Transcription
Darwin's theory of evolution asserts two main propositions. First, it asserts that the history of life can be best depicted as a kind of great branching tree where the forms of life that we see today represent the branches at the top of the tree and the trunk of the tree is represents the first one-celled organism from which everything else came. So it asserts that life has arisen as a as the result of a a slow gradual and continuous process of change from that very first simple ancestor to all the forms of life that have developed from it right up to the present.
The second main proposition that Darwin's theory asserts has to do with the mechanism by which that continuous and gradual change occurred. That is Darwin's famous mechanism of natural selection acting on random variations or now modern biologists would talk about a particular kind of variation known as mutations which are uh copying errors in the genetic material in the sequence of of digital characters in the in the DNA. Um and that second uh proposition of of u natural selection acting on random mutations is thought by both Darwinists and modern neodyarwinists to be a completely unguided and undirected process. It's nature selecting the outcome not an intelligent agent. Okay. And so uh in in modern neodyarwinism, natural selection and random mutation is thought to be a kind of designer substitute that can produce the appearance of design in living organisms without those organisms actually having been designed by any kind of guided or directed process uh or or mind. So the famous Darwinian biologist Francisco Ayala has said that Darwinism uh gives us design without a designer.
Proponents of the modern version of Darwin's theory known as neodyarwinism often claim that the fossil record provides either the best support for the the theory or that it provides unequivocal support for the modern form of Darwinian theory. But in fact, from Darwin's time right up to the present, the fossil record has posed a very considerable challenge to the Darwinian first picture of the treelike picture of the history of life, but also to the idea of the creative power of the mutation and natural selection mechanism. Because what we see in the fossil record in particular when we're looking at major innovations in biological form and structure is the abrupt appearance of such major innovations where in each case there those new biological forms are lacking any discernable connection to similar forms in the lower sedimentary strata. So you get an abrupt appearance of a new form of life, usually persisting through the fossil record with some slight variation, but the basic form remaining static over long periods of time and then either the form going extinct or it persisting right up to the present. We don't see the gradual morphing of form from one major type of organism to another that is described by Darwin's tree of life and predicted on the basis of the action of his mechanism of natural selection and random variation/mutation.
There are many examples of the abrupt appearance of new forms of animal and plant life in the fossil record. I wrote a book about one of the greatest of those events called the Cambrian Explosion, which is an event about 520 to 530 million years ago where the first animal forms arose abruptly in the fossil record with no discernable connection to similar forms in the lower precamrian strata. It's really dramatic. But the Cambrian explosion isn't the only such event in the history of life. There are many. Uh a little bit later in the fossil record, there's an event called the great or division biodiversity event or goi where there's a whole slew of new forms of life that come into existence. And then as you go up the and down the the sedimentary column, you find that the first winged insects, the first uh the first dinosaurs, the first turtles, the first birds, the first u marine reptiles, the first flowering plants that the the first flowering flowering plants come into the fossil record, an event that's now known as the the the the big bloom, the biological big bloom. And then another striking event occurs in the Eocene period where you get the first mammals where there are between 15 and 17 new orders of mammals that come suddenly into to the fossil record again with no discernable connection to similar creatures in the lower strata beneath the eosene. And so this pattern is repeated over and over again with paleontologist Gunter Beckley. recently wrote a an article, a scientific article about 17 separate uh fossil explosions in the history of life. And so sometimes people will say, well, the Cambrian explosion is an isolated anomaly. But after that, everything is very smooth and gradual and conforms nicely to the picture of the history of life that Darwin provided with his great tree of life picture. But that's actually completely false that the overriding pattern as the uh uh as Stephen Jay Gold and Niles Eldridge pointed out back in the 1970s and 80s is one of abrupt appearance and stasis where the basic forms of life once they appear remain u remain static over long periods of time with slight variations on the basic theme. But we don't see the kind of morphing from one major morphological innovation into another that you would expect on the basis of Darwinian theory.
>> Yeah. Darwin was well aware of the problem pres that the fossil record presented to his theory. In particular, he was acutely aware of the problem of the of what we now call the Cambrian explosion. and he he acknowledged that the this case must remain ex as inexplicable at the time. Uh but he thought that future fossil finds would resolve the the mystery of the missing fossils, the missing ancestral forms. And so he thought that as as as paleontologists scoured the fossil record, they would find those missing pre ancestral intermediates or uh or precursor forms. U and he used a charming illustration to get this across. He rep he he depicted the fossil record as something like a book that had a few of the pages still in it but many of them had been torn out maybe by erosion or something else. And this became known as the artifact hypothesis. The idea that the the abrupt appearance of the fossil forms as depicted in our current fossil record is an artifact either of incomplete sampling, we haven't looked hard enough, or incomplete preservation.
Now, in the 20th and 21st century, in our current uh times, we now have good reasons to doubt the artifact hypothesis. First, we've had 160 years to look for the missing, for example, pre-Cambrian ancestors to the the the Cambrian animal forms that first arose in the Cambrian period. And rather than find those missing ancestors, what the paleontologists actually found is a whole new set, a whole new array of Cambrian animals that were unknown in Darwin's time, such that the abrupt appearance now is even more abrupt. There are more forms that appear that we now know appeared abruptly in the Cambrian, each of which is still lacking any discernable connection to ancestral forms in the in the earlier strata. So the Cambrian explosion from our point of view has become more explosive.
