THE LIVING WORLD - 3
Taxonomy
● Gk. taxis = arrangement, nomos = law.
● It is the branch of science that deals with principles and procedures of
identification, nomenclature and classification of organisms.
● This word was proposed by A.P. de Candolle in his book “Theories elementaire de
la botanique” (Theory of elementary botany).
A.P. de Candolle
● Taxonomy includes study of following points:
1. Identification: The procedure to recognize an organism from the other
already known organisms and assigning it to a particular taxonomic group.
2. Nomenclature: Naming of organisms as per international scientific rules.
3. Classification: Arrangement of organisms into convenient categories or
groups on the basis of their similarities and differences in certain easily
observable but fundamental characters.
Systematics
● Term given by: Linnaeus.
● Latin: Systema = systematic arrangement of organisms.
● Linnaeus used Systema Naturae as a title of his publication.
● Identification, nomenclature, classification and evolutionary relationship
between organisms are included in systematics.
Points to be noted…
● Significance of taxonomy: Identification of
unknown organism.
● Maximum diversity is found in tropical rain
forest.
● Second maximum diversity is found in coral
reefs.
● The number of species that are known and
described range between 1.7-1.8 million. It is
the biodiversity of organisms present on earth.
Nomenclature
● Scientific or Technical Names: A scientific name is the one which is given by
biologists and is understood to represent a particular organism in every part
of the world.
Binomial Nomenclature
● Given by Carolus Linnaeus.
● Linnaeus developed this system of nomenclature for the first time and
proposed scientific names of plants and animals in “Species Plantarum” and
the 10th edition of his book “Systema Naturae”.
ICBN- International Code of Botanical Nomenclature
● Rules of nomenclature of plants.
● Main Rules of ICBN:
1. According to binomial system, name of any organism consists of two
words or components:
(i) Generic name: Name of Genus
(ii) Specific epithet
Eg. Solanum tuberosum (Potato) Mangifera indica (Mango)
Generic name Specific epithet Generic name Specific epithet
2. In plant nomenclature, tautonyms are not valid, i.e., generic name and
specific epithet should not be same in plants.
Eg. Mangifera mangifera
Note: Tautonyms are valid in animal nomenclature.
ICZN: International Code of Zoological Nomenclature
Eg. Naja naja (Indian cobra)
Rattus rattus (Rat)
3. First letter of generic name should be in capital letter and first letter of specific
epithet should be in small letter.
Eg. Mangifera indica
4. When written with free hand or typed, then generic name and specific epithet
should be separately underligned but during printing, the name should be in
italics to indicate their latin origin.
5. Name of scientist (who proposed nomenclature) should be written in short
after the specific epithet.
Eg. Mangifera indica Linn.
6. Name of scientist should be neither underlined nor in italics but it is
written in roman letters (simple alphabets).
7. The original name were taken from Latin and Greek languages. New
names are now derived either from Latin language or are latinised. This is
because latin language is dead and therefore, it will not change in form or
spellings with the passage of time.
Trinomial System of Nomenclature
● Name of any organism consists of three words:
1. Generic name 2. Specific epithet 3. Subspecific epithet
Eg. Brassica oleracea botrytis (Caulifower)
Brassica oleracea capitata (Cabbage)
Brassica oleracea cauloropa (Knol-Khol)
Chalo Batao…
● Which of the following is the first step in taxonomy?
a) Phylogeny of the organism
b) Identification of the organism
c) Nomenclature of the organism
d) Classification of the organism
Chalo Batao…
● Which of the following is the first step in taxonomy?
a) Phylogeny of the organism
b) Identification of the organism
c) Nomenclature of the organism
d) Classification of the organism
Chalo Batao…
● Taxonomical known number of species is:
a) 1.7 billion
b) 1.7 lakh
c) 5-30 million
d) 1.7 million
Chalo Batao…
● Taxonomical known number of species is:
a) 1.7 billion
b) 1.7 lakh
c) 5-30 million
d) 1.7 million
Chalo Batao…
● Linnaeus evolved a system of nomenclature called-
a) Monomial
b) Vernacular
c) Binomial
d) Polynomial
Chalo Batao…
● Linnaeus evolved a system of nomenclature called-
a) Monomial
b) Vernacular
c) Binomial
d) Polynomial
Chalo Batao…
● Classification of organisms is required because:
a) It makes the study of organisms easier and simpler
b) It enables us to study geographical distribution of some organisms
c) It makes the study of organisms complex
d) None of the above
Chalo Batao…
● Classification of organisms is required because:
a) It makes the study of organisms easier and simpler
b) It enables us to study geographical distribution of some organisms
c) It makes the study of organisms complex
d) None of the above
Taxonomic Categories
● The process of classification of living organisms is not a single step process.
