Georgia Tech School of Biology
What is Life?
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Summer 2012
Georgia Tech School of Biology
What will happen if organisms reproduce,
imperfectly, and the variation makes a
difference in survival and reproduction of the
organism?
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Summer 2012
Georgia Tech School of Biology
What will happen if organisms reproduce,
imperfectly, and the variation makes a
difference in survival and reproduction of the
organism?
School children modeled this by drawing copies of a
drawing of animal. Then most of these copies were
eliminated (disaster or climate change), and they drew
copies of the surviving drawings, for 6 successive
generations. These drawings were animated to
produce this video:
http://www.youtube.com/watch?v=N8X-j0dbZWs
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Summer 2012
Georgia Tech School of Biology
Evolution is an inevitable consequence
of life on Earth
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•
•
•
•
Heritable variation – mutation, recombination.
Competition for limited resources.
Natural selection.
Time – many generations.
Long-term environmental changes.
Bio@Tech
Summer 2012
Georgia Tech School of Biology
Hutton’s Unconformity
Red sandstone (horizontal)
Grey shale (vertical)
“… no vestige of a beginning,
no prospect of an end.”
–James Hutton
(photo: Anne Burgess)
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http://en.wikipedia.org/wiki/Image:Siccar_Point.jpg
Summer 2012
Georgia Tech School of Biology
Homology of Mammalian Limbs
• Buffon (1707-1788) noted
the homologous structure
of mammal limbs and
suggested descent from a
common ancestor.
• Common structures in
four very different
mammals:
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–
–
–
–
humerus (gray)
radius (orange)
ulna (beige)
carpals (yellow)
phalanges (brown)
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Campbell & Reece, Fig. 22.14
Summer 2012
Georgia Tech School of Biology
Sean Carroll - http://www.hhmi.org/biointeractive/evolution/lectures.html
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Summer 2012
Georgia Tech School of Biology
Sean Carroll - http://www.hhmi.org/biointeractive/evolution/lectures.html
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Summer 2012
Georgia Tech School of Biology
What the fossil record shows
Foraminiferans – www.don-lindsay-archive.org/creation/foram_work.gif
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Summer 2012
Georgia Tech School of Biology
Evolution of Horses
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Summer 2012
Georgia Tech School of Biology
Horsetoes!
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Summer 2012
Georgia Tech School of Biology
Darwin's Original Insights
• Descent with modification from a common
ancestor – a tree describes genealogy of life
• Natural selection – the mechanism of
evolution
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Summer 2012
Georgia Tech School of Biology
Darwin's Tree Illustrations
1859 Origin of Species – only figure
1837 notebook page
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Summer 2012
Georgia Tech School of Biology
Natural Selection and Time
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
How often does a black coat mutation arise?
Depends on:
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Summer 2012
Georgia Tech School of Biology
How often can we expect a black rock
pocket mouse to arise by mutation?
Mutation rate for black MCIR allele = 2 x 10-8
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
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Summer 2012
Georgia Tech School of Biology
Evolutionary hypotheses are testable
and falsifiable
• Discovery and characterization of new
transitional fossils
• DNA sequence comparisons
• Radiometric and isotopic dating
• Geological record
• Astrophysics
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Summer 2012
Georgia Tech School of Biology
Thomas Huxley's grandchildren
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Summer 2012
Georgia Tech School of Biology
Modern Biology Is Evolutionary Biology
•
“Nothing in biology makes sense except
in the light of evolution.”
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•
Theodosius Dobzhansky
“The alternative to thinking in
evolutionary terms is not to think at all.”
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Peter Medawar, Nobel Laureate, 1960
Summer 2012
Georgia Tech School of Biology
Useful Websites
• National Academy of Sciences: Teaching About
Evolution and the Nature of Science
– A good overview of evolution and science.
• UC Museum of Paleontology
– Info on the theory and history of evolution
• Talk Origins Archive
– Info on evolution and creationism
• Talk Origins Archive FAQ
– A good entry point to the Talk Origins Archive
Bio@Tech
Summer 2012