NCERT Class 11 Biology Biology: Chapter 2 — Biological Classification
This chapter, Biological Classification, from NCERT Class 11 Biology, delves into the historical attempts and scientific basis for classifying living organisms. It begins by acknowledging early, instinct-driven classifications based on utility, then introduces Aristotle's morphological approach. The text discusses the limitations of the Two Kingdom system (Plantae and Animalia) proposed by Linnaeus, highlighting its failure to distinguish between prokaryotes and eukaryotes, unicellular and multicellular organisms, and photosynthetic and non-photosynthetic life. It explains the inadequacy of this system and the need for incorporating characteristics like cell structure, mode of nutrition, and evolutionary relationships. The chapter introduces R.H. Whittaker's Five Kingdom Classification (Monera, Protista, Fungi, Plantae, Animalia) as a significant advancement, detailing the main criteria used: cell structure, body organization, mode of nutrition, reproduction, and phylogenetic relationships. It also briefly mentions the three-domain system. This chapter provides a foundational understanding of the evolution of classification systems and the rationale behind the widely accepted five-kingdom model, crucial for CBSE Biology learning.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 11 |
| Subject | Biology |
| Book | Biology |
| Chapter | Chapter 2 — Biological Classification |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 4 minutes |
| Word count | 704 |
Learning outcomes
- Understand the historical development of biological classification systems.
- Identify the limitations of the Two Kingdom classification.
- Explain the criteria used in R.H. Whittaker's Five Kingdom Classification.
- Differentiate between the characteristics of the five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia.
- Recognize the importance of biological classification in understanding life on Earth.
Vocabulary
| Word | Meaning |
|---|---|
| Morphological | Relating to the form and structure of organisms. |
| Eukaryotes | Organisms whose cells contain a nucleus and other organelles enclosed within membranes. |
| Prokaryotes | Organisms whose cells lack a nucleus and other membrane-bound organelles. |
| Photosynthetic | Capable of producing food using light energy. |
| Heterotrophic | Organisms that cannot produce their own food and rely on other organisms for nutrition. |
| Chitin | A tough, structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi. |
| Phylogenetic | Relating to the evolutionary development and diversification of a species or group of organisms. |
| Saprophytic | An organism that feeds on dead or decaying organic matter. |
| Holozic | Obtaining nutrients by ingesting solid food particles. |
The complete chapter text is read in the official NCERT PDF viewer below (streamed from ncert.nic.in). This page provides NCERT Help study material — summary, vocabulary, practice questions, and FAQs — not a full reproduction of the textbook.
Read chapter online
This PDF is loaded from the official NCERT website (ncert.nic.in). Use the page buttons below to read — download is disabled on NCERT Help.
Read page by page below. PDF is streamed from the official NCERT website — no download button on this page.
Practice questions
- Who was one of the earliest scientists to attempt a scientific basis for classification? Answer: Aristotle.
- What were the two kingdoms proposed by Linnaeus? Answer: Plantae and Animalia.
- What are the five kingdoms proposed by R.H. Whittaker? Answer: Monera, Protista, Fungi, Plantae, and Animalia.
- Name one criterion used by R.H. Whittaker for classification. Answer: Cell structure, body organisation, mode of nutrition, reproduction, or phylogenetic relationships.
- What is the cell wall composition of fungi? Answer: Chitin.
Frequently asked questions
What is biological classification?
Biological classification is the scientific process of grouping organisms based on shared characteristics and evolutionary relationships.
Why was the Two Kingdom classification system found inadequate?
It failed to distinguish between eukaryotes and prokaryotes, unicellular and multicellular organisms, and photosynthetic and non-photosynthetic organisms, grouping vastly different life forms together.
Who proposed the Five Kingdom Classification?
R.H. Whittaker proposed the Five Kingdom Classification in 1969.
What are the five kingdoms in Whittaker's classification?
The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia.
What are the main criteria used for the Five Kingdom Classification?
The main criteria include cell structure, body organisation, mode of nutrition, reproduction, and phylogenetic relationships.
What is the cell wall made of in Kingdom Monera?
The cell wall in Monera is noncellulosic, composed of polysaccharide and amino acid.
What is the mode of nutrition in Kingdom Fungi?
Fungi are heterotrophic, primarily saprophytic or parasitic.
Related resources
Important topics
Topics covered
NCERT Class 11 Biology — Biology — Chapter 2 — Biological Classification. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.