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It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting.

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Presentation on theme: "It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting."— Presentation transcript:

1 It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.... There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved. Parts of last paragraph of Charles Darwins, Origin of Species by Means of Natural Selection or the Preservation of Favored Races in the Struggle for Life Sixth Edition, January 1872

2 12 shirts 1 carpet bag 1 pair slippers 1 pair of light walking shoes 1 microscope (a single lens model by Bancks & Son, London) 1 geological compass 1 plain compass 2 pistols (with spare parts) 1 rifle (with spare parts) 1 telescope 1 pencil case 1 geological hammer 5 simisometers 3 mountain barometers 1 clinometer 1 camera obscura 1 hygrometer (belonged to FitzRoy) 1 taxidermy book 2-3 Spanish language books 14 other books, including Humboldt's "Personal Narrative" and Lyell's "Principles of Geology Vol. 1" 1 coin purse (Fanny Owen's gift) 1 pin with a lock of Sarah Owen's hair (Fanny's sister)Lyell's Voyage of the Beagle

3 © AboutDarwin.com © AboutDarwin.com (good link) Voyage of the Beagle

4 Fig 22.5 Voyage of the Beagle

5 Home again Sand Walk, site of much of Darwins contemplation Down House, in Downe, Kentshire, England, south of London. Darwins home from 1842 to 1882

6 Alfred Wallace British naturalist letter from West Indies with article to review for Darwin to forward to geologist, Lyell Proposed theory of evolution identical to the one Darwin was working on

7 Darwin Publishes Origin of Species presented later in 1858 (32 years after then end of his voyage) and published 1 st in 1859 Both men jointly presented their ideas to the London Philospophical Society

8 The Origin of Species Evolution is the explanation for lifes unity and diversity Natural selection is the mechanism What evidence did Darwin draw on?

9 Reproductive potential Species have great potential powers of reproduction Populations would increase exponentially if all individuals survived and reproduced

10 Populations are stable But populations tend to remain stable over time Except for seasonal fluctuations Moose population on island in Lake Superior

11 Limited resources Environmental resources are limited Discussion in Malthus, Essay on the Principle of Population helped clarify this Lucky Lynx and its 1 hare

12 Observation 4 Individuals in a population vary extensively

13 Variation is inherited Much of this variation is heritable However, Darwin did not know the mechanism

14 Adaptation Organisms are adapted to their environments A floral mantid on a flower. Please look at the entire figure in the text

15 Artificial selection Of plants and animals by humans Vegetables selected by humans from wild kole

16 Other evidence Homologous structures Forearm bones in mammals

17 Biogeography Adaptive radiation of Australian marsupials compared to similarities among other mammals

18 Fossils Fossil Trilobites Elephant evolution based on fossils

19 Charles Darwins Legacy (a selection of his writing) Journal of Researches into the Natural History and Geology of the countries visited during the voyage round the world of H.M.S. Beagle On the origin of species by means of natural selection On the various contrivances by which British and foreign orchids are fertilised The variation of animals and plants under domestication The descent of man and selection in relation to sex The expression of the emotions in man and animals The effects of cross and self fertilisation in the vegetable kingdom The formation of vegetable mould, through the action of worms John van Wyhes web site with links to web copies of all of Charles Darwins writings

20 Darwins mechanism Natural selection Four conditions *Populations of species vary in their characters *Some of the aspects governing the characters are heritable *More offspring produced than can be supported by resources *Those best able to cope (= reach reproductive age) leave the most offspring

21 Darwins mechanism Net result – survival of the fittest *best adaptive characteristics survive *least adaptive perish *in next generation populations of the species What is needed? *populations (individuals dont evolve) *environments *time – lots of time


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