The ministry of Ken Ham’s Answers in Genesis exists, in part, to provide Christians with responses to what they believe are anti-biblical beliefs about the age of the earth and the origin of biological diversity. To provide these answers, AiG has assembled a small group of geologists and biologists. These employees provide answers to questions that cover the full range of these large scientific disciplines. As a result, they are often required to engage in scientific discussion in fields for which they have no formal or practical training. This is especially true when it comes to the topic of evolutionary biology.
There are only two Ph.D. biologists on staff at AiG, neither of which – that I can tell – have formal training in evolutionary biology. Ken Ham has a bachelor’s degree in environmental biology, and he taught high school biology for several years before entering the creation science ministry. Because he lacks any personal research experience and doesn’t have a background in evolutionary biology, he has to trust the people he has hired to provide him with answers that he so dogmatically proclaims in his presentations and articles. Unfortunately, his faith is misplaced. His faulty understanding of evolutionary processes and the history and development of evolutionary biology is reinforced by information fed to him by employees whom he believes are experts.
In recent years, Answers in Genesis has increasingly turned its attention to providing explanations for the patterns of biological diversity we observe alive today and in the fossil record. In other words, they have been putting more effort into seeking alternative hypotheses to evolutionary theory which encompasses a suite of processes, including natural selection, by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.
As they move into the arena of explaining biological diversity, AiG has sought to embrace some evolutionary terminology while distancing themselves from the word “evolution” itself. One example of this is a video that is frequently re-posted on Facebook and has a prominent position on the AiG website shows Dr. Purdom answering the question: Is natural selection the same thing as evolution?
Dr. Purdom is not an evolutionary biologist, nor can I find evidence that she has ever taken an evolutionary biology course. She graduated from a college that had an anti-evolution curriculum and obtained here Ph.D. from a graduate program at The Ohio State University that would not have required any evolutionary biology training nor provided any further knowledge of evolutionary biology to complete her degree. So, it is not surprising that her grasp of evolutionary theory could be rather limited.
Unfortunately, Dr. Purdom has a position of authority to speak on this subject and is therefore an authority figure or “expert” in the eyes of her target audience. This is what is particularly troublesome to me about her presentation. I see the same nonsensical language on FaceBook every day and I hear the same kinds of comments from lay Christians at seminars and conferences that I attend. Christians who rely on AiG feel that they are fully justified in their criticisms of evolutionary theory because they believe that “experts” like Dr. Purdom are providing them with competent answers.
I don’t fault non-biologists struggling to understand species concepts, genetic diversity and natural selection for latching onto ideas that fit their pre-conceived notions of evolution. But public figures like Dr. Purdom have a much great responsibility for providing accurate statements and fair analyses because they are in a position of influence. Regardless of how well supported – or not supported – you think evolutionary theory may be, I would hope that we all expect that those that speak as authority figures would have a good understanding of what they are teaching.
Just how poor is Dr. Purdom’s grasp of evolutionary theory?
I wondered, just how might biology undergraduate students respond to the same question: Is natural selection the same things as evolution?
I decided to find out. A week ago, I gave 35 students (mostly junior and senior biology majors) the following writing assignment: Watch this video by Dr. Georgia Purdom and write a short essay about how you might respond. Where do you think she is correct and where do you think she is either confused or misleading?
I am hoping I can share one or more of those essays in the next post and share my thoughts about the quality of the students’ work. Hint: there was a huge difference in the quality of writing and development of thought, but all the students could pick out significant errors in Dr. Purdom’s presentation.
Before I provide the student responses, I will provide my own assessment of Dr. Purdom’s video. The video can be found at the top of this Answers in Genesis webpage: https://answersingenesis.org/natural-selection/ Below is a transcript I produced of the most important parts of that video.
“Is natural selection the same things as evolution? Well, the short answer to that is no. But let’s take a more in-depth look at why that’s the case. The first thing we need to do is define natural selection and evolution. Natural selection is an observable process in which organisms with certain characteristics survive better in a given environment, and there is a loss of information in the DNA. Genetic information decreases as a result of this process. Evolution is defined as an unobservable process which has occurred over long periods of time in which a single-celled organism has become all the organisms that we have today and have had in the past. It is directional in the sense that dinosaurs have evolved into birds and genetic information must increase in order for this process to occur. So, as you can see from the definitions they are very, very different.”
