Monday 9 June 2014
On mathematics and Darwinism II
A Mathematician's View of Evolution
Granville Sewell
In 1996, Lehigh University biochemist Michael Behe published a book
entitled "Darwin's Black Box" [Free Press], whose central theme is
that every living cell is loaded with features and biochemical processes
which are "irreducibly complex"--that is, they require the existence of
numerous complex components, each essential for function. Thus, these
features and processes cannot be explained by gradual Darwinian
improvements, because until all the components are in place, these
assemblages are completely useless, and thus provide no selective
advantage. Behe spends over 100 pages describing some of these
irreducibly complex biochemical systems in detail, then summarizes the
results of an exhaustive search of the biochemical literature for
Darwinian explanations. He concludes that while biochemistry texts
often pay lip-service to the idea that natural selection of random
mutations can explain everything in the cell, such claims are pure
"bluster", because "there is no publication in the scientific literature
that describes how molecular evolution of any real, complex, biochemical
system either did occur or even might have occurred."
When Dr. Behe was at the University of Texas El Paso in May of 1997
to give an invited talk, I told him that I thought he would find
more support for his ideas in mathematics, physics and computer
science departments than in his own field. I know a good many
mathematicians, physicists and computer scientists who, like me, are
appalled that Darwin's explanation for the development of life is so
widely accepted in the life sciences. Few of them ever speak out or
write on this issue, however--perhaps because they feel the question is
simply out of their domain. However, I believe there are two central
arguments against Darwinism, and both seem to be most readily appreciated
by those in the more mathematical sciences.
- The cornerstone of Darwinism is the idea that major (complex)
improvements can be built up through many minor improvements;
that the new organs and new systems of organs which gave rise to
new orders, classes and phyla developed gradually, through many
very minor improvements. We should first note that the fossil
record does not support this idea, for example, Harvard paleontologist
George Gaylord Simpson ["The History of Life," in Volume I of
"Evolution after Darwin," University of Chicago Press, 1960] writes:
"It is a feature of the known fossil record that most taxa appear abruptly. They are not, as a rule, led up to by a sequence of almost imperceptibly changing forerunners such as Darwin believed should be usual in evolution...This phenomenon becomes more universal and more intense as the hierarchy of categories is ascended. Gaps among known species are sporadic and often small. Gaps among known orders, classes and phyla are systematic and almost always large. These peculiarities of the record pose one of the most important theoretical problems in the whole history of life: Is the sudden appearance of higher categories a phenomenon of evolution or of the record only, due to sampling bias and other inadequacies?"
An April, 1982, Life Magazine article (excerpted from Francis Hitching's book, "The Neck of the Giraffe: Where Darwin Went Wrong") contains the following report:
"When you look for links between major groups of animals, they simply aren't there...'Instead of finding the gradual unfolding of life', writes David M. Raup, a curator of Chicago's Field Museum of Natural History, 'what geologists of Darwin's time and geologists of the present day actually find is a highly uneven or jerky record; that is, species appear in the fossil sequence very suddenly, show little or no change during their existence, then abruptly disappear.' These are not negligible gaps. They are periods, in all the major evolutionary transitions, when immense physiological changes had to take place."
Even among biologists, the idea that new organs, and thus higher categories, could develop gradually through tiny improvements has often been challenged. How could the "survival of the fittest" guide the development of new organs through their initial useless stages, during which they obviously present no selective advantage? (This is often referred to as the "problem of novelties".) Or guide the development of entire new systems, such as nervous, circulatory, digestive, respiratory and reproductive systems, which would require the simultaneous development of several new interdependent organs, none of which is useful, or provides any selective advantage, by itself? French biologist Jean Rostand, for example, wrote ["A Biologist's View," Wm. Heinemann Ltd. 1956]:
"It does not seem strictly impossible that mutations should have introduced into the animal kingdom the differences which exist between one species and the next...hence it is very tempting to lay also at their door the differences between classes, families and orders, and, in short, the whole of evolution. But it is obvious that such an extrapolation involves the gratuitous attribution to the mutations of the past of a magnitude and power of innovation much greater than is shown by those of today."
Behe's book is primarily a challenge to this cornerstone of Darwinism at the microscopic level. Although we may not be familiar with the complex biochemical systems discussed in this book, I believe mathematicians are well qualified to appreciate the general ideas involved. And although an analogy is only an analogy, perhaps the best way to understand Behe's argument is by comparing the development of the genetic code of life with the development of a computer program. Suppose an engineer attempts to design a structural analysis computer program, writing it in a machine language that is totally unknown to him. He simply types out random characters at his keyboard, and periodically runs tests on the program to recognize and select out chance improvements when they occur. The improvements are permanently incorporated into the program while the other changes are discarded. If our engineer continues this process of random changes and testing for a long enough time, could he eventually develop a sophisticated structural analysis program? (Of course, when intelligent humans decide what constitutes an "improvement", this is really artificial selection, so the analogy is far too generous.) If a billion engineers were to type at the rate of one random character per second, there is virtually no chance that any one of them would, given the 4.5 billion year age of the Earth to work on it, accidentally duplicate a given 20-character improvement. Thus our engineer cannot count on making any major improvements through chance alone. But could he not perhaps make progress through the accumulation of very small improvements? The Darwinist would presumably say, yes, but to anyone who has had minimal programming experience this idea is equally implausible. Major improvements to a computer program often require the addition or modification of hundreds of interdependent lines, no one of which makes any sense, or results in any improvement, when added by itself. Even the smallest improvements usually require adding several new lines. It is conceivable that a programmer unable to look ahead more than 5 or 6 characters at a time might be able to make some very slight improvements to a computer program, but it is inconceivable that he could design anything sophisticated without the ability to plan far ahead and to guide his changes toward that plan.
If archeologists of some future society were to unearth the many versions of my PDE solver, PDE2D , which I have produced over the last 20 years, they would certainly note a steady increase in complexity over time, and they would see many obvious similarities between each new version and the previous one. In the beginning it was only able to solve a single linear, steady-state, 2D equation in a polygonal region. Since then, PDE2D has developed many new abilities: it now solves nonlinear problems, time-dependent and eigenvalue problems, systems of simultaneous equations, and it now handles general curved 2D regions. Over the years, many new types of graphical output capabilities have evolved, and in 1991 it developed an interactive preprocessor, and more recently PDE2D has adapted to 3D and 1D problems. An archeologist attempting to explain the evolution of this computer program in terms of many tiny improvements might be puzzled to find that each of these major advances (new classes or phyla??) appeared suddenly in new versions; for example, the ability to solve 3D problems first appeared in version 4.0. Less major improvements (new families or orders??) appeared suddenly in new subversions, for example, the ability to solve 3D problems with periodic boundary conditions first appeared in version 5.6. In fact, the record of PDE2D's development would be similar to the fossil record, with large gaps where major new features appeared, and smaller gaps where minor ones appeared. That is because the multitude of intermediate programs between versions or subversions which the archeologist might expect to find never existed, because-- for example--none of the changes I made for edition 4.0 made any sense, or provided PDE2D any advantage whatever in solving 3D problems (or anything else) until hundreds of lines had been added.
