APPENDIX

Darwin––True or False: Did He Get It Right?

Were Darwin alive today, he would be overwhelmed by the myriad changes that have transpired in the past 150 years. Survival and reproduction, the core of evolution, upended. Urban society, modern medicine, in vitro fertilization, climate change, domestication, accelerating extinction, genetic engineering . . . Nonetheless, being the great naturalist and observer that he was, Darwin would certainly revisit his concepts and note what would need to be updated and modified. After all, he did rewrite sections of Origins five times after the original came out.1 He would also realize that many of his core concepts still ring true, often in ways he could not have anticipated. Let’s look first at the most important one.

Evolution through descent with modification. True.

This core principle is as true today as it was when Darwin penned the concept in 1859.2 Modern species still reproduce and their offspring display different traits, which begets an ongoing cycle of change to every species. However, a dramatic shift is occurring in the processes involved. Darwin proposed natural selection and variation to be the basic mechanisms of speciation. In the early twentieth century, with the rediscovery of Mendel’s work and the roles of genes and mutations in biology, scientists proposed the modern synthesis theory of evolution that you still learn in school today—natural selection and random mutation are the core drivers of evolution. We have proposed that over the past century there has begun a large-scale shift in their prominence—a shift in the balance of forces that drive evolution. A shift from natural selection toward unnatural selection. A shift from random mutation toward nonrandom mutation. Moreover, we believe Darwin would recognize this shift and understand it better than any of us.

Darwin intimately understood unnatural selection. For him, this was domestication of animals and plants by humans, which he termed “artificial selection,” or “selection by man.” He extensively experimented, studied, wrote, and thought about the breeding of pigeons, sheep, flowers, and many other species. He understood how traits were identified and selected by breeders, how they were propagated within a breed, and how they could dissipate if a species was returned to the wild. Darwin wrote, “We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own uses.”3

So today he would not be surprised that we have improved our abilities to select beneficial traits for tastier, more healthful food, as well as novel breeds of animals and plants. However, he would be stunned that unnatural selection, through reckless human actions, has resulted in unintended mass extinctions, invasive species wreaking havoc, and global outbreaks of ever more antibiotic-resistant infectious diseases. Hence, Darwin would recognize that unnatural selection, driven directly and indirectly by humans, has become a challenger to natural selection.

What of nonrandom mutation? Darwin did not know about genes, DNA variants, or mutations, so he preferred to call it variation. While he generally felt that variation was random, based on his observations, particularly of domesticated species, he said the following: “I have hitherto sometimes spoken as if the variations—so common and multiform in organic beings under domestication, and in a lesser degree in those in a state of nature—had been due to chance. This, of course, is a wholly incorrect expression, but it serves to acknowledge plainly our ignorance of the cause of each particular variation.”4 In fact, he used the word “ignorance” frequently when writing about how variation arises in offspring. Today, he would recognize, like all geneticists of the past hundred years, that random mutation is a cornerstone of evolution and variation. However, he would also recognize that epigenetics and our microbiomes and viromes can behave in predictable ways to modify us and our progeny and species on Earth. This is key to many of the unexplained trends of the past century. Moreover, the burgeoning power of gene therapy and editing, in the hands of humans who love to tinker, will increasingly drive the balance of forces toward nonrandom mutation in our future evolution.

What about other concepts Darwin espoused? Are they still valid or would he need to modify them? Here is a quick inventory of what has proven true, false, or has yet to be determined.

The term “species” cannot be defined. True.

Darwin wrote, “I look at the term species, as one arbitrarily given for the sake of convenience to a set of individuals closely resembling each other.”5 And “The amount of difference considered necessary to give to two forms the rank of species is quite indefinite.”6 Ironic that the title of Darwin’s book included the word “species,” which he could not define. While we all recognize that an octopus and a human are different species, it’s very difficult to separate two very similar living entities as being a species, subspecies, variety, strain . . . Today you can find at least twenty-six major scientific definitions of “species” that have been promulgated because every definition has exceptions. Recent DNA sequencing renders any definition virtually meaningless, because where do you draw the line? At 50 percent identical, 80 percent, 95 percent, 99 percent, 99.9 percent? It should also be noted that, like Supreme Court justice Potter Stewart’s famous comment on pornography, Darwin realized that “every naturalist knows vaguely what he means when he speaks of species.”7 Certainly we know humans and Neanderthals are different species—right? Maybe? No?

Transgenerational inheritance passes newly created traits from parent to child. True.

