Q1 Page 156 - Chapter 9 Class 10 - Heredity and Evolution

Give an example of characteristics being used to determine how close two species are in evolutionary terms.

Answer:

Presence of similar characteristics in organisms can be used to determine if the particular species have common ancestors and are related on evolutionary grounds.

For Example - 

In case of Homologous characteristics :

• Basic structure of the limbs of frogs, lizards, birds and humans is the same .
• But, their functions are different .

• This means they evolved differently from a common ancestor due to different usage of limbs. This is known as Divergent Evolution . 

In case of Analogous Characteristics :

• Both birds and bats have wings.
• Structure of bat wings is skin stretched over elongated fingers
• In birds , the arms (wings) are covered in feathers .
• Their origin and structure are different but function is the same ; they help to fly, so they are examples of Convergent Evolution .
• They are also called Analogous Characteristics .

These characteristics can hence be used to determine how close two species are in evolutionary terms.