Whether at the microscopic or macroscopic level, major, complex, evolutionary advances, involving new features (as opposed to minor, quantitative changes such as an increase in the length of the giraffe's neck1, or the darkening of the wings of a moth, which clearly could occur gradually) also involve the addition of many interrelated and interdependent pieces. These complex advances, like those made to computer programs, are not always "irreducibly complex"--sometimes there are intermediate useful stages. But just as major improvements to a computer program cannot be made 5 or 6 characters at a time, certainly no major evolutionary advance is reducible to a chain of tiny improvements, each small enough to be bridged by a single random mutation.
- The other point is very simple, but also seems to be appreciated only by more mathematically-oriented people. It is that to attribute the development of life on Earth to natural selection is to assign to it--and to it alone, of all known natural "forces"--the ability to violate the second law of thermodynamics and to cause order to arise from disorder. It is often argued that since the Earth is not a closed system--it receives energy from the Sun, for example-- the second law is not applicable in this case. It is true that order can increase locally, if the local increase is compensated by a decrease elsewhere, ie, an open system can be taken to a less probable state by importing order from outside. For example, we could transport a truckload of encyclopedias and computers to the moon, thereby increasing the order on the moon, without violating the second law. But the second law of thermodynamics--at least the underlying principle behind this law--simply says that natural forces do not cause extremely improbable things to happen2, and it is absurd to argue that because the Earth receives energy from the Sun, this principle was not violated here when the original rearrangement of atoms into encyclopedias and computers occurred. The biologist studies the details of natural history, and when he looks at the similarities between two species of butterflies, he is understandably reluctant to attribute the small differences to the supernatural. But the mathematician or physicist is likely to take the broader view. I imagine visiting the Earth when it was young and returning now to find highways with automobiles on them, airports with jet airplanes, and tall buildings full of complicated equipment, such as televisions, telephones and computers. Then I imagine the construction of a gigantic computer model which starts with the initial conditions on Earth 4 billion years ago and tries to simulate the effects that the four known forces of physics (the gravitational, electromagnetic and strong and weak nuclear forces) would have on every atom and every subatomic particle on our planet (perhaps using random number generators to model quantum uncertainties!). If we ran such a simulation out to the present day, would it predict that the basic forces of Nature would reorganize the basic particles of Nature into libraries full of encyclopedias, science texts and novels, nuclear power plants, aircraft carriers with supersonic jets parked on deck, and computers connected to laser printers, CRTs and keyboards? If we graphically displayed the positions of the atoms at the end of the simulation, would we find that cars and trucks had formed, or that supercomputers had arisen? Certainly we would not, and I do not believe that adding sunlight to the model would help much. Clearly something extremely improbable has happened here on our planet, with the origin and development of life, and especially with the development of human consciousness and creativity.
Sunday 8 June 2014
Thursday 5 June 2014
Logic and commonsense re:the design debate.I
A reproduction of the Watchtower Society's article.
Question 2
Question 2
Is Any Form of Life Really Simple?
Your body is one of the most complex structures in the universe. It is made up of some 100 trillion tiny cells—bone cells, blood cells, brain cells, to name a few.7 In fact, there are more than 200 different types of cells in your body.8
Despite their amazing diversity in shape and function, your cells form an intricate, integrated network. The Internet, with its millions of computers and high-speed data cables, is clumsy in comparison. No human invention can compete with the technical brilliance evident in even the most basic of cells. How did the cells that make up the human body come into existence?
What do many scientists claim? All living cells fall into two major categories—those with a nucleus and those without. Human, animal, and plant cells have a nucleus. Bacterial cells do not. Cells with a nucleus are called eukaryotic. Those without a nucleus are known as prokaryotic. Since prokaryotic cells are relatively less complex than eukaryotic cells, many believe that animal and plant cells must have evolved from bacterial cells.
In fact, many teach that for millions of years, some “simple” prokaryotic cells swallowed other cells but did not digest them. Instead, the theory goes, unintelligent “nature” figured out a way not only to make radical changes in the function of the ingested cells but also to keep the adapted cells inside of the “host” cell when it replicated.9*
What does the Bible say? The Bible states that life on earth is the product of an intelligent mind. Note the Bible’s clear logic: “Of course, every house is constructed by someone, but he that constructed all things is God.” (Hebrews 3:4) Another Bible passage says: “How many your works are, O Jehovah! All of them in wisdom you have made. The earth is full of your productions. . . . There are moving things without number, living creatures, small as well as great.”—Psalm 104:24, 25.
What does the evidence reveal? Advances in microbiology have made it possible to peer into the awe-inspiring interior of the simplest living prokaryotic cells known. Evolutionary scientists theorize that the first living cells must have looked something like these cells.10
If the theory of evolution is true, it should offer a plausible explanation of how the first “simple” cell formed by chance. On the other hand, if life was created, there should be evidence of ingenious design even in the smallest of creatures. Why not take a tour of a prokaryotic cell? As you do so, ask yourself whether such a cell could arise by chance.
THE CELL’S PROTECTIVE WALL
To tour a prokaryotic cell, you would have to shrink to a size that is hundreds of times smaller than the period at the end of this sentence. Keeping you out of the cell is a tough, flexible membrane that acts like a brick and mortar wall surrounding a factory. It would take some 10,000 layers of this membrane to equal the thickness of a sheet of paper. But the membrane of a cell is much more sophisticated than the brick wall. In what ways?
Like the wall surrounding a factory, the membrane of a cell shields the contents from a potentially hostile environment. However, the membrane is not solid; it allows the cell to “breathe,” permitting small molecules, such as oxygen, to pass in or out. But the membrane blocks more complex, potentially damaging molecules from entering without the cell’s permission. The membrane also prevents useful molecules from leaving the cell. How does the membrane manage such feats?
Think again of a factory. It might have security guards who monitor the products that enter and leave through the doorways in the factory wall. Similarly, the cell membrane has special protein molecules embedded in it that act like the doors and the security guards.
Some of these proteins (1) have a hole through the middle of them that allows only specific types of molecules in and out of the cell. Other proteins are open on one side of the cell membrane (2) and closed on the other. They have a docking site (3) shaped to fit a specific substance. When that substance docks, the other end of the protein opens and releases the cargo through the membrane (4). All this activity is happening on the surface of even the simplest of cells.
