Evidence for Evolution - Fossils Can get relative dates using geologic principles - older layers are at the bottom, younger layers at the top Fossils that are in the same layer are likely the same age. Can get an absolute date using radiometric dating ( ½ lives) Tell us about relationships between animals, plants, and environment Show that different forms of life existed on earth Can estimate when a life form became extinct.

Fossils show transitional forms Whales – placement of nostrils Horse feet – show transitional forms 4 toes( Eohippus) to 1 toe ( Equus) not direct ancestors, but an evolutionary tree

Homologous Structures Homologous structures are similar features that originated in a shared ancestor Similar in skeletal structure but have different functions Derived from the same structures in the embryo

Vestigial Structures Vestigial structures are features that were useful to an ancestor, but they are not useful to the modern organism Examples: Some snakes have tiny pelvic and limb bones Whales have pelvic bones

Embryology The early stages of different vertebrate embryos are similar to each other Indicate a common ancestry Embryonic similarities fade as development proceeds

DNA evidence The more base pairs = more similarities Chimp = 98% Cat: 90% Cow: 80% Mouse: 75% Fruit Fly: 60% Banana: 50%90%80%75% 60%50%

Vocab – Put in the back of your journal Fold pages into three sections Word Meaning (in your words) Illustration or Clue Control Controlled Variable Hominid Evolution Morphology Homologous Structures Vestigial Structures

Read Essays on Essay 1 – Fossils : Traces of Life that has gone by ( add in red pen information to your notes that were taken in class on Fossils) ADD info for essay 2 and three after Red pen corrections of Essay 1 Essay 2- Technologies that strengthen Fossil Evidence Summarize how stratigraphy works Summarize how radioactive isotopes are used. ( provide examples and be able to explain half – life) Essay 3 – Modern Life : Evidence of evolutionary change Create a frayer model for the following words - Homology Vestigial Structure