CBSE Class 12 Biology Chapter 1: Reproduction in Organisms NCERT Solutions

Reviewed by NCERT Help Editorial Team · Updated on 29 Jul 2026

NCERT Solutions PDF Class 12 PDF

This resource provides detailed NCERT Solutions for CBSE Class 12 Biology, Chapter 1: Reproduction in Organisms. It covers fundamental concepts such as the essential role of reproduction for species continuity, the advantages of sexual reproduction over asexual reproduction due to genetic variation, and the reasons why offspring from asexual reproduction are termed clones. The solutions also explore the survival benefits of sexual reproduction in diverse environments while acknowledging situations where asexual reproduction might be more advantageous. This chapter is crucial for understanding the diversity of life and the mechanisms that ensure its perpetuation. These solutions are designed to help students grasp these core biological principles, clarify doubts, and prepare effectively for their board examinations by offering clear explanations and logical reasoning for each question.

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Quick info

Board	CBSE
Class	Class 12
Subject	Biology
Session	2026
Language	English
Type	NCERT Solutions
Chapter	Chapter 1: Reproduction in Organisms

Chapter summary

Chapter 1 of the NCERT Class 12 Biology textbook focuses on Reproduction in Organisms. This section delves into the significance of reproduction for the survival of species, comparing and contrasting asexual and sexual modes of reproduction. It explains the concept of clones formed through asexual reproduction and discusses the evolutionary advantages and survival prospects associated with sexual reproduction, while also considering specific scenarios where asexual reproduction is beneficial. The solutions provided here clarify these key concepts with detailed explanations.

Learning outcomes

Understand the fundamental importance of reproduction for the existence of species.
Differentiate between sexual and asexual reproduction, identifying the advantages of each.
Explain why offspring produced through asexual reproduction are considered clones.
Analyze the survival advantages of offspring produced through sexual reproduction.
Evaluate the conditions under which asexual reproduction can be more advantageous than sexual reproduction.

Topics covered

Paper topics

Importance of Reproduction
Modes of Reproduction
Asexual Reproduction
Sexual Reproduction
Clones
Genetic Variation
Adaptation
Evolution
Survival of Species
Comparison of Reproductive Modes

Important topics

Comparison of Sexual and Asexual Reproduction
Significance of Genetic Variation
Concept of Clones
Survival Advantages in Different Environments
Role of Reproduction in Species Continuity

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Questions and Solutions

Question 1

Why is reproduction essential for organisms?

Solution: Reproduction is a fundamental biological process that is vital for all living organisms. Its primary importance lies in ensuring the continuity of species from one generation to the next. Through reproduction, organisms produce offspring that are similar to themselves, thereby preventing the species from becoming extinct and maintaining its presence on Earth over time. Without reproduction, a species would cease to exist once the current individuals die.

Question 2

Which is a better mode of reproduction, sexual or asexual? Why?

Solution: Sexual reproduction is generally considered a better mode of reproduction compared to asexual reproduction. This is primarily because sexual reproduction involves the combination of genetic material from two different individuals (usually male and female). This process leads to the formation of new variants (offspring) that are not identical to their parents or to each other. These genetic variations are crucial as they allow individuals to adapt to constantly changing and challenging environmental conditions, increasing their chances of survival. Furthermore, these variations contribute to the evolution of better-suited organisms, ensuring the greater survival and long-term persistence of a species. In contrast, asexual reproduction typically produces offspring that are exact copies of the parent, offering little to no genetic variation and thus limiting adaptability.

Question 3

Why is the offspring formed by asexual reproduction referred to as a clone?

Solution: The offspring formed through asexual reproduction are referred to as clones because they are morphologically (structurally) and genetically identical to their single parent. In asexual reproduction, there is no involvement of gametes or the fusion of genetic material from two different individuals. Consequently, the new organism that develops is essentially a precise copy of the parent organism, exhibiting the same traits and genetic makeup. A clone is defined as a group of individuals that are genetically and morphologically identical.

Question 4

Offspring formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?

Solution: Offspring formed through sexual reproduction generally have better chances of survival because the process involves the fusion of male and female gametes, leading to the combination of DNA from two parents. This results in genetic variations among the offspring. These variations are highly advantageous as they enable individuals to adapt to diverse and changing environmental conditions. Organisms with variations that are better suited to their environment are more likely to survive and reproduce. However, this statement is not always true. In certain situations, asexual reproduction can be more advantageous. For instance, for organisms that are sessile (do not move) and are well-adapted to a stable environment, asexual reproduction can be a faster and more energy-efficient mode of reproduction. It allows them to quickly produce offspring that are already suited to their specific habitat without the risks and complexities associated with finding a mate and the slower process of sexual reproduction.

Common mistakes

Overlooking the evolutionary significance of variation introduced by sexual reproduction.
Assuming sexual reproduction always confers a survival advantage without considering environmental context.
Confusing the terms 'clone' and 'offspring' without understanding the genetic implications.
Not recognizing the energy and time efficiency of asexual reproduction in certain contexts.

Revision tips

Focus on the key differences and advantages of sexual versus asexual reproduction.
Understand the genetic basis for why asexual offspring are clones.
Consider the environmental factors that influence the 'better' mode of reproduction.
Review the definitions of key terms like 'gamete', 'variant', and 'clone'.

Practice MCQs

Q1. What is the primary biological purpose of reproduction for any organism?

Q2. Which mode of reproduction is generally considered better for adaptation and evolution?

Q3. Offspring produced through asexual reproduction are called clones because they are:

Q4. What is the main advantage of genetic variation introduced by sexual reproduction?

Q5. Under what circumstances might asexual reproduction be more advantageous than sexual reproduction?

Frequently asked questions

Why is reproduction considered essential for living organisms?

Reproduction is essential because it ensures the continuity of species on Earth. Without it, species would eventually become extinct as individuals die.

What makes sexual reproduction generally better than asexual reproduction?

Sexual reproduction creates genetic variations by combining DNA from two parents. These variations improve the adaptability of offspring to changing environments and drive evolution, leading to better survival chances.

Why are the offspring from asexual reproduction called clones?

Offspring from asexual reproduction are called clones because they are morphologically and genetically identical to the single parent, as there is no fusion of gametes or mixing of genetic material.

Does sexual reproduction always guarantee better survival for offspring?

Not always. While sexual reproduction generally provides advantages through variation, asexual reproduction can be more beneficial for organisms that are well-established in a stable environment due to its speed and efficiency.

What is the role of variation in reproduction?

Variation, primarily introduced through sexual reproduction, allows populations to adapt to environmental changes. This increases the likelihood that some individuals will survive and reproduce, ensuring the species' long-term persistence.

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