After a short discussion of the development of antibiotic resistance in bacteria, Purdom continues:
“So what have we really observed here? First of all, bacteria remain bacteria. It is non-directional and genetic information has been lost as a result of this process. So, even if you give natural selection long periods of time, such as millions of years, it simply can’t do what evolution requires of it which is move in a certain direction and to add genetic information. There is no doubt natural selection has resulted in changes within kinds of animals.” https://answersingenesis.org/natural-selection/
So let’s dig into Dr. Purdom’s attempt to redefine evolutionary theory. She begins by saying that terms need to be defined. I certainly agree. But then she goes on to produce some highly unorthodox definitions and then claims that the definitions are “very, very different.” If you do a Google search for definitions of biological evolution and natural selection and pick 10 different sources and see if any of them match Dr. Purdom’s definition. You won’t find a close match unless you hit upon the Answers in Genesis website itself and find their definition. But more importantly, dig up 10 scholarly books on evolutionary theory and see if you can find her definitions in them?
Why does she not use accepted scholarly definitions, thus putting the best position of her opposition forward? By beginning with unorthodox, if not unique, definitions, we can strongly suspect there is some sort of shell-game going on whereby terms are being defined differently than the rest of the scientific community.
But let’s look a bit closer at some of her statements.
Yes, evolution is not the same as natural selection – well, sort of
No proponent of evolution theory is saying that natural selection is, by itself, evolution. The strongest statement they may make is that natural selection is an important mechanism for causing evolution to occur.
Evolution is a “change in the heritable traits of biological populations over successive generations” (1) and rather than being a wholly different process, natural selection is but a partial explanation for how this change may come about. Evolutionary theory includes a number of process that work together to cause change and provide an explanation for the observed change in organisms over time as witnessed by the fossils record, genome studies, etc. The other mechanisms that should be considered are genetic drift and gene flow. Essential to all of these processes are mutations which provide the raw source of variation upon which selection and genetic drift can act.
Put most simply, evolution is a response/result of natural selection. Natural selection does not fully explain evolution because, by itself, it does not explain all the changes in heritable traits over successive generation.
By definition, does genetic information always decrease as a result of natural selection?
A loss of information has never been part of the definition of natural selection. It is true that natural selection acting on a population of individuals may cause some genetic variation to be lost in successive generations. The definition of “loss of information” in creationist literature is fuzzy, despite being a favorite phrase of creationists. Notice the important part that this auxiliary idea plays in Dr. Purdom’s and AiG’s definition of natural selection and evolution. Natural selection is said to cause a loss of information, but evolution is a process that is said to require an increase in information over time.
Maybe “information” is similar to the idea of genetic variation. But natural selection does not by definition result in a loss of genetic variation or diversity. Yes, it would not be incorrect to say that natural selection can result in a loss of alleles from a population, thus reducing overall genetic variation, but such an outcome is by no means guaranteed. In fact, at times selection can serve to preserve genetic variation. I would suggest that Dr. Purdom look up negative-frequency dependent selection, balancing selection, and heterozygote advantage.
Dr. Purdom is free to propose a new hypothesis about the effects of natural selection and provide evidence that loss of information is a necessary outcome of natural selection, but it should not be included in the definition when no other scholars use such a phrase and the evidence doesn’t support her assertion.
Under some circumstances, natural selection can certainly select for new functions of genes, especially in the case of duplicated genes where both versions are not needed. The duplication event itself would be a mutation – which is not acknowledged by Purdom as an important process – but the selection of new mutations in the duplicated gene for new functions is done primarily by the process of natural selection. A new function would by any measure constitute an increase in genetic variation or “information”. So natural selection, which acts to select for beneficial genetic variation, can lead to the establishment of new genetic material within a population over time. Again, this is evolution, since this constitutes a change in the frequency of alleles in a population. Furthermore, these genetic changes are capable of causing speciation to occur, which Dr. Purdom apparently does agree can happen – “There is no doubt natural selection has resulted in changes within kinds of animals.”
“Evolution is defined as an unobservable process occurring over long periods of time”
This may sound like a reasonable start to a definition to the average non-biologist, but even here we see that Dr. Purdom has a special definition of evolution in mind, quite different from that of the scientific community. By using the phrase “defined as an unobservable process,” she is by definition excluding all known processes of evolution from being or causing evolution to occur. But what then does she think that process is? Apparently this unobservable process does not include natural selection, genetic drift, gene flow, or mutations because these are all readily observed processes, which have all been demonstrated to cause populations to change over successive generation through time – i.e. evolution.
