What are the characteristics of living organisms?

The defining characteristics of living organisms are: growth, reproduction, metabolism, cellular organisation, consciousness, and ability to sense and respond to stimuli. However, no single characteristic is unique to living organisms — all features must be considered together.

What is the difference between taxonomy and systematics?

Taxonomy is the science of classification — identification, nomenclature, and classification of organisms. Systematics is broader — it includes taxonomy plus the study of evolutionary relationships (phylogeny) among organisms.

Living World Exercise Solutions | KalviGavani

Q: What is the taxonomic hierarchy?

The taxonomic hierarchy (from broadest to most specific) is: Kingdom → Phylum/Division → Class → Order → Family → Genus → Species. Each rank is called a taxon. Species is the basic unit of classification.

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How to Use This Page

Solve each Samacheer Kalvi exercise question on your own first, then compare your answer with the solutions below. The Living World chapter is the foundation of Botany — master the concepts of life, taxonomy, and nomenclature before moving to later chapters.

Key Concepts (Quick Recap)

Characteristics of Living Organisms

Growth: Increase in number of cells (by cell division) or mass. In plants, growth is indeterminate (throughout life). In animals, growth is determinate (stops at maturity).
Reproduction: Production of offspring. Not essential for an individual's survival, but essential for species continuation. Note: sterile hybrids and mules are living but cannot reproduce.
Metabolism: Sum total of all chemical reactions in the body (anabolism + catabolism). Occurs in all living organisms, even in unicellular ones.
Cellular Organisation: All living organisms are composed of cells. This is the most defining characteristic of life.
Consciousness: Ability to sense and respond to stimuli (environmental, chemical, physical). This is the most obvious and complicated feature of living organisms.
Homeostasis: Maintenance of a stable internal environment despite external changes.

Important Distinctions

Growth in plants vs animals: Plants grow throughout life (indeterminate) by cell division in meristems. Animals grow only up to a certain age (determinate).
Growth in living vs non-living: Living growth is from inside (by cell division). Non-living growth is by accumulation of material on the surface (e.g., crystal growth, mountain growth).
Reproduction: Not a defining characteristic because (1) sterile organisms are still living, (2) non-living things can also "reproduce" (e.g., crystals), (3) reproduction is absent in some organisms.

Diversity in the Living World

Estimated 1.7–1.8 million species known and described
Number of species yet to be discovered is much larger
India has rich biodiversity — among 12 megadiversity countries

Taxonomy

Taxonomy: The science of classification — identification, nomenclature, and classification of organisms
Systematics: Study of diversity of organisms and their evolutionary relationships (broader than taxonomy)
Alpha taxonomy: Description of new species
Omega taxonomy: All information about a species including its phylogeny

Taxonomic Hierarchy (from broadest to most specific)

Kingdom → Phylum/Division → Class → Order → Family → Genus → Species

Binomial Nomenclature

Introduced by Carl Linnaeus (Father of Taxonomy)
Two-word system: Genus (capitalised) + species (lowercase)
Written in italics (or underlined when handwritten)
Example: Mangifera indica (mango), Oryza sativa (rice)
Rules governed by ICBN (International Code of Botanical Nomenclature) / ICN
Type specimen: The actual specimen on which the original description is based

Taxonomic Categories

Category	Example (Human)	Example (Mango)
Kingdom	Animalia	Plantae
Phylum/Division	Chordata	Angiospermae
Class	Mammalia	Dicotyledonae
Order	Primates	Sapindales
Family	Hominidae	Anacardiaceae
Genus	Homo	Mangifera
Species	sapiens	indica

Taxonomical Aids

Herbarium: Collection of dried, pressed, and preserved plant specimens on sheets (with label showing name, collector, date, location)
Botanical Garden: Living collection of plants for study and conservation (e.g., Kew Botanical Garden, NBRI Lucknow)
Museum: Collection of preserved plant and animal specimens
Zoological Park: Living animals in protected environments
Key: Analytical device for identification — uses contrasting characters (couplet)
Flora: Book describing all plant species in a region
Manual: Book providing information for identification of species in a region
Monograph: Detailed study of a single taxon (genus or family)
Catalogue: Alphabetical list of species with brief descriptions