INSIDE THE FACTORY
Imagine that you have been allowed past the “security guard” and are now inside the cell. The interior of a prokaryotic cell is filled with a watery fluid that is rich in nutrients, salts, and other substances. The cell uses these raw ingredients to manufacture the products it needs. But the process is not haphazard. Like an efficiently run factory, the cell organizes thousands of chemical reactions so that they take place in a specific order and according to a set timetable.
A cell spends a lot of its time making proteins. How does it do so? First, you would see the cell make about 20 different basic building blocks called amino acids. These building blocks are delivered to the ribosomes (5), which may be likened to automated machines that link the amino acids in a precise order to form a specific protein. Just as the operations of a factory might be governed by a central computer program, many of the functions of a cell are governed by a “computer program,” or code, known as DNA (6). From the DNA, the ribosome receives a copy of detailed instructions that tell it which protein to build and how to build it (7).
What happens as the protein is made is nothing short of amazing! Each one folds into a unique three-dimensional shape (8). It is this shape that determines the specialized job that the protein will do.* Picture a production line where engine parts are being assembled. Each part needs to be precisely constructed if the engine is to work. Similarly, if a protein is not precisely constructed and folded to exactly the right shape, it will not be able to do its work properly and may even damage the cell.
How does the protein find its way from where it was made to where it is needed? Each protein the cell makes has a built-in “address tag” that ensures that the protein will be delivered to where it is needed. Although thousands of proteins are built and delivered each minute, each one arrives at the correct destination.
Why do these facts matter? The complex molecules in the simplest living thing cannot reproduce alone. Outside the cell, they break down. Inside the cell, they cannot reproduce without the help of other complex molecules. For example, enzymes are needed to produce a special energy molecule called adenosine triphosphate (ATP), but energy from ATP is needed to produce enzymes. Similarly, DNA (section 3 discusses this molecule) is required to make enzymes, but enzymes are required to make DNA. Also, other proteins can be made only by a cell, but a cell can be made only with proteins.*
Microbiologist Radu Popa does not agree with the Bible’s account of creation. Yet, in 2004 he asked: “How can nature make life if we failed with all the experimental conditions controlled?”13 He also stated: “The complexity of the mechanisms required for the functioning of a living cell is so large that a simultaneous emergence by chance seems impossible.”14
What do you think? The theory of evolution tries to account for the origin of life on earth without the necessity of divine intervention. However, the more that scientists discover about life, the less likely it appears that it could arise by chance. To sidestep this dilemma, some evolutionary scientists would like to make a distinction between the theory of evolution and the question of the origin of life. But does that sound reasonable to you?
The theory of evolution rests on the notion that a long series of fortunate accidents produced life to start with. It then proposes that another series of undirected accidents produced the astonishing diversity and complexity of all living things. However, if the foundation of the theory is missing, what happens to the other theories that are built on this assumption? Just as a skyscraper built without a foundation would collapse, a theory of evolution that cannot explain the origin of life will crumble.
After briefly considering the structure and function of a “simple” cell, what do you see—evidence of many accidents or proof of brilliant design? If you are still unsure, take a closer look at the “master program” that controls the functions of all cells.
[Footnotes]
No experimental evidence exists to show that such an event is possible.
Enzymes are one example of proteins made by cells. Each enzyme is folded in a special way to accelerate a particular chemical reaction. Hundreds of enzymes cooperate to regulate the cell’s activities.
Some of the cells in the human body are made up of about 10,000,000,000 protein molecules11 of several hundred thousand different kinds.12
[Box/Picture on page 11]
HOW FAST CAN A CELL REPRODUCE?
Some bacteria can make replicas of themselves within 20 minutes. Each cell copies all the controlling “computer programs.” Then it divides. If it had unlimited access to fuel, just one cell could increase in number exponentially. At that rate, it would take only two days to produce a clump of cells with a weight more than 2,500 times greater than that of the earth.15 Cells that are more complex can also replicate quickly. For example, when you were developing in your mother’s womb, new brain cells formed at the astounding rate of 250,000 per minute!16
Human manufacturers often have to sacrifice quality to produce an item at a fast pace. How is it possible, then, that cells can reproduce so fast and so accurately if they are the product of undirected accidents?
[Box on page 12]
FACTS AND QUESTIONS
▪ Fact: The extraordinarily complex molecules that make up a cell—DNA, RNA, proteins—seem designed to work together.
Question: What seems more likely to you? Did unintelligent evolution construct the intricate machines depicted on page 10, or were those machines the product of an intelligent mind?
▪ Fact: Some respected scientists say that even a “simple” cell is far too complex to have arisen by chance on earth.
Question: If some scientists are willing to speculate that life came from an extraterrestrial source, what is the basis for ruling out God as that Source?
[Diagram on page 10]
(For fully formatted text, see publication)
The cell membrane has “security guards” that allow only specific substances to pass in or out
[Diagram on page 10, 11]
(For fully formatted text, see publication)
The Cell “Factory”
How Proteins Are Made
Like an automated factory, the cell is full of machines that assemble and deliver complex products
[Pictures on page 8, 9]
Could the more than 200 different kinds of cells that make up your body really form by accident?
Brain cell
Eye cells
Bone cell
Muscle cells
Red blood cells
[Picture on page 9]
Could even a “simple” cell really arise from nonliving chemicals?
[Picture on page 12]
If this skyscraper must collapse because it has a flimsy foundation, must not the theory of evolution collapse because it has no explanation for the origin of life?
logic and commonsense re:the design debate.II
A reproduction of the Watchtower Society's article
Question 5
Is It Reasonable to Believe the Bible?
Question 5
Is It Reasonable to Believe the Bible?
Have you ever been misled about a person? Maybe you heard others talk about him or quote him. You expected to dislike him—only to find, on getting to know him, that he had been misrepresented. Many have had such an experience regarding the Bible.
More than a few educated people take a dim view of the Bible. Can you understand why? That book is often represented or quoted in such a way that it sounds unreasonable, unscientific, or just plain wrong. Is it possible that the Bible has been misrepresented?
In the course of reading this brochure, were you surprised to learn that what the Bible says is scientifically accurate? Many people are. They are equally surprised to learn that the Bible does not say some of the things that many religions claim that it says. Some say, for example, that the Bible teaches that God made the universe and all life in it within six 24-hour days. In fact, there is nothing in the Bible that contradicts scientists’ various estimates on the age of the universe or the earth.*
Furthermore, the Bible’s brief outline of how God brought life into being on this planet leaves ample room for scientific inquiry and theory. The Bible does state that God created all life and that living things are made “according to their kinds.” (Genesis 1:11, 21, 24) These statements may be at odds with certain scientific theories, but not with established scientific fact. The history of science shows that theories come and go; the facts remain.
There are many people, though, who hesitate to investigate the Bible because they are disillusioned with religion. They look at organized religion and see hypocrisy, corruption, warmongering. But is it fair to judge the Bible by the behavior of some who claim to represent it? Many humane and sincere scientists have been horrified by the way that some violent bigots have used the evolution theory to support their racist aims. Would it be fair to judge the theory of evolution on that basis? Surely it is better to investigate the theory’s claims and compare them with the available evidence.
We urge you to do the same with the Bible. You may be pleasantly surprised to learn how profoundly its teachings differ from those of most organized religions. Far from promoting wars and ethnic violence, the Bible teaches that God’s servants must repudiate war and even the hatred that leads to such violence. (Isaiah 2:2-4; Matthew 5:43, 44; 26:52) Far from advocating fanaticism and belief without evidence, the Bible teaches that evidence is essential to genuine faith and that the power of reason is an indispensable aid to serving God. (Romans 12:1; Hebrews 11:1) Far from squelching curiosity, the Bible encourages us to probe some of the most fascinating and challenging questions that humans have ever faced.
For example, have you ever wondered, ‘If there is a God, why does he allow wickedness?’ The Bible addresses that question, as well as many others, in a satisfying way.* We urge you to pursue your quest for truth. You can find answers that are fascinating, thrilling, reasonable—and based on convincing evidence. And that is no accident.
Bibliography
1. How Did Life Begin?
1. How Life Began—Evolution’s Three Geneses, by Alexandre Meinesz, translated by Daniel Simberloff, 2008, pp. 30-33, 45.
a. Life Itself—Its Origin and Nature, by Francis Crick, 1981, pp. 15-16, 141-153.
2. Scientific American, “A Simpler Origin for Life,” by Robert Shapiro, June 2007, p. 48.
a. The New York Times, “A Leading Mystery of Life’s Origins Is Seemingly Solved,” by Nicholas Wade, May 14, 2009, p. A23.
3. Scientific American, June 2007, p. 48.
4. Scientific American, June 2007, pp. 47, 49-50.
5. Information Theory, Evolution, and the Origin of Life, by Hubert P. Yockey, 2005, p. 182.
6. NASA’s Astrobiology Magazine, “Life’s Working Definition—Does It Work?” (http://www.nasa.gov/ vision/universe/starsgalaxies/ life’s_working_definition.html), accessed 3/17/2009.
2. Is Any Form of Life Really Simple?
7. Princeton Weekly Bulletin, “Nuts, Bolts of Who We Are,” by Steven Schultz, May 1, 2000, (http://www.princeton.edu/ pr/pwb/00/0501/p/brain.shtml), accessed 3/27/2009.
a. “The Nobel Prize in Physiology or Medicine 2002,” Press Release, October 7, 2002, (http://nobelprize.org/ nobel_prizes/medicine/laureates/2002/ press.html), accessed 3/27/2009.
8. “The Nobel Prize in Physiology or Medicine 2002,” October 7, 2002.
9. Encyclopædia Britannica, CD 2003, “Cell,” “The Mitochondrion and the Chloroplast,” subhead, “The Endosymbiont Hypothesis.”
10. How Life Began—Evolution’s Three Geneses, p. 32.
11. Molecular Biology of the Cell, Second Edition, by Bruce Alberts et al, 1989, p. 405.
12. Molecular Human Reproduction, “The Role of Proteomics in Defining the Human Embryonic Secretome,” by M. G. Katz-Jaffe, S. McReynolds, D. K. Gardner, and W. B. Schoolcraft, 2009, p. 271.
13. Between Necessity and Probability: Searching for the Definition and Origin of Life, by Radu Popa, 2004, p. 129.
14. Between Necessity and Probability: Searching for the Definition and Origin of Life, pp. 126-127.
(Box) How Fast Can a Cell Reproduce?
15. Origin of Mitochondria and Hydrogenosomes, by William F. Martin and Miklós Müller, 2007, p. 21.
16. Brain Matters—Translating Research Into Classroom Practice, by Pat Wolfe, 2001, p. 16.
3. Where Did the Instructions Come From?
17. Research News Berkeley Lab, (http://www.lbl.gov/Science-Articles/Archive/ LSD-molecular-DNA.html), article: “Molecular DNA Switch Found to Be the Same for All Life,” contact: Lynn Yarris, p. 1 of 4; accessed 2/10/2009.
18. Life Script, by Nicholas Wade, 2001, p. 79.
19. Bioinformatics Methods in Clinical Research, edited by Rune Matthiesen, 2010, p. 49.
20. Scientific American, “Computing With DNA,” by Leonard M. Adleman, August 1998, p. 61.
21. Nano Letters, “Enumeration of DNA Molecules Bound to a Nanomechanical Oscillator,” by B. Ilic, Y. Yang, K. Aubin, R. Reichenbach, S. Krylov, and H. G. Craighead, Vol. 5, No. 5, 2005, pp. 925, 929.
22. Genome—The Autobiography of a Species in 23 Chapters, by Matt Ridley, 1999, pp. 7-8.
23. Essential Cell Biology, Second Edition, by Bruce Alberts, Dennis Bray, Karen Hopkin, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter, 2004, p. 201.
24. Molecular Biology of the Cell, Fourth Edition, by Bruce Alberts et al, 2002, p. 258.
25. No Ordinary Genius—The Illustrated Richard Feynman, edited by Christopher Sykes, 1994, photo with no page number supplied; note caption.
a. New Scientist, “Second Genesis—Life, but Not As We Know It,” by Bob Holmes, March 11, 2009, (http://www.newscientist.com/article/ mg20126990.100) accessed 3/11/2009.
26. The Search for Extraterrestrial Intelligence—A Philosophical Inquiry, by David Lamb, 2001, p. 83.
27. Associated Press Newswires, “Famous Atheist Now Believes in God,” by Richard N. Ostling, December 9, 2004.
(Box) A Molecule That Can Be Read and Copied
28. Intelligent Life in the Universe, Second Edition, by Peter Ulmschneider, 2006, p. 125.
4. Has All Life Descended From a Common Ancestor?
29. Biology and Philosophy, “The Concept of Monophyly: A Speculative Essay,” by Malcolm S. Gordon, 1999, p. 335.
30. New Scientist, “Uprooting Darwin’s Tree,” by Graham Lawton, January 24, 2009, p. 34.
31. New Scientist, January 24, 2009, pp. 37, 39.
32. Field Museum of Natural History Bulletin, “Conflicts Between Darwin and Paleontology,” by David M. Raup, January 1979, p. 23.
33. Archaeology, “The Origin of Form Was Abrupt Not Gradual,” by Suzan Mazur, October 11, 2008, (www.archaeology.org/online/ interviews/newman.html), accessed 2/23/2009.
34. In Search of Deep Time—Beyond the Fossil Record to a New History of Life, by Henry Gee, 1999, p. 23.
35. Biology and Philosophy, p. 340.
36. National Geographic, “Fossil Evidence,” November 2004, p. 25.
37. The Evolutionists—The Struggle for Darwin’s Soul, by Richard Morris, 2001, pp. 104-105.
(Box) What About Human Evolution?
38. The Human Lineage, by Matt Cartmill and Fred H. Smith, 2009, Preface, p. xi.
39. Fossils, Teeth and Sex—New Perspectives on Human Evolution, by Charles E. Oxnard, 1987, Preface, pp. xi, xii.
a. From Lucy to Language, by Donald Johanson and Blake Edgar, 1996, p. 22.
b. Anthropologie, XLII/1, “Palaeodemography and Dental Microwear of Homo Habilis From East Africa,” by Laura M. MartÃnez, Jordi Galbany, and Alejandro Pérez-Pérez, 2004, p. 53.
c. In Search of Deep Time—Beyond the Fossil Record to a New History of Life, p. 22.
40. Critique of Anthropology, Volume 29(2), “Patenting Hominins—Taxonomies, Fossils and Egos,” by Robin Derricourt, 2009, pp. 195-196, 198.
41. Nature, “A New Species of Great Ape From the Late Miocene Epoch in Ethiopia,” by Gen Suwa, Reiko T. Kono, Shigehiro Katoh, Berhane Asfaw, and Yonas Beyene, August 23, 2007, p. 921.
42. Acta Biologica Szegediensis, Volume 46(1-2), “New Findings—New Problems in Classification of Hominids,” by Gyula Gyenis, 2002, pp. 57, 59.
43. New Scientist, “A Fine Fossil—But a Missing Link She’s Not,” by Chris Bead, May 30, 2009, p. 18.
44. The Guardian, London, “Fossil Ida: Extraordinary Find Is ‘Missing Link’ in Human Evolution,” by James Randerson, May 19, 2009, (http://www.guardian.co.uk/science/2009/ may/19/ida-fossil-missing-link), accessed 8/25/2009.
45. New Scientist, May 30, 2009, pp. 18-19.
46. Critique of Anthropology, Volume 29(2), p. 202.
47. Science and Justice, Vol. 43, No. 4, (2003) section, Forensic Anthropology, “Anthropological Facial ‘Reconstruction’—Recognizing the Fallacies, ‘Unembracing’ the Errors, and Realizing Method Limits,” by C. N. Stephan, p. 195.
48. The Human Fossil Record—Volume Three, by Ralph L. Holloway, Douglas C. Broadfield, and Michael S. Yuan, 2004, Preface xvi.
49. Scientific American Mind, “Intelligence Evolved,” by Ursula Dicke and Gerhard Roth, August/September 2008, p. 72.
50. American Journal of Physical Anthropology, “How Neandertals Inform Human Variation,” by Milford H. Wolpoff, 2009, p. 91.
51. Conceptual Issues in Human Modern Origins Research, Editors G. A. Clark and C. M. Willermet, 1997, pp. 5, 60.
a. Wonderful Life—The Burgess Shale and the Nature of History, by Stephen Jay Gould, 1989, p. 28.
Logic and Commonsense re:the design debate.III
A reproduction of the Watchtower Society's article
Question 1
Question 1
How Did Life Begin?
When you were a child, did you ever startle your parents by asking, “Where do babies come from?” If so, how did they respond? Depending on your age and their personality, your parents might have ignored the question or given you a hurried, embarrassed answer. Or perhaps they told you some fanciful tales that you later found to be false. Of course, if a child is to be properly prepared for adulthood and marriage, he or she eventually needs to learn about the wonders of sexual reproduction.
Just as many parents feel awkward about discussing where babies come from, some scientists seem reluctant to discuss an even more fundamental question—Where did life come from? Receiving a credible answer to that question can have a profound effect on a person’s outlook on life. So how did life begin?
What do many scientists claim? Many who believe in evolution would tell you that billions of years ago, life began on the edge of an ancient tidal pool or deep in the ocean. They feel that in some such location, chemicals spontaneously assembled into bubblelike structures, formed complex molecules, and began replicating. They believe that all life on earth originated by accident from one or more of these “simple” original cells.
Other equally respected scientists who also support evolution disagree. They speculate that the first cells or at least their major components arrived on earth from outer space. Why? Because, despite their best efforts, scientists have been unable to prove that life can spring from nonliving molecules. In 2008, Professor of Biology Alexandre Meinesz highlighted the dilemma. He stated that over the last 50 years, “no empirical evidence supports the hypotheses of the spontaneous appearance of life on Earth from nothing but a molecular soup, and no significant advance in scientific knowledge leads in this direction.”1
What does the evidence reveal? The answer to the question, Where do babies come from? is well-documented and uncontroversial. Life always comes from preexisting life. However, if we go back far enough in time, is it really possible that this fundamental law was broken? Could life really spontaneously spring from nonliving chemicals? What are the chances that such an event could happen?
Researchers have learned that for a cell to survive, at least three different types of complex molecules must work together—DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and proteins. Today, few scientists would assert that a complete living cell suddenly formed by chance from a mix of inanimate chemicals. What, though, is the probability that RNA or proteins could form by chance?*
Many scientists feel that life could arise by chance because of an experiment first conducted in 1953. In that year, Stanley L. Miller was able to produce some amino acids, the chemical building blocks of proteins, by discharging electricity into a mixture of gases that was thought to represent the atmosphere of primitive earth. Since then, amino acids have also been found in a meteorite. Do these findings mean that all the basic building blocks of life could easily be produced by chance?
“Some writers,” says Robert Shapiro, professor emeritus of chemistry at New York University, “have presumed that all life’s building blocks could be formed with ease in Miller-type experiments and were present in meteorites. This is not the case.”2*
Consider the RNA molecule. It is constructed of smaller molecules called nucleotides. A nucleotide is a different molecule from an amino acid and is only slightly more complex. Shapiro says that “no nucleotides of any kind have been reported as products of spark-discharge experiments or in studies of meteorites.”3 He further states that the probability of a self-replicating RNA molecule randomly assembling from a pool of chemical building blocks “is so vanishingly small that its happening even once anywhere in the visible universe would count as a piece of exceptional good luck.”4
What about protein molecules? They can be made from as few as 50 or as many as several thousand amino acids bound together in a highly specific order. The average functional protein in a “simple” cell contains 200 amino acids. Even in those cells, there are thousands of different types of proteins. The probability that just one protein containing only 100 amino acids could ever randomly form on earth has been calculated to be about one chance in a million billion.
Researcher Hubert P. Yockey, who supports the teaching of evolution, goes further. He says: “It is impossible that the origin of life was ‘proteins first.’”5 RNA is required to make proteins, yet proteins are involved in the production of RNA. What if, despite the extremely small odds, both proteins and RNA molecules did appear by chance in the same place at the same time? How likely would it be for them to cooperate to form a self-replicating, self-sustaining type of life? “The probability of this happening by chance (given a random mixture of proteins and RNA) seems astronomically low,” says Dr. Carol Cleland*, a member of the National Aeronautics and Space Administration’s Astrobiology Institute. “Yet,” she continues, “most researchers seem to assume that if they can make sense of the independent production of proteins and RNA under natural primordial conditions, the coordination will somehow take care of itself.” Regarding the current theories of how these building blocks of life could have arisen by chance, she says: “None of them have provided us with a very satisfying story about how this happened.”6
Why do these facts matter? Think of the challenge facing researchers who feel that life arose by chance. They have found some amino acids that also appear in living cells. In their laboratories, they have, by means of carefully designed and directed experiments, manufactured other more complex molecules. Ultimately, they hope to build all the parts needed to construct a “simple” cell. Their situation could be likened to that of a scientist who takes naturally occurring elements; transforms them into steel, plastic, silicone, and wire; and constructs a robot. He then programs the robot to be able to build copies of itself. By doing so, what will he prove? At best, that an intelligent entity can create an impressive machine.
Similarly, if scientists ever did construct a cell, they would accomplish something truly amazing—but would they prove that the cell could be made by accident? If anything, they would prove the very opposite, would they not?
What do you think? All scientific evidence to date indicates that life can come only from previously existing life. To believe that even a “simple” living cell arose by chance from nonliving chemicals requires a huge leap of faith.
Given the facts, are you willing to make such a leap? Before answering that question, take a closer look at the way a cell is made. Doing so will help you discern whether the theories some scientists propound about where life came from are sound or are as fanciful as the tales some parents tell about where babies come from.
[Footnotes]
The probability of DNA forming by chance will be discussed in section 3, “Where Did the Instructions Come From?”
Professor Shapiro does not believe that life was created. He believes that life arose by chance in some fashion not yet fully understood. In 2009, scientists at the University of Manchester, England, reported making some nucleotides in their lab. However, Shapiro states that their recipe “definitely does not meet my criteria for a plausible pathway to the RNA world.”
Dr. Cleland is not a creationist. She believes that life arose by chance in some fashion not yet fully understood.
[Box on page 7]
FACTS AND QUESTIONS
▪ Fact: All scientific research indicates that life cannot spring from nonliving matter.
Question: What is the scientific basis for saying that the first cell sprang from nonliving chemicals?
▪ Fact: Researchers have recreated in the laboratory the environmental conditions that they believe existed early in the earth’s history. In these experiments, a few scientists have manufactured some of the molecules found in living things.
Question: If the chemicals in the experiment represent the earth’s early environment and the molecules produced represent the building blocks of life, whom or what does the scientist who performed the experiment represent? Does he or she represent blind chance or an intelligent entity?
▪ Fact: Protein and RNA molecules must work together for a cell to survive. Scientists admit that it is highly unlikely that RNA formed by chance. The odds against even one protein forming by chance are astronomical. It is exceedingly improbable that RNA and proteins should form by chance in the same place at the same time and be able to work together.
Question: What takes greater faith—to believe that the millions of intricately coordinated parts of a cell arose by chance or to believe that the cell is the product of an intelligent mind?
[Diagram on page 6]
(For fully formatted text, see publication)
RNA 1 is required to make proteins 2, yet proteins are involved in the production of RNA. How could either one arise by chance, let alone both? Ribosomes 3 will be discussed in section 2.
If the creation of complex molecules in the laboratory requires the skill of a scientist, could the far more complex molecules in a cell really arise by chance?
[Picture on page 4]
A fertilized human egg cell, shown about 800 times its actual size
[Picture on page 5]
Stanley Miller, 1953
[Picture on page 7]
If it takes an intelligent entity to create and program a lifeless robot, what would it take to create a living cell, let alone a human?
Logic and commonsense re:the design debate.IV
A reproduction of the Watchtower Society's article.
Question 3
Question 3
Where Did the Instructions Come From?
Why do you look the way you do? What determines the color of your eyes, your hair, your skin? What about your height, your build, or your resemblance to one or both of your parents? What tells the ends of your fingers to grow soft pads on one side and hard, protective nails on the other?
In Charles Darwin’s day, the answers to such questions were shrouded in mystery. Darwin himself was fascinated by the way traits are passed along from one generation to the next, but he knew little about the laws of genetics and even less about the mechanisms within the cell that govern heredity. Now, however, biologists have spent decades studying human genetics and the detailed instructions that are embedded in the amazing molecule called DNA (deoxyribonucleic acid). Of course, the big question is, Where did these instructions come from?
What do many scientists claim? Many biologists and other scientists feel that DNA and its coded instructions came about through undirected chance events that took place over the course of millions of years. They say that there is no evidence of design in the structure of this molecule nor in the information that it carries and transmits nor in the way that it functions.17
What does the Bible say? The Bible suggests that the formation of our different body parts—and even the timing of their formation—involves a figurative book that originates with God. Notice how King David was inspired to describe matters, saying of God: “Your eyes saw even the embryo of me, and in your book all its parts were down in writing, as regards the days when they were formed and there was not yet one among them.”—Psalm 139:16.
What does the evidence reveal? If evolution is true, then it should seem at least reasonably possible that DNA could have come about by means of a series of chance events. If the Bible is true, then DNA should provide strong evidence that it is the product of an orderly, intelligent mind.
When considered in the simplest of terms, the subject of DNA is quite understandable—and fascinating. So let us take another trip to the inside of a cell. This time, though, we will visit a human cell. Imagine that you are going to a museum designed to teach you about how such a cell works. The whole museum is a model of a typical human cell—but magnified some 13,000,000 times. It is the size of a giant sports arena, the kind that can seat an audience of about 70,000 people.
You enter the museum and stare awestruck at this wondrous place full of strange forms and structures. Near the center of the cell stands the nucleus, a sphere about 20 stories tall. You make your way there.
You go through a door in the nucleus’ outer skin, or membrane, and look around you. Dominating this chamber are 46 chromosomes. Arranged in identical pairs, they vary in height, but the pair nearest you is about 12 stories tall (1). Each chromosome has a pinched place near the middle, so it looks a bit like a link sausage but is as thick as a massive tree trunk. You see a variety of bands running across the model chromosomes. As you draw closer, you see that each horizontal band is divided by vertical lines. Between those are shorter horizontal lines (2). Are they stacks of books? No; they are the outer edges of loops, packed tightly in columns. You pull at one of them, and it comes free. You are amazed to see that the loop is composed of smaller coils (3), also neatly arranged. Within those coils is the main feature of all of this—something resembling a long, long rope. What is it?
