Last updated: January 30, 2015
Images like the above have long caused me to wonder whether I suffered from a mild form of PTSD caused by biology teachers from schools I attended in Communist Romania. Just kidding, I really don't get any flashbacks of primates and humans aligned, almost in a ritualistic fashion, to give credence to the fact that we, humans, are nothing more than the result of a long process of evolution. These representations of human evolution are nothing more than fiction, and modern humans have actually regressed, rather than evolved, over the last few millennia.
If Humans Ever Evolved, They Did It Through Genetic Mutations
Since the discovery of DNA, it has become obvious that, in order for evolution to happen as Darwin and neo-Darwinians envisioned it, significant changes in the genetic code would have needed to occur and be transmitted to offspring. Thus, the mantra of random, beneficial mutations, underlying small changes that occurred over very long intervals of time, was born. Or, as Julian Huxley and others like Carl Sagan put it, "Mutations [...] provide the raw material of evolution." And, for a superficial observer, this may make some sense. After all, mutations do happen, and who can tell what the end result of millions of years of mutations can be?
One would expect there are huge amounts of scientific data documenting how these beneficial mutations happen, and the manner in which they enrich the genome. One would also expect to find a plethora of examples of beneficial mutations to support this mechanism, if the theory were true. However, a careful study of the evidence shows a blaring scarcity of data. To make matterw worse, the few examples of beneficial mutations are not at all convincing.
A Look At Human Mutations In Recent History
It is estimated (by evolutionists) that a total of 108 billion modern humans were born on earth so far. Of these, over 98% were born after 8,000 B.C., and still a majority (over 56%) were born after 1 A.D. In other words, more than half of all humans who have ever lived were born during the last two thousand years. There are some questions about the accuracy of these numbers, but overall, they are the best estimates offered. I am not endorsing here these figures or ages. I am just using them to prove a point.
It is estimated that each human is born with an average of about 100 de novo germline mutations (or, to be more exact, 1.2 × 10−8 per nucleotide site per germline cell division). Of note, the rate of mutations goes up significantly in older parents, especially in fathers, with a doubling of the mutation rates for every additional 16.5 years of age for the father. Assuming a constant rate of mutations, we get 10.5 trillion mutations that occurred in the human population over the last 10,000 years (108 billion X 98% x 100 = 10.584 trillion mutations). Over 5 trillion of these mutations occurred since the birth of Christ, as more than half of modern humans were born after 1 AD. This is a huge number of mutations, no matter how we look at it. Really huge! In fact, numbers this large are very hard to grasp. Think of it this way: one trillion seconds is equivalent to about 31,688 years. If we assign one second to each mutation, it would take over 160,000 years for all the mutations that occurred in the human population since 1 A.D. to take place!
One would assume that, if evolution works the way is presented, a 10.5 trillion pool of mutations was sufficient to allow for some really beneficial ones to emerge and be preserved by Darwinian natural selection, and we should be able to observe a large number (maybe over half) of them in the DNA of humans that were born during the last two millennia. Why, one would even think we would be a much better species by now, compared to those stubborn, hard to teach disciples of Jesus...
What Do We See?
A review of examples of beneficial mutations among humans (see this, for example), yields a grand total that can almost be be counted on the fingers of one hand. Here are the ones most commonly cited:
- the ccr5-Δ32 mutation, which is actually a deletion of a genetic sequence that apparently was selected in European human populations during the bubonic plague in the Middle Ages, but was found to confer some protection against HIV (and a couple of other viral) infections.
- the lactose tolerance mutation, which makes drinking lactose containing milk beyond early childhood possible.
- the sickle-cell anemia mutation, where people with only one copy of the hemoglobin gene is mutated (HbS) are resistant to malaria. Another similar mutation, called the HbC, gives a similar protection against malaria
- Apo-AIM mutation, which is associated with a reduced risk of heart attack and stroke in a small Italian community where people who have this mutation live.
- the LRP5 mutation, which causes an increase in bone density, presumably providing protection against osteoporosis.
A careful observer would notice, looking at the examples above, that they are more indicative of adaptations to environmental pressures, rather than mutations that altered human nature significantly. A human adult that is able to drink the milk of another species without developing diarrhea is still as human as another person who cannot tolerate lactose. Other mutations - such as the ccr5-Δ32 mutation - involve selection (yes, natural selection in this sense is real, and it is not at all synonymous with evolution) under rather catastrophic conditions. Finally, for other mutations, such as the sickle-cell one, the argument for them being beneficial is very questionable, as any person who suffers from this disease would tell you.
But Evolution Takes Millions, Not Thousands of Years...
Because evolution is always presented as occurring over time expanses that have at least six zeros after one, some may be tempted to discard my observations above as irrelevant. The scenario above is, however, still very relevant to this discussion, for one simple reason: it is often stated that common ancestor populations for humans were quite small, consisting, at any given time, of less than 10,000 individuals. In the context of uniformitarianism, what happened to a population of 10,000 hypothetical human ancestors over 6 million years shouldn't be much different than what happened to 60 billion humans born after the Word became flesh in a manger in Bethlehem.
Yet another objection is that mutation rates we observe today are not necessarily the same as they were in the distant past, when evolution supposedly took place. I am not claiming here that mutations rates have not changed over time. In fact, I am quite comfortable with the idea that they did, and I think the rates we see today are higher that at certain times in the past, and are likely to become even worse in time. But working with lower mutations rates in the distant past makes the prospects of beneficial mutations taking place and having any meaningful evolutionary impact even more remote.
