(by Ray Bohlin)
Darwinian evolution has been described by Daniel Dennett as a universal acid that eats through everything it touches. What he meant was that evolution as an idea, what he called “Darwin’s dangerous idea,” is an all-encompassing worldview. Darwinism forms the basis of the way many people think and act. It touches everything. What Darwin proposed in 1859 was simply that all organisms are related by common descent. This process of descent or evolution was carried out by natural selection acting on variation found in populations. There was no guidance, no purpose, and no design in nature. The modern Neo-Darwinian variety of evolution identifies the source of variation as genetic mutation, changes in the DNA structure of organisms. Therefore, evolution is described as the common descent of all organisms by mutation and natural selection and is assumed to be able to explain everything we see in the biological realm.
The explanatory power of Darwinism is what Dennett refers to as Darwin’s dangerous idea. Darwinism assumes there is no plan or purpose to life. Therefore, everything we see in the life history of an organism, including human beings, derives in some way from evolution, meaning mutation and natural selection. This includes our ways of thinking and the ways we behave. Even religion is said to have arisen as a survival mechanism to promote group unity that aids individual survival and reproduction.
Since evolution has become the cornerstone of the dominant worldview of our time—scientific naturalism—those who hold to it would be expected to take notice when somebody says it’s wrong! A growing number of scientists and philosophers are saying with greater confidence that Darwinism, as a mode of explaining all of life, is failing and failing badly. Much of the criticism is targeted at the cornerstone of evolution, mutation and natural selection and the evidence for its pervasiveness in natural history. One of the biggest stumbling blocks is evolution’s repudiation of any form of design or purpose in nature. Even the staunch Darwinist and evolutionary naturalist, Britain’s Richard Dawkins, admits, “Biology is the study of complicated things that give the appearance of having been designed for a purpose.”
No one denies that biological structures and organisms look designed; the argument is over what has caused this apparent design. Is it due to a natural process that merely mimics design as Dawkins believes, or is it actually designed with true purpose woven into the fabric of life? Darwinian evolution claims to have the explanatory power and the evidence to fully explain life’s apparent design. Let’s explore the evidence.
The Limits of Biological Change
It is assumed by most that evolution makes possible almost unlimited biological change. However, a few simple observations will tell us that there are indeed limits to change. Certainly the ubiquitous presence of convergence suggests that biological change is not limitless since certain solutions are arrived at again and again. There appear to be only so many ways that organisms can propel themselves through water on land or through the air. The wings of insect, birds and bats, though not ancestrally related all show certain design similarities. At the very least, various physical parameters constrain biological change and adaptation. So there are certainly physical constraints, but what about biological constraints?
Darwin relied heavily on his analogy to artificial selection as evidence of natural selection. Darwin became a skilled breeder of pigeons and he clearly recognized that just about any identifiable trait could be accentuated or diminished, whether the color scheme of feathers, length of the tail, or size of the bird itself. Darwin reasoned that natural selection could accomplish the same thing. It would just need more time.
But artificial selection has proven just the opposite. Though they usually harbor some variability, there has always been a limit for essentially every trait. Whether the organisms are roses, dogs, pigeons, horses, cattle, protein content in corn, sugar content in beets selection is certainly possible. But all selected qualities eventually fizzle out. Chickens don’t produce cylindrical eggs. We can’t produce a plum the size of a pea or a grapefruit. There are limits to how far we can go. Some people grow as tall as seven feet, and some grow no taller than three; but none are over twelve feet or under two. There are limits to change.
It should have been instructive when we had to wait for the 1950s, almost 100 years after the publication of Origin of Species, for a documental case of natural selection, the famous Peppered Moth (Biston betularia). The story begins with the observation that before the industrial revolution, moth collections of Great Britain contained the peppered variety, a light colored, but speckled moth. With the rise of industrial pollution, a dark form or melanic variety became more prevalent. As environmental controls were enacted, pollution levels decreased and the peppered variety made a strong come back.
It seemed that as pollution increased, the lichens on trees died off and the bark became blackened. The previously camouflaged peppered variety was now conspicuous and the previously conspicuous melanic form was now camouflaged. Birds could more readily see the conspicuous variety and the two forms changed frequency depending on their surrounding conditions. This was natural selection at work.