I. Choose the Best Answer (MCQs)

Q1. The most defining characteristic of living organisms is (a) Growth (b) Reproduction (c) Cellular organisation (d) Metabolism

Answer(c) Cellular organisation — All living organisms are composed of cells. While growth, reproduction, and metabolism are important, cellular organisation is the most fundamental and defining characteristic. Even unicellular organisms have cellular organisation.

Q2. Binomial nomenclature was introduced by (a) Charles Darwin (b) Carolus Linnaeus (c) Aristotle (d) John Ray

Answer(b) Carolus Linnaeus — Carl Linnaeus (also known as Carolus Linnaeus) introduced the binomial nomenclature system of naming organisms with two words — Genus + species.

Q3. In binomial nomenclature, the first word represents (a) Species (b) Genus (c) Family (d) Order

Answer(b) Genus — In binomial nomenclature, the first word is the genus name (always capitalised) and the second word is the species epithet (always lowercase). Example: Mangifera indica — Mangifera is the genus.

Q4. Which taxonomic category includes organisms that can interbreed among themselves? (a) Genus (b) Family (c) Order (d) Species

Answer(d) Species — Species is the basic unit of classification. Members of the same species can interbreed and produce fertile offspring. Organisms of different species generally cannot interbreed.

Q5. The correct sequence of taxonomic hierarchy is (a) Kingdom → Class → Phylum → Order → Family → Genus → Species (b) Kingdom → Phylum → Class → Order → Family → Genus → Species (c) Kingdom → Order → Class → Phylum → Family → Genus → Species (d) Kingdom → Phylum → Order → Class → Family → Genus → Species

Answer(b) Kingdom → Phylum → Class → Order → Family → Genus → Species — This is the correct taxonomic hierarchy from broadest to most specific. Remember: King Philip Came Over For Good Soup.

Q6. ICBN stands for (a) International Code of Botanical Nomenclature (b) International Classification of Botanical Names (c) Indian Code of Botanical Nomenclature (d) International Code of Biological Nomenclature

Answer(a) International Code of Botanical Nomenclature — ICBN (now called ICN — International Code of Nomenclature) governs the rules for naming plants, algae, and fungi.

Q7. A collection of dried, pressed plant specimens is called (a) Museum (b) Herbarium (c) Botanical garden (d) Zoo

Answer(b) Herbarium — A herbarium is a collection of dried, pressed, and preserved plant specimens mounted on sheets, each with a label showing name, place of collection, date, and collector's name.

II. Fill in the Blanks

1. The two-word naming system is called binomial nomenclature. 2. The first word in a scientific name represents the genus. 3. The second word in a scientific name represents the species. 4. In binomial nomenclature, the genus name starts with a capital letter. 5. The species name starts with a lowercase (small) letter. 6. Scientific names are printed in italics. 7. The basic unit of classification is species. 8. The taxonomic hierarchy from broadest to most specific is Kingdom → Phylum → Class → Order → Family → Genus → Species. 9. Linnaeus is called the Father of Taxonomy. 10. A herbarium is a collection of dried, pressed plant specimens. 11. The study of diversity of organisms and evolutionary relationships is called systematics. 12. Growth in plants is indeterminate (continuous throughout life). 13. Growth in animals is determinate (stops at maturity). 14. The sum total of all chemical reactions in the body is called metabolism.

III. True or False (with corrections for false statements)

Q1. Reproduction is the defining characteristic of living organisms.

AnswerFalse — Correction: Reproduction is NOT the defining characteristic because (1) sterile organisms like mules are still living, (2) some organisms reproduce asexually, (3) non-living things like crystals can also "grow" and "reproduce." Cellular organisation and metabolism are more defining.

