Page 1 - 2.Lession Notes-Introduction, Classification and Evolution
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SAI International School
Subject- Biology, Class-IX
Chapter- Diversity in Living organisms
Subtopic- Introduction, Classification and Evolution
Module-23
Lesson Notes
Diversity---- 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. Diversity refers to the existence of variations of different characteristics in
a group of organisms.
Need for classification of living organisms :-
• 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.
Basis of classification of living organisms
Fundamental characteristics need to be decided which would form the foundation for
classifying. Classification can be carried out based on many factors such as:
