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Evolution v. Intelligent Design. Do We Teach the Controversy?. Michael J. Bruno January 12, 2005. The Origin of Doubt.
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Evolution v. Intelligent Design Do We Teach the Controversy? Michael J. Bruno January 12, 2005
The Origin of Doubt • “If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.” • Charles Darwin “The Origin of Species”
What Is Science? • is liable to be falsified by data • is tested by observation and experiment • makes predictions
Biology ≠ Physics • Retrodiction v. prediction • Stability v. instability • Short-term v. long-term ≠
The Scientific Method • Conjecture – a judgment based on inconclusive or incomplete evidence • Hypothesis - a tentative explanation that accounts for a set of facts • Theory - a set of statements or principles devised to explain a group of facts or phenomena
The Scientific Method 1. Observation and description of a phenomenon 2. Formulation of an hypothesis to explain the phenomena 3. Use of the hypothesis to predict the existence of other phenomena 4. Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments
What Did Darwin Say? • All organisms descended from a common ancestor • The mechanism by which they descended is natural selection
Neo-Darwinism: A Modern Synthesis of Genetics and Evolution • Several mechanisms of evolution • Natural selection • Genetic drift • Common descent • Population variation due to allelic differences in genes • Speciation due to gradual accumulation of genetic changes • Punctuated equilbrium • Microevolution v. macroevolution
Evolution of Darwinism Date Stage Modification 1883-1886 Weismann End of soft inheritance; diploidy and genetic recombination recognized 1900 Mendelism Genetic constancy accepted and blending inheritance rejected 1918-1933 Fisherism Evolution considered to be a matter of gene frequencies and the force of even small selection pressures 1936-1947 Evolutionary Population thinking emphasized; interest in the synthesis evolution of diversity, geographic speciation, variable evolutionary rates 1947-1972 Post-Synthesis Individual increasingly seen as target of selection; a more holistic approach; increased recognition of chance and constraints 1954-1972 Punctuated equilibria Importance of speciational evolution 1969-1980 Rediscovery of Importance of reproductive success for selection sexual selection
Arguments of Intelligent Design • Evolution has never been observed • Evolution defies the 2nd Law of Thermodynamics • Lack of transitional fossils • Life could not have arisen or proceeded by random chance alone • Evolution is only a theory; it has not been proved
Irreducible Complexity • Biochemical evidence for design • Several well-matched, integrating parts • All parts contribute to the function • Structure ceases to work when one of the parts is removed
Irreducible Complexity • Biochemical evidence for design • Several well-matched, integrating parts • All parts contribute to the function • Structure ceases to work when one of the parts is removed
Irreducible Complexity "An irreducibly complex system cannot be produced directly by numerous, successive, slight modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional.” -Michael Behe, Darwin’s Black Box
Evolution: Grand Unifying Theory • Replication • Heredity • Catalysis • Metabolism
Evidence of Transitional Fossils The Legged Seacow:
Molecular Evidence for Evolution • Pseudogenes • Functional redundancy • Transposable elements • Mechanism of punctuated equilbria
Transposition, the Immune System and Irreducible Complexity • V(D)J Recombination • Three Basic “Parts” • RAG proteins • Recombination signal sequences (RSS) • Antibody-encoding genes • Transposons have RAG-like proteins and RSSs
Questions to Ponder • Is ID theory creationism or science? • Is ID Theory even a theory? • Has irreducible complexity actually been discredited? • Is it too early to discuss ID in schools?