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The Selfless GeneLIVING WITH GOD AND DARWIN
By Charles Foster
Thomas NelsonCopyright © 2009 Charles Foster
All right reserved.
Chapter OneThe Tangled Bank
It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gonecycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. -Charles Darwin, The Origin of Species, chapter 14
Imagine, as Darwin did, a tangled bank. To magnify its beauty, brutality, and complexity, imagine that it is in the tropics.
It is covered in writhing plants. They wrestle and barge each other. Their roots probe the earth, seeking to take water and nutrients from their neighbors. They do not steal, because nothing holds any title that can be violated. Each organism has what it possesses for the moment. Generally things are taken, not given. There are no rights.
The plants trap sunlight in sugar, and that makes them prey. They are crushed and ground between the teeth of herbivores, and their cells are smashed up by enzymes and bacteria in big fermenting tanks. The sunlight therefore flows for a while into the bodies of the herbivores. How long it stays there depends on many things. It depends on the acuity of the herbivore's eyes; on the efficiency with which sodium and potassium gates open and shut in the membranes of its nose nerves; on the integrity of the wiring linking its ears to its legs; on the strength of the tendons; on how fearful it is; on how fearful its parents were; on whether or not the night wind has caused a branch to fall in the path along which it bolts.
If it is caught, it may die quickly, or it may die very slowly. If it is a mammal, its nervous system will go on screaming in (so far as we know) very much the way that ours does until the thing (whatever it is) that made it a live rather than a dead mammal has fled or been extinguished. Probably, if it is a mammal being eaten by another mammal, the death will be relatively quick, because the continued life of a victim is an inconvenience for a predator. It makes the victim flounder around, which gets in the way of the feed. But on the way to the death there are dislocations, breaks, and rips. The eyes roll. Death does not seem to be welcomed.
Sometimes the death is prolonged. In the stream running by the side of the tangled bank, a fish has been caught by a lamprey. Two weeks ago the lamprey attached itself to the side of the fish, like a large leech. Its grinding jaws eroded the fish's body wall, and the head of the lamprey, and most of its body, is now inside the body cavity, still grinding away, but destroying nothing vital. To kill would be to change desirably fresh fish to carrion. Only the lamprey's tail now waves in the water. The waving tail attracts a larger predatory fish. Both the lamprey and its victim are swallowed whole. They will be marinated in digestive enzymes and dissolved into the body of the larger fish.
Back on the bank, a vole is eating seeds made partly from the body of a weasel which had thrived five years ago on the vole's great-great-great-great-great-grandparents. The bank is a graveyard, seething with life. Everything is a cannibal. The whole place is profoundly and vitally septic. Take away the bacteria that coat everything, and the bank would weigh a lot less and would soon be a desert.
The bank is a culture of intimate interdependence. The vole needs the owl that kills it no less than the owl needs the vole. One of the hawk moth species on the bank has acquired transparent wings to pretend to be a bumblebee and, unlike most moths, has changed its schedule to fly alongside the bees during the day. Some of the orchids have fashioned cups that fill with nectar to entice insects. When an insect lands, it depresses the landing stage. As the insect crawls towards the cup, the stage springs back up, trapping the insect. The only way out is past hanging baskets of pollen. The insect flies away full of sugar and dusty with sperm.
There is someone watching all this, and describing it. He is a man. What he makes of it all will depend on what he believes about himself. But whatever he makes of it, he thinks that it is interesting and terrible. And something in him dislikes the idea of being eaten by worms.
If he is a typical creationist, he believes that the species on the tangled bank are broadly as they were when they were created by God six to ten thousand years ago (depending on how you read the biblical chronologies). There has been some speciation since, but only in the direction of degeneration-as the genome sheds information like confetti. Man himself has no familial relationship with any of the creatures on the bank, and the different species on the bank are themselves related only by the fact that they spill, rather than share, one another's blood. The horrors of the bank are the fault of primordial man, whose arrogant usurping of the divine prerogative corrupted, by an obscure spiritual mechanism, the whole of creation. All species were originally vegetarian, and lived in happy coexistence-a proposition that of course assumes that plants are happy being eaten. Before Eve plucked the forbidden fruit, there was no death, no pain, and no predation. The water creatures, the birds, and humans (but not, apparently, the plants or the land animals) were commanded to multiply. The strategy for ensuring that there was not catastrophic overpopulation is not clear.
