Naturalists
and the redefinition of nature 1800-1898.

What did Charles Darwin know and when did he know it?

"all life descended from a common ancestor."

1828, credulous Christian divinity student 1833, naive witness to creation 1837, starts work on his "Species Book" 1838, September 28, accidental Malthusian about "geometric increase." 1839, thoughtful agnostic 1842-44, manuscript compiler 1848, Zeitgeist of resistance (reaction) and revolution (reform) 1858, a shock in the mail, manuscript from Alfred Russel Wallace 1859, the reluctant revolutionary

Timeline of indecision

Henslow's Botany Book

Codiscoverer of natural selection

Alfred Russell Wallace, naturalist

Why revolutionary?

• species are not fixed and unchanging (fixity of species)
• natural selection is not a process of perfectibility, but of adjustment

1. maladaptive
2. adaptive

• populations not types are the proper foci of natural history
• there is no need for teleology in a stochastic (semi-random) world of chance

Wallace's line demarcating species variattion and abundance east of Bali and Java.

Critics charged that Darwin had discovered the

• Law of the higgedly piggedly!
• Monkeys were our ancestors.
• artifice of, not nature, but the English factory system!
• means of undoing special creation from human conceit.
• Hobbesian state of war of all against all in the English garden.

Wallace defended Darwin and published, in 1860s, a book on Dawinism, he marveled at the sheer number of creatures and the variety of their forms.

Evidence, the quality of one's data is crucial.

Fossils as anomalies

bird's beaks.

Darwin's Finches
same species?	broad beaked	narrower beaked

Natural Selection

Intermediate species:

The centrality of yell's Geology to Darwin's reconceptualization:

Deep time or Geological Time is older than anyone in Darwin's world could have ever imagined.

Life has changed the face of the Earth over geological time.

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