Chapter-Chapter 2. Diversity in the Living World Science Curiosity class 6 in english Medium CBSE Notes

Chapter 2. Diversity in the Living World

In this chapter, you have studied the diversity of plants and animals found around us, their classification, and their important characteristics. Every living organism on Earth has its own unique features. Scientists classify living organisms into different groups based on these characteristics. This chapter explains in detail the classification of plants based on their types, leaf venation, root systems, and cotyledons.

Detailed Notes

This chapter teaches students how to observe nature, identify the similarities and differences among living organisms, and study them scientifically. Classification makes the study of millions of living organisms simple, systematic, and meaningful.

Diversity in the Living World

A wide variety of plants, animals, birds, insects, and other living organisms are found around us. They differ from one another in their size, colour, food habits, habitat, movement, and many other characteristics. These differences create the rich biodiversity found on Earth.

For example, some plants are small while others are very tall. Some birds can fly, whereas others can only walk. Fish live in water, while camels are adapted to survive in deserts.

Biodiversity

The variety of all kinds of plants, animals, and microorganisms found in a particular region is known as biodiversity. Every living organism performs an important role in nature. If the population of even one organism decreases significantly or becomes extinct, it can affect the entire ecosystem.

Importance of Biodiversity

• Maintains ecological balance.
• Supports the food chain.
• Helps conserve natural resources.
• Provides food, medicines, and other useful resources for human life.

Classification of Living Organisms

Millions of different kinds of living organisms exist on Earth. Studying each one separately would be very difficult. Therefore, scientists place organisms with similar characteristics into the same group. This process is known as classification.

Advantages of Classification

• Makes the identification of organisms easier.
• Makes the study of living organisms systematic and simple.
• Helps us understand similarities and differences among organisms.
• Helps in identifying newly discovered organisms.

Classification of Plants

Plants are classified into five major groups based on their height, the nature of their stem, and the pattern of branching.

1. Herbs

Herbs are small plants with soft, green, and tender stems.

Examples: Spinach, Coriander, Tomato, Wheat, Rice.

2. Shrubs

Shrubs are medium-sized plants with hard, woody stems. Their branches arise near the base of the stem.

Examples: Rose, Tulsi (Holy Basil), Henna.

3. Trees

Trees are large and tall plants. They have thick, hard, woody stems called trunks. Their branches arise at some height above the ground.

Examples: Mango, Neem, Banyan, Peepal.

4. Climbers

Climbers have weak stems and cannot stand upright on their own. They grow upward with the support of other objects.

Examples: Grapevine, Pea, Money Plant.

5. Creepers

Creepers have very weak stems. They spread and grow along the ground.

Examples: Pumpkin, Watermelon, Muskmelon.

Leaf Venation

The fine lines visible on a leaf are called veins. The arrangement of these veins is known as leaf venation.

Reticulate Venation

In this type of leaf, the veins form a network-like pattern.

Examples: Mango, Rose, Marigold, Mustard.

Parallel Venation

In this type of leaf, the veins run parallel to one another.

Examples: Wheat, Rice, Maize, Banana.

Types of Roots

The root is the part of a plant that anchors it firmly in the soil and absorbs water and minerals.

Tap Root

A taproot system has one main root from which many smaller lateral roots arise.

Examples: Mustard, Radish, Carrot, Gram.

Fibrous Root

A fibrous root system consists of many thin roots of similar size, and there is no main root.

Examples: Wheat, Rice, Maize, Grass.

Classification of Plants Based on Cotyledons

The food-storing part present inside a seed is called a cotyledon. Based on the number of cotyledons, plants are classified into two groups.

Monocot Plants

• Have one cotyledon.
• Show parallel venation.
• Have a fibrous root system.
• Examples: Wheat, Rice, Maize.

Dicot Plants

• Have two cotyledons.
• Show reticulate venation.
• Have a taproot system.
• Examples: Gram, Pea, Mustard, Mango.

Relationship Between Reticulate Venation and Taproot

Generally, plants with reticulate venation have a taproot system. Such plants are usually dicots.

Relationship Between Parallel Venation and Fibrous Root

Generally, plants with parallel venation have a fibrous root system. Such plants are usually monocots.

Importance of Nature Conservation

Every living organism is important for maintaining the balance of nature. Therefore, we should not harm plants and animals unnecessarily. Conserving biodiversity is the responsibility of every citizen.

Remember Points

• Biodiversity is one of Earth's greatest natural treasures.
• Classification makes the study of living organisms easier.
• Herbs, shrubs, trees, climbers, and creepers are the major groups of plants.
• Reticulate Venation → Taproot → Dicot.
• Parallel Venation → Fibrous Root → Monocot.
• Every living organism plays an important role in the environment.

Chapter Summary

In this chapter, you have learnt about the diversity of living organisms, the importance of biodiversity, the need for classification, the major groups of plants, leaf venation, types of roots, and the characteristics of monocot and dicot plants. These concepts help students identify, compare, and scientifically classify living organisms with ease.

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