Living organisms were not independently created, but have descended and diversified over time from common ancestors. And thus, no other biological theory so elegantly explains this. Evolutionary theory has withstood the test of time—by way of vicarious experimentation, observation, analysis, and relentless criticism, though opposing viewpoints still cling to the concept of "design." As a person of the biological sciences, I cannot subscribe to such misguided notions that suggest static biological states. Clearly, proper examination of the natural world reveal evolutionary trajectories—some random, others nonrandom—and all having observable genetic implications. It is only when we apply evolutionary explanations to living systems that it becomes ever so clear. The world was not specifically designed with us in mind, but rather we long since adapted and conformed to our surroundings, only giving it the illusionary appearance of "design.

The essential quality that an entity needs, if it is to become an effective gene vehicle, is this. It must have an impartial exit channel into the future, for all the genes inside it. This is true of an individual wolf. The channel is the thin stream of sperms, or eggs, which it manufactures by meiosis. It is not true of the pack of wolves. Genes have something to gain from selfishly promoting the welfare of their own individual bodies, at the expense of other genes in the wolf pack. A bee-hive, when it swarms, appears to reproduce by broad-fronted budding, like a wolf pack. But if we look more carefully we find that, as far as the genes are concerned, their destiny is largely shared. The future of the genes in the swarm is, at least to a large extent, lodged in the ovaries of one queen. This is why — it is just another way of expressing the message of earlier chapters — the bee colony looks and behaves like a truly integrated single vehicle.

The total amount of suffering per year in the natural world is beyond all decent contemplation. During the minute that it takes me to compose this sentence, thousands of animals are being eaten alive, many others are running for their lives, whimpering with fear, others are slowly being devoured from within by rasping parasites, thousands of all kinds are dying of starvation, thirst, and disease. It must be so. If there ever is a time of plenty, this very fact will automatically lead to an increase in the population until the natural state of starvation and misery is restored. In a universe of electrons and selfish genes, blind physical forces and genetic replication, some people are going to get hurt, other people are going to get lucky, and you won't find any rhyme or reason in it, nor any justice. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but pitiless indifference.

That all plants immediately and substantially stem from the element water alone I have learnt from the following experiment. I took an earthern vessel in which I placed two hundred pounds of earth dried in an oven, and watered with rain water. I planted in it a willow tree weighing five pounds. Five years later it had developed a tree weighing one hundred and sixty-nine pounds and about three ounces. Nothing but rain (or distilled water) had been added. The large vessel was placed in earth and covered by an iron lid with a tin-surface that was pierced with many holes. I have not weighed the leaves that came off in the four autumn seasons. Finally I dried the earth in the vessel again and found the same two hundred pounds of it diminished by about two ounces. Hence one hundred and sixty-four pounds of wood, bark and roots had come up from water alone. (1648)[A diligent experiment that was quantitatively correct only as far as it goes. He overlooked the essential role of air and photosynthesis in the growth process]

Chloroplasts bear chlorophyll; they give the green world its color, and they carry out the business of photosynthesis. Around the inside perimeter of each gigantic cell trailed a continuous loop of these bright green dots. They spun . . . they pulsed, pressed, and thronged . . . they shone, they swarmed in ever-shifting files around and around the edge of the cell; they wandered, they charged, they milled, raced . . . they flowed and trooped greenly . . . All the green in the planted world consists of these whole, rounded chloroplasts . . . If you analyze a molecule of chlorophyll itself, what you get is one hundred thirty-six atoms of hydrogen, carbon, oxygen, and nitrogen arranged in an exact and complex relationship around a central ring. At the ring’s center is a single atom of magnesium. Now: If you remove the atom of magnesium and in its place put an atom of iron, you get a molecule of hemoglobin. The iron atom combines with all the other atoms to make red blood, the streaming red dots in the goldfish’s tail.

It is difficult to overstate the importance of understanding mirror neurons and their function. They may well be central to social learning, imitation, and the cultural transmission of skills and attitudes—perhaps even of the pressed-together sound clusters we call words. By hyperdeveloping the mirror-neuron system, evolution in effect turned culture into the new genome. Armed with culture, humans could adapt to hostile new environments and figure out how to exploit formerly inaccessible or poisonous food sources in just one or two generations—instead of the hundreds or thousands of generations such adaptations would have taken to accomplish through genetic evolution.Thus culture became a significant new source of evolutionary pressure, which helped select brains that had even better mirror-neuron systems and the imitative learning associated with them. The result was one of the many self-amplifying snowball effects that culminated in Homo sapiens, the ape that looked into its own mind and saw the whole cosmos reflected inside.