There were always a few problems with this standard story. What did it really show? First, the melanic form was always in the population just at very low frequencies. So we start with two varieties of the peppered moth and we still have two forms. The frequencies change but nothing new has been added to the population. Second, we really don’t know the genetics of industrial melanism in these moths. We don’t have a detailed explanation of how the two forms are generated. And third, in some populations, the frequencies of the two moths changed whether there was a corresponding change in the tree bark or not. The only consistent factor is pollution. The most well-known example of evolution in action reduces to a mere footnote. Regarding this change in the Peppered Moth story, evolutionary biologist Jerry Coyne lamented that “From time to time evolutionists re-examine a classic experimental study and find, to their horror, that it is flawed or downright wrong.”
Even Darwin’s famous finches from the Galapagos Islands tell us little of large scale evolution. The thirteen species of finches on the Galapagos show subtle variation in the size and shape of their beaks based on the primary food source of the particular species of finch. Jonathan Wiener’s, Beak of the Finch , nicely summarizes the decades of work by ornithologists Peter and Rosemary Grant. While the finches do show change over time in response to environmental factors, hence natural selection, the change is reversible! The ground finches (six species) do interbreed in the wild and the size and shape of their beaks will vary slightly depending on whether the year is wet or dry (varying the size of seeds produced) and revert back when the conditions reverse. There is no directional change. It is even possible that the thirteen species are more like 6-7 species since hybrids form so readily, especially among the ground finches, and survive quite well. Once again, where is the real evolution?
There are many other documented examples of natural selection operating in the wild. They all show that limited change is possible, but that there are limits to change. No one questions the reality of natural selection. The real issue is that examples such as the Peppered Moth and Darwin’s finches tell us nothing about evolution.
Is It in the Genes?
But the refrain heard from evolutionists is that, of course, natural selection is not sufficient without a continual source of variation. In the Neo-Darwinian Synthesis, mutations of all sorts fill that role. These mutations fall into two main categories, mutations to structural genes and mutations to developmental genes. I will define structural genes as those which code for a protein that performs a maintenance, metabolic, support or specialized function in the cell. Developmental genes influence specific tasks in embryological development and therefore can change the morphology or actual appearance of an organism
Most evolutionary studies have focused on mutations in structural genes. But in order for large scale changes to happen, mutations in developmental genes must be explored. As Scott Gilbert writes, “Therefore, to study large changes in evolution, biologists needed to look for changes in the regulatory genes that make the embryo, not just in the structural genes that provide fitness within populations.” We’ll come back to these developmental mutations a little later.
Most examples that we have of mutations generating evolutionary change involve structural genes. The most common example of these kinds of mutations producing significant evolutionary change involves microbial antibiotic resistance. Since the introduction of penicillin during World War II, the use of antibiotics has mushroomed. Much to everyone’s surprise, bacteria have been found to have the uncanny ability to become resistant to these antibiotics. This has been trumpeted far and wide as real evidence that nature’s struggle for existence results in genetic change.
But microbial antibiotic resistance comes in many forms that aren’t so dramatic. Sometimes the genetic mutation simply allows the antibiotic to be pumped out of the cell faster than normal or taken into the cell more slowly. Other times the antibiotic is deactivated inside the cell by a closely related enzyme already present. In other cases, the molecule inside the cell that is the target of the antibiotic is ever so slightly modified so that the antibiotic no longer affects it. All of these mechanisms occur naturally and the mutations simply intensify an ability the cell already has. No new genetic information is added.
In addition, genetically programmed antibiotic resistance is passed from one bacteria to another by special DNA molecules called plasmids. These are circular pieces of DNA that have only a few genes. Bacteria readily exchange plasmids as a matter of course, even across species lines. Therefore, rarely is a new mutation required when bacteria “become” resistant. They probably received the genes from another bacterium.
Most bacteria also suffer a metabolic cost to achieve antibiotic resistance. That is, they grow more slowly than wild-type bacteria, even when the antibiotic is not present. And we have never observed a bacteria changing from a single-celled organism to a multicellular form by mutation. You just get a slightly different bacterium of the same species. The great French evolutionist, Pierre Paul-Grasse when speaking about the mutations of bacteria said, “What is the use of their unceasing mutations if they do not change? In sum the mutations of bacteria and viruses are merely hereditary fluctuations around a median position; a swing to the right, a swing to the left, but no final evolutionary effect.”
From Micro to Macro?
What I have been describing so far is what is often referred to as microevolution. Evolutionists have basically assumed that the well-documented processes of microevolution eventually produce macroevolutionary changes given enough time. But this has been coming under greater scrutiny lately, even by evolutionists. There appears to be a real discontinuity between microevolution and the kind of change necessary to turn an amoeba-like organism into a fish, even over hundreds of millions of years.
