“You might be surprised to learn that this phrase [“survival of the fittest”] does not appear within the text of The Origin of Species.”
For his part, Darwin knew that he didn’t have all the answers. He would not be surprised that many of his hesitant conclusions have evolved over the more than 150 years since his most famous work, On the Origin of Species by Means of Natural Selection, was published in 1859.
Darwin may have been unfairly vilified for his role in the controversy of evolutionary theory; The Origin of Species is light on conclusion and heavy on observation. In other words, Darwin was only really responsible for unpacking more pieces of the puzzle. At most, he merely promoted the notion that his observations did not support many of the contemporary scientific and theological conclusions of his time.
Darwin is infamously attributed with coining the phrase “survival of the fittest.” You might be surprised to learn that this phrase does not appear within the text of The Origin of Species. Darwin later adopted the phrase, but it was not one of Darwin’s original thoughts, nor was it even his own. The core of Darwin’s text stipulates only three main elements: variation between individuals within the same species, natural selection based on environmentally preferential variations that aid survival, and finally, inheritance of (those) traits between generations.
Darwin is possibly most unfairly criticized for promoting the conclusion that humans descended from apes and that the human species is perched atop the evolutionary tree as the apex solution. Remarkably, Darwin didn’t actually say that. Darwin merely suggested that apes and humans might share common ancestry (given the similarity of our traits possibly inherited from divergent generations).
Today there is no doubt within the scientific community that microevolution is a fact: choosing to ignore it, discount it or even argue against it would be somewhat futile. But, before you log out in disgust, please read on, at least long enough to understand the two critical caveats that are equally unarguable. It’s important to realize that understanding microevolution does not solve the creation-of-life question or the origin of any species, especially the human species. Darwin didn’t try to solve this riddle; in fact, he specifically suggested that both of these questions would have to be answered by someone else in the future.
The mechanism of microevolution is real; it is well understood; it has been observed and can be replicated. To understand the process, you must first accept that the underlying mechanisms tend to act over very long periods of time, spanning many, many generations. Subsequently, scientists tend to focus their studies on simple organisms having short reproductive cycles and short lifespans. At the core of the evolutionary mechanism is random genetic mutation. Genetic mutation is not deliberate or intentional; individual organisms don’t mutate directly in response to external environmental pressures. Instead, individual members of a species may develop a random genetic mutation (Darwin’s first core principle - variation between individuals) that could cause them to develop in such a way as to provide them with a survival advantage (Darwin’s second core principle - natural selection based on environmentally preferential variations that aid survival). If that mutation also provides a competitive advantage, then those individuals are more likely to be the first (or only) to reproduce which further perpetuates their genetic traits (Darwin’s third core principle - inheritance).
Case Study - Haras of Horses
To illustrate this idea, imagine a haras (group) of horses grazing on the low hanging fruits of a sandy orchard. Now imagine a lonely horse off by itself, alienated from the rest due a genetic deformity that burdened it with an unusually long neck. This deformed horse did not grow a long neck for any specific reason, nor did it adapt to accommodate any environmental condition. In this illustration, the horse is unexplainably deformed, “such that the works of God might be displayed in him” (John 9:3). However, now imagine that there are so many horses in this harass that they eat all the low hanging fruit from the trees. Now there is no readily available food within the reach of the horses, and they start to die off, all except those with the longest necks who can still reach the fruit higher up within the trees. The only horses left behind to reproduce are the long-necked horses. Subsequently, the long-neck gene which was once just a random deformity, is now a dominant inherited trait that makes the long-necked horse the fittest to survive in that sandy orchard.
The Haras of Horses case study is an over-simplified alegory, but it serves to explain the basics of micro-evolution. It does not explain where the horses came from, nor does it suggest what the horses will become. It certainly does not suggest that these horses will become giraffes, and Darwin would certainly not make that case either. However, many are tempted to make this leap. Many others actually do make that leap and cross the line into the realm of macroevolution. Macroevolution is generally misunderstood as being just a culmination of multiple microevolutions. However, macroevolution is the theoretical process by which one species becomes classified as another. The generally accepted standard for classifying one species as being different from another similar species is their ability to produce fertile offspring.
Human microevolution can also be illustrated quite simply. However, the following case studies are not allegories; they are real.
Case Study - Lesser of Two Evils
Malaria is a disease that infects human red blood cells. It’s caused by a parasite that is carried and transmitted to humans by female mosquitoes. The World Health Organization (WHO) estimates that this deadly disease threatens more than half of the human population and kills almost half a million of us each year. Malaria is commonly deadly, especially when contracted by infants who, on average, die before their fifth birthday, long before they are sexually mature. While pharmaceutical immunity, to those who can afford it, is now common across the world, these effective malaria medicines are only a recent development in human history. So why did malaria not wipe out humanity long ago? There are two components to the answer.