Darwin noted, “The question is not, at what period of life any variation has been caused, but at what period it is fully displayed. The cause may have acted, and I believe generally has acted, even before the embryo formed; and the variation may be due to the male and female sexual elements having been affected by conditions to which either parent, or their ancestors, have been exposed.”8 Darwin observed that offspring, particularly in domesticated species, displayed a wide variety of new traits, which he believed were effected through the parents. Thus he would be delighted to learn that science is uncovering the roles of our four genomes in creating and propagating new traits in our children and grandchildren.

How variations/mutations arise will be solved by a new scientific field. True.

“Our ignorance of the laws of variation is profound,”9 Darwin said. Also: “A grand and almost untrodden field of inquiry will be opened, on the causes and laws of variation, on correlation, on the effects of use and disuse, on the direct action of external conditions, and so forth.”10 Darwin would be in awe of our scientific progress and appreciate that he had underestimated the future. Not one but actually many new fields of science now exist to study variation—genomics, epigenomics, microbiomics, evolutionary genomics, synthetic biology . . . Nonetheless, whereas many questions about variation, mutation, and evolution have been answered, many more remain to be elucidated, so his statement remains prescient and true today.

All species are derived from one progenitor. True?

Darwin wrote, “Therefore, I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed.”11 We find it amazing that in the mid-1800s Darwin projected backward in time to the genesis of life from a single organism. We now believe that the three kingdoms of life likely arose from a single common ancestor or perhaps several ancestors. Darwin would be fascinated by current theories and experiments on the origins of life, including panspermia from other planets.12

Mankind can produce highly beneficial plants and animals. True.

“We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own uses, through the accumulation of slight but useful variations, given to him by the hand of Nature,” said Darwin.13 The twentieth century witnessed industrialization of animal and crop breeding programs that filled our stores with ample food and other products. In the twenty-first century this process is accelerating.

A changing environment alters traits in a species. True.

Per Darwin: “A change in the conditions of life, by specially acting on the reproductive system, causes or increases variability.”14 For 150 years this has borne itself out, and Darwin would appreciate the breadth of examples that underscore this principle.

Human “fanciers” love extremes. True.

In discussing his fellow animal and plant breeders, Darwin pointed out that it’s an “acknowledged principle that ‘fanciers do not and will not admire a medium standard, but like extremes.’”15 Flashy, showy, ostentatious. P. T. Barnum taught us that tumbling pigeons and other oddities excite people. We crave the latest fads, especially in health, pets, and floral displays. Give us more Botox, blond hair, bronze tans, and the latest fashions. Thus, don’t we already know what Darwin would expect to see from future animal and plant “fanciers” with access to gene technologies? And from future tattoo artists?

Dominant species beget future species, few species survive, most go extinct. True.

Darwin said: “The dominant species belonging to large and dominant groups tend to leave many modified descendants, which form new sub-groups and groups. As these are formed, the species of the less vigorous groups, from their inferiority inherited from a common progenitor, tend to become extinct together, and to leave no modified offspring on the face of the earth.”16 And then there was one—Homo sapiens. Look around today and we find 7 billion humans and no other hominins. We are dominant. Where will we go from here? On the other hand, if we can’t define when one species becomes another, perhaps we will be challenged to define what it means for current humans to become extinct.

Two closely related species will compete with each other leading to extinction. True.

Darwin wrote: “Consequently, each new variety or species, during the progress of its formation, will generally press hardest on its nearest kindred, and tend to exterminate them.”17 Wow, what is in store for humans as our descendants continue to evolve? By the way, where did all those Neanderthals go?

No exercise and lots of food begets fat pigs. True.

“The effects on the whole organism of lessened exercise together with abundant food . . . is apparently one chief cause of the great modification which the breeds of swine have undergone.”18 Hm . . . Darwin would probably not modify this truism, though he would now appreciate the evolutionary factors involved.

Beauty is in the eye of the beholder. True.

Darwin said, “The idea of what is beautiful, is not innate or unalterable.”19 Likely an eternal truth as species continue to come and go.

Domestication tends to eliminate sterility. Possibly true.

“Long-continued domestication apparently tends to eliminate sterility,” said Darwin.20 Perhaps this explains the decline in infertility among women in the United States?21

Evolution is slow. True and false.