Below is just a quick sampling of such comments and musings from the current literature:
“One of the oldest problems in evolutionary biology remains largely unsolved. . . . [H]istorically, the neo-Darwinian synthesizers stressed the predominance of micromutations in evolution, whereas others noted the similarities between some dramatic mutations and evolutionary transitions to argue for macromutationism.”
“A long-standing issue in evolutionary biology is whether the processes observable in extant populations and species (microevolution) are sufficient to account for the larger-scale changes evident over longer periods of life’s history (macroevolution).”
“A persistent debate in evolutionary biology is one over the continuity of microevolution and macroevolution – whether macroevolutionary trends are governed by the principles of microevolution.”
While each of the above authors does not question evolution directly, they are questioning whether what we have been studying all these years, microevolution, has anything to do with the more important question of what leads to macroevolution. And if not microevolution is not the process, then what is?
The fundamental question which needs addressing is how have we come to have sponges, starfish, cockroaches, butterflies, eels, frogs, woodpeckers and humans from single cell beginnings with no design, purpose or plan? All the above listed organisms have very different body plans. A body plan simply describes how an organism is put together. Can we discover just how all these different body plans can arise by mutation and natural selection? This is a far bigger and more difficult problem than antibiotic resistance, a mere biochemical change. Now we have to consider just how morphological change comes about.
The problem of macroevolution requires developmental mutations. Simply changing a protein here and there won’t do it. We somehow have to change how the organism is built. Structural genes tend to have little effect on the development of a body plan. But the genes that control development and ultimately influence the body plan tend to find their expression quite early in development. But this is a problem because the developing embryo is quite sensitive to early developmental mutations. According to Wallace Arthur, “Those genes that control key early developmental processes are involved in the establishment of the basic body plan. Mutations in these genes will usually be extremely disadvantageous, and it is conceivable that they are always so.”
But these are the mutations needed for altering body plans. However, evolutionists for decades have been studying the wrong mutations. Those dealing with structural genes, microevolution, only deal with how organisms survive as they are, it doesn’t tell us how they got to be the way they are. Consider the following quotes:
The Modern Synthesis is a remarkable achievement. However, starting in the 1970’s, many biologists began questioning its adequacy in explaining evolution .… Microevolution looks at adaptations that concern only the survival of the fittest, not the arrival of the fittest.
In a developmentally explicit approach it is clear that many late changes can not accumulate to give an early one. Thus if taxonomically distant organisms differ right back to their early embryogenesis, as is often the case, the mutations involved in their evolutionary divergence did not involve the same genes as those involved in the typical speciation event.
To sum up our current dilemma, significant morphological change requires early developmental mutations. But these mutations are nearly universally disadvantageous. And microevolution, despite its presence in textbooks as proof of evolution, actually tells us precious little about the evolutionary process. If these developmental mutations that can offer an actual benefit are so rare, then macroevolution would be expected to be a slow and difficult, yet bumpy process. Indeed Darwin expected that “[a]s natural selection acts solely by accumulating slight, successive, favorable variations, it can produce no great or sudden modifications; it can only act in short and slow steps.”
The Fossil Record
The origin of body plans is wrapped up in the evidence of paleontology, the fossils and developmental biology. What does the fossil record have to say about the origin of basic body plans? When we look for fossils indicating Darwin’s expected slow gradual process we are greatly disappointed. The Cambrian Explosion continues to mystify and intrigue. The Cambrian Explosion occurred around 543 million years ago according to paleontologists. In the space of just a few million years, nearly all the animal phyla make their first appearance. This sudden appearance is without evidence of ancestry in the previous periods. S. Conway Morris explains:
The term “explosion” should not be taken too literally, but in terms of evolution it is still very dramatic. What it means is rapid diversification of animal life. “Rapid” in this case means a few million years, rather than the tens or even hundreds of millions of years that are more typical . . .
Prior to the Cambrian, (550-485 million years ago), during the Vendian (620-550 million years ago) we find fossil evidence for simple sponges, perhaps some cnidarians and the enigmatic Ediacaran assemblage. For the most part we find only single cell organisms such as bacteria, cyanobacteria, algae, and protozoan. Suddenly, in the Cambrian explosion (545-535 million years ago), we find sponges, cnidarians, platyhelminthes, ctenophores, mollusks, annelids, chordates (even a primitive fish), and echinoderms.
