Darwin’s On The Origin of Species knocked me on my ass. I’d studied the concepts in school along with everyone else, and the idea of survival of the fittest is so deeply embedded in our culture that I fully expected the book to be a review of what I already knew and feared that it would be weighed down by rococo Victorian prose. Instead I got a beautiful and impeccably constructed argument for how life on earth works, delivered with such charm and precision that I found myself nodding happily throughout. And to tell the truth I now believe I’d never actually understood natural selection properly until I let Darin present it to me. This book was a revelation.
According to the introduction of my volume, Darwin wrote the book to get his theory on record, just as a rival scientist was about to announce a very similar theory of his own. The book is written for the non-scientist, and in plain English he builds an argument with one clear observation stacked upon another, one obvious thing added to the next, until you are able to look back at the vast reach and incredible clarity of his core idea. This is a delightful experience for anyone expecting to encounter a plodding academic lecture, to instead find yourself on a sturdy walk through the natural world with a guide who takes you step by step to a clear and ultimately breathtaking view.
Along with the rest of the world, I came to the book familiar with the well-travelled concept of survival of the fittest, and I expected Darwin to run through a bunch of things that I already really know. Imagine my surprise when I discovered that I’d been thinking about the whole thing from the wrong perspective, and I was delighted to have Darwin set me straight. I’d always conceived of survival of the fittest from the perspective of the individual, projecting myself into this struggle, as I saw it. But what I realized in reading Darwin is that the survival of the individual is irrelevant—his theory is all about the survival and evolution of species. It’s the fitness of the species, not the individual, that matters. It’s embarrassing to admit that I was so wrong.
Darwin goes on at some length early in the book about the basic math of survival, and how species invariably overproduced by massive degrees, because at some points during their reproduction cycle most all of the individuals faced death. Either three-quarters of the eggs are eaten by predators, or half the young die after birth, or half the flock dies during winter, but in every case it’s nothing but a numbers game. In this context, you can see that any variation that confers some slight advantage will become a dominant trait simply because those with that advantage are the ones who survive and reproduce, and it becomes a standard feature of the species.
Beginning with the mechanics of inheritance, Darwin talks about pigeons and other domesticated animals, and the clear and well understood ways in which animal husbandry has led to distinct breeds. Then he takes us into the natural world and talks about how selection works the same way there, guiding us through example after example of how this works. From there he talks about the geological record, largely to address some of his theory’s challenges related to the imperfections of the geological record. However, the effect is also to take the reader to a completely different time scale, which forces one to confront the vastness of time in which all of this occurs. Ultimately, I came to see the world consisting of a broad and ever-changing equilibrium, in which an incredible array of living things battle for whatever resources are available. In this scheme, the fitness of one individual is basically meaningless, and even the extinction of a species is just part of the whole process. As Darwin puts it:
Battle within battle must ever be recurring with varying success; and yet in the long-run the forces are so nicely balanced, that the face of nature remains uniform for long periods of time, though assuredly the merest trifle would often give the victory to one organic being over another. Nevertheless so profound is our ignorance, and so high our presumption, that we marvel when we hear of the extinction of an organic being; and as we do not see the cause, we invoke cataclysms to desolate the world, or invent laws on the duration of the forms of life!
Darwin does a wonderful job bringing the whole thing to life and putting the complexity of his theory into perfectly understandable terms. When talking about the interconnectedness of an ecosystem, he lays out this completely quaint example:
I am tempted to give one more instance showing how plants and animals, most remote in the scale of nature, are bound together by a web of complex relations. I shall hereafter have occasion to show that the exotic Lobelia fulgens, in this part of England, is never visited by insects, and consequently, from its peculiar structure, never can set a seed. Many of our orchidaceous plants absolutely require the visits of moths to remove their pollen-masses and thus to fertilise them. I have, also, reason to believe that humble-bees are indispensable to the fertilisation of the heartsease (Viola tricolor), for other bees do not visit this flower. From experiments which I have tried, I have found that the visits of bees, if not indispensable, are at least highly beneficial to the fertilisation of our clovers; but humble-bees alone visit the common red clover (Trifolium pratense), as other bees cannot reach the nectar. Hence I have very little doubt, that if the whole genus of humble-bees became extinct or very rare in England, the heartsease and red clover would become very rare, or wholly disappear. The number of humble-bees in any district depends in a great degree on the number of field-mice, which destroy their combs and nests; and Mr. H. Newman, who has long attended to the habits of humble-bees, believes that “more than two thirds of them are thus destroyed all over England.” Now the number of mice is largely dependent, as every one knows, on the number of cats; and Mr. Newman says, “Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice.” Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!
One is reminded throughout the book that Darwin is working hard to present a theory that explains the things he sees in the natural world in a way that makes sense, in contrast to the magical thinking that drove much contemporary thought. When one believes that every species is perfect, created and put onto earth by God himself, it is a challenge to explain, for example, the many variations of specific species that exist, the disappearance of old forms, and various other points of dissonance between leading thinkers and the natural record. Darwin maintains a cordial disdain for those holding such views for the most part, but he occasionally lapses into what I read as overt contempt, discussing the intellectual contortions necessary to square the visible world with theological explanations:
To admit this view is, as it seems to me, to reject a real for an unreal, or at least for an unknown, cause. It makes the works of God a mere mockery and deception; I would almost as soon believe with the old and ignorant cosmogonists, that fossil shells had never lived, but had been created in stone so as to mock the shells now living on the sea-shore.
