evidence for common descent - bio unit 9

fossil record

yuh look at dose fossils

law of superposition

older fossils in lower rock layer, younger in higher

transitional features

traits in fossils that show that evolution happened in steps rather than all at once

homologies: anatomical

similarities in physical structures between different species that results from inheriting them from a common ancestor

vestigal traits

anatomical homology has lost its function (monkeys and tails, humans and appendix)

atavism

reversion back to ancestral trait (human born with tail)

homologies: developmental

similarities in embryos

homologies: molecular

similarities in DNA