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Charles Darwin and His Origin of Species. Darwin’s Background. Born in England, 1809 Studied Medicine at Edinburgh University Transferred to Cambridge University Studied to be a Minister. Library of Congress, Prints and Photographs Division [reproduction number, e.g., LC-USZ61-104].
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Darwin’s Background • Born in England, 1809 • Studied Medicine at Edinburgh University • Transferred to Cambridge University • Studied to be a Minister Library of Congress, Prints and Photographs Division [reproduction number, e.g., LC-USZ61-104].
Darwin’s Expedition - 1831 • Hired as Naturalist on H.M.S. Beagle • Sailed on Five Year Scientific Expedition • Down East Coast of South America • Up Pacific Coast to Galapagos Islands • Made Stops on Mainland and Islands • Observed Variety of Life and Habitats
Darwin’s Work • Outlined Theory in his Book in 1859: • On the Origin of Species by Means of Natural Selection • Published Other Works on Biology • Died in 1882
Summary of Origin of Species • Proposed Evolution Resulting from Natural Selection: • Organisms Produce Many Offspring • Competition for Food, Territory, Mates, etc. • Those With Best Traits Survive • Organisms Change Over Many Generations • Time Frame: Millions of Years
Darwin’s Support for His Theory • Characteristics of Organisms Coincide With Habitats • Changes Produced by Breeding of Organisms • Geologic Ages Suggested by Charles Lyell • Similarities of Various Organisms
Limitations of Darwin’s Theory • Apparent Limits to Variation • No Mechanism For Sufficiently New Characteristics • Transitional Forms Would Require Special Environments • Oversimplified View of Living Cells • The Origin of Life Unexplained • Limitations of Fossil Record
Chicago Daily News negatives collection, DN-0006585. Courtesy of the Chicago Historical Society. American Memory Collection Limitations of the Fossil Record • Sudden Appearance of Complex Life • Lack of Clear Transitional Forms • Gives More Evidence For Species Disappearance
Limitations of the Fossil Record • Sudden Appearance of Complex Life • Lack of Clear Transitional Forms • Gives More Evidence For Species Disappearance • Explanation of Strata Insufficient
Bryce Canyon, Utah Fossils on Display Western History/Genealogy Department, Denver Public Library, American Memory Collection Limitations of the Fossil Record
Strata Better Explained by Hydrologic Catastrophe • Magnitude of Fossil Graveyards
Strata Better Explained by Hydrologic Catastrophe Petrified forest American Environmental Photographs Collection, [AEP Image Number, e.g., AEP-AZS8], Department of Special Collections, University of Chicago Library, American Memory Collection.
Strata Better Explained by Hydrologic Catastrophe • Magnitude of Fossil Graveyards • Polystrate Fossils
Strata Better Explained by Hydrologic Catastrophe Vertical Fossil Trees American Environmental Photographs Collection, [AEP Image Number, e.g., AEP-WYS32], Department of Special Collections, University of Chicago Library, American Memory Collection.
Strata Better Explained by Hydrologic Catastrophe • Magnitude of Fossil Graveyards • Polystrate Fossils • Inconsistent Fossil Distribution
Strata Better Explained by Hydrologic Catastrophe • Magnitude of Fossil Graveyards • Polystrate Fossils • Inconsistent Fossil Distribution • Fossils Found Together From Separate Ages
Strata Better Explained by Hydrologic Catastrophe • Magnitude of Fossil Graveyards • Polystrate Fossils • Inconsistent Fossil Distribution • Fossils Found Together From Separate Ages • Simple (“Older”) Organisms Above Complex (“Younger”)
Scientists’ Initial Reactions to Darwin’s Work • A Compilation of Assertions and Hypotheses • Unsupported by Scientific Testing • Contains Assumptions that Cannot Be Supported • Violates the Principles of Cause and Effect • Illogical Conclusions
So Why Was It Eventually Accepted? • It Passed Rigorous Scientific Testing? • No, His Hypotheses Are Not Testable • Were Transitional Fossils Found? • No Clearly Substantiated Links Found Yet • A Mechanism to Produce New Traits Discovered? • Mutations Result in Lost Genetic Information
The Acceptance of Darwin’s Theory of Evolution • Natural Selection of Genetic Variations is Observable • Limited to Genes Already Present • New Traits Produced Only By Mutations • Overwhelming Odds Against Good Mutations
Ultimately, Acceptance Depended On One Factor: Willingness to Accept a Naturalistic Explanation
Credits • All clip art is from ClickArt by Broderbund • All photographs were accessed through the Library of Congress American Memory Collection. • The Darwin photograph is from Library of Congress, Prints and Photographs Division. • The dinosaur fossil photo is from the Chicago Daily News negatives collection, Courtesy of the Chicago Historical Society. • The Bryce Canyon and fossil display photos are from the Western History/Genealogy Department, Denver Public Library. • The fossil trees and Petrified Forest photos are from the American Environmental Photographs Collection, Department of Special Collections, University of Chicago Library.