What went wrong when the king rode under the arch?

It was too low and knocked off his crown

How does the chain of blame unfold in the poem?

Each accused person blames another, ending with the king's own changes

Why are living organisms classified?

Because it is nearly impossible to study every one of the millions of organisms individually; classification groups them into convenient categories that make study, identification and comparison practical.

What is binomial nomenclature and who introduced it?

It is the system of giving each organism a two-part scientific name (generic name and specific epithet); it was introduced by Carolus Linnaeus.

Write the rules for writing a scientific name.

Names are in Latin and italicised; the genus begins with a capital letter and the specific epithet with a small letter; when handwritten both words are separately underlined.

Arrange the taxonomic categories in ascending order.

Species, genus, family, order, class, phylum (or division in plants), and kingdom.

Differentiate between ICBN and ICZN.

The ICBN (International Code for Botanical Nomenclature) governs naming of plants, while the ICZN (International Code of Zoological Nomenclature) governs naming of animals.

What is a taxon? Give examples at different levels.

A taxon is a group at any rank of classification; examples include the species Homo sapiens, the genus Panthera and the family Felidae.

How do shared characters change as we move up the hierarchy?

As we ascend from species to kingdom the number of common characteristics among members decreases, so relationships become harder to determine.

What is the difference between taxonomy and systematics?

Taxonomy deals with identification, nomenclature and classification; systematics additionally takes evolutionary relationships among organisms into account.

Give the genus and family of the lion, tiger and leopard.

They all belong to the genus Panthera and the family Felidae.

Why do classification systems keep changing?

Because new criteria such as cell structure, mode of nutrition and evolutionary relationships are added as understanding improves, leading to revised groupings.

The Living World

Class 11 Biology · Biology · Chapter 1

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CBSE Class 11 · Biology

19 chapters: every table, cycle and pathway

Marks booster + cheatsheet: key concepts in 2 lines each, common traps
18 marks: Unit V, breathing to hormones
15 marks each: Units I and III
Common traps, corrected
Five kingdoms classification table
Physiological numbers, with page numbers

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₹159See the full kit

CBSE Class 11 · Biology

19 chapters: every table, cycle and pathway

Marks booster + cheatsheet: key concepts in 2 lines each, common traps
18 marks: Unit V, breathing to hormones
15 marks each: Units I and III
Common traps, corrected
Five kingdoms classification table
Physiological numbers, with page numbers

Page 1 free about 8 min read, Full kit about 55 min read

₹159See the full kit

View all 44 amazing Marks Booster kits →

Summary

This opening chapter asks what distinguishes the living from the non-living and how biologists make sense of the enormous diversity of life, with between 1.7 and 1.8 million species described so far. Because local names vary from place to place, a universal system of naming is needed; this is nomenclature, and it works only after an organism is correctly identified. Each scientific name has two parts under binomial nomenclature, given by Carolus Linnaeus: a generic name and a specific epithet, written in Latin and in italics, as in Mangifera indica for mango. Plant names follow the ICBN and animal names the ICZN. Classification groups organisms into convenient categories called taxa, and the study of classification with its underlying rules of identification, naming and arrangement is taxonomy, while systematics additionally considers evolutionary relationships. The chapter then builds the taxonomic hierarchy from species upward through genus, family, order, class, phylum or division, and finally kingdom. As one moves up this ladder the number of shared characters decreases, so higher categories are harder to relate. Worked examples for man, housefly, mango and wheat show how each organism occupies a definite place at every rank.

Diversity in the living worldNeed for nomenclature and identificationBinomial nomenclature and its rulesTaxonomy, classification and systematicsTaxonomic categories: species to kingdomTaxonomic hierarchy with examples

Key terms

Taxonomy

The branch of biology dealing with identification, nomenclature and classification of organisms based on their characters.

Binomial nomenclature

The two-word naming system, given by Linnaeus, in which a name has a generic name and a specific epithet.

Taxon

A unit or group of classification at any rank, such as a species, genus or family.

Taxonomic hierarchy

The arrangement of categories from species up to kingdom in ascending order of rank.

Species

A group of individual organisms with fundamental similarities, distinguishable from closely related species by morphological differences.

Systematics

The study of the diversity of organisms and their relationships, taking evolutionary relationships into account.

Extra questions & answers

Try one from this chapter

The two-word naming system for organisms, given by Linnaeus, is called:

Flashcards & interactive practice