Question 1 Page 83 - Chapter 7 Class 9 - Diversity In Living Organisms

Which organisms are called primitive and how are they different from the so-called advanced organisms?

Answer:

1. Primitive organisms - The organisms having characteristics like  simple cellular structure and no division of labour that came into existence earlier are known as "primitive organisms".
2. Advanced organisms - The organisms having characteristics like millions of cells and different organ and organ systems that came into existence later are known as "advanced organisms".

For example:  

Primitive organisms- Prokaryotic Bacterias, algae etc.

Advanced organisms- Mammals, birds etc.

Primitive organisms are different from Advanced organisms on the basis of nature, number and complexity of cells they possess.