree is short, but it does not thereby become a herb.

Herbs

Usually small plants with soft, tender, green stems; tomato is the chapter's example.

Shrubs

Woody plants with branches arising close to the base; rose and hibiscus are examples.

Trees

Generally tall plants with a thick, hard, woody main stem; branches arise higher above the ground. Mango is an example.

Climbers and creepers

A weak stem may climb with support or spread along the ground. These describe how a plant grows, so do not classify a plant by height alone.

Venation is the arrangement of veins in a leaf. Reticulate venation forms a branching network, as in hibiscus. Parallel venation has veins running alongside one another, as in grass and banana.

A taproot system has a prominent main root with smaller side roots; mustard and hibiscus are examples. A fibrous root system has many thin roots arising near the stem base, without one dominant main root, as in grass.

The chapter's comparisons include lemongrass and wheat with parallel veins and fibrous roots, and sadabahar (periwinkle) and chickpea with reticulate veins and taproots. This is a general relationship, not a rule without exceptions. A leaf suggests what to investigate; it does not replace examining the plant.

Cotyledons are seed leaves. The number distinguishes the two groups introduced here: monocotyledons have one cotyledon and dicotyledons have two. In the activity, soaked chickpea seeds separate into two cotyledons; maize has one.

Dicots generally show reticulate venation and a taproot system; monocots generally show parallel venation and fibrous roots. Keep the defining seed feature separate from these associated patterns.

Chickpea / kidney bean

Two cotyledons: dicot examples. Look for the usual net-like leaf veins and taproot pattern.

Maize / wheat

One cotyledon: monocot examples. Look for the usual parallel leaf veins and fibrous root pattern.

Look before concluding

Seed size, seed colour and the number of visible halves of a dry grain are not reliable substitutes for identifying cotyledons. The textbook uses soaking and careful observation.

Record both the movement and the body part involved. One animal can have several modes of movement, so a single label may leave out useful information.

Walking and jumping

Ants walk using legs; goats walk and jump. Compare the observed action rather than assuming that all legs work in exactly the same way.

Flying and walking

Pigeons and houseflies use wings for flight and legs for walking. Wings alone do not describe everything they do.

Swimming

Fish use fins in movement through water. Their streamlined bodies help them move through it.

Comparing feet

A duck's webbed feet help push against water when swimming. Comparing them with a pigeon's feet links a visible difference to a different way of moving.

An adaptation is a feature that helps an organism survive in its surroundings. Explain the connection between feature and condition, rather than just listing unusual body parts. The examples describe existing features; they do not mean an individual chooses a new feature whenever its surroundings change.

Cactus in a desert

A thick, fleshy stem stores water where water can be scarce.

Deodar in mountains

A conical shape and sloping, flexible branches help snow slide off.

Rhododendrons in two regions

The chapter contrasts shorter plants with smaller leaves in the windy Nilgiri Shola region with taller plants in Sikkim. Its comparison concerns these regional examples, not a rule for every mountain plant.

Hot and cold desert camels

The Rajasthan example has one hump, long legs and broad feet suited to sand. Ladakh's two-humped camel has shorter legs and long hair that helps in cold winters.

Scientific clarification · camels

Humps store fat, not water. Camels conserve water, but it is inaccurate to say they never sweat: the Bactrian camel can delay perspiration. These clarifications use San Diego Zoo and Animal Diversity Web in the references.

A habitat is the place where an organism lives. It supplies conditions and resources such as food, water, air and shelter. Many different plants and animals may share a habitat.

Terrestrial habitats are on land: forests, grasslands, deserts and mountains are examples. Aquatic habitats include ponds, lakes, rivers and oceans. The broad categories contain very different conditions; a desert and a forest are both terrestrial but are not interchangeable.

Frogs use both land and water and are amphibians. For the exercise, distinguish where an animal lives from its biological group: merely using both environments is not enough to identify an animal as an amphibian. Observe its identity as well as its habitat.

When a forest is cleared, plants are removed and animals can lose food, shelter and breeding places. Other organisms that depend on them may also be affected. Conservation therefore needs attention to relationships and habitats, not just individual animals.

Protecting remaining habitat and restoring damaged areas help address habitat loss. Planting a few trees alone should not be assumed to replace a diverse, established forest.

E. K. Janaki Ammal (1897–1984)

The chapter describes her work documenting plant diversity and her support for protecting Silent Valley. The Kerala example connects botanical knowledge with conservation of an evergreen forest.

Salim Ali (1896–1987)

His observations of birds, their habitats and movements contributed to bird study and conservation. The chapter links his work with Keoladeo in Rajasthan and Ranganathittu in Karnataka.

Conservation initiatives

The textbook gives Project Tiger (1973), cheetah reintroduction (2022), and protected habitats for the Great Indian Bustard in Gujarat, Rajasthan and Maharashtra as examples. These are historical textbook references, not current population counts or assessments of project success.

Sacred groves

Communities protect some forest patches through local traditions. Such groves can conserve diverse plants, including medicinal plants, and their associated life. Community protection should not be confused with every grove having the same legal status.

Use these adapted tasks after reading. Record evidence and uncertainty; do not disturb wildlife or uproot plants from a natural habitat.

1. Make a small biodiversity record

   For plants, record height, stem, branching, leaf arrangement and venation; for animals, record place, food observed, movement and body parts used. Add date and location. Use fallen leaves or attached leaves without plucking. A gardener or knowledgeable local person can help identify an unfamiliar plant.

2. Compare plants and seeds

   With permission, examine nursery saplings before planting to compare roots and leaves; replant gently. Soak chickpea and maize seeds for two to three days and compare cotyledons. Sketch observations and mark features that remain uncertain. This combines the purpose of Activities 2.4–2.8 without requiring repeated plant collection.

3. Try a different grouping

   Choose several observed animals and state a clear criterion. Regroup them using another feature and explain why membership changes. Then compare a mountain goat with a plains goat and connect an observed difference with conditions; do not invent an adaptation from appearance alone.

4. Retrieve the reasoning

   Without looking back, explain why hibiscus is a shrub, predict the usual venation of a taproot plant such as radish, and compare wheat with kidney bean. Sketch a leaf-based grouping with hibiscus and grass, but label it as a comparison of these examples rather than a universal identification key.

5. Connect observation with conservation

   Explain a chain of effects from clearing a forest, then suggest protection or restoration steps. Ask elders about local changes, distinguishing memories from measured trends. For further reading, the chapter names researchers including Divya Mudappa, Usha Lachungpa, Ghazala Shahabuddin, Nandini Velho, Vidya Athreya, Uma Ramakrishnan and Divya Karnad; verify a specific person's work before recording it.

Choose an answer, check the explanation, and revise your choice if needed. The explanation matters more than memorising an example.