Could Low Selection Pressure In Humans Explain the Obvious Stasis?
Recently, a friend objected that the selection pressure among modern humans has been very weak, and therefore we should not expect to see much change. This is not a valid objection either, and here is why.
A new human life involves the release of 40 million (but in some cases up to 1.2 billion) sperm cells that compete, with rare exceptions in the case of some multiple gestations, for a single egg. One would be tempted to think that after such tremendous competition, the resulting egg has such great fitness that guarantees its survival. In reality, one in five pregnancies end in spontaneous miscarriage during the first trimester of pregnancy, mostly due to genetic errors in the egg. These defects, by the way, are another example of how deleterious genetic mutations are.
Those modern humans who made it to birth faced a rather dismal life expectancy of only 20-30 years, throughout much of our history. One in three children died before age 5, obviously before having a chance to reproduce. The majority fell victim to infectious diseases that are now prevented by sanitation and mass immunization programs or treated with antibiotics, but famine, wars, poverty, and a host of other environmental stressors took their toll, too. The high infant/childhood mortality rates skewed the "life expectancy" downward in a dramatic way for most of known history, so much so that for those who survived to age 10 or 15, life expectancy was several decades longer (except for women of child-bearing age, 20% of which used to die from birth-related infecious or other complications). By that time, it was abundantly clear to everybody that life was tough and death was very real. If anything, this is a picture of strong selective pressure, exerted mostly during the first years of life, before and during reproductive years, creating ideal (though extremely cruel) conditions for the fittest to survive and pass on their genes, beneficial mutations (if there were any) included, to their offspring.
Mutations Cause Disease and Degeneration
There are over 188,000 DNA mutations in the human genome associated with a disease condition, and the list is growing by over 10,000 a year. For some conditions, like autism, there are hundreds of mutations involved. These are all diseases well documented in the medical literature. They can be, and are, studied, and those affected are people as real as you and me.
In fact, the burden of genetic mutations in humans has recently been the focus of very interesting research even in evolutionist circles. Five years ago, Michael Lynch, professor of biology at Indiana University, published in PNAS a very interesting article, under the title Rate, molecular spectrum, and consequences of human mutation.
He evaluates the impact of genetic mutations on the "genetic fitness" of humans, and draws some rather sobering conclusions for the future of humanity. Here are some highlights:
- "it is difficult to escape the conclusion that the per-generation reduction in fitness due to recurrent mutation is at least 1% in humans, and quite possibly as high as 5%".
- modern "human activities cause an increase in the mutation rate itself (by increasing levels of environmental mutagens). A doubling in the mutation rate would imply a 2% to 10% decline in fitness per generation, and by extension, a 12% to 60% decline in 200 years."
- "it has become increasingly clear that most of the mutation load is associated with mutations with very small effects distributed at unpredictable locations over the entire genome, rendering the prospects for long-term management of the human gene pool by genetic counseling highly unlikely for all but perhaps a few hundred key loci underlying debilitating monogenic genetic disorders".
I cannot overemphasize the impact of deleterious mutations! One of the most surprising findings for me, when doing research for this article, was the scarcity of specifics in the evolutionary literature when it comes to the ratio of beneficial vs. neutral vs. detrimental mutations. One of the few estimates I have found gave a proportion of beneficial mutations of roughly one in a million! Even if the odds were to be orders of magnitude higher in favor of beneficial mutations (but, again, the data does not support this), the only realistic outcome one could expect over time is genetic degradation. For an in depth analysis of this issue, I highly recommend the book Genetic Entropy, by Dr. John Sanford, a Cornell University geneticist.
What Does Future Holds for Humanity?
"Without a reduction in the germline transmission of deleterious mutations, the mean phenotypes of the residents of industrialized nations are likely to be rather different in just two or three centuries, with significant incapacitation at the morphological, physiological, and neurobiological levels."
(Rate, molecular spectrum, and consequences of human mutation).
Not a bright future at all! Certainly, not a future where we see humans evolving, but rather where genetic degeneration reaches a tipping point, and becomes increasingly apparent in both the physical and mental/psychological domains.
One doesn't have to look too far back to see the horrific results of previous attempts at eugenics and "purifying" "superior" races. What an increasingly degenerated human race would resort to in its attempts to "remedy" it's genetic pool remains to be seen, but I have a feeling it won't be pretty at all.
Despite claims to the contrary, random mutations are not likely, even over very long expanses of time, to generate significant new genetic material to cause macroevolution. Making matters worse, though, is the significant burden of deleterious mutations, which oupaces by far any positive effect beneficial mutations may have. If, indeed, the long periods of time evolution requires were real, life on earth as we know it would likely have ceased to exist a long time ago, in large part due to mutational meltdown.
A final note: I am well aware there are people out there that will shut their mind off from such arguments and rather look for another way to explain how evolution works - things like genetic drift/flow, exchanges between genetic pools, rapid evolution, etc. There is no lack of fanciful new theories trying to patch the gaps of neo-Darwinism, or even replace it altogether, but they all are plagued by the same problem: the lack of evidence.
For a more comprehensive study of this topic, I recommend David Plaisted's article Rates of Evolution, where he brings into discussion a number of pertinent points regarding beneficial mutations and why, even allowing for incredibly long periods of time, there would still not be enough time for evolution to happen. Others have provided similar insights into the how impossible the odds of evolution through random mutations are.
In terms of the grim prospect for humanity that some of the studies above portray, there is hope. I personally am looking forward to the day when "this perishable body must put on the imperishable, and this mortal body must put on immortality." (1 Chor. 15:53).