Puzzle Piece 6: is there good evidence for macroevolution?
In our examination of the information contained within the DNA molecule (see Puzzle Piece 5) we discovered several things that work together to show that not only is a naturalistic explanation for its origins unlikely in the extreme, even impossible, the very fact that each cell contains information cries out for an intelligent source. We saw that every source of information that we encounter in everyday life comes from an intelligent source without exception; that the appearance of design is so strong that Darwinists must keep reminding themselves to ignore it; and that this debate is really not one of science vs religion, but of good science vs bad science. Finally, we saw that the very definition of science is designed (no pun intended) to keep ID out from the beginning, and that ID isn’t simply a god-of-the-gaps explanation. This time we are going to move from the origin of the DNA molecule itself to the idea that all life shares a common ancestor.
Before beginning our investigation in earnest we need to ask a very important question, the same question we asked last time about the definition of science: what do you mean by that? Specifically, what do we mean when we use the term evolution? As you will very quickly see when you look at the scientific literature the term evolution has a variety of meanings and Darwinists often use the word to talk about very different things. Firstly, in its most broad characterisation it can mean simply change over time, the idea that livings things have changed as time has passed. This definition of evolution is uncontested by even the most ardent Creationist and is thus describing something that people across the full spectrum of origin beliefs all believe to be real. Secondly, it is used to describe changes within a species. A good example of this is the way a finch’s beak in the Galapagos lengthens or shortens over successive generations. When there is a drought and only the hard, tough seeds are left for food the finches with long, strong beaks are the only ones capable of cracking open the seeds to eat what’s inside. As a result, only the long-beaked finches survive. When times are better and there are plenty of soft seeds around the finches with shorter, weaker beaks are still able to feed and thus the average beak length of the population shortens. This type of change is also uncontested by all involved in this debate and is sometimes called microevolution.
Finally, the word evolution is used to refer to what we might call macroevolution, the idea that the tiny changes of microevolution result in entirely new body types and novel features. It’s important to note these differing uses of the same word because when you read about the latest ‘proof’ of evolution you need to be able to see which version of the word is being used. It is also important that you realise that while the evidence for microevolution is solid, macroevolution has never been observed to take place. Darwin took his idea of micro changes and said that with great time these small changes would result in large changes, and modern day Darwinists are using the same line of reasoning. So, with this as our foundation, let’s begin our investigation into macroevolution and see if the evidence for it really stacks up.
In their book I Don’t Have Enough Faith to be an Atheist, Norm Geisler and Frank Turek list five reasons why micro changes are insufficient to explain the diversity of the biological world. Let’s look at what they are.
1. Genetic Limits – genetic limits seem to be built into the types of animals that exist, allowing small changes (microevolution) but not large changes (macroevolution). Consider the following example: it is possible to breed animals for certain genetic characteristics. Various types of dogs are a great example of this. We breed some dogs for size, others for length of hair, or type of hair, or a particular ability like scent tracking. Note that although this shows that minor changes have occurred the dogs still remain dogs! Scientists have performed similar experiments on fruit flies which have a life span of only a few weeks allowing us to observe many generations over a relatively short time and have found that not only do the fruit flies stay fruit flies the genetic changes are actually detrimental to the fly, not advantageous. This is frequently the case when you look at the changes brought about by natural selection.
Sometimes, however, a change might be advantageous to an organism, allowing it to resist a particular disease for example, but this is at the cost of genetic diversity. Antibiotic resistant bacteria are a good example of this.[1] Sometimes, a mutation will occur within a bacterium whereby the mechanism that pumps nutrients into the cell from outside breaks down and is less efficient. This means that the cell takes in less or no antibiotics and is not killed. This cell then multiplies and a new strain develops that is resistant to drugs. But see what’s actually happened? The new strain is actually a damaged version of the original – no new information or features have arisen, just a corruption of an existing thing. This is what some call “devolution”, the loss of genetic information, and it certainly cannot account for the massive amounts of new information that is needed to get from a simple organism to a more complex one.
2. Cyclical Change – Not only are there limits to the amount of change that we see within types, it seems that the changes are cyclical. In other words, the changes shift back and forth within the limits and are not directional towards the development of a new type of life as the theory of macroevolution claims. In the above example of the finches the beak length changed with the seasons: average beak length was long in the dry periods and shorter in the wet periods. This change moved back and forth and never led to anything new – the finches stayed finches! What changed was the proportion of long-beaked to short-beaked finches. It’s important to note also that this was a change on an existing species and nothing in this process can explain the origin of species to begin with.