Q2. In binomial nomenclature, both words begin with capital letters.

AnswerFalse — Correction: Only the FIRST word (genus) begins with a capital letter. The SECOND word (species epithet) always begins with a lowercase letter. Example: Mangifera indica, not Mangifera Indica.

Q3. A species can interbreed among its members.

AnswerTrue — Species is a group of organisms that can interbreed among themselves and produce fertile offspring, but are reproductively isolated from other such groups.

Q4. Systematics and taxonomy are the same.

AnswerFalse — Correction: Systematics is broader than taxonomy. Taxonomy deals with identification, nomenclature, and classification. Systematics includes taxonomy PLUS the study of evolutionary relationships (phylogeny).

Q5. Growth in plants is determinate.

AnswerFalse — Correction: Growth in plants is INDETERMINATE — it continues throughout the plant's life through cell division in meristematic tissues. Growth in animals is determinate — it stops at maturity.

IV. Match the Following

Column A	Column B	Answer
1. Linnaeus	(a) Basic unit of classification	(b) Binomial nomenclature
2. Species	(b) Binomial nomenclature	(a) Basic unit of classification
3. Herbarium	(c) Living collection of plants	(d) Dried plant specimens
4. Botanical garden	(d) Dried plant specimens	(c) Living collection of plants
5. ICBN	(e) Study of evolutionary relationships	(f) Rules for naming plants
6. Systematics	(f) Rules for naming plants	(e) Study of evolutionary relationships

V. Answer Briefly (2-mark questions)

Q1. What are the defining characteristics of living organisms?

Answer

The defining characteristics of living organisms are: 1. Growth: Increase in cell number or mass 2. Reproduction: Production of offspring (though not unique to living) 3. Metabolism: Sum total of all chemical reactions (anabolism + catabolism) 4. Cellular organisation: All living organisms are made of cells 5. Consciousness: Ability to sense and respond to stimuli 6. Homeostasis: Maintenance of stable internal environment

Q2. What is binomial nomenclature? Give two rules.

Answer

Binomial nomenclature is a two-word naming system for organisms developed by Carl Linnaeus. Each organism is given a scientific name with two words — the first is the genus (capitalised) and the second is the species epithet (lowercase). Rules: (1) Scientific names are in Latin and printed in italics (underlined when handwritten). (2) The genus name starts with a capital letter and the species name starts with a lowercase letter. Example: Mangifera indica.

Q3. Distinguish between taxonomy and systematics.

Answer

| Feature | Taxonomy | Systematics | |---|---|---| | Definition | Science of classification | Study of diversity + evolutionary relationships | | Scope | Identification, nomenclature, classification | Includes taxonomy + phylogeny | | Focus | Grouping organisms | Understanding relationships | | Founder | Linnaeus | Simpson |

Q4. What is a herbarium? What information does a herbarium sheet contain?

Answer

A herbarium is a collection of dried, pressed, and preserved plant specimens mounted on sheets. Each herbarium sheet contains: 1. Scientific name of the plant 2. Name of the collector 3. Date of collection 4. Place of collection (locality) 5. Name of the family 6. Sometimes, local/vernacular name

VI. Answer in Detail (5-mark questions)

Q1. Explain the taxonomic hierarchy with an example.

Answer

The taxonomic hierarchy is a system of classification where organisms are arranged in a series of ranks from the broadest (Kingdom) to the most specific (Species). Each rank is called a taxon. Taxonomic Hierarchy (broadest → most specific): 1. Kingdom: Broadest category. E.g., Plantae (all plants) 2. Phylum/Division: Groups of related classes. E.g., Angiospermae (flowering plants) 3. Class: Groups of related orders. E.g., Dicotyledonae (dicots) 4. Order: Groups of related families. E.g., Sapindales 5. Family: Groups of related genera. E.g., Anacardiaceae 6. Genus: Groups of related species. E.g., Mangifera 7. Species: Basic unit — organisms that can interbreed. E.g., indica Example — Mango (Mangifera indica): Kingdom: Plantae → Division: Angiospermae → Class: Dicotyledonae → Order: Sapindales → Family: Anacardiaceae → Genus: Mangifera → Species: indica

Q2. Explain the rules of binomial nomenclature with examples.

