"Darwinism...we mean evolution by (means of) natural selection"

 Darwin replaced earlier belief with at least five theories the last of which is natural selection.

pp. 36-37


 

Darwin's separate contributions to biological thought

previous ideas in Natural History replacement by Darwinians general term
1 static world of no extinctions dynamic with extinctions normal "evolution"
2 common special creation common descent from parent species speciation 
3 fixity of species (never change) multiplication of species adaptive radiation
4 catastrophism gradualism uniformitarian
5 creative selection natural selection survival of the fittest

 
 Examples:

1    fossils of trilobytes
2    finches (mocking birds) , tortoises, pines
3    manatees, sea turtles, mangrove forests
4    Mt. St. Helens, White Pine Forest succession to beech and maple hardwoods
5    bacterial and insect resistance 


 Definition of natural selection as a

One step vs. two-step process 

1) -- abundant genetic variation every generation;

2) -- limited survival of the offspring who reproduce.

 "mechanism of adaptive change"

harmony and adaptability of the organic world 68

 Is it "an essentially mechanical explanation." ?

"Yes, in that it is a material and physical examination of natural change and variation and is not metaphysical.
He accounts for variation in terms of "survival of the fortunate."
 



Numerate

Darwin's idea forms the heart of the modern biological synthesis
 

Evolution  Genetics  modern synthesis
by means of natural selection cellular and molecular biology combine to form
naturalists Mendelians biology

individuals convey variation +
reproductive success to selection from among the survivors
abundant offspring not all variants are "hardy" in that they reproduce.

69

Population thinking:
 

Analog to animal and plant breeders is:
artificial selection to natural selection
humans select humans do not select
"breeding pairs" are selected vs. Differential survival


Literate

 There is no definitive answer to whether or not Darwin was externally influenced by his times (zeitgeist) and what he read, or was he influenced internally by his method of evaluating evidence he collected by contrasting and comparing his findings with practitioners and writers.

69.

After 1833-36 voyage he was, with some help of ornithologist John Gould in 1837, a determined "evolutionist" .... Gould upon reviewing the mocking birds Darwin had gathered from different islands in the Galapagos concluded that there wer three doifferent species where Darwin had originally conjectured there were only one species with three varieties.
 

What this meant was he had altered the status of human beings in the worldview of creation, natural history and biological thought.

 July, 1837, in Darwin's own mind,nature and human order were altered and thus his personal worldview became out of step with his fellow naturalists (asynchrony):

Darwin's five concepts.

Ernst Mayr One Long Argument (1991) Cambridge: Harvard U. Press. pages: 36. 37. 54-60. 69.

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Last Updated on 20-Dec-2006 .