Depending on whether the creationist believes Genesis 1 or Genesis 2, he should believe either that man was spoken into existence after the animals, and set over them as ruler; or that man was formed from the dust of the earth, before the creation of the animals, the plants, or even the first rainfall, and that the animals were thought of originally as company for him. Probably, though, in a way mysterious to most of us, he will believe both.
If the observer is a mainstream evolutionist, he is in many ways more mystical than the creationist. He believes, like Genesis 2, that he was fashioned from dust, but believes that it was stardust. He describes, and if he is that way inclined, senses, an intimate familial communion with all the animals and plants on the bank. His wondering fascination with the biochemistry of the bacteria means that he sees no slight in being called their cousin. His sense of the immense age of the world gives him an exhilarating chronological vertigo when he looks at the bank. He thinks that the universe was formed about 15 billion years ago, and the earth about 4.5 billion years ago. If he thinks that there is a God, his God must be very big and very old.
He thinks that conditions on the earth were for a long time incompatible with life, but probably thinks that life sprang into existence about as soon as it could-about 3.8 billion years ago. Life is not only tenacious and fecund once it exists, but also seems to loathe nonexistence.
If the evolutionist is honest, he has no idea how life began, and points out that evolution itself does not pretend to have anything to say on the subject. He acknowledges that the promise shown by the 1953 Miller-Urey experiment that we all learned about at school (in which amino acids were formed by discharging lightning-simulating voltages through an atmosphere of water, methane, ammonia, and hydrogen) has evaporated: most think that the experiment made unsustainable assumptions about the chemistry of the early earth. He thinks that early forms of life were unicellular. The genesis of the cell is again, if he is candid, a complete mystery, although there are some elegant hypotheses. He notes that the general direction of evolution has been toward increased size and increased complexity. Cells initially got together in loose conglomerations. The conglomerations then became organized, centrally directed, and so transmuted into multicellular organisms.
Several forces drove this magnificent white-knuckle ride toward complexity. The evolutionist will not agree with all his fellows about the relative contribution of the various forces, but there will be a fair degree of agreement. He will subscribe, along with almost all of the scientific world, to the neo-Darwinian synthesis.
In The Origin of Species, published in 1859, Darwin set out the idea of evolution (which everyone acknowledged had happened) by natural selection (which was the real novelty). The idea was outrageously simple. Thomas Huxley, when he heard of it, is said to have slapped his forehead and said, "How stupid of me not to have thought of that." Darwin, through his round-the-world trip on the Beagle, his readings of Malthus, his afternoon perambulations around the Sandwalk at Downe House, and his obsessive observations of worms, finches, rocks, beetles, men, and everything else, had been compelled to the conclusion that since
many more individuals of each species are born than can possibly survive, and as consequently there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of survival and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.
Darwin had no idea about the mechanism of "the strong principle of inheritance." It was supplied just seven years after the publication of The Origin of Species by the Austrian Augustinian monk Gregor Mendel and his pea plants. The peas indicated that the units of inheritance were physically discrete. They would later be called "genes" and identified as the sequences of nucleotides on the DNA molecule that determine the amino acid sequences of, and therefore the characteristics of, proteins. Biology starts from the presumption that I am the sum of my proteins, and then gets interesting.
Mendel's 1866 paper was forgotten during his own lifetime, but was rediscovered and dusted down at the start of the twentieth century. Darwinism, languishing for want of an explanation of heredity, acquired new energy and confidence. The fusion of Darwin's original thesis with the new science of genetics is what is described as the "neo-Darwinian synthesis." The synthesis reformulated Darwin's thesis by defining selective advantage. A characteristic coded for by gene X was advantageous in evolutionary terms if it increased the incidence of gene X in subsequent generations.