No doubt Dr. Purdom believes that these process are not capable of producing the full diversity of life, but her definition implies that evolutionary theory includes different non-observed processes that are responsible for cladogenesis (speciation). However, I am unaware of what these unobserved processes evolutionists have proposed may be if they are not natural selection, genetic drift, mutations and migration, which are all readily observed.
I suspect Dr. Purdom believes that there is some special biological process by which a family of species gives rise to another family of species. However, this is a gross misunderstanding of evolutionary theory. There is no special process proposed for such changes, since families don’t give rise to other families. Evolutionary theory posits that all diversity results from species potentially giving rise to new species. Dr. Purdom admits that new species are formed via natural selection – a process of evolution – and so has agreed, albeit unwillingly – that evolution is observable.
She is free to provide reasons why speciation may be limited, such that though species may be formed from a common ancestor those species are unable to grow more dissimilar over time resulting in application of classification terms such as genera and families. But again I would point out that genera and families are not formed via any proposed unobserved process, so how can she say that a never-proposed process is part of the definition of evolution?
Not to belabor the point, but it is important. Here is a quote from a popular bio-majors textbook on evolution (Douglas Futuyma “Evolution” 2nd edition):
We now know that Darwin’s hypothesis of natural selection on hereditary variation was correct, but we also know that there are more causes of evolution than Darwin realized, and that natural selection and hereditary variation themselves are more complex than he imagined. A body of ideas about the causes of evolution, including mutation, recombination, gene flow, isolation, random genetic drift, the many forms of natural selection, and other factors, constitute our current theory of evolution, or “evolutionary theory.”
Note that there are a number of processes that Futuyma lists that cause evolution. All of these are observable phenomena. There is no hint here, despite the clause “other factors,” that Futuyma thinks there is another important cause, or process, which is an important component of evolution that works at the level of a family. Futuyma is not excluding the evolution of diverse life from common ancestors in his description and thus he is indicating that these observable processes are the very same processes responsible for evolution of populations, species and eventually leading to the formation of families and larger groups. Again, families and higher groups do not evolve as if they were some real entity but the species in those groups continue to change over time.
I wonder what these mysterious unobserved processes Dr. Purdom has in mind that are the cause of evolution that does not include any of the causes that Dr. Futuyma mentions. Of course, the full scope of change in organisms over time has not been directly observed, but evolutionary theory does not propose a different set of mechanisms for changes that have happened in the past. However, any process that occurs over time such as plate tectonics, volcanic activity, water erosion, etc., can be expected to leave behind a trail of forensic evidence which can be used to infer what has happened in the past. For evolution, this trail of breadcrumbs of evolution having happened in the past, as it does in the present, can be observed in the fossil record, DNA sequences and genome structure, and increasingly in ancient DNA studies.
Must evolution “move in a certain direction”?
Evolution may appear to be directional because in hindsight you see what has happened. But how could any change not have a direction? When natural selection causes cave fish to lose the ability to see, this is an adaption to that environment and makes the fish more fit for – better able to survive and reproduce in – that environment. Seeing how that has happened, you could say that the direction of evolution was to lose eyesight and sometimes even a portion of the organ for eyesight. With the energy saved by not performing a useless function, the fish can use that portion of its brain and the energy saved to do things that other fish are unable to.
But I believe that Dr. Purdom is saying something more here. She knows her audience will interpret “directional” as becoming more advanced, in the same way that most people hear mutation as meaning “bad.” But why must birds be seen as more advanced than dinosaurs? Is a cat more advanced than a T. rex or a dog more advanced than kangaroo? Were dinosaurs waiting around to turn into birds because that was the direction they were supposed evolve? Direction, for YECs such as Dr. Purdom, doesn’t just refer to advanced features; it has a teleological aspect to it. It suggests evolution is some sort of conscious entity – a process with a mind – that is directing species to predetermined end-points.
This is where Dr. Purdom’s concepts of evolution are far removed from reality – or at least the reality of the last century. She is painting evolution as having a goal and being driven by a mysterious non-observed mechanism. She is harkening back to the “great chain of being” idea and the hierarchical views that were popular up through the 1800s wherein evolution was sometimes cast as striving toward a goal, with humans as its crowning achievement. Hence, she says that evolution must be directional and that direction is to add information – or to become more complex. This again sets up the contrast with natural selection, which she has already painted as a process that is working in the opposite direction – reducing information and thus simplifying organisms over time. This fits with what she believes is the designed purpose – with a big P – of natural selection: to sort specially created variation into distinct genealogical lineages – aka species. Because the resultant species will not have as much genetic variation as the ex nihlo created first member of the “kind” this process by definition is always going to result in species with less genetic variation. Hence she believes that natural selection only results in information loss.