THE STRUCTURE OF AN AMAZING MOLECULE
Let us simply call this part of the model chromosome a rope. It is about an inch [2.6 cm] thick. It is looped tightly around spools (4), which help to form the coils within coils. These coils are attached to a kind of scaffold that holds them in place. A sign on the display explains that the rope is packed very efficiently. If you were to pull the rope from each of these model chromosomes and lay it all out, from end to end it would stretch about halfway around the earth!*
One science book calls this efficient packaging system “an extraordinary feat of engineering.”18 Does the suggestion that there was no engineer behind this feat sound credible to you? If this museum had a huge store with millions of items for sale and they were all so tidily arranged that you could easily find any item you needed, would you assume that no one had organized the place? Of course not! But such order would be a simple feat by comparison.
In the museum display, a sign invites you to take a length of this rope in your hands for a closer look (5). As you run it between your fingers, you see that this is no ordinary rope. It is composed of two strands twisted around each other. The strands are connected by tiny bars, evenly spaced. The rope looks like a ladder that has been twisted until it resembles a spiral staircase (6). Then it hits you: You are holding a model of the DNA molecule—one of the great mysteries of life!
A single DNA molecule, tidily packaged with its spools and scaffold, makes up a chromosome. The rungs of the ladder are known as base pairs (7). What do they do? What is all of this for? A display sign offers a simplified explanation.
THE ULTIMATE INFORMATION STORAGE SYSTEM
The key to the DNA, the sign says, lies in those rungs, the bars connecting the two sides of the ladder. Imagine the ladder split apart. Each side has partial rungs sticking out. They come in only four types. Scientists dub them A, T, G, and C. Scientists were amazed to discover that the order of those letters conveys information in a sort of code.
You may know that Morse code was invented in the 19th century so that people could communicate by telegraph. That code had only two “letters”—a dot and a dash. Yet, it could be used to spell out countless words or sentences. Well, DNA has a four-letter code. The order in which those letters—A, T, G, and C—appear forms “words” called codons. Codons are arranged in “stories” called genes. Each gene contains, on average, 27,000 letters. These genes and the long stretches between them are compiled into chapters of a sort—the individual chromosomes. It takes 23 chromosomes to form the complete “book”—the genome, or total of genetic information about an organism.*
The genome would be a huge book. How much information would it hold? All told, the human genome is made up of about three billion base pairs, or rungs, on the DNA ladder.19 Imagine a set of encyclopedias in which each volume is over a thousand pages long. The genome would fill 428 of such volumes. Adding the second copy that is found in each cell would make that 856 volumes. If you were to type out the genome by yourself, it would be a full-time job—with no vacations—lasting some 80 years!
Of course, what you would end up with after all that typing would be useless to your body. How would you fit hundreds of bulky volumes into each of your 100 trillion microscopic cells? To compress so much information so greatly is far beyond us.
A professor of molecular biology and computer science noted: “One gram of DNA, which when dry would occupy a volume of approximately one cubic centimeter, can store as much information as approximately one trillion CDs [compact discs].”20 What does that mean? Remember, the DNA contains the genes, the instructions for building a unique human body. Each cell has a complete set of instructions. DNA is so dense with information that a single teaspoonful of it could carry the instructions for building about 350 times the number of humans alive today! The DNA required for the seven billion people living on earth now would barely make a film on the surface of that teaspoon.21
A BOOK WITH NO AUTHOR?
Despite advances in miniaturization, no man-made information storage device can approach such a capacity. Yet, the compact disc offers an apt comparison. Consider this: A compact disc may impress us with its symmetrical shape, its gleaming surface, its efficient design. We see clear evidence that intelligent people made it. But what if it is embedded with information—not random gibberish, but coherent, detailed instructions for building, maintaining, and repairing complex machinery? That information does not perceptibly change the weight or the size of the disc. Yet, it is the most important feature of that disc. Would not those written instructions convince you that there must be some intelligent mind at work here? Does not writing require a writer?
It is not far-fetched to compare DNA to a compact disc or to a book. In fact, one book about the genome notes: “The idea of the genome as a book is not, strictly speaking, even a metaphor. It is literally true. A book is a piece of digital information . . . So is a genome.” The author adds: “The genome is a very clever book, because in the right conditions it can both photocopy itself and read itself.”22 That brings up another important aspect of DNA.
MACHINES IN MOTION
As you stand there in the quiet, you find yourself wondering if the nucleus of a cell is really as still as a museum. Then you notice another display. Above a glass case containing a length of model DNA is a sign that reads: “Push Button for Demonstration.” You push the button, and a narrator explains: “DNA has at least two very important jobs. The first is called replication. DNA has to be copied so that every new cell will have a complete copy of the same genetic information. Please watch this simulation.”
Through a door at one end of the display comes a complex-looking machine. It is actually a cluster of robots closely linked together. The machine goes to the DNA, attaches itself, and begins to move along the DNA as a train might follow a track. It moves a little too fast for you to see exactly what it is doing, but you can easily see that behind it, there are now two complete DNA ropes instead of one.
The narrator explains: “This is a greatly simplified version of what goes on when DNA is replicated. A group of molecular machines called enzymes travel along the DNA, first splitting it in two, then using each strand as a template to make a new, complementary strand. We cannot show you all the parts involved—such as the tiny device that runs ahead of the replication machine and snips one side of the DNA so that it can twirl around freely instead of getting wound up too tight. Nor can we show you how the DNA is ‘proofread’ several times. Errors are detected and corrected to an amazing degree of accuracy.”—See the diagram on pages 16 and 17.
The narrator continues: “What we can show you clearly is the speed. You noticed this robot moving at a pretty good clip, didn’t you? Well, the actual enzyme machinery moves along the DNA ‘track’ at a rate of about 100 rungs, or base pairs, every second.23 If the ‘track’ were the size of a railroad track, this ‘engine’ would be barreling along at the rate of over 50 miles [80 km] per hour. In bacteria, these little replication machines can move ten times faster than that! In the human cell, armies of hundreds of these replication machines go to work at different spots along the DNA ‘track.’ They copy the entire genome in just eight hours.”24 (See the box “A Molecule That Can Be Read and Copied,” on page 20.)
“READING” DNA
The DNA-replicating robots trundle off the scene. Another machine appears. It too moves along a stretch of DNA, but more slowly. You see the DNA rope entering one end of this machine and emerging from the other—unchanged. But a single strand, a new one, is coming out of a separate opening in the machine, like a growing tail. What is going on?
