The Evolution of Animals. A Brief History of Evolutionary Thinking

Transcription

1 The Evolution of Animals A Brief History of Evolutionary Thinking

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4 Figure 01.07b

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29 Early Viewpoints about Diversity The prevailing view for most of history in the "educated civilized world" was that all species were created, perfect, & immutable. What is immutable? The concept is traceable to the Greek philosopher Aristotle & has been kept alive by judeo-christian teachings.

30 Two 18 th century, church doctrines (that are alive & well today!!) 1) Separate Creation - all creatures have been created independently of one another by God and organized into a hierarchy ("chain of being") with Man occupying the most elevated rank beneath God. 2) 6,000 year limit on the age of the planet.

31 But things were being found disturbing things.

32 Fossils from the Burgess Shale

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35 Fossils were difficult to dismiss Thinkers began doubting separate creation & immutability

36 So who discovered evolution? NOT DARWIN!! Not any one person

37 France was a hotspot of research and thought about animals and their diversity: Buffon Lamarck Cuvier English scientists were also important: Malthus Lyell Wallace Darwin

38 Georges-Louis Leclerc, Comte de Buffon ( ) 100 years before Darwin, Buffon, in his Historie Naturelle, a 44 volume encyclopedia describing everything known about the natural world, wrestled with the similarities of humans and apes and even talked about common ancestry of Man and apes. Although Buffon believed in organic change, he did not provide a coherent mechanism Buffon also published Les Epoques de la Nature (1788) where he openly suggested that the planet was much older than the 6,000 years proclaimed by the church.

39 Jean-Baptiste Lamarck ( ) "Do we not therefore perceive that by the action of the laws of organization... nature has in favorable times, places, and climates multiplied her first germs of animality, given place to developments of their organizations,... and increased and diversified their organs? Then... aided by much time and by a slow but constant diversity of circumstances, she has gradually brought about in this respect the state of things which we now observe. How grand is this consideration, and especially how remote is it from all that is generally thought on this subject!" Text of a lecture given by Lamarck at the Musée National d'histoire Naturelle, Paris, May 1803

40 Lamarck proposed an evolutionary mechanism: Inheritance of Acquired Characteristics Lamarck s First Law: use or disuse causes structures to enlarge or shrink. Lamarck's "Second Law" stated that all such changes were heritable. Results of Laws 1 & 2 -- continuous, gradual change of all organisms, as they became adapted to their environments.

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42 Lamarcks s theory is called transformational Darwin s theory is called variational What does this mean?

43 Side-Note Grandfather Erasmus Darwin also proposed a use/disuse model of evolutionary change. Erasmus Darwin and Lamarck overlapped in time, but did not know of each others thinking.

44 MYTH Darwin Discovered Evolution

45 Darwin s Contribution: EVOLUTION by NATURAL SELECTION

46 CLASS: Take 5 min & summarize Darwin s concept of Evolution by Natural Selection

47 KEY TO DARWIN S THINKING Thomas Malthus ( ) "In October 1838, that is, fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long- continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work". Charles Darwin, from his autobiography (1876)

48 Malthus political economist Essay on the Principle of Population produced The Malthusian Doctrine Malthus focused on 2 unquenchable hungers : * Needing/Wanting Food * Needing/Wanting sex Humans can t control either!!

49 Essence of Malthus: Population increases geometrically while the means of subsistence increases arithmetically. Geometric Increase of People dn = rn dt N = population size r = rate of increase (= births deaths) N t = N o e rt N o = beginning pop size

50 Arithmetic Increase of Food df = k dt F t = F o + kt

51 geometric increase arithmetic increase

52 Malthus

53 In the world of Malthus, human population size seemed stable How? Why? War, famine, and disease provide the checks on population growth.

54 QUESTION: In 2010, is Malthus still valid?

55 The Path of Charles Darwin Career attempt 1: Med School Career attempt 2: The Ministry Career attempt 3: Naturalist (scientist)

56 Age 22: Set sail on the Beagle returned 5 years later with radical ideas.

57 Great Book: The Voyage of the Beagle

58 Darwin Characteristics Ultra-cautious Deliberate Thorough Systematic Sickly Fearful of public & church reaction

59 This book rocked the world in 1859 most Western civilized countries have come to terms with it. One country has not. The USA Why??

60 The book did 2 things: ** It convinced many people that evolution has happened. A massive book of evidence that crushed the concept of immutability. Instead SLOW CHANGE! ** It proposed a mechanism.

61 A cottage industry of Darwin caricature began with the publication of Origin.

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63 Figure 06.14

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68 Evolution by Natural Selection Know This!!

69 I hardly know whether I at first felt more vexed at the solution not having occurred to me, than pleased that it had been found at all Alfred Newton How extremely stupid not to have thought of that. T.H. Huxley I coulda dunnit easy piece a cake! B. Rehnberg

70 All Animals Have Excessive Reproductive Capacity 750 years 2 elephants 19,000,000 elephants 5 months 2 houseflies 191 x houseflies 48 hours 1 bacterium bacteria cover the earth to a depth of 7 feet 2 humans?? FROM MALTHUS!

71 Anatomical Variability FROM OBSERVATIONS ON THE BEAGLE

72 Physiological Variability

73 Biochemical Variability Behavioral Variability Immunological Variability etc. etc.

74 Survival Advantage??

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80 How many have heard of Alfred Wallace?

81 Wallace was 14 years younger than Darwin. Grew up relatively poor and could not go to college. While working as a surveyor, he began to develop an interest in natural history. Few jobs in England.. few career options he became a collector.

82 He launched two large-scale collecting expeditions: 1) Amazon River basin -- set sail at age 25! 2) South Pacific (Malay Archipelago). Animal diversity shocked him! Started thinking.

83 Caught malaria high fever hallucinations his thoughts turned to Malthus!! Light bulb!! Concept of natural selection popped into his head. 1 week later, a manuscript was on a ship to England. Who did Wallace send it to??? To Darwin!!!

84 Imagine the horror of June 18, 1858 when Darwin opened that letter. 10 days later, Darwin s baby boy, Charles, died of scarlet fever. He was a crushed man. Darwin gave Wallace s letter and ms to Charles Lyell the rest is happy history. Joint Wallace/Darwin paper was read in Darwin waited almost 20 years to publish his ideas - why??

85 Darwin Characteristics Ultra-cautious Deliberate Thorough Systematic Sickly Fearful of public & church reaction

86 Fast forward 146 years Kent, England York County, Pennsylvania Dover school board rejects a popular high school biology text because it is laced with Darwinism

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90 The Evolution of an Idea Creationism Scientific Creationism Intelligent Design Fair and Balanced Treatment in Public Schools??

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92 What is it about the United States? No other advanced country is going through evolution agony. Why us?

93 New Pub: Answers Research Journal a free online journal devoted to research on recent Creation and the global Flood within a biblical framework. Papers will be peer-reviewed by those who support the positions taken by the journal. (!!!)

94 The End

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