● It involves a number of steps, i.e., hierarchy of steps in which each step
represents a rank or category.
● Each category is referred to as a unit of classification.
Taxon (plural : taxa)
● Taxon represents any level of grouping of organisms on the basis of certain
easily observable common characteristics.
● Each rank or taxon represents a group of organisms which share some
unique features among members of their group or category which are
different from organisms kept in various other ranks or taxon.
Chalo Batao…
● The word ‘taxon’ signifies:
a) Developmental process of an organism
b) Scientific name of an organism
c) Taxonomic group of any rank
d) Ecological importance of an organism
Chalo Batao…
● The word ‘taxon’ signifies:
a) Developmental process of an organism
b) Scientific name of an organism
c) Taxonomic group of any rank
d) Ecological importance of an organism
Taxonomic Categories
Kingdom
Phylum / Division
Class
Order
Family
Genus
Species
Suffix for taxa (Taxon)
● Division – phyta
● Sub division – phytina
● Class – opsida, phyceae, ae
● Order – ales
● Family - aceae
Classification of Mango
● Kingdom : Plantae
● Division : Angiospermae
● Class : Dicotyledonae
● Order : Sapindales
● Family : Anacardiaceae
● Genus : Mangifera
● Species : Mangifera indica
Classification of Human
● Kingdom : Animalia
● Phylum : Chordata
● Class : Mammalia
● Order : Primates
● Family : Hominidae
● Genus : Homo
● Species : Homo sapiens
Some important points
● Classification of any plant or animal is written in ascending or descending
order.
● Hierarchy: Ascending or descending arrangement of taxonomic categories.
● Species: Smallest taxonomic category. Species is the basic unit of
classification.
● Note: As we go higher from species to kingdom: number of common
characters decreases.
Species
● It is a natural population of individuals or group of populations which
resemble one another in all essential morphological (i.e., body form, size,
shape etc.) and reproductive characters that they are able to interbreed
freely and produce fertile offsprings.
● Group of organisms capable of interbreeding and producing fertile
offsprings.
● For eg. Mango - Mangifera indica, Potato - Solanum tuberosum
Lion – Panthera leo Tiger- Panthera tigris
Genus Specific epithet Common names
1. Solanum tuberosum Potato
melongena Brinjal
nigrum Black nightshade or
makoi
2. Canis familiaris Dog
lupus Wolf
aureus Jackal
3. Panthera leo Lion
tigris Tiger
pardus Leopard
Biological Concept of Species
● Given by Ernst Mayr.
● Species is a group of actually or potentially interbreeding populations that
are reproductively isolated from other such groups.
Chalo Batao…
● Pick the incorrect statement about species:
a) Each species has some distinct morphological features than other species.
b) The group of organisms in a particular species freely interbreed among
themselves.
c) The second part of biological name consists of specific epithet.
d) Each species may have one or more genus.
Chalo Batao…
● Pick the incorrect statement about species:
a) Each species has some distinct morphological features than other species.
b) The group of organisms in a particular species freely interbreed among
themselves.
c) The second part of biological name consists of specific epithet.
d) Each species may have one or more genus.
Chalo Batao…
● The specific epithet in Ocimum sanctum and Triticum aestivum is:
a) Ocimum and Triticum
b) Ocimum and aestivum
c) sanctum and Triticum
d) sanctum and aestivum
Chalo Batao…
● The specific epithet in Ocimum sanctum and Triticum aestivum is:
a) Ocimum and Triticum
b) Ocimum and aestivum
c) sanctum and Triticum
d) sanctum and aestivum
