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 organismExamples:Some snakes have tiny pelvic and limb bonesWhales 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 similaritiesChimp = 98%Cat: 90%Cow: 80%Mouse: 75%Fruit Fly: 60%Banana: 50%
Vocab – Put in the back of your journalFold pages into three sectionsWord Meaning (in your words) Illustration or ClueControlControlled VariableHominidEvolutionMorphologyHomologous StructuresVestigial Structures
Read Essays on 102- 109Essay 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
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