While many animal phyla are not present in the Cambrian, those absent are mostly phyla of few members and unlikely to be fossilized in these conditions. James Valentine goes further in saying that “the diversity of body plans indicated by combining all of these Early Cambrian remains is very great. Judging from the phylogenetic tree of life, all living phyla (animal) were probably present by the close of the explosion interval.” Later Valentine assures us that the fossil record of the explosion period is as good as or better than an average section of the geologic column. So, we just can’t resort to the notion that the fossil record is just too incomplete as many evolutionists do.
In the Cambrian Explosion we have the first appearance of most animal body plans. This explosion of body plans requires a quantum increase of biological information. New genetic information and regulation is required. Mutations at the earliest stages of embryological development are required and they must come in almost rapid fire sequence. Some have suggested that perhaps the genetic regulation of body plans was just more flexible back then, making for more experimentation. But we find some of the same organisms in the strata from China to Canada and throughout the period of the explosion. These organisms do not show evidence of greater flexibility of form.
The rate of mutation is definitely a problem. Susumo Ohno points out that “it still takes 10 million years to undergo 1% change in DNA base sequences. . . .[The] emergence of nearly all the extant phyla of the Kingdom Animalia within the time span of 6-10 million years can’t possibly be explained by mutational divergence of individual gene functions.”
Darwinism would also require early similarities between organisms with slow diversification. Phyla should only become recognizable after perhaps hundreds of millions of years of descent with modification. Yet the great diversity of the Cambrian Explosion appears first with gradual drifting afterward, the opposite of what evolution would predict. Again some suggest that the genetic structure of early organisms was less constrained today allowing early developmental mutations with less severe results. But there would still be some developmental trajectory that would exist; so the selective advantage of the mutation would have to outweigh the disruption of an already established developmental pathway.
But each of these speculations is unobservable and untestable. It is quite possible that developmental constraints may be even more rigid with fewer genes. But even if the constraints were weaker, then there should be more variability in morphology of species over space and time. But as I said earlier, the Cambrian fauna are easily recognizable from the early Cambrian deposits in China and Greenland to the middle Cambrian deposits of the Burgess Shale. There is no testable or observational basis for hypothesizing less stringent developmental constraints.
This stunning burst of body plans in the early Cambrian and the lack of significant new body plans since the Cambrian indicate a limit to change. Evolutionary developmental biologist Rudolf Raff told Time magazine over ten years ago, “There must be limits to change. After all, we’ve had these same old body plans for half a billion years.” Indeed, perhaps these limits to change are far more pervasive and genetically determined than even Raff suspects.
The functionality of these intermediate organisms transporting from one body plan to another has long puzzled even the most dedicated evolutionists. S. J. Gould, the late Harvard paleontologist asked, “But how can a series of reasonable intermediates be constructed? . . .The dung-mimicking insect is well protected, but can there be any edge in looking only 5 percent like a turd?”
With his usual flair, Gould asks a penetrating question. Most have no problem with natural selection taking a nearly completed design and making it just a little bit more effective. Where the trouble really starts is trying to create a whole new design from old parts. Evolution has still not answered this critical question. I fully believe that evolution is incapable of answering this question with anything more than “I think it can.” However, unlike the little train that could, it will take far more than willpower to come up with the evidence.
There are many other challenges to evolution than the ones I have raised here. Most notable are those of Michael Behe who has argued that living cells are irreducibly complex and thus could not have evolved from simpler forms; and of William Dembski who has pointed to the existence of “specified complexity” in nature that points to the existence of intelligent design. Space does not permit a discussion of these other issues. Suffice it to say that evolution is truly is a theory in crisis.
Ray Bohlin is the President of Probe Ministries (www.probe.org), a Christian apologetics ministry located in Richardson, Texas.
Want to Read More About Creation and Evolution?
Darwins Black Box: the Biochemical Challenge to Evolution by Michael J. Behe (Free Press)
Signs of Intelligence: Understanding Intelligent Design eds. William A. Dembski and James M. Kushiner (Brazos)
The Privileged Planet: How Our Place in the Cosmos Is Designed for Discovery by Guillermo Gonzalez and Jay W. Richards (Regnery)
The Collapse of Evolution by Scott M. Huse (Baker)
Darwin On Trial by Phillip E. Johnson (InterVarsity)
Bones of Contention: A Creationist Assessment of Human Fossils by Marvin L. Lubenow (Baker)
Battle for the Beginning: Creation, Evolution and the Bible by John F. MacArthur (W Publishing)
Three Views on Creation and Evolution eds. J.P. Moreland and John Mark Reynolds (Zondervan)
The Ten Things You Should Know about the Creation Vs. Evolution Debate by Ron Rhodes (Harvest House)