BIOdiversity class9 cbse

1. DIVERSITY IN
LIVING ORGANISMS
CH : 7

2. DEFINITION
CLASSIFICATION
A system of arrangement of
organisms into different groups on
the basis of their similarities,
differences and relationship.

3. Classification is also known as
TAXONOMY.
It is the branch of science
which deals with and is defined
as Identification, nomenclature
and classification of organisms
with certain principles.

4. NEED / IMPORTANCE OF CLASSIFICATION
1. It makes the study of wide variety of organism
easy.
2. The study of organisms is made easy as learning
about an organism belonging to a specific
‘GROUP’ is easy.
3. It also helps to understand the interrelationship
among different organisms.
4. Many other biological sciences depend on the
correct knowledge of characteristics of
organisms which classification provide. Eg in
ecology, forestry, biogeography , applied

5. Hierarchy of Classification Groups
As classification deals with grouping the
organisms ,which are called TAXA {Taxon} ,
each taxa is given a name and they are
arranged in a specific pattern in the flowchart
of order/sequence.
The organisms that closely resemble are
placed in a taxon and further the taxa related
are put together in a larger taxon. There are 7
such taxa.

6. KINGDOM [largest]
PHYLLUM/DIVISION
CLASS
ORDER
FAMILY
GENUS
SPECIES [smallest]

7. HISTORY
• Aristotle gave the first but crude
classification.
• Carolus Linnaeus in the 18th
century gave the
first basis of modern classification. He divided
organisms into 2 kingdoms : PLANTAE [ Plant
Kingdom] and ANIMALIA [ animal kingdom]
because he could see only these .
• Ernst Haeckel , a german zoologist , further
added one more kingdom PROTISTA which
included all unicellular organisms.

8. • Robert Whittaker , as more
developments in biological sciences
happened, found that there were
significant differences among organisms
of the protista and hence he defined two
more kingdoms MONERA , FUNGI.
• Thus the 5 kingdom classification by R.H.
Whittaker came into existence, which is
still the basis of modern classification.

9. Whittaker based his classification on 4
factors namely :
1.Cellular structure- whether the organism is
Prokaryotic or Eukaryotic.
2.Cellular organization- whether the organism
is Unicellular or Multicellular. In multicellular
organisms what is the level of organization.
3.Mode of source of nutrition- whether the
organism is Autotrophic or Heterotrophic.
4.Phylogenetic relationships- phylogeny means
evolutionary history of a species.

10. CAROLUS LINNAEUS R.H.WHITTAKER

11. Evolution and Classification
• Darwin's theory of evolution states that all
present – day organisms have originated from
the same source and during the course of
time have evolved into complex organisms by
bringing about variations within it’s body to
adapt to the changing environment.
• This can be easily seen and studied in the
classification because it is an arrangement
where phylogeny is considered as one of the
main criteria.

12. Classification and Nomenclature
• Nomenclature means to name an organism.
• Naming an organism is essential to identify it
as well as distinguish it from the others.
• In biology all organisms are given specific
scientific names. This is done to avoid any
confusion when an interaction is held among
people of different vernacular regions.
• Binomial Nomenclature : It was proposed by
Carolus Linnaeus, according to this a scientific
name consists of 2 components, first the
generic name and second is the specific name.

13. • This system is accepted internationally and is
guided by rules stated in the INTERNATIONAL
CODE OF NOMENCLATURE. They are further
branched as international code of botanical
nomenclature , international code of Zoological
nomenclature, international code of bacterial nomenclature
as plants, animals and bacteria are named with slightly
different codes.
• General rules to name an organism scientifically are: