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In What Sense Design? Biochemistry, Metabolism, & Life’s Origin Stephen M. Contakes Agenda 1. What’s the Big Deal? 2. Mainstream Science’s Explanation for Life 3. Intelligent Design’s Evaluation of the Data 4. Metabolism 5. A Suggested Way Forward Part 1 What’s the Big Deal? “Can you believe in God and Evolution?”: “…you cannot coherently affirm the Christian-truth claim and the dominant model of evolutionary theory at the same time. … Evangelicals must absolutely affirm the special creation of humans in God's image, with no physical evolution from any nonhuman species.” Albert Mohler, President, Southern Baptist Theological Seminary* Time, August 15, 2005. We no longer have to resort to superstition when faced with the deep problems: Is there a meaning to life? What are we for? What is man? After posing the last of these questions, the eminent zoologist G. G. Simpson put it thus: ‘The point I now want to make is that all attempts to answer that question before 1859 are worthless and that we will be better off if we ignore them completely.’ Richard Dawkins, The Selfish Gene Making Pronouncements “[evolution] has not published and so it should perish.” Michael Behe, Biochemist and Intelligent Design Proponent in Darwin’s Black Box, 1995 “…you cannot coherently affirm the Christian-truth claim and the dominant model of evolutionary theory at the same time. … Evangelicals must absolutely affirm the special creation of humans in God's image, with no physical evolution from any nonhuman species.” Albert Mohler, President, Southern Baptist Theological Seminary* *Quoted in Time, August 15, 2005. Making Pronouncements “a delusive and arbitrary hypothesis tending towards infidelity.” “…false, and entirely contrary to the Holy Scripture.” Making Pronouncements Can Sometimes Make Us Look Foolish “John Owen and John Wesley … rejected it as a delusive and arbitrary hypothesis tending towards infidelity.” Quoted in Schaff, Philip History of the Christian Church, vol. 8: the Swiss Reformation, 1882. “…false, and entirely contrary to the Holy Scripture.” Pope Paul V, 1616 These statements refer to the “Theory” that the Earth revolves around the Sun Can the Biblical creation accounts be interpreted in harmony with evolution? Yes. Interpretations of Genesis 1 & 2 that are consistent with naturalistic theories for Life’s origin do exist… … although they may not accord with the dominant understanding of these passages in Church history. But, Should the Biblical creation accounts be interpreted in harmony with evolution? Part 2 What is it we’re concerned about? Mainstream Science’s Explanation for Life How did modern life arise? Scientific Questions 1. How did living systems arise from nonliving matter? 2. How did modern life forms come into existence? How did modern life arise? Science’s Model 1. Chemical evolution How did simple molecules become biomolecules? 2. Self-Organization How were the biomolecules organized into a living system? 3. Biological evolution How did living systems attain their present form? Figure is taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004. How did modern life arise? Science’s Answers 1. Chemical evolution Don’t really know but have a few ideas 2. Self-Organization Don’t really know but have a few ideas 3. Biological evolution Evolutionary theory Figure is taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004. What is Evolution? Types of Evolution “Microevolution” Changes within a species – easily observed & reproducible “Macroevolution” divergence of two species from a common ancestor – not observed directly Original Darwinian view: Natural selection working on variation Explains diversity of species, extinction, etc.. in a rough way No convincing explanation of the underlying mechanism Modification by Classical Genetics Selection of genes is the underlying mechanism Seen as changes in allelic frequencies between generations Macroevolution/genes arise through chance mutations Darwin’s Theory has Explanatory Power Artificial Selection had already been observed in the breeding of animals Natural selection applied this principle to the distribution of species in different environments The figure at left is taken from www.evolution.berkeley.edu; that at right from