Give an example of characteristics being used to determine how close two species are in evolutionary terms.
(1) The study of fossils provide direct evidence of evolutionary relationship among species. For example, dinosaurs had feathers, as fossils indicate. However, they could not fly. Later on, birds adapted the feathers to use them for flight. This means that birds are very closely related to reptiles as dinosaurs were reptiles.
(2) Another method is of comparison of the DNA of different species. The more closely the DNAs of two species are related, the more common evolutionary history these species have.