All organisms vary. It is in the highest degree improbable that any given variety should have exactly the same relations to surrounding conditions as the parent stock. In that case it is either better fitted (when the variation may be called useful), or worse fitted, to cope with them. If better, it will tend to supplant the parent stock; if worse, it will tend to be extinguished by the parent stock.If (as is hardly conceivable) the new variety is so perfectly adapted to the conditions that no improvement upon it is possible,—it will persist, because, though it does not cease to vary, the varieties will be inferior to itself.If, as is more probable, the new variety is by no means perfectly adapted to its conditions, but only fairly well adapted to them, it will persist, so long as none of the varieties which it throws off are better adapted than itself.On the other hand, as soon as it varies in a useful way, i.e. when the variation is such as to adapt it more perfectly to its conditions, the fresh variety will tend to supplant the former.

Men write more books. Men give more lectures. Men ask more questions after lectures. Men post more e-mail to Internet discussion groups. To say this is due to patriarchy is to beg the question of the behavior's origin. If men control society, why don't they just shut up and enjoy their supposed prerogatives? The answer is obvious when you consider sexual competition: men can't be quiet because that would give other men a chance to show off verbally. Men often bully women into silence, but this is usually to make room for their own verbal display. If men were dominating public language just to maintain patriarchy, that would qualify as a puzzling example of evolutionary altruism--a costly, risky individual act that helps all of one's sexual competitors (other males) as much as oneself. The ocean of male language that confronts modern women in bookstores, television, newspapers, classrooms, parliaments, and businesses does not necessarily come from a male conspiracy to deny women their voice. It may come from an evolutionary history of sexual selection in which the male motivation to talk was vital to their reproduction.

When in 1863 Thomas Huxley coined the phrase 'Man's Place in Nature,' it was to name a short collection of his essays applying to man Darwin's theory of evolution. The Origin of Species had been published only four years before, and the thesis that man was literally a part of nature, rather than an earthy vessel charged with some sublimer stuff, was so novel and so offensive to current metaphysics that it needed the most vigorous defense. Half the civilized world was rudely shocked, the other half skeptically amused.Nearly a century has passed since the Origin shattered the complacency of the Victorian world and initiated what may be called the Darwinian revolution, an upheaval of man's ideas comparable to and probably exceeding in significance the revolution that issued from Copernicus's demonstration that the earth moves around the sun. The theory of evolution was but one of many factors contributing to the destruction of the ancient beliefs; it only toppled over what had already been weakened by centuries of decay, rendered suspect by the assaults of many intellectual disciplines; but it marked the beginning of the end of the era of faith.

George Gey paid his way through a biology degree at the University of Pittsburgh by working as a carpenter and mason, and he could make nearly anything for cheap or free. During his second year in medical school, he rigged a microscope with a time-lapse motion picture camera to capture live cells on film. It was a Frankensteinish mishmash of microscope parts, glass, and 16-millimeter camera equipment from who knows where, plus metal scraps, and an old motor from Shapiro’s junkyard. He built it in a hole he’d blasted in the foundation of Hopkins, right below the morgue, its base entirely underground and surrounded by a thick wall of cork to keep it from jiggling when streetcars passed. At night, a Lithuanian lab assistant slept next to the camera on a cot, listening to its constant tick, making sure it stayed stable through the night, waking every hour to refocus it. With that camera, Gey and his mentor, Warren Lewis, filmed the growth of cells, a process so slow - like the growth of a flower - the naked eye couldn’t see it. They played the film at high speed so they could watch cell division on the screen in one smooth motion, like a story unfolding in a flip book.

Every day, hundreds of observations and experiments pour into the hopper of the scientific literature. Many of them don't have much to do with evolution - they're observations about the details of physiology, biochemistry, development, and so on - but many of them do. And every fact that has something to do with evolution confirms its truth. Every fossil that we find, every DNA molecule that we sequence, every organ system that we dissect, supports the idea that species evolved from common ancestors. Despite innumerable possible observations that could prove evolution untrue, we don't have a single one. We don't find mammals in Precambrian rocks, humans in the same layers as dinosaurs, or any other fossils out of evolutionary order. DNA sequencing supports the evolutionary relationships of species originally deduced from the fossil record. And, as natural selection predicts, we find no species with adaptations that only benefit a different species. We do find dead genes and vestigial organs, incomprehensible under the idea of special creation. Despite a million chances to be wrong, evolution always comes up right. That is as close as we can get to a scientific truth.

