Life evolves! What is life? What is evolution? Evidence for evolution Testing evolutionary hypotheses.

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