Answer

Binomial nomenclature is the two-word naming system introduced by Carl Linnaeus. The rules are: 1. Two words: Each organism has a two-word name — the first is the genus and the second is the species epithet. E.g., Mangifera indica 2. Latin: Scientific names are in Latin or Latinised form. E.g., Solanum tuberosum (potato) 3. Italics: When printed, scientific names are in italics. When handwritten, they are underlined. E.g., Mangifera indica 4. Capitalisation: The genus name starts with a capital letter and the species name starts with a lowercase letter. E.g., Mangifera indica, not mangifera Indica 5. Unique name: Each organism has a unique scientific name. No two organisms can have the same name. 6. Author name: The name of the scientist who first described the species may be appended. E.g., Mangifera indica L. (L. stands for Linnaeus) 7. Governed by ICBN/ICN: The naming of plants, algae, and fungi is governed by the International Code of Botanical Nomenclature (now called ICN).

Q3. What are taxonomical aids? Explain any four.

Answer

Taxonomical aids are collections, tools, and techniques used for the identification, classification, and study of organisms. 1. Herbarium: A collection of dried, pressed, and preserved plant specimens mounted on sheets with labels. It serves as a reference for identification and research. The largest herbarium in the world is at the Royal Botanic Gardens, Kew (London). 2. Botanical Garden: A living collection of plants grown for study, conservation, and education. Plants are labelled with their scientific names and families. Examples: Kew Botanical Garden (London), NBRI (Lucknow), Indian Botanical Garden (Howrah). 3. Museum: A collection of preserved plant and animal specimens for study and reference. Specimens may be preserved in jars (wet preservation) or as dry specimens (insects pinned, skeletons). 4. Key: An analytical device used for identification of organisms based on contrasting characters. A key consists of couplets — each couplet offers two contrasting choices, and the user follows the matching choice to identify the organism.

Common Mistakes to Avoid

Capitalising the species epithet: In Mangifera indica, only the genus (Mangifera) is capitalised. The species (indica) is always lowercase.
Not italicising scientific names: Scientific names must be in italics when printed (or underlined when handwritten).
Confusing taxonomy and systematics: Taxonomy = classification only. Systematics = classification + evolutionary relationships.
Saying reproduction is THE defining characteristic: Reproduction is important but NOT the sole defining characteristic. Sterile organisms (mules) are still living. Metabolism and cellular organisation are more defining.
Confusing growth in living vs non-living: Living growth is from inside (cell division). Non-living growth is accumulation on the surface (crystal growth).
Reversing the taxonomic hierarchy: It is Kingdom → Phylum → Class → Order → Family → Genus → Species (broadest to most specific). Remember: King Philip Came Over For Good Soup.

Exam Checklist

[ ] Can you list the characteristics of living organisms and explain why no single one is the defining feature?
[ ] Can you explain binomial nomenclature with its rules and examples?
[ ] Can you write the taxonomic hierarchy in correct order?
[ ] Can you classify an organism (e.g., mango, human, rice) through all taxonomic ranks?
[ ] Can you distinguish between taxonomy and systematics?
[ ] Can you define species, genus, family, order, class, phylum, and kingdom?
[ ] Can you explain what a herbarium is and what information it contains?
[ ] Can you distinguish between herbarium, botanical garden, museum, and key?
[ ] Can you explain ICBN/ICN and its role in plant nomenclature?
[ ] Can you give at least 4 rules of binomial nomenclature with examples?

Frequently Asked Questions

Binomial nomenclature is a two-word naming system for organisms developed by Carl Linnaeus. Each organism is given a scientific name consisting of Genus (capitalised) + species (lowercase), written in italics, e.g. Mangifera indica for mango.