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].

Darwin’s Expedition 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

Sudden Appearance of Complex Life Lack of Clear Transitional Forms Gives More Evidence For Species Disappearance Limitations of the Fossil Record Chicago Daily News negatives collection, DN Courtesy of the Chicago Historical Society. American Memory Collection

Sudden Appearance of Complex Life Lack of Clear Transitional Forms Gives More Evidence For Species Disappearance Explanation of Strata Insufficient Limitations of the Fossil Record

Bryce Canyon, Utah Fossils on Display Western History/Genealogy Department, Denver Public Library, American Memory Collection

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 American Environmental Photographs Collection, [AEP Image Number, e.g., AEP-WYS32], Department of Special Collections, University of Chicago Library, American Memory Collection. Vertical Fossil Trees

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.