Diversity in Living Organisms Class 9 PPT - Chapter 7 PDF Download

 Page 1


CHAPTER - 7
DIVERSITY  IN  LIVING  
ORGANISMS
CLASS :- IX 
MADE BY :- SHIV A  PRASAD
SCHOOL :- K.V . 2. KALPAKKAM
Page 2


CHAPTER - 7
DIVERSITY  IN  LIVING  
ORGANISMS
CLASS :- IX 
MADE BY :- SHIV A  PRASAD
SCHOOL :- K.V . 2. KALPAKKAM
1) Need for classification of living organisms :-
Living organisms have evolved on the earth over millions of years. 
There is a vast variety of living organisms. Living organisms show a 
wide range of variations.
- Some microscopic bacteria are of a few micrometres in size and some 
like whales and red wood trees are about 30 metres and 100 metres in 
size.
- Some pine trees live for thousands of years while insects like 
mosquitoes die within a few days.
- Some organisms are colourless and even transparent and some are 
brightly coloured.
To understand and study all these organisms is impossible. If they are 
arranged into different groups based on their similarities in 
characteristics, then it is easier to study the different groups as a whole.
Classification of living organisms :- The arranging of organisms 
into different groups on the basis of the similarities in their 
characteristics is called classification of living organisms.   
Page 3


CHAPTER - 7
DIVERSITY  IN  LIVING  
ORGANISMS
CLASS :- IX 
MADE BY :- SHIV A  PRASAD
SCHOOL :- K.V . 2. KALPAKKAM
1) Need for classification of living organisms :-
Living organisms have evolved on the earth over millions of years. 
There is a vast variety of living organisms. Living organisms show a 
wide range of variations.
- Some microscopic bacteria are of a few micrometres in size and some 
like whales and red wood trees are about 30 metres and 100 metres in 
size.
- Some pine trees live for thousands of years while insects like 
mosquitoes die within a few days.
- Some organisms are colourless and even transparent and some are 
brightly coloured.
To understand and study all these organisms is impossible. If they are 
arranged into different groups based on their similarities in 
characteristics, then it is easier to study the different groups as a whole.
Classification of living organisms :- The arranging of organisms 
into different groups on the basis of the similarities in their 
characteristics is called classification of living organisms.   
2) Basis of classification of living organisms :-
The main characteristics which are considered for 
classification of living organisms into different groups are :-
- Whether they are made of prokaryotic or eukaryotic cells.
- Whether the cells occur singly or they are grouped 
together and live as an indivisible group.
- Whether they produce their own food by photosynthesis 
or get their food from outside.
- Of the organisms which produce their own food (plants) 
what is the level of organisation of their body ?
- Of the animals what is the level of organisation of their 
body and what are their special organs and their functions ?
The characteristics used for classification of plants will be 
different from the characteristics used for classification of 
animals because plants make their own food and animals 
get their food from outside.
Page 4


