Q. Give an example of characteristics being used to determine how close two species are in evolutionary terms.
Different organisms with common ancestry in the past, are more likely to have similar characteristics due to inheritance. These similar characteristics are used to determine evolutionary relationships. Basic structure of Forelimbs in human and birds is one such example of a characteristic which shows closeness of two species in evolutionary terms. The forelimbs in both the species, have similar bones structure and similar origin, but, over period of time, spanning generations, they have been developed to perform different suitable functions as per the need. Such organs that have similar basic structure but perform different functions are called homologous organs. These are used to find out evolutionary relationships.