History of evolutionary thought 2 Darwin

Historical Context for Darwin’s Ideas

Erasmus Darwin ( ) Robert Darwin Charles Darwin ( ) Darwin’s family Darwin at 7 yrs

University of Edinburgh -medicine University of Cambridge -theology Darwin’s education Shrewsbury

John Stevens Henslow ( ) 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 ( ) 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 Oct 1836

Charles DarwinEmma Wedgewood Cousins 10 children 5-7 survived

Poor health (Chaga’s disease) Confined to home Correspondence Down house

Accumulated data Published various works Did not publish on origin of species Letter from Wallace outlining same mechanism Urged to publish immediately (Lyell & Hooker) Publications

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 s-1930s Evolution established as fact Natural selection rejected as mechanism

Anti-Darwinian theories Neo-Lamarckism Orthogenesis Mutationism

Gregor Mendel ( ) Genetics work rediscovered Mechanism of inheritance

Evolutionary synthesis 1930s-1940s aka Neo-Darwinian synthesis Reconciled natural selection & genetics