3. Irreducible Complexity – In 1859 Darwin wrote, “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.” Since Darwin’s day we have found biological systems that fit his description, like the ‘simple’ cell. The cell is a system that we can call ‘irreducibly complex’, something that is “composed of several well matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.” This is the definition given by Dr Michael Behe in his book Darwin’s Black Box, the book that popularised this argument. In other words all the parts of the molecular machine must be completely formed, in the right places, in the right sizes, in operating order, at the same time, for the machine to function. A car engine is an example of an irreducibly complex system. If you change one part, the size of the pistons for example, you must also change a whole number of other components (like the cam shaft, engine block and cooling system) or the engine will not function. This means that living things like the cell cannot be explained through a process of gradual and successive changes, because if they are missing any one part the whole will not function, and functionality is something that must be maintained at all times for a Darwinian mechanism to take place.
4. Nonviability of Transitional Forms – For natural selection to account for the development of new species there must be transitional forms, a creature that is between two species. For example, the Darwinian account of the origin of birds is that they evolved from reptiles. If this is the case there must have been (probably hundreds of) creatures that were between birds and reptiles, exhibiting features of both. Now, putting aside the problem that the fossil record contains no record of such transitional forms (more on this later) would such a creature be viable? Would it be able to survive long enough to pass its unique DNA on to subsequent generations? It doesn’t seem likely. Consider the reptile-to-bird scenario. There must have been an animal that had something in between scales and feathers, yet feathers are an irreducibly complex system. Without fully developed feathers the creature could not fly. It would lack the protection offered by scales and would we easy prey on land and water. You must remember that we are talking about a single reptile being born with some kind of mutation that is on the path to feathers and that single reptile needs to be able to breed and pass on that genetic mistake to its offspring etc. Even the death of a single creature on this chain from reptile to bird would stunt the process! So the problem for Darwinists is twofold. Firstly, there is no mechanism that can allow such a transition to occur, and secondly the transitional form would be unlikely to survive.
5. Molecular Isolation – for many Darwinists the greatest evidence of common descent is the fact that all living things contain DNA and that many creatures share a large percentage of their DNA with other creatures. This is taken as a sign of common origin since we share similar genetics. Often you will hear people saying that the DNA of humans and apes is 95% similar showing that they are our closest living relative. But is this evidence for common ancestry or evidence for a common designer? It could be interpreted either way! Perhaps we share a common genetic code because a designer designed us to all live in the same biosphere. After all, if every living creature were biochemically different would the food chain exist? Perhaps it’s not possible to have life forms with significantly different biochemistries living in the same biosphere.
But is similarity even enough? Some studies suggest that humans also share about 90% of their DNA with mice, yet no one suggests that a mouse is a particularly close ancestor! In 2006 New Scientist reported a study that showed that horses and bats are more closely related (genetically speaking) than horses and cows![2] It should be noted at this point that the studies that claim a 95%+ similarity between humans and apes are not talking about the whole DNA, just the small coding region that makes up about 10% of the DNA strand. So 10% is about 95% similar and there are significant differences in the remainder.
Finally, we should expect to see similarities across the species at the molecular level if they are all related. For example, proteins, the building blocks of life, are composed of long chains of amino acids; usually more than 100 long and they must be in a very specific order. If all species share a common ancestor shouldn’t we expect to find similarities between fish and amphibians, or reptiles and mammals? We don’t. Michael Denton, molecular biologist, writes that:
At a molecular level there is no trace of the evolutionary transition from fish to amphibian to reptile to mammal. So amphibian, always traditionally considered intermediate between fish and the other terrestrial vertebrates are in molecular terms as far from fish as any group of reptiles or mammals!
So even though all organisms share a common genetic code, the code has ordered our molecules in such a way that the basic types are in molecular isolation from one another.
What about the Fossil Record?
If macro evolution really took place over billions of years, producing countless transitional forms, we should expect to see huge amounts of these preserved in the fossil record. But we don’t. This was a problem Darwin himself recognised when he asked, “Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain, and this, perhaps, is the most obvious and gravest objection which can be urged against my theory.” Darwin thought that we would eventually discover these fossils, but he was wrong. Today, 150 years after he wrote those words, there is still not sufficient evidence from the fossil record to prove his claims. There should be thousands, possibly millions, of fossils depicting a slowly increasing complexity over time, but they are simply missing. This is recognised by people on both sides of the debate. The late Steven J Gould, a palaeontologist from Harvard University and an evolutionist, said this:
The history of most fossil species includes two features particularly inconsistent with gradualism: 1). Stasis. Most species exhibit no directional change during their tenure on earth. They appear in the fossil record looking much the same as when they disappear; Morphological change is usually limited and directionless. 2). Sudden Appearance. In any local area, a species does not arise gradually by steady transformation of its ancestors; it appears all at once and ‘fully formed’.
In other words, fossil types appear suddenly, fully formed, and remain the same until they go extinct. Gould, recognising the problems this presented Darwinism, went on the postulate a theory called “Punctuated Equilibria” where species evolve rapidly over short periods of time, but could propose no naturalistic mechanism that might allow this to happen.
