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The Eclipse of Darwinism around 1900
Much of the debate that followed publication of the Origin focused on
the question of evolution itself, rather than on Darwin’s proposed
mechanism. After the fact of evolution had become established,
however, Darwin’s proposed mechanism came under close scrutiny.
Beginning about 1880, many scientists—including some of Darwin’s
most ardent defenders—expressed discomfort with the element of
randomness in the theory of natural selection, suspecting that
random variation, even if selected, could not alone produce the
seemingly endless examples of living biological adaption.
This situation led to the advocacy of various strands of antiDarwinism, ultimately culminating in a crisis for Darwinism
around 1900, a period Julian Huxley would later refer
to as the “eclipse of Darwinism”.
Samuel Butler, victorian novelist (1835-1902)
The American school of Neo-Lamarckian Paleontology
Bitter feud with O. C. Marsh over both his
Neo-Lamarkianism and dinosaur fossils
Religious motivation in his denial of
Darwinism
Edward Drinker Cope, American Paleontologist (1840-1897)
at Haverford College from 1864-1870?
Darwinism purged of its “Lamarckian” elements!
(but in fact unleashed a backlash of anti-Darwinian sentiment)
August Weismann (1834-1814)
In 1889 cut the tails off of 1,500 rats over 20 generations
Das Keim Plasma: a theory of heredity (1892)
From Simpson, GG, Life: An introduction to Biology, 1957
(modified from Wilson, EB, The Cell in Development and Evolution, 1896)
Feud between Herbert Spencer and Weismann
Herbert Spencer, “The inadequacy of natural selection”, 1893
Weismann, “The Allmacht (all-sufficiency) of natural selection”, 1893
“Unpermissibly weak!”
“As if that were certain!”
Neo-Lamarckism continues deep into 20th Century
The Inheritance of Acquired Characteristics,
1924 (English Translation)
Paul Kammerer (1820-1926)
Conrad Hal Waddington (1905–1975)
Epigenetic Landscape
Organisers and Genes, 1940
Branching Track Model
of Development
Genetic Assimilation (Waddington, 1953)
(idea also developed by I. I. Schmalhausen, referred to as “stabilizing selection”)
“Organic” Evolution
"A New Factor in Evolution” (1896)
by American psychologist James Mark Baldwin
American Naturalist 30: 441-451,536-553.
(also Lloyd Morgan and Henry Fairfield Osborn at about same time)
Coined the “Baldwin Effect” by G. G. Simpson in an article
whose purpose was to challenge importance of the idea
“The Baldwin Effect” (1953) Evolution 7: 110-117
The learned (voluntary or conscious?) behavior of a species or group
can shape the evolution of that species or group.
Learned Behavior
Genetically Encoded Instinct
Hinton and Nowlan’s Simulation of the Baldwin Effect
[Put Figure on here]
Hinton and Nowlan (1987) How learning can guide evolution Complex Systems 1: 495-502.