Darwin viewed speciation as a slow process: “New species have appeared very slowly, one after another, both on land and in the waters.”22 However, he ascribed speciation to natural selection, which “will always act very slowly, only at long intervals of time.”23 However, he did recognize how quickly man can select new traits in domesticated plants and animals. As previously stated: “We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own uses, through the accumulation of slight but useful variations, given to him by the hand of Nature.”24 Furthermore, with the advent of genetic engineering, transgenics, gene therapy, and other technologies, our ability to create new organisms or even new species is at hand. Through unnatural selection and nonrandom mutation, the pace of evolution is accelerating.

Extinction is irreversible. True, but likely to become false.

Darwin claimed, “When a species has once disappeared from the face of the earth, we have reason to believe that the same identical form never reappears.”25 The Revive & Restore project headed by Stewart Brand, Ryan Phelan, George Church, and others is working to bring back the passenger pigeon and other extinct species using DNA synthesis and editing technologies.26 How about woolly mammoths? Neanderthals?

The actual “tree of life” cannot be deduced. Perhaps true.

As Darwin looked at classification systems for millions of species on the planet he must have felt overwhelmed by the fact that there were not enough ways to classify organisms to provide an accurate tree of how they were related, not a clear evolutionary tree. He said, “We shall never, probably, disentangle the inextricable web of affinities between the members of any one class.”27 Yet today, comparison of DNA sequences among many species is enabling us to determine relatedness with phenomenal accuracy and to build family trees, including efforts to reconstitute sequences of “missing links” that preceded present-day species. These efforts, however, will not be 100 percent accurate but will have a statistical similarity to the course of evolution. While Darwin sketched a treelike structure in his writing, this quote is interesting in that Darwin used the term “web,” which is likely a better metaphor than “tree” for evolution.

Natural selection is more powerful than human-driven unnatural selection. False.

Darwin wrote, “But Natural Selection . . . is a power incessantly ready for action, and is as immeasurably superior to man’s feeble efforts, as the works of Nature are to those of Art.”28 What a difference 150 years makes! Enough said. You should be able to draw your own conclusions at this point.

New traits cannot be created by humans. False.

Darwin said: “Man does not actually produce variability; he only unintentionally exposes organic beings to new conditions of life, and then nature acts on the organisation, and causes variability.”29 Darwin would need to write a new chapter in his book about genetic engineering, transgenic plants and animals, gene therapy, as well as unintentional human-caused mutations and traits such as antibiotic resistance and toxin-driven cancers and deformities.

Successful males will have more children. False for humans.

“The most vigorous males, or those which have most successfully struggled with their conditions of life, will generally leave most progeny,” Darwin wrote.30 He would be surprised by the low birth rate in developed nations and the fact that societies and individuals who succeed have experienced a fall in their birth rates over the past century. (He also noted that in winning females and procreating “success will often depend on having special weapons or means of defence, or on the charms of the male.”)31

The number of species on the planet is constrained by resources and climate. True.

Darwin wrote: “Climate plays an important part in determining the average numbers of a species, and periodical seasons of extreme cold or drought, I believe to be the most effective of all checks.”32 Despite Malthusian predictions about food, arable land, water, and energy shortages, the human population has exploded. However, there is an ongoing decrease in the number of rural species on the planet due to habitat destruction, both natural and unnatural, often involving climate change. As humans put increasing pressures on natural resources, biodiversity is limited in many ecological niches. Darwin would realize his observation was correct but would be horrified, as a naturalist, that it was being effected through such human-driven, unnatural means. Ultimately, asteroids and other global calamities are the ne plus ultra of reducing biodiversity through climate change, something we now appreciate better than Darwin did.

Darwin and religion are compatible. A toss-up; you decide.

“I see no good reasons why the views given in this volume should shock the religious feelings of any one,”33 Darwin said. Darwin and religion are inextricably linked in an open dialogue that has continued for more than 150 years, generally involving more heat than light. Most religions—or at least a meaningful subset of most major religions, including Catholicism, Islam, Hinduism, Buddhism, and Judaism—view Darwinian evolution as compatible with their religion (or at least not incompatible).34 This compatibility perspective is often termed “theistic evolution” or perhaps “evolutionary creationism.”35 What each individual, church, school board, cult, militia, country, or society believes can vary considerably.

Evolution tends to progress toward perfection. (Please discuss, and get back to us.)

Darwin seems a bit contradictory on this point. He notes that “as natural selection works solely by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection.”36 But he also states that “natural selection, or the survival of the fittest, does not necessarily include progressive development.”37 Of course, today the balance is shifting away from natural selection toward unnatural selection as the dominant force on the planet. And as humans gain greater control over the evolution of themselves and other species, “perfection” is likely to come in many forms.