What we find in the fossil record is that almost all of the major groups of animals appear suddenly in the fossil record in a stratum that is from the Cambrian period, some 500-600 million years ago. According to Jonathan Wells, “The fossil evidence is so strong, and the event so dramatic, that it has become known as ‘the Cambrian explosion,’ or ‘biology’s big bang.’” The fossil record simply cannot establish the ancestral relationship between species. Indeed, the evidence that it provides is so bad that Henry Gee, chief science writer for the pro-evolution magazine Nature, says that using fossils to show common ancestry isn’t even scientific: “To take a line of fossils and claim that they represent a lineage is not a scientific hypothesis that can be tested, but an assertion that carries the same validity as a bedtime story – amusing, perhaps even instructive, but not scientific.”
So why do so many people cling to Darwinism? We have seen that it cannot account for almost any part of the biological world, and that design is a better explanation that certainly makes more sense, but the idea of common descent is still held to by many people, lots of whom have the letters Ph.D. after their names! There are a couple of reasons that should be considered.
1. This isn’t purely an intellectual issue. There is more at stake! Richard Lewontin, evolutionary biologist and geneticist, has very candidly stated the motivations behind many Darwinists adherence to an explanation that he admits is sometimes absurd:
We take the side of science in spite of the patent absurdity of some of its constructs, in spite of its failure to fulfil many of its extravagant promises of health and life, in spite of the tolerance of the scientific community for unsubstantiated just-so stories, because we have a prior commitment, a commitment to materialism. It is not that the methods and institutions of science somehow compel us to accept a material explanation of the phenomenal world, but, on the contrary, that we are forced by our a priori adherence to material causes to create an apparatus of investigation and a set of concepts that produce material explanations, no matter how counter-intuitive, no matter how mystifying to the uninitiated. Moreover, that materialism is absolute, for we cannot allow a Divine Foot in the door.[3]
British novelist Aldous Huxley is very candid about his reasons for not wanting there to be a God, which is the logical inference if ID is true:
I had motive for not wanting the world to have a meaning; consequently assumed that it had none, and was able without any difficulty to find satisfying reasons for this assumption. The philosopher who finds no meaning in the world is...concerned to prove that there is no valid reason why he personally should not do as he wants to do, or why his friends should not seize political power and govern in the way that they find most advantageous to themselves. … For myself, the philosophy of meaninglessness was essentially an instrument of liberation, sexual and political.[4]
Former atheist Lee Strobel reveals that he had the same motivation for accepting a Darwinian explanation, “I was more than happy to latch onto Darwinism as an excuse to jettison the idea of God so I could unabashedly pursue my own agenda in life without moral constraints.” In Darwinism there is no moral accountability, and people can live life however they wish. This is not to say that all people who hold to evolution do so for these reasons, but it is certainly a powerful motivator for some!
2. Some people are truly persuaded by the evidence that Darwinism is true, that the evidence actually supports their position, but many people don’t look at all the evidence in fields outside their own. Jonathan Wells observes that “most biologists are honest, hard-working scientists who insist on accurate presentation of the evidence, but who rarely venture outside their own fields.” People have been so indoctrinated into believing that evolution is fact that even if they find little evidence for evolution in their field, they’re confident the evidence is elsewhere, maybe in genetics, or another area of biology. This means that many people don’t challenge the accepted story.
3. Finally, the pressure in academic circles to accept Darwinism is nearly overwhelming! Consider Ben Stein’s recent documentary Expelled: No Intelligence Allowed in which he discovers that many highly qualified scientist have been fired or had research grants taken away from them because they’ve publically supported ID. Even if they don’t find themselves on the receiving end of formal academic sanctions, they are often subjected to ridicule. Consider this quote from Richard Dawkins, “It is absolutely safe to say that if you meet somebody who claims not to believe in evolution, that person is ignorant, stupid or insane...”.
What we’ve seen in this particular Puzzle Piece is that macroevolution, the idea that all life shares a common ancestor, is unsupported by evidence but that many people still cling to it for a variety of reasons, not all of which stem from an objective examination of the evidence. Next time, we’ll get into the issue of morality and see if true right and wrong exist and if God is necessary to account for them.
[1] “Anthrax and antibiotics: is evolution relevant?”, by Dr Jonathan Sarfati, http://creation.com/anthrax-and-antibiotics-is-evolution-relevant, accessed Sunday August 1 2010.
[2] “Bats and horses get strangely chummy”, http://www.newscientist.com/article/dn9402-bats-and-horses-get-strangely-chummy.html, accessed Sunday August 1 2010.
[3] “Billions and Billions of Demons”, Richard Lewontin, http://www.drjbloom.com/Public%20files/Lewontin_Review.htm, accessed Sunday August 1 2010.
[4] Ends and Means, 1937, pp. 270, in http://creation.com/aldous-huxley-admits-motive-for-anti-theistic-bias, accessed Sunday August 1 2010.
Prepared by D England using material from Chapter 6 of I Don’t Have Enough Faith to be an Atheist by Geisler and Turek, unless otherwise cited. Translated for Youth by J Simmons.
