Question

how the evolution or classiication are interlinked with each other??

Answer 1

Classification involves grouping of organism into a formal system based on similarities in internal and external structure or evolutionary history.
Two species are more closely related if they have more characteristics in common. And if two species are more closely related, then it means they have a more recent ancestor.
For example, in a family, a brother and sister are closely related and they have a recent common ancestor i.e., their parents. A brother and his cousin are also related but less than the sister and her brother. This is because the brother and his cousin have a common ancestor i.e., their grandparents in the second generation whereas the parents were from the first generation.
With subsequent generations, the variations make organisms more different than their ancestors.
This discussion clearly proves that we classify organisms according to their resemblance which is similar to creating an evolutionary tree.

Answer 2

Organisms differ in their form, structure and mode of living. Hence, based on their similarities they should be grouped. The grouping of related organisms helps us in studying their evolutionary relationships. Classification is the division of organisms on the basis of characteristics into groups and sub-groups. A characteristic may be a particular form or function.
For example, classification of animals can be done based on some criteria.

Criteria for classification:

 Animals are classified on the basis of different features.
*Cellular or tissue level of body organisation.
*Body symmetry.
*Type of body cavity called as coelom.
*Presence or absence of segmentation.
*Presence or absence of a backbone.



Evolution:
 It is the sequence of gradual changes over millions of years in which new species are produced. Classification of species is done by knowing the characteristics which evolved over a long period of time.