http://focus.hms.harvard.edu/2006/090106/genetics.shtml Evolutionary Theory and Common Ancestry Key Idea All life arose from a common ancestor LUCA Last Universal Common Ancestor A “tree of life” can be constructed showing how life arose Notes Species present when divergence occurred are called common ancestors A common ancestor isn’t strictly necessary for “macroevolution” to be true LUCA Figure is taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004. Biochemistry & Molecular Biology Expand the Picture Molecular Biology Biochemistry Genes are DNA sequences that encode for functional molecules i.e. molecules encode information behind life Most organisms are similar at the molecular level organism organ tissues molecules molecular assemblies Figures are taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004. cells sub-cellular organelles Molecular Evolution Protein and gene sequences contain embedded information about evolutionary history Assumptions: Organisms evolved from common ancestors by altering those ancestor’s protein and gene sequences. Key idea: Look at the sequence of the same protein from different species. The number and location of differences relates to how long ago the two species diverged from a common ancestor. e.g. comparison of Myoglobin and the Hemoglobin a chain: Figure is taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004. Differences Accumulate over time The # of differences between sequences increases linearly with “time since divergence” from the fossil record Most differences don’t matter i.e. don’t affect molecular function Probably evolutionary accidents # of differences per 100 amino acids What does Molecular Evolution Tell Us? Millions of years since divergence (estimated from the fossil record) Selecting out the bad occurs more often than selecting for the good If your molecules don’t work you die, if they work better, you have a slightly greater chance of reproducing You can only get new function if you first copy the gene This lets you keep the old design while you tinker with a new one Figure is taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004 and is based on Dickerson, R. E. The structures of cytochrome c and their rates of molecular evolution. J Mol Evol. 1971;1(1):26–45. For more information see: Kimura, M; Tomoko Ohta, T. Proc Natl Acad Sci U S A. 1974 July; 71(7): 2848–2852. Gene Duplication is Believed to be A Major Mechanism for Molecular Evolution The figure is taken from Fenchel, T. Origin and Early Evolution of Life., Oxford, 2002. Molecular Evolution and Genome Sequencing Support Gene Duplication Taken from Cornish-Bowden, A. The Pursuit of Perfection: Biochemical Aspects of Evolution, Oxford, 2004. Part 3 Intelligent Design’s Evaluation of the Biochemical Data Intelligent Design (ID): “the Biochemical Challenge to Evolution”? "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. But I can find out no such case.” Charles Darwin, The Origin of Species Intelligent Design (ID): “The Biochemical Challenge to Evolution”? Irreducible Complexity = Designer • Numerous cellular components are irreducibly complex i.e. loss or malfunction of one component leads to loss of function • Consequently, they couldn’t have arisen by adaption • So life must have been designed by a designer The image at lower left is from Voet, D; Voet, J.; Biochemistry,3rd ed., Wiley, 2004. Examples of “Irreducibly Complex” Systems Bacterial Flagella The Blood-Clotting Cascade Images are from Voet, D; Voet, J.; Biochemistry,3rd ed., Wiley, 2004 and Voet, D; Voet, J.; & Pratt Fundamentals of Biochemistry, Wiley, 2004. How did modern life arise? ID’s Answers 1. Chemical evolution • No reasonable naturalistic explanation • “Best explanation” a designer 2. Self-Organization • No reasonable naturalistic explanation • “Best explanation” a designer 3. Biological evolution • Microevolution is OK • Evolution hasn’t really explained the origin of cells and higher-level structures • “Best explanation” a designer Figure is taken from Voet, D.; Voet, J. G. Biochemistry , 3rd ed., Wiley, 2004. Is ID Science? What is science? How Science works today: Methodological Naturalism Philosophical Naturalism/Scientism Only the physical world exists and everything can be explained in terms of naturalistic explanations. God does not