What, after all, is so special about genes? The answer is that they are replicators. The laws of physics are supposed to be true all over the accessible universe. Are there any principles of biology which are likely to have similar universal validity? When astronauts voyage to distant planets and look for life, they can expect to find creatures too strange and unearthly for us to imagine. But is there anything which must be true of all life, wherever it is found, and whatever the basis of its chemistry? If forms of life exist whose chemistry is based on silicon rather than carbon, or ammonia rather than water, if creatures are discovered which boil to death at -100 degrees centigrade, if a form of life is found which is not based on chemistry at all, but on electronic reverberating circuits, will there still be any general principle which is true of all life? Obviously I do not know but, if I had to bet, I would put my money on one fundamental principle. This is the law that all life evolves by the differential survival of replicating entities. The gene, the DNA molecule, happens to be the replicating entity which prevails on our own planet. There may be others. If there are, provided certain conditions are met, they will almost inevitably tend to becomethe basis for an evolutionary process.

The Earth Speaks, clearly, distinctly, and, in many of the realms of Nature, loudly, to William Jennings Bryan, but he fails to hear a single sound. The earth speaks from the remotest periods in its wonderful life history in the Archaeozoic Age, when it reveals only a few tissues of its primitive plants. Fifty million years ago it begins to speak as 'the waters bring forth abundantly the moving creatures that hath life.' In successive eons of time the various kinds of animals leave their remains in the rocks which compose the deeper layers of the earth, and when the rocks are laid bare by wind, frost, and storm we find wondrous lines of ascent invariably following the principles of creative evolution, whereby the simpler and more lowly forms always precede the higher and more specialized forms.The earth speaks not of a succession of distinct creations but of a continuous ascent, in which, as the millions of years roll by, increasing perfection of structure and beauty of form are found; out of the water-breathing fish arises the air-breathing amphibian; out of the land-living amphibian arises the land-living, air-breathing reptile, these two kinds of creeping things resembling each other closely. The earth speaks loudly and clearly of the ascent of the bird from one kind of reptile and of the mammal from another kind of reptile.

Who gave the decisive deathblow to the argument from design on the basis of biological complexity? Both philosophers and biologists are divided on this point (Oppy 1996; Dawkins 1986; Sober 2008). Some have claimed that the biological design argument did not falter until Darwin provided a proper naturalistic explanation for adaptive complexity; others maintain that David Hume had already shattered the argument to pieces by sheer logical force several decades earlier, in his Dialogues Concerning Natural Religion (Hume 2007 [1779]). Elliott Sober has been among the philosophers who maintain that, as Hume was not in a position to offer a serious alternative explanation of adaptive complexity, it is hardly surprising that 'intelligent people strongly favored the design hypothesis' (Sober 2000, 36). In his most recent book, however, Sober (2008) carefully develops what he thinks is the most charitable reconstruction of the design argument, and proceeds to show why it is defective for intrinsic reasons (for earlier version of this argument, see Sober 1999, 2002). Sober argues that the design argument can be rejected even without the need to consider alternative explanations for adaptive complexity (Sober 2008, 126): 'To see why the design argument is defective, there is no need to have a view as to whether Darwin’s theory of evolution is true' (Sober 2008, 154).

To list all the great discoveries in the field of science and medicine during the past century, such as aspirin, insulin, penicillin, and the streptomycin drugs would require the undivided attention of a medical historian and a veritable encyclopedia to record them.And yet, there are still many diseases that plague man of which he has no knowledge. They eat and ravage his mind and body with excruciating pain and torture, and he is utterly helpless against them. He not only does not know their origin, but has not the slightest inkling of their nature or how to fortify himself against their attacks. He must sit, like a condemned criminal, in agonizing torture, waiting for blessed death.If man, and the other forms of life upon this earth, are a mere by-product of an 'over-all plan' of a 'supreme intelligence,' then I denounce such a scheme as tyrannical and barbaric. Why should we be made to suffer such excruciating pains and penalties of life to satisfy that from which we derive no benefit, and where death negates all of our efforts; and which makes the purpose of life, our hopes and desires, our ambitions and aspirations, a cruel mockery?O prayer, thy name is failure!O God, thou art a cruel myth!You will not find a single mention of these great humanitarian achievements in the so-called 'Book of Books'; not a single reference about the nature and cure of disease; not a word regarding those inventions that have so mercifully lifted the burden of toil from the backs of labor.