Biodiversity-Taxonomy-Nomenclature | uksir-notes | Diversity-Living-World1
Diversity in Living World 1
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| Taxonomy |
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· Diversity in the living world
- the sum total of differences between the living organisms may be called as Biodiversity or Diversity in living organism.-
Planet
Earth exhibits a large variety of living organisms like plants, animals, fungi,
etc.
-
These
all constitute our 'Biodiversity'.
-
The
number of species (known Species)- between 1.7-1.8 million.
Bio
Diversity Divided to 3 levels:
1)
Genetic
Diversity : Diversity or
differences at the level of Genetic
Information or Gene Level. Ex- Rice having more then 50,000 genetically
different varieties, Mango have ~ 1000 varieties.
2)
Species
Diversity: There is difference between species of
all organisms. And also diversity found in their abundance. Ex- Parrot – Above
390 sp. Rose- above 150 sp.
3)
Ecological
Diversity: diversity at ecological level or
ecosystem level or habitat level.
Ex- India having diverse ecosystems of Rainforest, wetland, deserts etc.
· Classification :
- This arrangement of organisms into convenient categories or groups on the basis of their similarities, differences and fundamental characters is called classification.Taxonomy / systematics
·
The
branch of science, that deals with identification, nomenclature and classification
of organisms is called taxonomy.
·
The
term taxonomy was given by AP de Candolle in 1813.
·
Systematies-
branch of science that deals with identification, nomenclature, classification
and evolutionary history of an organism.
Branches of taxonomy:
Various branches of taxonomy are as follows1. Classical taxonomy or alpha –taxonomy = based on the morphological traits.
2. Morpho taxonomy= based on morphological studies of organisms.
3. Natural taxonomy = based on the natural similarities among organisms.
4. Phylogenetic
taxonomy = based on phylogeny or evolutionary history of a species.
5. Experimental
taxonomy = based on experimental determination of genetic inter-relationships.
6. Chemotaxonomy =
based on the presence or absence of certain chemicals.
7. Numerical taxonomy=
based on the number of shared characters of various organisms.
8. Cytotaxonomy =
based on cytological studies.
9. Karyotaxonomy=
based on nuclear and chromosomal studies.
10. Neosystematics= concept
of systematics that considers a species to be the product of evolution.
Nomenclature:
- providing distinct and proper name to the
organisms.
- helpful in their recognition
and differentiation.
- names can be
vernacular (common) and scientific
(technical).
Vernacular names or common names
- local names which vary from place to place, even within a
country.
- may be many vernacular name of a single
organism.
- have no significance.
- have incorrect
meanings.
- A
single name may often be used for two or
more species.
Scientific or technical names
-
names
given to the organisms based on some principles and criteria.
-
acceptable
all over the world.
-
Decided
by:
• ICBN ( i.e. International Code for Botanical
Nomenclature)
ICZN (International Code
for Zoological Nomenclature)
• ICNB (International Code for Nomenclature of
Bacteria)
• ICNCP (International Code of Nomenclature for Cultivated
Plants)
• ICTV (International Committee on Taxonomy of
Viruse
Systems of scientific nomenclature:
Binomial system of nomenclature
-
proposed
by C. Linnaeus in his book Species Plantarum in 1753.
-
Scientific name of any organism consists of
two parts or epithets, i.e. generic epithet and specific epithet.
e.g. Homo sapiens.
International rules of binomial nomenclature
(i)
All
the names have words in Greek or Latin
language.
(ii)
Generic
epithet begins with capital letter (Homo)
and is placed before specific epithet.
(iii)
specific
epithet start with a small letter (sapiens).
(iv)
The
scientific name should be either underline, in case it is hand written or italicized
if printed.
(v)
Name
of the author should be written after specific
epithet in an abbreviated form.
Nomenclature type and
typification:
- A nomenclature type
acts as a source for the naming of a certain taxonomic group.)
- Using a type for
fixing the name of a taxon is called typification.
1. Holotype- It is a
single type specimen upon which the description and name of a new species is
based.
2. Isotype- duplicate of the holotype.
3. Syntype- any one
of the two or more similar specimens (biological types).
4. Paratype-other
then the holotypeor an isotypeor one of the syntypes.
5. Lectotype- A specimen or other element selected from
the original material when holotype no longer exists.
6. Neotype- new specimen
selected to serve as a nomenclatural type as others are absent.
Taxonomic categories or taxon
·
The
term "Taxon' was introduced for the first time by ICBN in 1956.
·
Mayr
(1964) defined taxon as a taxonomic group of any rank that is sufficiently
distinct to be worthy of being assigned a definite category.
Taxonomic hierarchy
·
taxonomic
categories arranged in a proper descending or ascending order is called
taxonomic hierarchy.
·
also
called Linnaean hierarchy as it was first proposed by Carolus Linnaeus.
·
The
hierarchy includes seven obligate categories.
as follows-
 |
| Hierarchy |
Kingdom
Phylum in animals or Division in plants
Class
Order
Family
Genus
Species
Species
-
It
is the fundamental or smallest unit of classification.
-
The
concept of species was proposed by John Ray and Carolus
Linnaeus.
-
a
group of individuals which resemble each other in morphological,
physiological, biochemical behavioral characters
and are
capable of breeding freely in between themselves
under
natural conditions.
Genus
-
Term
"Genus' was coined by Tournefort.
-
Genera
are the aggregates of closely related species.
.
Family
·
a
group of related genera having some common features
·
less
numbers of similarities as compared to the genus and species
·
characterized
on the basis of both vegetative and
reproductive features
Order
·
it
is an assemblage of families
·
similar characters are less in number as
compared to different genera included in a
family
Class
·
Linnaeus
gave the term class for a group of related orders.
·
For
example, order- Primata comprising monkey, gorilla
and gibbon is placed in class- Mammalia
Phylum (for Animals) or division (for Plants)
·
The
term 'Phylum' was coined by Cuvier.
·
Phylum
is a group of various classes.
·
The term division was coined by
Eichler.
Kingdom
·
It
is the highest taxonomic category.
·
All
plants are included in kingdom-Plantae, while all animals in Animalia.
Taxon of Wheat Human
kingdom- Plantae Animalia.
Phylum/Divn Angiospermae Chordata
Class Monocotyledonae Mammalia
Order Poales Primata
Family Poaceae Hominidae
Genera Triticum Homo
Species aestivum sapiens
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