exist. Methodological Naturalism Science advances by looking for natural causes to explain phenomena. The supernatural cannot be invoked as an explanation. Science, fundamentally, is a game. It is a game with one overriding and defining rule. Rule No. 1: Let us see how far and to what extent we can explain the behavior of the physical and material universe in terms of purely physical and material causes, without invoking the supernatural. Dickerson, R. E. Perspectives on Science and Faith, 1992, 44,137. What is Science? Who should decide? The final point I want to make about Richard Dickerson’s argument is that although he certainly didn’t intend it, it is a prescription for timidity. It tries to restrict science to more of the same, disallowing a fundamentally different explanation. It tries to place reality in a tiny box, but the universe will not be placed in a box... Behe, M. Darwins Black Box, Free Press, 1996. Science, fundamentally, is a game. It is a game with one overriding and defining rule. Rule No. 1: Let us see how far and to what extent we can explain the behavior of the physical and material universe in terms of purely physical and material causes, without invoking the supernatural. Dickerson, R. E. Perspectives on Science and Faith, 1992, 44,137. Is the Flagellum Irreducibly Complex? Bacterial Flagellum Type III Secretory Pathway Key Idea: The type III secretory pathway looks like a flagella without the filament It is a plausible evolutionary precursor for the flagellum ID response: But it doesn’t work as a flagellum It doesn’t fully explain the evolution of the flagellum Images reproduced from Dembski, W.; Ruse, M. Debating Design, Oxford, 2004. Part 4 Metabolism & ID Metabolism: the Ultimate in Irreducible Complexity Metabolism Sum of all chemical reactions an organism uses to: • obtain & use energy • grow • sustain itself • reproduce Simplified Diagram of the Metabolic Pathways in a Typical Cell → All the reactions are interconnected!!! i.e. they depend on one another The figure is taken from Voet, Voet, Pratt Fundamentals of Biochemistry 2nd ed., Wiley, 2004. Metabolism Made Simple Catabolism Example – Aerobic metabolism of glucose • Fuel is “burned” to make energy: Food & energy store oxidation gives electrons + Reduction of an electron acceptor to give energy Anabolism • Energy is used to make biomolecules: Use electrons and energy from catabolism to make biomolecules C6H12O6 + 6 O2 → 6 CO2 + 6 H2O C6H12O6 + 3 O2 → 3 ATP + 6 CO2 + 12 e+ 12 e- + 3 O2 + 12 H+ → 6 H2O + ~30 ATP Metabolism Made Slightly Less Simple Food & energy stores ATP (energy) and NADH (electrons) Acetyl-CoA NADH (electrons) and GTP (energy) CO2 NADH (electrons) O2 H 2O The figure is adapted from Voet, Voet, Pratt Fundamentals of Biochemistry 2nd ed., Wiley, 2004. Is the Citric Acid Cycle “Irreducibly Complex”? Modern Aerobic Metabolism glucose Glycolysis Glucose → 2 pyruvate pyruvate Acetyl-CoA Synthesis pyruvate → Acetyl-CoA + CO2 Acetyl-CoA Citric Acid Cycle CO2 CO2 Citric Acid Cycle Result: Acetyl group → 2 CO2 Figures are adapted from Fenchel, T. Origin and Early Evolution of Life., Oxford, 2002 & Voet, Voet, Pratt Fundamentals of Biochemistry, 2nd ed. Wiley, 2004. Is the Citric Acid Cycle “Irreducibly Complex”? Modern Aerobic Metabolism glucose Glycolysis Glucose → 2 pyruvate Many “Ancient” Prokaryotes only have part of the Citric Acid Cycle The “reductive branch” is run in reverse to recover electrons from fermentations pyruvate Acetyl-CoA Synthesis pyruvate → Acetyl-CoA + CO2 Acetyl-CoA Citric Acid Cycle CO2 CO2 Citric Acid Cycle Result: Acetyl group → 2 CO2 Figures are adapted from Fenchel, T. Origin and Early Evolution of Life., Oxford, 2002 & Voet, Voet, Pratt Fundamentals of Biochemistry, 2nd ed. Wiley, 2004. Is the Citric Acid Cycle “Irreducibly Complex”? Modern Aerobic Metabolism glucose Glycolysis Glucose → 2 pyruvate Many prokaryotes only have part of the Citric Acid Cycle and/or the “oxidative branch” is run forward in some modern prokaryotes grown anaerobically pyruvate Acetyl-CoA Synthesis pyruvate → Acetyl-CoA + CO2 Acetyl-CoA Citric Acid Cycle CO2 CO2 Citric Acid Cycle Result: Acetyl group → 2 CO2 Figures are adapted from Fenchel, T. Origin and Early Evolution of Life., Oxford, 2002 & Voet, Voet, Pratt Fundamentals of Biochemistry, 