>> Well, the other part of the the artifact hypothesis was the the idea that perhaps the ancestral forms were simply not preserved because they were either too soft or too small or the depositional environments weren't uh adequate to preserve anything. And we've had a decisive test of that hypothesis in southern China in a place called CH near Chiang Jang in a formation called the Maashan Formation. There's been a massive find of new Cambrian animal forms uh documenting that the explosion was even more dramatic than than Darwin was aware in the 1860s. But in addition to that, in a layer of shale beneath the shale that documents the uh the Cambrian explosion, a layer called the Duchantu shale, paleontologists have discovered late precamrian embryo fossils. Now the embryos are of course extremely small and they're being embryos extremely soft. So here we have an example of softbodied forms, softbodied microscopic forms that are being perfectly preserved, but in that same layer, there is no evidence of the ancestors to the Cambrian animals that come immediately after in the fossil record. And that raises a question. If you can preserve soft embryos, why aren't you preserving the hard parts of the ancestral precursors to say trilobytes or the primitive fishes or the other forms of life that first arose in the Cambrian? And the Chinese paleontologists by and large have concluded that the reason that there's no preservation of those alleged pre-cambrian ancestors is that they're those ancestors weren't there. They simply weren't there. So the artifact hypothesis, the claim that the ancestral forms were not preserved because they were too soft and too small have been has been directly refuted by finds like that at the Duchantu shale which show that softbodied forms can be preserved. Even microscopic softbodied forms can be preserved but in the same layers you find no evidence of the the ancestors of the animals that come later.
Darwin's theory predicts that for every form of life there must be an ancestor and there must be transitional forms connecting the ancestor to the the present form. There are a few examples of transitionals within fairly narrow taxonomic groups. So we do know that there's variability within the basic body plan of of certain kinds of animals. But the overwhelming pattern in the fossil record is one of discontinuity especially as it pertains to the major morphological um innovations in the history of life and the separate body plans that they exhibit. So the the the missing the the problem of transitional intermediates is actually quite uh significant and though there are a few a few examples of of of transitions within within the framework of a of a given body plan. The horse transition for example is is is reasonable but but the major transitions exhibit discontinuity.
Well, population genetics is in a sense the mathematical expression of the neodyarwinian theory or what's known as the neodyarwinian synthesis. And population genetics allows um evolutionary biologists to calculate how much change would be expected in a given amount of time if they know certain factors like the mutation rate, the generation time from uh from adult to offspring, the um and and the size of populations. Thus the name population genetics. Uh it also allows conversely the um calculation of how long it would take for any given change to occur on average if you know those same factors. What's called the waiting times problem is derivative of the population genetics. Population genetics is the mathematical expression of Darwinian theory and it allows uh evolutionary biologists to calculate how long on average they ought to wait for a given amount of evolutionary change to occur if they know something about the mutation rate, the generation time, the time between adults and offspring in a given species and the size of populations. And the waiting times problem has emerged as as evolutionary biologists have realized that certain biological traits or anatomical features would require coordinated mutations. And whereas a single mutation might not take that long to occur, we might not have to wait very long on average for a single mutation to occur. With each additional mutation, the waiting times, the expected waiting times for such an event to occur rises exponentially. And so if you have complex adaptations or anatomical structures that would require multiple coordinated mutations, you're going to by the math of population genetics, the mathematical expression of neodyarwinian theory, you're going to have to wait an enormously long time on average for such mutations to occur, such coordinated mutations to occur. And so once you get behind about three coordinated mutations, the waiting times rise dramatically, exponentially into the hundreds of millions or billions of years, far more time than is allowed for the appearance of given anatomical traits as we find them arising in the fossil record.
If if the Darwinian mechanism lacks the creative power to generate the the largecale what are called morphological innovations, the big changes in form that arise in the fossil record. That raises the question, well, what what could produce those new forms of life? And what we know from biology is that whenever you see new forms of life arising, you also have to have new information. It's very much like in our computer world, if you want to give your computer a new function, you have to provide code. You have to provide information in the form of software. And something very similar is true in life. If you want to build a new form of animal life, you have to have new organs and tissues. But new organs and tissues require new dedicated proteins to service those organs and tissues. For example, many of the animals that came into the uh fossil record in the Cambrian period had had had a gut. But guts require digestive enzymes. and digestive enzymes are proteins and proteins are built in accord with the instructions stored on the DNA molecule. So as you see these explosions of form in the Cambrian period or other periods in the history of life, what you're also seeing therefore is explosions of biological information. Biological form requires biological information, genetic information and other forms of information. And that raises the question, where did that information come from? Now, what we know from our uniform and repeated experience, which is the basis of all scientific reasoning about the past, is that information, especially in a digital form, always comes from an intelligent source. Whether we're talking about a paragraph in a book or a section of software or a hieroglyphic inscription or even information embedded in a radio signal, whenever we see information and we trace it back to its ultimate source, we inevitably find a mind, not a material process.
Well, if the mutation selection mechanism is not capable of generating the amount of information necessary to build new forms of life, then a better explanation is actually intelligent design. It's that a mind played a role in the origin of those new forms of life. And that's consistent with everything we know about the cause and effect structure of the world. Mutations degrade information, but minds generate information. And therefore mind provides a better explanation for the origin of information than the Darwinian mechanism.