it is a type of evolution in which different species have common ancestor. for example if we take members of one species and put them in different environments then it is observed that there is some changes in the species according to environment
Similar traits can be either homologous or analogous. Homologous structures share a similar embryonic origin. Analogous organs have a similar function. For example, the bones in a whale's front flipper are homologous to the bones in the human arm.