2nd ed. Wiley, 2004. Is the Citric Acid Cycle “Irreducibly Complex”? Modern Aerobic Metabolism glucose A Reverse Citric Acid Cycle could have been used to “fix” carbon Glycolysis Glucose → 2 pyruvate Some deeply-rooted Archea actually run the cycle in reverse pyruvate Acetyl-CoA Synthesis pyruvate → Acetyl-CoA + CO2 Biosynthesis Acetyl-CoA Acetyl-CoA Citric Acid Cycle CO2 Reversed Citric Acid Cycle CO2 CO2 Citric Acid Cycle Result: Acetyl group → 2 CO2 CO2 2 CO2 → Acetyl group Figures are adapted from Fenchel, T. Origin and Early Evolution of Life., Oxford, 2002. Part 5 A Suggested Way Forward ? Possible Implications for an ID-based Faith Short-term No real effect or a slight loss of credibility with most scientists Danger of subjugating Christianity to a particular science-based worldview Possible long-term effects Nothing – if no credible evolutionary pathways will be discovered ID’s “god of the gaps” will shrink if credible evolutionary pathways are discovered Possible loss of faith if “irreducible complexity” and ID collapse due to the discovery of highly-credible evolutionary pathways Possible Implications for Accepting Evolution Short-term No real effect/loss of credibility with some Christians Danger of subjugating our faith to a particular science-based worldview Must face implications of evolution for our understanding of God & the nature of Biblical revelation Possible long-term effects You will have to rethink your theology if future work eliminates evolution as a scientific possibility Nothing - if credible evolutionary pathways are discovered Lessons from History Natural Theology & William Paley’s Watch … if the different parts had been differently shaped from what they are, of a different size from what they are, or placed after any other manner or in any other order than that in which they are placed, either no motion at all would have been carried on in the machine, or none which would have answered the use that is now served by it. William Paley, Natural Theology, 1800 Natural Theology at the Bar of History “…whether natural theology, by claiming so much authority from science, might not have dug its own grave…had Christian apologists not placed too great a burden on arguments from design? … In fact, it would be a great mistake to imagine that when the kind of phsico-theology we have been considering finally collapsed, it came as a shock and embarrassment to every sector of the Christian church. The vicissitudes of a science-based natural theology were arousing anxieties in Britain from the earlier years of the nineteenth century.” John Hedley Brooke* *in Science and Religion: Some Historical Perspectives, Cambridge, 1991. Perspectives to Consider One Scientist’s: Philosophically sophisticated people know that a “scientific” attack upon religious belief is usually no less faulty than a defense of it. Scientists do not speak on religion from a privileged position except insofar as those with a predilection for the Argument from Design have better opportunities than laymen to see the grandeur of the natural order of things, whatever they may make of it. P. B. Medawar, Advice to a Young Scientist One Theologian’s: In matters that are so obscure and far beyond our vision, we find in Holy Scripture passages than can be interpreted in very different ways without prejudice to the faith we have received. In such cases we should not rush in headlong and so firmly take our stand on one side that, if further progress in the search for truth justly undermines our position, we too fall with it. Augustine of Hippo, On the Literal Meaning of Genesis* *quoted by Francis Collins in The Language of God. Intelligent Design or “Evolution”? We should consider our answer with carefulness, humility, & intellectual integrity For we know in part and we prophesy in part, but when the perfect comes, the partial will pass away. … For now we see in a mirror dimly, but then face to face. Now I know if part; then I shall know fully, even as I have been fully known. Paul the Apostle, 1 Cor 13:9-10,12 *quoted in Williams, R.J.P.; daSilva J.J.R.F. The Natural Selection of the Chemical Elements, Oxford: 1996. Acknowledgements Bioc 380/381 Students, Fall 2006 – Spring 2007 Prof. Josh Morris, Azusa Pacific University Prof. Sarah Richart, Azusa Pacific University