Dedicated to all Zoologists

2. Evolution of theory of nomenclature
By
Noor Zada Khan
Submitted to : Dr. Rafiq Hussain
Department of Zoology
Kohat University of Science and Technology, Kohat-26000 Khyber
Pakhtunkhwa, Pakistan

3. Binomial nomenclature
 The word nomenclature is derived from two latten words i.e
 “nomen” which means name
 “clare” means to call
 so it means to call by name. it can be defined as “ the system which is
responsible for giving name to an organism is called nomenclature”,

4. History
 As common names are not authentic and can not be used for
scientific purposes b/c these names changed from language to
language.
 Carl Linnaeus proposed the system of naming to each organism
which is called binomial nomenclature in 1758.
 In this system organism are named and their name consist of two
parts,
 The first part indicate genus and 2nd species from which the
organism belong.

5. Rules
 Each binomial name of an organism consist of two Latin words
 Ist word indicate genus while 2nd indicate species
 The generic name will be start with capital letter and species name
with small letter
 The binomial name should be Italic or under lined. e.g. Homo
sapiens
 Two taxa can not have same name

6. Essential requisites of binomial nomenclature
 There are three most important requisites which should be in
mind before giving any name to taxon.
1. Uniqueness:
The scientific name should be unique and individual. It must be
the only name within that nomenclature.

7. 2. Universally
The scientific name should be universal and acceptable
throughout the world and biological societies.
Ordinary names can not be used in nomenclature b/c it is very
difficult for taxanomist to learn names of taxa in ordinary
language.

8. 3. Stability
Scientific name should be stable and authentic and can not be
changeable.
Scientific name is the key to information about a particular organism,
therefore even the principal of priority can be set aside by the
international commission.

9. International code of Zoological Nomenclature
 All the rules of nomenclature are preserved in an authentic
document known as international code of zoological
nomenclature(ICZN).
 Most of the work in nomenclature, its rules, its phenomena was
done in 20th century(1901-1964).
 In 1901, 5th international congress of zoology formulated the rules
and named them as “international rules of zoological nomenclature.

10. The original code and its revision were the work of international
congress of zoology.
However, now these congresses are non operational and their rules
has been taken by the general assemblies of the international
union biological sciences(IUBS)

11. International commission on Zoological
nomenclature
 This commission was found in 1895 having 5 members.
 Its member increased to 28 in Zoological congress held in Paris
in 1948.

12. Evolution of theory of nomenclature
 Many provisions of the code are the result of compromise b/t
conflicting principles which goes back to Linnaeus.
 Certain important changes occurred in last 150 years.

13. The changes includes :
a) basic concept of taxonomy
b) nature of type of name
c) Complication of basic principal
d) Categorical status of infra specific names
e) Laws of nomenclature