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History of evolutionary thought
2 Darwin
Historical Context for Darwin’s Ideas
Darwin’s family
Erasmus Darwin (1731-1802)
Robert Darwin
Charles Darwin (1809-1882)
Darwin at 7 yrs
Darwin’s education
Shrewsbury
University of Edinburgh
-medicine
University of Cambridge
-theology
John Stevens Henslow (1796-1861)
Cambridge professor
Theologian, naturalist
Would walk the gardens with Darwin
Darwin called, “the man who walks
with Henslow”
Recommended Darwin for Beagle
voyage
Captain Robert Fitzroy (1805-1865)
Young
Meticulous
Christian
"Afterwards on becoming very intimate with Fitzroy, I heard that I had
run a very narrow risk of being rejected [as the Beagle's naturalist], on
account of the shape of my nose! He was an ardent disciple of Lavater,
and was convinced that he could judge a man's character by the outline
of his features; and he doubted whether anyone with my nose could
possess sufficient energy and determination for the voyage. But I think
he was afterwards well-satisfied that my nose had spoken falsely."
Charles Darwin
Darwin’s Voyage on the HMS Beagle
Dec 1831 - Oct 1836
Charles Darwin
Cousins
10 children
5-7 survived
Emma Wedgewood
Down house
Poor health (Chaga’s disease)
Confined to home
Correspondence
Publications
Accumulated data
Published various works
Did not publish on origin of species
Letter from Wallace outlining same mechanism
Urged to publish immediately (Lyell & Hooker)
Darwin’s Theory of Evolution:
A Scientific Revolution
• Descent with modification provides an
explanation for the pattern of unity and
diversity in living organisms
– species have similar features because they
evolved from a common ancestor
• Natural selection is the mechanism that
results in adaptation
– species are different because unique traits are
favored in contrasting environments
Geographic Distribution of Species
Plant and Animal Breeding
The Unique Flora and Fauna of the
Galapagos Islands
• Species were unique to particular islands.
• Species closely resembled those on the mainland.
• How did the differences among species arise?
Darwin’s Theory of Evolution:
Descent with modification from a common ancestor
History of evolutionary
thought
3 Post-Darwin
Historical Context for Darwin’s Ideas
Golden age of evolution - 1870s-1930s
Evolution established as fact
Natural selection rejected as mechanism
Anti-Darwinian theories
Neo-Lamarckism
Orthogenesis
Mutationism
Gregor Mendel (1822-1884)
Genetics work rediscovered
Mechanism of inheritance
Evolutionary synthesis 1930s-1940s
aka Neo-Darwinian synthesis
Reconciled natural selection & genetics