Why do we classify organisms?

We classify organisms because:

1. It makes the study of evolutionary history of organisms simpler and convenient.
2. If we have classified the organisms in different groups it will be simpler for us to study any one representative from a group and assign the same characters to rest of the group.
3. It will be easier to assign any new organism its place in the existing (or new) group according to the similarities or dissimarities to other organisms.