CBSE Class 9 Science Chapter 7: Diversity in Living Organisms NCERT Solutions
CBSE Class 9 Science Chapter 7: Diversity in Living Organisms introduces the importance of classifying the immense variety of life on Earth. It explains that understanding the fundamental characteristics, like cell type (prokaryotic or eukaryotic) and nutrition (autotrophic or heterotrophic), is key to organizing organisms, rather than just their environment. The chapter explores the significant differences between plants and animals, focusing on features like cell walls and mobility. These NCERT Solutions offer clear explanations and detailed reasoning, helping students comprehend the principles of biological classification. This resource is designed to build a strong foundation for understanding the relationships between different life forms and to prepare students thoroughly for their examinations by demystifying the complex world of biodiversity.
Quick info
| Board | CBSE |
|---|---|
| Class | Class 9 |
| Subject | Science |
| Session | 2026 |
| Language | English |
| Type | NCERT Solutions |
| Chapter | Chapter 7: Diversity in Living Organisms |
Chapter summary
Chapter 7, 'Diversity in Living Organisms,' focuses on the principles and necessity of classifying the immense variety of life on Earth. It explains how basic characteristics like cell type and nutritional modes form the foundation for grouping organisms. The solutions cover the primary divisions in classification, such as prokaryotic and eukaryotic organisms, and differentiate between plants and animals based on key features like cell walls and mobility. This chapter equips students with the foundational knowledge of biological taxonomy.
Learning outcomes
- Understand the importance of classifying living organisms.
- Identify and describe the range of variations in life forms.
- Differentiate between basic and superficial characteristics for classification.
- Explain the primary basis for the initial division of organisms.
- Compare and contrast plants and animals based on key biological features.
Topics covered
Paper topics
- Classification of Organisms
- Importance of Classification
- Range of Variations in Life Forms
- Basic Characteristics for Classification
- Cellular Organization (Prokaryotic vs. Eukaryotic)
- Plants vs. Animals
- Autotrophs and Heterotrophs
- Cell Wall
- Mobility in Organisms
- Biological Diversity
Important topics
- Importance of Classification
- Basic Characteristics for Classification
- Prokaryotic vs. Eukaryotic Cells
- Differences between Plants and Animals
- Autotrophic vs. Heterotrophic Nutrition
PDF preview
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Questions and Solutions
Question 1
We classify organisms because there are millions of species on Earth, making it impossible for anyone to study each one individually. Classification helps us organize and study these diverse life forms by grouping them based on certain shared characteristics. This systematic approach simplifies the vastness of biological diversity.
Question 2
Here are three examples illustrating the wide range of variations in life forms:
- Insects and Arthropods: Within a single building, you might find ants, cockroaches, spiders, and houseflies. Although they all belong to the phylum Arthropoda, they exhibit significant differences in their appearance and structure.
- Mammals: In a neighborhood, humans, monkeys, cats, and dogs coexist. Despite belonging to the class Mammalia, they display distinct physical features and behaviors.
- Plants: A local park can showcase a remarkable variety of plant life, ranging from small, low-growing grasses to large, towering trees like the banyan tree, demonstrating diversity in size and form.
Question 1
The kind of cells an organism is made of is a more basic and scientifically sound characteristic for classification than the place where they live. Here's why:
- Scientific Basis: The cellular structure (e.g., presence or absence of a nucleus, cell wall composition) provides a fundamental biological basis for grouping organisms.
- Habitat Diversity: A particular dwelling place (habitat) can be inhabited by a wide variety of organisms belonging to different groups. For instance, a pond contains plants, animals, and microorganisms, all with different cellular makeups. Therefore, habitat is not a reliable primary characteristic for broad classification.
Question 2
The primary characteristic on which the first division of organisms is made is the organization of their nucleus. Based on this, organisms are broadly divided into two main groups: prokaryotic organisms (which lack a well-defined nucleus and other membrane-bound organelles) and eukaryotic organisms (which possess a true nucleus and membrane-bound organelles).
Question 3
Plants and animals are placed into different categories based on several key distinguishing features:
- Mode of Nutrition: Plants are generally autotrophs, meaning they produce their own food through photosynthesis. Animals, on the other hand, are heterotrophs; they obtain their food by consuming other organisms.
- Cell Wall: Plant cells possess a rigid cell wall made primarily of cellulose, which provides structural support. Animal cells lack a cell wall.
- Mobility: Most animals are capable of movement and can move from one place to another, often in search of food, shelter, or mates. Plants are typically stationary and do not move from their location, although parts of them may grow or respond to stimuli.
Common mistakes
- Considering habitat as a primary classification characteristic over cell type.
- Overlooking the fundamental differences between prokaryotic and eukaryotic cells.
- Confusing superficial variations with basic characteristics for classification.
Revision tips
- Focus on understanding *why* classification is necessary before memorizing categories.
- Create a table comparing plants and animals based on the criteria discussed in the solutions.
- Review the distinction between prokaryotic and eukaryotic cells as a fundamental concept.
- Use the examples provided to visualize the range of diversity in living organisms.
Practice MCQs
Q1. What is the primary reason for classifying organisms?
Explanation: Classification simplifies the study of the vast number of species on Earth by grouping them based on common characteristics, making it impossible to study each one individually.
Q2. Which characteristic is considered more basic for classification?
Explanation: The type of cells an organism is composed of is a fundamental, scientific basis for classification, unlike habitat which can host diverse organisms.
Q3. The first division of organisms is primarily based on:
Explanation: The initial classification of organisms is based on the presence or absence of a well-organized nucleus, distinguishing between prokaryotic and eukaryotic cells.
Q4. Which of the following is a key difference between plants and animals?
Explanation: Plants are typically autotrophs (make their own food), while animals are heterotrophs (obtain food from other organisms). Plants also possess cell walls, which are absent in animal cells.
Frequently asked questions
Why is it important to classify living organisms?
Classification is essential because the Earth hosts millions of species. Studying each one individually is impossible. Classification groups organisms based on common characteristics, making their study systematic and manageable.
What is a more fundamental characteristic for classification: habitat or cell type?
The kind of cells an organism is made of is a more fundamental characteristic. This is because a single habitat can contain a wide variety of organisms with different cell structures, whereas cell type provides a scientific basis for grouping.
What is the primary basis for the very first division of organisms in classification?
The primary basis for the first division is the organization of the nucleus. Organisms are broadly divided into prokaryotic (lacking a true nucleus) and eukaryotic (having a true nucleus).
How are plants and animals primarily distinguished in classification?
Plants and animals are primarily distinguished by their mode of nutrition (plants are autotrophs, animals are heterotrophs), the presence of a cell wall (in plants, absent in animals), and their ability to move (most animals move, while plants are generally stationary).
Are there variations even within the same broad group of organisms?
Yes, there is a wide range of variations. For example, ants, cockroaches, and spiders all belong to Arthropoda but look very different from each other. Similarly, a park can have tiny grasses and giant banyan trees.
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