These ideas are not reflective of modern evolutionary theory. Evolutionary theory says nothing of a direction that organisms must take. It is true that natural selection does cause adaptation to environments and thus the direction of this change is not random. However, that direction is not, by definition, toward more complexity or “more information.” My cave fish example illustrates that a loss of eyesight is an adaptation to a cave habitat. At the same time some blind cave fish have adapted their fins to climb the walls of caves to find algae to eat (2). Both of these adaptations entail changes in the use of genes including new uses of genes and likely even new genes. Some of these changes certainly constitute functional additions to what DNA could previously encoded. The direction of change is determined by the needs of the organism not a will to increase information. In many cases additional genes or new uses of genes can be adaptations to the environment that an organism finds itself living in and so natural selection can result in adding new features to an organism but this is not required for evolution to happen.
More simply, direction is something that is observed in hindsight. It is the result of what has happened not the original intent of the organism itself.
The missing part of the equation: mutations
Since evolution is a change in heritable traits over generations, there is one very important condition that must be met for evolution to occur: there must be heritable genetic variation in a population. We can observe that all populations of all species have genetic variation, though some have more than others.
What is the origin of this genetic variation? Here we find another difference between AiG’s opinion about how change occurs and that of evolutionary theory. Their sources of variation are different: AiG states that the original “kinds” were created with all the variation needed to create the species that they would diversity into. In other words, the original creation is the lone source of the genetic material for the genetic variation for evolution to happen. However, evolutionary theory depends on mutations to form the raw resources for evolution. Evolutionary theory predicts that populations in the past contained, on average, similar amounts of genetic diversity than they do in the present rather than much higher amounts of diversity.
In the video Dr. Purdom admits that mutations can happen and that they may allow for an organism like a bacteria to adapt to its environment. In this case, a mutation allows resistance to anti-biotics and then natural selection chooses that new mutation because it makes a bacterium more fit for its environment. This results in a change in the heritable traits over generations. But Dr. Purdom then dismisses this as having anything to do with evolution because she has already defined evolution as something other than mutations and natural selection. She says this is just natural selection and not evolution. She then tries to further dismiss the importance of mutations by suggesting the environment could change leaving that new mutation less fit for the environment. Without saying it she is implying the mutation, though originally positive, would end up being bad for the bacteria. So she is proposing that all mutations are bad and don’t really add “information” to the bacteria in the long run.
Dr. Purdom completely misses the point of bacterial evolution and, almost laughably, her appeal to the environment changing and thus changing the direction of selection making a mutation turn from good to bad is exactly why evolution is not directional as she defined it.
Dr. Purdom acts as if there are two separate processes: evolution and natural selection. We have seen that the question posed by Dr. Purdom and her answers appear to set evolution and natural selection in opposition to one another (eg. gain vs. loss of information, directional vs directionless, and unobserved vs observed process). However, natural selection is but one process that results in evolution.
We could ask, is Dr. Purdom simply uninformed about evolutionary theory or is she is consciously revising the definitions to confuse her audience? It is hard not to conclude that both are probably true but I would give more weight to the first. Given her background and the fact she has obviously chosen to further educate herself by relying on other young earth creationist materials it is likely that she profoundly misunderstands evolutionary theory.
(1) Hall, Brian K.; Hallgrímsson, Benedikt (2008). Strickberger’s Evolution (4th ed.). Sudbury, MA: Jones and Bartlett Publishers. ISBN 978-0-7637-0066-9.
(2) Brooke E. Flammang, Apinun Suvarnaraksha, Julie Markiewicz, Daphne Soares. Tetrapod-like pelvic girdle in a walking cavefish. Scientific Reports, 2016; 6: 23711 DOI: 1038/srep23711
For a simple description of how evolutionary biologists describe evolution and natural selection I recommend the following videos from Stated Clearly on YouTube.com
https://youtu.be/GhHOjC4oxh8 – What is Evolution
https://youtu.be/0SCjhI86grU – What is Natural Selection
Cover image: ladybug about to take flight. Credit: Joel Duff