Diversity in the Living World - 2nd Chapter | Science | 6th Standard

A friendly guide for Class 6 students — plants, animals, and the amazing places they call home

Look out of your window for a second. Maybe you see a coconut tree, a rose bush in a pot, a crow on a wire, and an ant crawling on the ground. None of them look alike — different heights, different shapes, different ways of moving. That's what scientists call diversity: the incredible variety of living things around us. In this chapter, we're going to become plant-and-animal detectives and figure out why living things look and behave so differently, and how each one is perfectly suited to the place it lives in. Diversity in the Living World for 6th Standard

Diversity in the Living World 6th standard Science

🌿 Part 1: Getting to Know a Plant

Every plant — whether it's a tiny mint sapling or a giant banyan tree — is built from the same basic parts: a stem, roots, leaves, and (for many plants) seeds. But the way each part looks can be completely different from plant to plant. Let's meet each part one by one.

1. The Stem — the plant's backbone

The stem does a lot of quiet, important work. It holds the plant upright, carries leaves up toward the sunlight, and acts like a pipeline — carrying water and minerals from the roots all the way up to the leaves, and food back down. Depending on how tall and how woody a plant's stem is, plants are sorted into a few neat categories:

• Herbs — small, soft, green-stemmed plants. Think mint, coriander, or wheat.

• Shrubs — medium-sized plants with hard but not-too-thick stems, branching close to the ground. Rose and lemon are good examples.

• Trees — tall plants with hard, woody stems (trunks). Mango and neem are classic trees.

• Climbers — plants with weak stems that use a support (a fence, a wall, another plant) to climb upward. Grapevine and pea are climbers.

• Creepers — plants with weak stems too, but instead of climbing, they spread out along the ground. Pumpkin and watermelon are creepers

Quick check: Is a banana plant a tree? It's tall, but its stem is actually soft, so botanically it's classified as a herb!

2. The Root — the anchor underground

Roots are the part of the plant hiding below the soil. They anchor the plant firmly in place and pull up water and minerals for it to use. Not all roots look the same though — there are two main types.

• Tap root — one thick main root grows straight down, with thinner side roots branching off it. Found in mustard, mango, and neem.

• Fibrous root — many thin, thread-like roots spread out from the base of the stem, like a mop. Found in wheat, maize, and grasses.

Roots have a hidden talent too: in plants like radish, carrot, and tapioca, the root swells up to store food, which is exactly why we love eating them!

3. The Leaf — the plant's kitchen

Leaves are green because of a pigment called chlorophyll, which traps sunlight. Using this sunlight, along with carbon dioxide from the air and water from the roots, leaves cook up food for the whole plant — a process called photosynthesis. That's why leaves are often called the "food factories" of a plant. They also let out extra water vapour through their surface, a process called transpiration.

If you hold a leaf up to the light, you'll notice a pattern of thin lines running through it — these are called veins, and the pattern they make is called venation.

• Reticulate venation — veins form a net-like pattern, as in peepal and mango leaves.

• Parallel venation — veins run side by side like straight lines, as in banana and grass leaves.

4. Seeds, and a neat pattern worth remembering

Inside every seed sits a tiny baby plant called an embryo, wrapped in one or two seed-leaves called cotyledons.

• Seeds with one cotyledon are called monocots — and monocot plants almost always have parallel venation and fibrous roots (think wheat, maize).

• Seeds with two cotyledons are called dicots — and dicot plants almost always have reticulate venation and tap roots (think mango, kidney beans).

Once you spot the venation on a leaf, you can actually predict what kind of root system that plant has, without ever digging up the soil! Parallel veins → fibrous roots. Net-like veins → tap root.

🐾 Part 2: Getting to Know Animals

Animals show off diversity just as much as plants do. Think about how differently they move — birds fly, fish swim, snakes crawl, rabbits hop, and cheetahs run. Each animal's body — its legs, wings, fins, or the shape of its body — is built for the particular way it needs to move. Animals also differ enormously in size, shape, structure, and colour, which is exactly why no two species look the same, even within the same habitat.

