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Evolution. Fossil Record as Fair Test (Part II). Theory of Evolution. All life on Earth descended from a common ancestor Life originated as a simple form, and became more diverse and complex over time. Fossil Record.
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Evolution Fossil Record as Fair Test(Part II)
Theory of Evolution • All life on Earth descended from a common ancestor • Life originated as a simple form, and became more diverse and complex over time
Fossil Record • Represents ~ 4,000,000,000 year long record of the natural history of our planet
I. Evidence in the Fossil Record • Evidence that life changed through time:simple complex • Evidence of change in one “type” of animal through the years • Transition species: evidence of “hybrids” between two types • 99% of all life which has ever existed is now extinct
What does the fossil record tell us? • Life originated in a simple form and become more complex and diverse with time. Example #1: Example #2: Example #3:
What does the fossil record tell us? 2) Organisms have changed over time Changes within a “type” of animal: • Sea Urchins (video) • Horse (video -can you describe?)
Horse Transitions • Each branch tip on the tree of horse evolution indicates a different genus, though the feet of only a few genera are illustrated to show the reduction of toes through time.
What does the fossil record tell us? 2) “ One problem with the theory of evolution is the conspicuous lack of transition fossils” Is this true?
Other Transition Fossils Transitions from one “type” into another: • Skulls: reptile/mammal “hybrids”(Why is this significant?) • Whale Transition Fossils (See pbs “evolution” series – cool show!)
Fossil Record:Evolution of Mammals • Skulls showing the changes in the jaw articulation and the ear region in the evolution from reptile to mammal.
And, (Drum roll, please….) Published April 6, 2006 …… See http://tiktaalik.uchicago.edu/
Fossil Called Missing Link From Sea to Land Animals Model of Tiktaalik roseae, a 375 million year old fish with many amphibian-like features and foot-like bone structure in its fins that could have helped it pull itself through shallow water and even out of the water for brief periods
What does the fossil record tell us? 3) 99% of all organisms which have ever existed are now extinct! (The life we observe today has not been the life through the ages!)