Nevertheless the simplicity of the view that each species was first produced within a single region captivates the mind. He who rejects it, rejects the vera causa of ordinary generation with subsequent migration, and calls in the agency of a miracle.
One forgives Darwin these lapses into rudeness because he is overall such a fair and generous teacher and guide on our journey. And one gets the impression that he was at once a serious student of the natural world, but also an awestruck admirer of its terrible power and beauty:
We need not marvel at extinction; if we must marvel, let it be at our presumption in imagining for a moment that we understand the many complex contingencies, on which the existence of each species depends.
This strikes me as earnest modesty from someone who had every right to be a superior prick had he so chosen. But that’s Darwin: brilliant, modest, generous, and interested in nothing more than the ability to grasp the world around him, and to share that grasp with those of us quite a bit less brilliant. It was a real pleasure to be able to spend the time with him, and I came away far better for having taken this journey.
Excerpt from On The Origin of Species, by Charles Darwin
Slave-making instinct.—This remarkable instinct was first discovered in the Formica (Polyerges) rufescens by Pierre Huber, a better observer even than his celebrated father. This ant is absolutely dependent on its slaves; without their aid, the species would certainly become extinct in a single year. The males and fertile females do no work. The workers or sterile females, though most energetic and courageous in capturing slaves, do no other work. They are incapable of making their own nests, or of feeding their own larvæ. When the old nest is found inconvenient, and they have to migrate, it is the slaves which determine the migration, and actually carry their masters in their jaws. So utterly helpless are the masters, that when Huber shut up thirty of them without a slave, but with plenty of the food which they like best, and with their larvæ and pupæ to stimulate them to work, they did nothing; they could not even feed themselves, and many perished of hunger. Huber then introduced a single slave (F. fusca), and she instantly set to work, fed and saved the survivors; made some cells and tended the larvæ, and put all to rights. What can be more extraordinary than these well-ascertained facts? If we had not known of any other slave-making ant, it would have been hopeless to have speculated how so wonderful an instinct could have been perfected.
Formica sanguinea was likewise first discovered by P. Huber to be a slave-making ant. This species is found in the southern parts of England, and its habits have been attended to by Mr. F. Smith, of the British Museum, to whom I am much indebted for information on this and other subjects. Although fully trusting to the statements of Huber and Mr. Smith, I tried to approach the subject in a sceptical frame of mind, as any one may well be excused for doubting the truth of so extraordinary and odious an instinct as that of making slaves. Hence I will give the observations which I have myself made, in some little detail. I opened fourteen nests of F. sanguinea, and found a few slaves in all. Males and fertile females of the slave-species are found only in their own proper communities, and have never been observed in the nests of F. sanguinea. The slaves are black and not above half the size of their red masters, so that the contrast in their appearance is very great. When the nest is slightly disturbed, the slaves occasionally come out, and like their masters are much agitated and defend the nest: when the nest is much disturbed and the larvæ and pupæ are exposed, the slaves work energetically with their masters in carrying them away to a place of safety. Hence, it is clear, that the slaves feel quite at home. During the months of June and July, on three successive years, I have watched for many hours several nests in Surrey and Sussex, and never saw a slave either leave or enter a nest. As, during these months, the slaves are very few in number, I thought that they might behave differently when more numerous; but Mr. Smith informs me that he has watched the nests at various hours during May, June and August, both in Surrey and Hampshire, and has never seen the slaves, though present in large numbers in August, either leave or enter the nest. Hence he considers them as strictly household slaves. The masters, on the other hand, may be constantly seen bringing in materials for the nest, and food of all kinds. During the present year, however, in the month of July, I came across a community with an unusually large stock of slaves, and I observed a few slaves mingled with their masters leaving the nest, and marching along the same road to a tall Scotch-fir-tree, twenty-five yards distant, which they ascended together, probably in search of aphides or cocci. According to Huber, who had ample opportunities for observation, in Switzerland the slaves habitually work with their masters in making the nest, and they alone open and close the doors in the morning and evening; and, as Huber expressly states, their principal office is to search for aphides. This difference in the usual habits of the masters and slaves in the two countries, probably depends merely on the slaves being captured in greater numbers in Switzerland than in England.
One day I fortunately chanced to witness a migration from one nest to another, and it was a most interesting spectacle to behold the masters carefully carrying, as Huber has described, their slaves in their jaws. Another day my attention was struck by about a score of the slave-makers haunting the same spot, and evidently not in search of food; they approached and were vigorously repulsed by an independent community of the slave species (F. fusca); sometimes as many as three of these ants clinging to the legs of the slave-making F. sanguinea. The latter ruthlessly killed their small opponents, and carried their dead bodies as food to their nest, twenty-nine yards distant; but they were prevented from getting any pupæ to rear as slaves. I then dug up a small parcel of the pupæ of F. fusca from another nest, and put them down on a bare spot near the place of combat; they were eagerly seized, and carried off by the tyrants, who perhaps fancied that, after all, they had been victorious in their late combat.