Life evolves!
What is life?What is evolution?Evidence for evolutionTesting evolutionary hypotheses
What is Life?
Discuss with your neighbors and write a consensus definition of LIFE.
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Early Evidence for Biological Evolution
1. Homology2. Fossil record3. Geological evidence
Homology homologous structure of mammal limbs suggest descent from a common ancestor
(Buffon, 1707-1788)
See also Fig. 22.17
Homology vs analogy
University of California Museum of Paleontology (http://evolution.berkeley.edu)
Testing predictions from evolutionary theory:are tetrapod limbs homologous?
University of California Museum of Paleontology (http://evolution.berkeley.edu)
Fossil ancestral tetrapods have same limb structure
University of California Museum of Paleontology (http://evolution.berkeley.edu)
Meet Ichthyostega 363 Mya
http://download.naturkundemuseum-berlin.de/presse/Darwin/Stuttgart/Fossil_Sclerocephalus.jpg
And lobe-finned fish have similar bone structure
390 mya
University of California Museum of Paleontology (http://evolution.berkeley.edu)
Oh no! The fossil record has a gap!
Tiktaalik.uchicago.edu
Where can we find exposed rocks of the right age and type?
Tiktaalik.uchicago.edu
Tiktaalik, a transitional fossil predicted by evolutionary theory
Tiktaalik.uchicago.edu