CHAPTER - 7
DIVERSITY  IN  LIVING  
ORGANISMS
CLASS :- IX 
MADE BY :- SHIV A  PRASAD
SCHOOL :- K.V . 2. KALPAKKAM
1) Need for classification of living organisms :-
Living organisms have evolved on the earth over millions of years. 
There is a vast variety of living organisms. Living organisms show a 
wide range of variations.
- Some microscopic bacteria are of a few micrometres in size and some 
like whales and red wood trees are about 30 metres and 100 metres in 
size.
- Some pine trees live for thousands of years while insects like 
mosquitoes die within a few days.
- Some organisms are colourless and even transparent and some are 
brightly coloured.
To understand and study all these organisms is impossible. If they are 
arranged into different groups based on their similarities in 
characteristics, then it is easier to study the different groups as a whole.
Classification of living organisms :- The arranging of organisms 
into different groups on the basis of the similarities in their 
characteristics is called classification of living organisms.   
2) Basis of classification of living organisms :-
The main characteristics which are considered for 
classification of living organisms into different groups are :-
- Whether they are made of prokaryotic or eukaryotic cells.
- Whether the cells occur singly or they are grouped 
together and live as an indivisible group.
- Whether they produce their own food by photosynthesis 
or get their food from outside.
- Of the organisms which produce their own food (plants) 
what is the level of organisation of their body ?
- Of the animals what is the level of organisation of their 
body and what are their special organs and their functions ?
The characteristics used for classification of plants will be 
different from the characteristics used for classification of 
animals because plants make their own food and animals 
get their food from outside.
3) Classification and evolution :-
The present day complex living organisms have evolved 
from the earlier simple forms due to the changes in their 
body designs over millions of years. 
The body designs of living organisms are gradually 
changing due to the changes in environment and the need 
to adapt themselves to the changes in the environment.
Some groups of organisms having ancient body designs 
have not changed much during evolution and have simple 
forms and structure. These organisms are called ‘primitive 
or lower organisms ’.
Some organisms have acquired their body designs 
relatively recently and have complex forms and structure. 
These organisms are called ‘advanced or higher 
organisms ’.  
Page 5


CHAPTER - 7
DIVERSITY  IN  LIVING  
ORGANISMS
CLASS :- IX 
MADE BY :- SHIV A  PRASAD
SCHOOL :- K.V . 2. KALPAKKAM
1) Need for classification of living organisms :-
Living organisms have evolved on the earth over millions of years. 
There is a vast variety of living organisms. Living organisms show a 
wide range of variations.
- Some microscopic bacteria are of a few micrometres in size and some 
like whales and red wood trees are about 30 metres and 100 metres in 
size.
- Some pine trees live for thousands of years while insects like 
mosquitoes die within a few days.
- Some organisms are colourless and even transparent and some are 
brightly coloured.
To understand and study all these organisms is impossible. If they are 
arranged into different groups based on their similarities in 
characteristics, then it is easier to study the different groups as a whole.
Classification of living organisms :- The arranging of organisms 
into different groups on the basis of the similarities in their 
characteristics is called classification of living organisms.   
2) Basis of classification of living organisms :-
The main characteristics which are considered for 
classification of living organisms into different groups are :-
- Whether they are made of prokaryotic or eukaryotic cells.
- Whether the cells occur singly or they are grouped 
together and live as an indivisible group.
- Whether they produce their own food by photosynthesis 
or get their food from outside.
- Of the organisms which produce their own food (plants) 
what is the level of organisation of their body ?
- Of the animals what is the level of organisation of their 
body and what are their special organs and their functions ?
The characteristics used for classification of plants will be 
different from the characteristics used for classification of 
animals because plants make their own food and animals 
get their food from outside.
3) Classification and evolution :-
The present day complex living organisms have evolved 
from the earlier simple forms due to the changes in their 
body designs over millions of years. 
The body designs of living organisms are gradually 
changing due to the changes in environment and the need 
to adapt themselves to the changes in the environment.
Some groups of organisms having ancient body designs 
have not changed much during evolution and have simple 
forms and structure. These organisms are called ‘primitive 
or lower organisms ’.
Some organisms have acquired their body designs 
relatively recently and have complex forms and structure. 
These organisms are called ‘advanced or higher 
organisms ’.  
4) The hierarchy of classification – Groups :-
Living organisms have been broadly classified into five main 
kingdoms. They are :-
i) Monera  ii) Protista  iii) Fungi  iv) Plante  v) Animalia
Each kingdom has been further classified into smaller 
sub - groups at various levels as :-
Kingdom
Phylum (for plants) / Division (for animals)
Class
Order
Family
Genus
Species 
By arranging organisms on the basis of hierarchy and characteristics 
into smaller and smaller groups we arrive at the basic unit of 
classification called species.
Species :- is group of organisms which are similar enough to breed 
and perpetuate.