The process of changing of an organism intoanother species through variation

Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction.

Evolution means the changes in the children of same parents.
Evolution*
Evolution means gradually change
Generation*
The process due to which xertain trait / allele / character changes in any species which makes it differ from its parents , due to heneration gap , is known as variation

Evolution is an on going process. The life forms we see today around us is the result of millions of yr. Of evolution. Simple inorganic molecules formed organic molecules that formed primitive life and then progressive changes resulted in the present day life forms . It is called organic evolution.

CHanges in time over years
Evolution is the sequence of gradual changes which take place in the primitive organisms over millions of years in which new species are produced
Evolution is the gradual process in which primitive organism over million of years in which new species are produced