Why does this matter? When homes, food sources, and natural resources are destroyed, animals and plants lose the ability to survive — this is called loss of biodiversity. Protecting nature means every living thing gets to keep thriving, including us!

🏡 Part 3: Home Sweet Home — Habitats and Adaptation

The place where a living thing naturally lives is called its habitat. Habitats on land are called terrestrial habitats, and habitats in water are called aquatic habitats. But simply living somewhere isn't enough — every plant and animal needs special features or behaviours to actually survive there. This is called adaptation.

Let's travel to four very different habitats and see how life adapts to each one.

Desert

Deserts are hot, dry, and short on water — so everything living there is built to save water.

• Plants: long roots to reach deep water, fleshy stems that store water, and leaves reduced to spines to cut down water loss.

• Animals: camels have long legs and wide hooves for walking on sand, and excrete very little urine to conserve water. Desert rats and snakes stay inactive and hide in burrows during the scorching day, coming out only at cool night.

Mountain

Mountains bring freezing cold, strong winds, and heavy snow.

• Plants: cone-shaped trees with sloping branches (so snow slides off instead of piling up and breaking them) and needle-like leaves close to the ground.

• Animals: thick fur and long hair trap body heat (the snow leopard is a great example). Some animals migrate to warmer areas, others hibernate through winter.

Grassland

Open, grassy stretches are home to both plant-eaters and hunters, so features here go in two very different directions.

• Plants: flexible stems, narrow leaves, and deep roots to survive grazing and drought.

• Herbivores (like deer): strong teeth for chewing grass, long legs for running from danger, and eyes on the sides of the head for a wide, all-round view.

• Carnivores (like lions): sharp claws, camouflage to sneak up on prey, eyes facing forward for sharp depth perception, and strong canine teeth.

Aquatic (water)

Living in water calls for a completely different toolkit.

• Plants: small roots (since absorbing water isn't a problem), waxy or hollow stems, and floating leaves with stomata on their upper surface (like the lotus) so they can still "breathe" while their underside stays wet.

• Animals: streamlined, spindle-shaped bodies that glide through water easily, along with gills, fins, and slippery skin. Even animals like the octopus and squid — which aren't naturally streamlined — reshape their bodies while swimming to reduce drag.

Neat fact: A duck's webbed feet act like built-in paddles, letting it push water backward and glide forward smoothly — a perfect adaptation for a bird that spends half its life swimming.

📝 Quick Recap

Concept	Key idea
Stems	Herb (soft) → Shrub (medium, woody) → Tree (tall, woody) → Climber/Creeper (weak, needs support or spreads on ground)
Roots	Tap root (one main root) vs Fibrous root (many thin roots)
Venation	Reticulate (net-like) vs Parallel (straight lines)
Seeds	Monocot (1 cotyledon, parallel venation, fibrous roots) vs Dicot (2 cotyledons, reticulate venation, tap root)
Habitats	Terrestrial (land) vs Aquatic (water)
Adaptation	Special features/behaviours that help a living thing survive in its habitat

🎯 Test Yourself

1. Why are leaves called the "food factories" of a plant?

Because they prepare the plant's food through photosynthesis, using sunlight, carbon dioxide, and water.

2. A grass plant and a rose plant are both being pulled out of the soil. Which comes out more easily, and why?

The grass plant, because it's a herb with shallow fibrous roots, while the rose is a shrub with a deep-penetrating tap root.

3. Why do desert plants often have a thick waxy coating on their stems?

The waxy layer reduces water loss through transpiration, helping the plant survive with very little water.

4. Why are the leaves of pine trees needle-shaped?

Needle-shaped leaves let snow and rainwater slide off easily, protecting the leaves from breaking under the weight of piled-up snow.

5. Name two plants with fibrous roots.

Wheat and grass.