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 the continuity of species, and a comparative analysis of asexual and sexual reproduction. The solutions explain why offspring from asexual reproduction are called clones, highlighting their genetic and morphological similarity to the parent. Furthermore, it delves into the advantages of sexual reproduction, emphasizing the role of genetic variation in adaptation and survival, while also discussing scenarios where this advantage might not always hold true. These solutions are designed to help students grasp the core principles of reproduction, clarify doubts, and prepare effectively for their board examinations by offering clear explanations and step-by-step reasoning.

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Quick info

Board	CBSE
Class	Class 12
Subject	Biology
Session	2026
Language	English
Type	NCERT Solutions
Chapter	Chapter 1

Chapter summary

Chapter 1 of the CBSE Class 12 Biology syllabus focuses on Reproduction in Organisms. These NCERT Solutions explain the necessity of reproduction for species survival, differentiate between asexual and sexual reproduction, and define clones. The solutions also explore the survival advantages conferred by variations arising from sexual reproduction, while acknowledging exceptions. This chapter is crucial for understanding the diversity of life and the mechanisms that ensure its continuation.

Learning outcomes

Understand the fundamental importance of reproduction for all living organisms.
Differentiate between asexual and sexual modes of reproduction.
Explain why offspring produced through asexual reproduction are considered clones.
Analyze the advantages of sexual reproduction in terms of genetic variation and adaptation.
Evaluate the conditions under which sexual reproduction offers better survival chances.
Recognize that asexual reproduction can be advantageous in specific environments.

Topics covered

Paper topics

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

Important topics

Asexual vs. Sexual Reproduction
Role of Genetic Variation
Concept of Clones
Continuance of Species
Advantages of Sexual Reproduction

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Questions and Solutions

Question 1

Why is reproduction essential for organisms?

Solution: Reproduction is a fundamental biological process that is crucial for the survival and continuation of all living organisms. It is the mechanism by which organisms produce new individuals, or offspring, that are similar to themselves. This process ensures that life continues from one generation to the next, thereby preventing the extinction of species. Without reproduction, a species would cease to exist after the lifespan of its current individuals ends.

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, leading to the formation of new variants. These variations, arising from the mixing of DNA, result in offspring that are not identical to their parents or to each other. Such genetic diversity is highly advantageous as it allows individuals to adapt to constantly changing and challenging environmental conditions, increasing the overall survival rate of the species and driving evolutionary progress. In contrast, asexual reproduction typically produces offspring that are exact copies of the parent, offering little to no genetic variation and thus making the population more vulnerable to environmental changes.

Question 3

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

Solution: The offspring produced 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 develops directly from the parent, inheriting its exact genetic makeup. This results in a group of individuals that are essentially exact replicas, or clones, of the parent.

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 genetic recombination and the creation of new variations. These variations allow individuals to adapt more effectively to diverse and changing environmental conditions. For instance, if the environment changes, some individuals with advantageous variations are more likely to survive and reproduce. However, this statement is not always true. In certain stable environments, or for organisms that are sessile (immobile) and well-adapted to their specific niche, asexual reproduction can be more advantageous. Asexual reproduction is a faster and more energy-efficient process, allowing for rapid population growth when conditions are favorable. Therefore, the advantage of sexual reproduction is context-dependent and not universally applicable in all scenarios.

Common mistakes

Assuming sexual reproduction always guarantees better survival for offspring.
Not fully understanding the genetic basis of variation in sexual reproduction.
Confusing the terms 'clone' and 'offspring' without considering the mode of reproduction.

Revision tips

Focus on the key differences between asexual and sexual reproduction.
Understand the concept of genetic variation and its role in evolution.
Pay attention to the specific conditions where asexual reproduction might be more beneficial.
Use the definitions of 'clone' and 'variation' to explain the outcomes of different reproductive strategies.

Practice MCQs

Q1. What is the primary reason reproduction is essential for organisms?

Q2. Why are offspring produced by asexual reproduction called clones?

Q3. Which mode of reproduction is generally considered better for adaptation and evolution?

Q4. Genetic variation in offspring is primarily a result of:

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 die out.

What is the main difference between asexual and sexual reproduction?

Asexual reproduction involves a single parent and produces offspring genetically identical to the parent, while sexual reproduction involves two parents and results in genetically diverse offspring.

Why are offspring from asexual reproduction called clones?

They are called clones because they are morphologically and genetically identical to the parent organism, being exact copies.

How does sexual reproduction contribute to the survival of a species?

Sexual reproduction creates genetic variations by combining DNA from two parents. These variations allow individuals to adapt to changing environments, increasing the species' chances of survival.

Is sexual reproduction always better than asexual reproduction for survival?

Not always. While sexual reproduction offers advantages through variation, asexual reproduction can be more efficient and advantageous for organisms in stable environments or those that are sessile.

What is the significance of genetic variation in reproduction?

Genetic variation, primarily arising from sexual reproduction, provides the raw material for evolution and helps populations adapt to environmental changes, thus enhancing survival.

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