Transcript The Spandrels of San Marco

The Spandrels of San Marco
Adaptation or Drift?
Gould and Lewontin (1979)
• The spandrels of San Marco and the
Panglossian paradigm: a critique of the
adaptationist programme.
• Do not assume that every trait is an
adaptation
• Cited more than 4000X
The Cathedral of San Marco
• Are spandrels necessary
architectural elements or
byproducts of having adjacent
arches?
• How many traits of living
organisms are spandrels rather
than adaptations?
• Organisms are more than
collections of traits.
Stephen Jay Gould,
1941-2002, USA
Richard Charles
Lewontin, 1929-present,
USA
• Empedocles: adaptation does not require a
purpose (final cause)
• Aristotle: adaptation requires a purpose
• Paley (Natural Theology): organisms perfectly
adapted through design toward a purpose
• Lamarck: adaptation through increased
complexity and influence of circumstances
• Darwin and Wallace: adaptation is ‘good
enough’ outcome of natural selection
Adaptation
• Genetic change in
response to changes
in habitat (Red
Queen Hypothesis)
• Co-adaptations
(diversification
between insects and
flowering plants in
Cretaceous)
• Compromise (e.g.
sexual selection)
Classic Research on Adaptation
• Peter and Rosemary
Grant (1973present)
• John Arthur Endler
(1980)
Genetic Drift
A
B
O
AB
United States
42%
10%
45%
3%
Chinese
31%
28%
34%
7%
Blackfoot
76%
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24%
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Navajo
24%
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76%
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Genetic Drift in Mice
Genetic drift in inbred mouse colonies happens slowly, subtly, and is difficult to detect and
control. It is caused by the same factors (Bailey 1977; Bailey DW. 1982. Immunology
Today 3:210-14) that lead to substrain divergence.
Developmental Allometry
Developmental Allometry of Humans
Developmental Allometry of Humans
Khrameeva et al. 2014. Neanderthal ancestry drives
evolution of lipid catabolism in contemporary Europeans.
Nature Communications. 5:3584 DOI: 10.1038/ncomms4584
Importance of Gould and Lewontin (1979)
• Cited ~4,000X
• Functioned as a heuristic
• When we examine traits should we assume
that they are adaptations or drift?
• G&L (1979) helped to make evolutionary
biology more rigorous.