Again the narrator provides an explanation: “DNA’s second job is called transcription. The DNA never leaves the safe shelter of the nucleus. So how can its genes—the recipes for all the proteins your body is made of—ever be read and used? Well, this enzyme machine finds a spot along the DNA where a gene has been switched on by chemical signals coming in from outside the cell nucleus. Then this machine uses a molecule called RNA (ribonucleic acid) to make a copy of that gene. RNA looks a lot like a single strand of DNA, but it is different. Its job is to pick up the information coded in the genes. The RNA gets that information while in the enzyme machine, then exits the nucleus and heads to one of the ribosomes, where the information will be used to build a protein.”
As you watch the demonstration, you are filled with wonder. You are deeply impressed by this museum and the ingenuity of those who designed and built its machines. But what if this entire place with all its exhibits could be set in motion, demonstrating all the thousands upon thousands of tasks that go on in the human cell at the same time? What an awe-inspiring spectacle that would be!
You realize, though, that all these processes carried out by tiny, complex machines are actually going on right now in your own 100 trillion cells! Your DNA is being read, providing directions to build the hundreds of thousands of different proteins that make up your body—its enzymes, tissues, organs, and so on. Right now your DNA is being copied and proofread for errors so that a fresh set of directions is there to be read in each new cell.
WHY DO THESE FACTS MATTER?
Again, let us ask ourselves, ‘Where did all these instructions come from?’ The Bible suggests that this “book” and its writing originate with a superhuman Author. Is that conclusion really out-of-date or unscientific?
Consider this: Could humans even build the museum just described? They would run into real difficulty if they tried. Much about the human genome and how it functions is little understood as yet. Scientists are still trying to figure out where all the genes are and what they do. And the genes comprise only a small part of the DNA strand. What about all those long stretches that do not contain genes? Scientists have called those parts junk DNA, but more recently they have been modifying that stance. Those parts may control how and to what extent the genes are used. And even if scientists could create a full model of the DNA and the machines that copy and proofread it, could they make it actually function as the real one does?
Famous scientist Richard Feynman left this note on a blackboard shortly before his death: “What I cannot create, I do not understand.”25 His candid humility is refreshing, and his statement, obviously true in the case of DNA. Scientists cannot create DNA with all its replication and transcription machinery; nor can they fully understand it. Yet, some assert that they know that it all came about by undirected chance and accidents. Does the evidence that you have considered really support such a conclusion?
Some learned men have decided that the evidence points the other way. For example, Francis Crick, a scientist who helped to discover DNA’s double-helix structure, decided that this molecule is far too organized to have come about through undirected events. He proposed that intelligent extraterrestrials may have sent DNA to the earth to help get life started here.26
More recently, noted philosopher Antony Flew, who advocated atheism for 50 years, did an about-face of sorts. At 81 years of age, he began to express a belief that some intelligence must have been at work in the creation of life. Why the change? A study of DNA. When asked if his new line of thought might prove unpopular among scientists, Flew reportedly answered: “That’s too bad. My whole life has been guided by the principle . . . [to] follow the evidence, wherever it leads.”27
What do you think? Where does the evidence lead? Imagine that you found a computer room in the heart of a factory. The computer is running a complex master program that directs all the workings of that factory. What is more, that program is constantly sending out instructions on how to build and maintain every machine there, and it is making copies of itself and proofreading them. What would that evidence lead you to conclude? That the computer and its program must have made themselves or that they were produced by orderly, intelligent minds? Really, the evidence speaks for itself.
[Footnotes]
The textbook Molecular Biology of the Cell uses a different scale. It says that trying to pack these long strands into a cell nucleus would be like trying to pack 24 miles [40 km] of very fine thread into a tennis ball—but in such a neat, organized way that each part of the thread remains easily accessible.
Each cell contains two complete copies of the genome, 46 chromosomes in all.
[Box/Picture on page 20]
A MOLECULE THAT CAN BE READ AND COPIED
How can DNA be read and copied so reliably? The four chemical bases used in the DNA ladder—A, T, G, and C—form the ladder’s individual rungs by always pairing in the same way: A with T, and G with C. If one side of a rung is A, the other side is always T; G always meets C. Therefore, if you have one side of the ladder, you know the other side of the ladder. Where one side of the ladder reads GTCA, the other side must read CAGT. The partial rungs differ in length, but when they pair up with their complements, they make complete rungs of one uniform length.
Discovering that fact led scientists to another breakthrough about this remarkable molecule: DNA is perfectly suited for being copied over and over. The enzyme machine that replicates DNA takes in free-floating units of those four chemicals from the environment in the nucleus. Then it uses them to complete each rung on the split DNA strand.
So a DNA molecule really is like a book that is read and copied over and over again. In the average life span of a human, DNA is copied some 10,000,000,000,000,000 times, with amazing fidelity.28
[Box on page 21]
FACTS AND QUESTIONS
▪ Fact: DNA is packaged within the chromosomes in a manner so efficient that it has been called a “feat of engineering.”
Question: How could such order and organization arise by undirected chance events?
▪ Fact: DNA’s capacity to store information still has no equal in today’s computer age.
Question: If human computer technicians cannot achieve such results, how could mindless matter do so on its own?
▪ Fact: DNA contains all the instructions needed to build a unique human body and maintain it throughout life.
Question: How could such writing come about without a writer, such programming without a programmer?
▪ Fact: For DNA to work, it has to be copied, read, and proofread by a swarm of complex molecular machines called enzymes, which must work together with precision and split-second timing.
Question: Do you believe that highly complex, highly reliable machinery can come about by chance? Without solid proof, would not such a belief amount to blind faith?
[Diagram on page 14, 15]
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A “Feat of Engineering”
How DNA Is Packed
Packing the DNA into the nucleus is an amazing feat of engineering—like packing 24 miles of very fine thread into a tennis ball
[Diagram on page 16, 17]
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Replication
How DNA Is Copied
1 This part of the enzyme machine splits the DNA into two separate strands
2 This part of the machine takes in a single strand of DNA and uses it as a template to create a double strand
3 Ring-shaped sliding clamp that guides and stabilizes the enzyme machine
4 Two complete DNA strands are formed
If DNA were the size of a railroad track, the enzyme machine would be moving at the rate of over 50 miles per hour
[Diagram on page 18, 19]
(For fully formatted text, see publication)
Transcription
How DNA Is “Read”
1 The DNA is unwound here. An exposed strand passes information to the RNA
2 The RNA “reads” the DNA, picking up the code within a gene. The DNA code tells the transcription machine where to start and stop
3 Loaded with information, the RNA exits the cell nucleus and goes to a ribosome, where it will impart the instructions on how to build a complex protein
4 Transcription machine
[Picture on page 18]
One gram of DNA carries as much information as a trillion CDs could
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