Malaria is an organism, albeit a single-celled protozoan, with its own genetic map and evolutionary heritage. Although there are records of malaria type infections in humans dating back more than five thousand years, the genesis of malaria is largely unknown. It’s very likely that large segments of the human population either migrated or already lived beyond what are now malaria-dense environments before the ancestors of the malaria protozoa mutated into the deadly variants that we know today. Secondly, and more tangibly, some humans exhibit a natural variation that makes them resistant to malaria. However, it’s important to remember that this human variance did not evolve in response to malaria and could possibly have evolved prior to the appearance of malaria. Regardless, quite coincidental to malaria, some humans developed a genetic deformity of their red blood cells that, by chance, prevented the malaria parasite from occupying and reproducing within those cells. Subsequently, individuals with this random variation are very poor hosts for the malaria parasite. Unfortunately, this miracle genetic mutation also causes a fatal human disease. But it might be the lesser of two evils because the afflicted person lives much longer and well into sexual maturity, enabling inheritance of the malaria resistant genetic code by their descendants. Those without this malaria tolerant mutation would almost certainly die from malaria as infants without passing on their fragile genes.
Malaria is most common in sub-Saharan Africa but can be found around the world at similar latitudes. If the malaria illustration we just studied is true, we should be able to find genetic evidence of malaria resistance within the descendants of those who proved fit to survive the sub-Saharan malaria environment. As it turns out, we can. That evidence can be found today in those who suffer from the ‘miracle’ disease: sickle-cell anemia. The highest morbidity of sickle-cell anemia can be found within those of African descent. Those who suffer from sickle-cell anemia do not typically contract malaria, but their life expectancy is only between the ages of 35-60.
Case Study - Ebola
The Ebola pandemic that swept across Africa and crept into other parts of the world in 2014. Although Ebola was well known to the medical community prior to the 2014 outbreak, it was confined to the African continent and was not widespread. Suddenly and inexplicably the Ebola virus proliferated and was widely considered to be a global threat. Human efforts to control this particularly virile disease were futile. Tens of thousands became infected and many subsequently died as a result. Interestingly though, although an Ebola infection was widely considered to be a death sentence, mortality was not 100%. Some infected individuals exhibited a natural ability to defend against the Ebola virus and survived the torturous illness. Those who were not genetically fit to survive Ebola died. Those who lived, remain to propagate their superior genes.
The word evolution is often misrepresented to imply positive change for a particular species. However, the process of microevolution is indifferent. Adaptations resulting from this natural process might ultimately lead to an evolutionary dead end, no matter how advantageous it is to the present generation. We could choose to examine several different examples of adaptations that have painted a species into an evolutionary corner, but one of the most intriguing examples is demonstrated by the phenomenon of symbiosis, specifically obligate mutualism. Obligate mutualism is a very specific type of symbiosis where both species not only gain a benefit from the other, but both are exclusively dependent on the other species for their very survival. In other words, they are obligated to mutually coexist, or they die. Such relationships are rare, but they are often cited by creationists as evidence of nature’s fine tuning. Their argument is that the conditions under which two species would coincidentally evolve in tandem, purely by random mutation, such that they were wholly dependent upon each other are vanishingly small.
Case Study - Obligatory Relationships
There exists a special relationship between hard coral and zooxanthellae (algae). Hard corals are actually animals not plants. They are non-autotrophic, so they cannot meet their own nutritional needs. Algae are photosynthetic plants that synthesize sugars from carbon dioxide, water, and other necessary molecular compounds, using energy from the sun to drive the process. The algae lives within the porous cavities of hard coral, which provides physical protection from herbivorous consumers. The hard corals also secrete organic compounds that the algae need for photosynthesis. In return the algae provides the coral with glucose, glycerol, and amino acids with which the corals make proteins, fats, carbohydrates, and calcium carbonate. Hard corals and their dependent zooxanthellae have evolved past the point of no return, possibly down an evolutionary dead end. They are forever obligated to each other. Neither can exist within their current environment on their own. In recent years the global population of hard coral has fallen into steep decline, suffering from what is being called bleaching. Hard corals around the planet have been observed to eject the zooxanthellae from their pores, which voids the coral of its color. It is believed that increases in ocean temperatures could contribute to this phenomenon, but marine scientists still have much to learn.
It could be argued that advances in modern medicine are decelerating human evolution. There are scant examples of unchecked environmental pressures that select only the most suitable human genes. In most cases medical intervention is now circumventing the natural forces that have sculpted the human form for millennia. Humans are surviving what might once have been fatal illnesses, illnesses that might have been eradicated by evolutionary forces but are now left to proliferate once the host procreates. One commonly examined evolutionary conundrum is that of the human appendix. Science continues to argue the evolutionary significance of the appendix, but it is widely accepted that it is now a useless intestinal relic, vulnerable to infection and rupture. Without modern medical intervention, those who fall victim to an appendix infection that ruptures are likely to die. People with a family history of appendicitis are more prone to this type of infection, which suggests that there are genetic markers responsible for this fatal flaw. If left unchecked, those humans born with a smaller appendix, who are genetically less vulnerable to appendix infections, would eventually win out over those who died before mating. Ultimately the appendix would have vanished from the anatomy of our descendants, much like our vestigial tail, which is now nothing more than a few fused bones at the base of our human spine. However, appendicitis is now rarely fatal. It is easily diagnosed and treated with a relatively simple surgery. Subsequently, the human gene that perpetuates our appendix is left unchecked. The evolutionary process that would have erased it (death) has been circumvented.
There are many examples of congenital human afflictions that are now being perpetuated by modern medicine. Humans who would previously have died prior to passing a fragile gene to their children are now living long enough to procreate, thus perpetuating that fragility into the human gene pool. Medically facilitated artificial selection has not just decelerated human evolution; it is actively devolving the human race physically.
Human devolution is not a novel concept. Playing God with genetic inheritance has been contemplated and explored ever since the concept of heredity was first understood. Our ancient ancestors probably understood the fundamentals of inheritance based solely on observations of potential mates. It is likely that outward attractiveness played a significant role in deciding which genes became merged. The best genes would have been attracted to the best genes...as they are today. Fragile and deformed humans would have been ostracized, cast out, or actively purged from ancient communities. It is unlikely that any would have survived long enough to replicate. The difference today is that fragile physical human traits are nurtured into adulthood, where they can replicate freely. Arresting this devolution and halting the path of human evolution is easily accomplished. However, the ethics of doing so are somewhat questionable.
We tend to think of playing God as an intentional act of intervention. We characterize it negatively, perhaps even labeling those who advocate for it as evil. History remembers several prominent characters who have attempted to play God with human genetics, and they are not remembered fondly. Their methods were brutal, cruel and inhumane; they are rightly maligned for their expedient practices. Perhaps the most notable examples of humans playing gods were the Nazis of Hitler’s Germany during the mid 20th century. Hitler’s efforts at genocide are well documented. Not only did Hitler advocate for subjective, artificial selection of perfect human traits, he facilitated the artificial de-selection of those whom he deemed to be flawed or somehow sub-human; these individuals were either forcibly sterilized or systematically eradicated.
Playing God with human genes did not end in the Germany of 1945. Much of the genetic research that was conducted during that era continues today, albeit less expeditiously. Once it was discovered that the human genome could be manipulated using molecular scissors, a whole new era of genetic engineering began. With gene manipulation came a newly revitalized conversation around the ethics of artificial selection. To what extent should we steer human evolution? To what extent are we ethically obligated to steer human evolution? To the extent that God Himself cleansed the Earth of those who did not find favor with Him (Genesis 6), is it ethically unacceptable to allow natural selection? Playing God might actually mean doing nothing, standing back to allow the natural order of things to steer human evolution down a path that keeps us in harmony with our environment, even if that path leads to a human race that would be unrecognizable to us today. Artificial selection may unwittingly take humans down an evolutionary dead end where we are not suited for an environment that is undeniably changing around us. The practicalities of artificially facilitating natural selection are somewhat unpalatable, though. To consider what that natural selection might look like, let’s start close to home. My own relationship with my appendix only lasted about 21 years. If I had been vacationing in rural Tanzania rather than in Florida at the time that it ruptured, I would probably have died. My fragile genes would have been naturally de-selected. Allowing my natural death in a Florida hospital would perhaps have been a little harsh, but in a post-modern type world that is more sensitive to natural selection rather than artificial selection, a more ethical course of action might be to sterilize me instead. Naturally, those of us who would otherwise die due to a congenital flaw wouldn’t then get to pass on those flawed genes, if the flaws manifested themselves before we were able to mate.
This is a slippery slope that gets quite steep quite quickly. Peanut allergies were all but unheard of prior to the 1990s. Since then there has been a marked increase in severe cases where exposure to even residual amounts of peanut oil can cause anaphylaxis, a serious medical condition that is usually fatal without immediate medical interventions. This fatal reaction to peanut oil tends to be more prevalent in people with a family history of food allergies, which reinforces the contention that a peanut allergy is genetic rather than environmental. Millions of children today carry emergency doses of epinephrine (synthetic adrenalin) just in case they are exposed to an allergen that would otherwise kill them. In our hypothetical post-modern, natural selection type world, perhaps these children would be chemically sterilized if they ever had to use their EpiPen. This is harsh to consider, but if we enacted this policy, peanut allergies might become moot in just a few generations, liberating countless millions of future children from this oppressive curse. Asthma, which only became prominent in the 1920s, could similarly be eradicated or significantly reduced in future generations if treatment included sterilization.
To be clear, I am not advocating for this hypothetical post-modern natural selection type world. However, this is Darwin’s evolution; this is how God shaped the fantastic diversity that we see all around us today. The mechanism of microevolution is undisputed within the scientific community and is frankly indisputable by even the most unreasonable of laypersons. Remember, however, that Darwin did not pretend to understand or explain where and how life began. Most importantly Darwin did not suggest how one species might become another (macroevolution). Almost two centuries have passed since Darwin first unpacked the pieces of the evolution puzzle, yet evolutionary morphology between species has neither been observed nor demonstrated, despite intense efforts to expose this missing link. Moreover, there is still no clear consensus within the scientific community regarding how one species might become classified as another through evolutionary pressure. In other words, Darwin’s theories accurately define how a harras of horses might, over time, evolve into a harras of long-necked horses, but even Darwin himself would flinch at the notion that they might, one day, become known as giraffes.