Determining Relatedness

Phylogenetic Trees A. Show how closely related various species are B. Some species look different, but are actually very similar

Comparative Anatomy A. Homologous Structures – Inherited from a common ancestor, but adapted to a different function (ex. human hand, bat wing, whale fin)

B. Analogous Structures – adapted for the same function, but NOT from a common ancestor (ex. Bird wings and butterfly wings)

C. Vestigial Structures – inherited but no longer serve a purpose (ex C. Vestigial Structures – inherited but no longer serve a purpose (ex. python and whale hip bones, human body hair)

III. Comparative Embryology – compare fetal development – longer two organisms are similar, the more closely related they are

Comparative Biochemistry – compare sequences of amino acids or DNA – the more similar they are the more closely related