The ratios in Mendel's pea paper allowed some exciting and intimidating mathematics to perfuse evolutionary biology. If you knew the mechanism of inheritance, you could determine the expected incidence of inherited traits. If you then compared this expected incidence with the observed incidence in populations, you were looking at more or less dim reflections of the forces of change themselves. You could begin to make mathematically informed guesses about the power, and possibly the nature, of the forces.
All evolutionists agree that classic natural selection is one of the forces. Genetic change occurs in various ways: mutations (most of which are harmful, but some of which will be beneficial); genetic recombination through the normal process of sexual reproduction; gene duplication (particularly in plants and bacteria); regulator genes, which switch on and off and otherwise determine the function of other genes; the introduction of new genes from other populations, and so on. There is bitter and highly technical disagreement about which of these mechanisms of change is predominant. The disagreements are irrelevant for the purposes of our look at the bank. Everyone agrees that genetic change occurs, and that at least some changes are detected by natural selection, which then gets to work, altering the gene frequency in subsequent generations. The really interesting disputes relate to the sensitivity of natural selection in picking up the change, and its efficacy in turning its detection into a final verdict on the relevant gene. We have noted that Darwin wrote, "Any being, if it vary however slightly in any manner profitable to itself ... will have a better chance of survival and thus be naturally selected." Much of modern evolutionary biology is concerned with how slight a variation can be before it attracts the approving or disapproving attention of natural selection, with the role of contingency, and with the ability of natural selection to fashion new species rather than merely altering existing ones.
It has to be said that natural selection, whether or not it is the sole or principal engine of evolutionary change, is surprisingly sensitive and powerful. A tiny change (for instance in the number of stripes on a snail shell) can result in a dramatic change in the chance of the snail being smashed and eaten by a thrush.
If natural selection is not the only thing producing change, what else might be? Various candidates have been put forward by orthodox science, but when their credentials are examined carefully, they all turn out to be chance, dressed up in various more or less exotic ways. This book will suggest another possibility. But there is nothing necessarily disreputable about chance. Our own anecdotal experience might lead us to prefer its candidacy. Genuine accidents, unavoidable by the most refined nervous system or most beautifully toned muscle, do happen. If you are at the pinnacle of the natural selective tree, your rigorously selected genes will not help you much if you are also at the pinnacle of an erupting volcano which smothers you in boiling lava. If the volcano has not erupted for a few million years, it can hardly be said that you were stupid to live there, and that the lava has sought out and dealt sternly with the genes making you stupid. Natural selection is very good at picking up the pieces; it is often pretty dismal at stopping the destruction in the first place.
The mammals were tiny, unimpressive creatures in the age of the dinosaurs. The extinction of the dinosaurs gave mammals their chance, and natural selection vigorously promoted the mammals. But natural selection did not direct the asteroid that may well have ushered the dinosaurs into the museums. If the asteroid had not landed, would mammals ever have had the chance to rule the earth?
If our bank-gazing evolutionist has been brought up conventionally in biology (and particularly if he has been brought up in the United Kingdom), he will tend to look at all the attributes of the bank-dwellers through an adaptationist lens. He will assume that everything about the hawk moth is precisely the way it is because natural selection has decreed it that way. He will credit natural selection with a superb eye for detail and the sculpting hand of a Michelangelo. He will credit little to chance, and nothing to God. God is a hypothesis of which he has no need, and indeed he will happily quote Laplace's dictum when given any opportunity. Chance produces the entirely random mutations which give natural selection something to get to work on, but natural selection is so assiduous at sifting the phenotypic nuances thrown up by mutation that it refuses to delegate to chance any of the sifting.
Excerpted from The Selfless Gene by Charles Foster Copyright © 2009 by Charles Foster. Excerpted by permission.
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