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