Biology · Class 11 Science
Ch 1The Living World — Class 11 Biology, concept-first.
The living world confronts us with wonder at every turn. Life exists in a staggering range of forms and thrives in the most extraordinary settings — icy mountain slopes, dense deciduous forests, the open ocean, freshwater lakes, arid deserts and even scalding hot springs.
Key concepts
Hover a concept to preview it and jump to its most relevant Q&A.
Biological Classification Purpose
Imagine walking into a huge library where every book has simply been dumped into one enormous pile. Finding anything would be hopeless.
Most relevant Q&A
Chapter contents
The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.
Introduction
The living world confronts us with wonder at every turn. Life exists in a staggering range of forms and thrives in the most extraordinary settings — icy mountain slopes, dense deciduous forests, the o…
Diversity in the Living World
Look around and you will find life in astonishing variety — potted plants, insects, birds, pets and other animals, alongside countless organisms too small for the naked eye to see.
Taxonomic Categories
Classification is not a single step but a hierarchy of steps, each step representing a rank or category.
Species
In taxonomy, a species is a group of individual organisms that share fundamental similarities. What sets one species apart from another closely related one are distinct morphological differences — dif…
Genus
A genus is a group of closely related species that have more characters in common with one another than they share with the species of any other genus.
Family
A family is the next category above genus and gathers together a group of related genera. Because it spans several genera, a family shares fewer similarities among its members than are found within a…
Order
Order is a taxonomic rank that sits above family. While the lower categories such as species, genus and family are recognised on the basis of a fairly large set of shared characters, the higher catego…
Class
A class is a taxonomic category that groups together related orders — orders that share a set of common features are placed in the same class.
Phylum
Phylum is the taxonomic category that lies just above class. Several classes that resemble one another in a few basic features are grouped together to form a phylum.
Kingdom
Kingdom is the highest taxonomic category. All the animals belonging to the various phyla are gathered into a single highest category — the Kingdom Animalia.
Summary
The living world is remarkably rich in variety. Millions of plants and animals have already been identified and described, yet a large number still remain unknown.
Exercises
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- 1.1Why are living organisms classified?Free
- 1.2Why are the classification systems changing every now and then?Free
- 1.3What different criteria would you choose to classify people that you meet often?Free
- 1.4What do we learn from identification of individuals and populations?Preview
- 1.5Given below is the scientific name of Mango. Identify the correctly written name. Mangifera Indica Mangifera indicaPreview
- 1.6Define a taxon. Give some examples of taxa at different hierarchical levels.Preview
- 1.7Can you identify the correct sequence of taxonomical categories? (a) Species → Order → Phylum → Kingdom (b) Genus → Species → Order → Kingdo…Preview
- 1.8Try to collect all the currently accepted meanings for the word 'species'. Discuss with your teacher the meaning of species in case of highe…Preview
- 1.9Define and understand the following terms: (i) Phylum (ii) Class (iii) Family (iv) Order (v) GenusPreview
- 1.10Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.Preview
NCERT Exemplar
Higher-order thinking problems from the NCERT Exemplar.
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- Q1As we go from species to kingdom in a taxonomic hierarchy, the number of common characteristics (a) Will decrease (b) Will increase (c) Rema…Free
- Q2Which of the following 'suffixes' used for units of classification in plants indicates a taxonomic category of 'family'? (a) – Ales (b) – On…Free
- Q3The term 'systematics' refers to: (a) Identification and study of organ systems of plants and animals (b) Identification and preservation of…Free
- Q4Genus represents (a) An individual plant or animal (b) A collection of plants or animals (c) A group of closely related species of plants or…Preview
- Q5The taxonomic unit 'Phylum' in the classification of animals is equivalent to which hierarchical level in classification of plants (a) Class…Preview
- Q6Match the following and choose the correct option: Column I: A. Family, B. Kingdom, C. Order, D. Species, E. Genus Column II: i. tuberosum,…Preview
- Q7Linnaeus is considered as Father of Taxonomy. Name two other botanists known for their contribution to the field of plant taxonomy.Preview
- Q8What does ICZN stand for?Preview
- Q9In a given habitat we have 20 plant species and 20 animal species. Should we call this as 'diversity' or 'biodiversity'? Justify your answer…Preview
- Q10International Code of Botanical Nomenclature (ICBN) has provided a code for classification of plants. Give hierarchy of units of classificat…Preview
- Q11A plant may have different names in different regions of the country or world. How do botanists solve this problem?Preview
- Q12Brinjal and potato belong to the same genus Solanum, but to two different species. What defines them as seperate species?Preview
- Q13The number and kinds of organism is not constant. How do you explain this statement?Preview
- Q14A scientist has come across a plant which he feels is a new species. How will he go about its identification, classification and nomenclatur…Preview
- Q15Brassica campestris Linn a. Give the common name of the plant. b. What do the first two parts of the name denote? c. Why are they written in…Preview
- Q16Define a taxon. What is meant by taxonomic hierarchy? Give a flow diagram from the lowest to highest category for a plant and an animal. Wha…Preview