Evidence of Evolution Several types of information support Darwin’s theory of evolution. anatomy homologous, analogous, and vestigial structures embryology The study of fetal development. macromolecules DNA, RNA, proteins, etc.

Homologous Structures Structures that are similar/same (homo) and have originated from a common ancestor. May look different on the outside, but have similar/same (homo) structure inside. Indicates that organisms may have shared a recent common ancestor.

Homologous Structures cont’d. The limbs of different organisms serve different functions, but have the same bone structure inside.

Analogous Structures Analogous Structures Structures that serve identical functions, but have different internal anatomy. Ex: wings of birds and insects Both allow organisms to fly, but have different development and structure. Shows a more distant relationship than homologous structures.

Vestigial Structures Vestigial – structures that were useful in ancestors but are no longer used by modern organisms Shows relationship between organisms with vestigial structure and those with a working version. ie. humans have tailbones homologous to tails of other animals

Vestigial Structures cont’d. Some organisms have genes that are conserved. Genes that have remained unchanged, but may be “turned off”. ie. whales have genes for hind legs Can give clues about early development of a species. ie. whales may have descended from an ancestor who lived on land

Embryology Embryology – study of early development Many organisms share similarities within the early stages of development. Can indicate a common ancestry among different species.

Embryology cont’d.

Similarities in Macromolecules Similarities within DNA, RNA and proteins of different species Genetic code is universal – all living things share the same code Closely related species have very similar gene sequences and protein sequences. Ex: hemoglobin in humans and gorillas differs by only 1 amino acid Can confirm ideas suggested by fossils and anatomy.