Georgia Tech School of Biology Summer 2012 Bio@Tech What is Life?
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Transcript of Georgia Tech School of Biology Summer 2012 Bio@Tech What is Life?
Bio@Tech
Georgia Tech School of Biology
Summer 2012
What is Life?
Bio@Tech
Georgia Tech School of Biology
Summer 2012
What will happen if organisms reproduce, imperfectly, and the variation makes a
difference in survival and reproduction of the organism?
Bio@Tech
Georgia Tech School of Biology
Summer 2012
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
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Evolution is an inevitable consequence of life on Earth
• Heritable variation – mutation, recombination.
• Competition for limited resources.
• Natural selection.
• Time – many generations.
• Long-term environmental changes.
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Hutton’s UnconformityRed sandstone (horizontal)
Grey shale (vertical)
“… no vestige of a beginning, no prospect of an end.”
–James Hutton
(photo: Anne Burgess)
http://en.wikipedia.org/wiki/Image:Siccar_Point.jpg
Bio@Tech
Georgia Tech School of Biology
Summer 2012
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:– humerus (gray)– radius (orange)– ulna (beige)– carpals (yellow)– phalanges (brown)
Campbell & Reece, Fig. 22.14
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Sean Carroll - http://www.hhmi.org/biointeractive/evolution/lectures.html
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Sean Carroll - http://www.hhmi.org/biointeractive/evolution/lectures.html
Bio@Tech
Georgia Tech School of Biology
Summer 2012
What the fossil record shows
Foraminiferans – www.don-lindsay-archive.org/creation/foram_work.gif
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Evolution of Horses
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Horsetoes!
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Darwin's Original Insights
• Descent with modification from a common ancestor – a tree describes genealogy of life
• Natural selection – the mechanism of evolution
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Darwin's Tree Illustrations
1859 Origin of Species – only figure
1837 notebook page
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Natural Selection and Time
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
How often does a black coat mutation arise?
Depends on:
Bio@Tech
Georgia Tech School of Biology
Summer 2012
How often can we expect a black rock pocket mouse to arise by mutation?
Mutation rate for black MCIR allele = 2 x 10-8
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Evolutionary hypotheses are testable and falsifiable
• Discovery and characterization of new transitional fossils
• DNA sequence comparisons
• Radiometric and isotopic dating
• Geological record
• Astrophysics
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Thomas Huxley's grandchildren
Bio@Tech
Georgia Tech School of Biology
Summer 2012
Modern Biology Is Evolutionary Biology
• “Nothing in biology makes sense except in the light of evolution.”
– Theodosius Dobzhansky
• “The alternative to thinking in evolutionary terms is not to think at all.”
– Peter Medawar, Nobel Laureate, 1960
Bio@Tech
Georgia Tech School of Biology
Summer 2012
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