Are there holes in the evidence of evolution

In England, where Darwin already graces the ten-pound note, a special two-pound coin will be struck. Cambridge University is hosting a five-day festival in July. Smithsonian's National Museum of Natural History established an "Evolution Trail" that highlights concepts from Darwin's work throughout the museum, and a special exhibit shows how orchids have evolved and adapted according to Darwin's theory.

As towering historical figures go, Charles Darwin does not provide much by way of posthumous scandals. The liberty-extolling Thomas Jefferson was slave master to his longtime mistress, Sally Hemings; Albert Einstein had his adulterous affairs and shockingly remote parenting style; James Watson and Francis Crick minimized their debt to colleague Rosalind Franklin's crucial DNA data.

But Darwin, who wrote more than a dozen scientific books, an autobiography and thousands of letters, notebooks, logs and other informal writings, seems to have loved his ten children three of whom did not survive childhood , been faithful to his wife, done his own work and given fair, if not exuberant, credit to his competitors.

He was born in Shrewsbury, England, on February 12, , into a well-off family of doctors and industrialists. But his up-bringing wasn't entirely conventional.

His family was active in progressive causes, including the antislavery movement. Indeed, an illuminating new book by Adrian Desmond and James Moore, Darwin's Sacred Cause , concludes that Darwin's interest in evolution can be traced to his, and his family's, hatred of slavery: Darwin's work proved the error of the idea that the human races were fundamentally different. Both of his grandfathers were famous for unorthodox thinking, and Darwin's mother and physician father followed in those footsteps.

Darwin's paternal grandfather, Erasmus Darwin, was a physician and natural philosopher of vast appetites—and correspondingly corpulent physique—who developed his own early theory of evolution. It was more purely conceptual than Charles' and missed the idea of natural selection. On his mother's side, Darwin's grandfather was the wealthy Josiah Wedgwood, founder of the eponymous pottery concern and a prominent abolitionist. Darwin began training to be a physician but didn't have a taste for doctoring, so he moved on to studying for the Anglican priesthood at Cambridge.

His real passion, however, was natural history. Shortly after graduation in , he signed on for an unpaid position as a naturalist aboard the Beagle , which was about to embark on a survey of South American coastlines. During the five-year voyage Darwin collected thousands of important specimens, discovered new species both living and extinct and immersed himself in biogeography—the study of where particular species live, and why.

Upon his return to England in , Darwin stayed busy, publishing scientific works on the geology of South America, the formation of coral reefs and the animals encountered during his Beagle expedition, as well as a best-selling popular account of his time aboard the ship. He married his cousin, Emma Wedgwood, in , and by the growing Darwin family was established at Down House, in a London suburb.

Charles, plagued by poor health, settled down with a vengeance. By , he was confiding in a letter to a fellow naturalist, "I am almost convinced quite contrary to opinion I started with that species are not it is like confessing a murder immutable.

He devoted eight full years to documenting minute anatomical variations in barnacles. A prolific letter writer, he sought samples, information and scientific advice from correspondents around the world.

It was a young naturalist and professional specimen collector named Alfred Russel Wallace who finally spurred Darwin to publish. Working first in the Amazon and then in the Malay Archipelago, Wallace had developed an evolution theory similar to Darwin's but not as fully substantiated. When, in , Wallace sent the older man a manuscript describing his theory of evolution, Darwin realized that Wallace could beat him into print.

Darwin had an essay he had written in and Wallace's manuscript read at a meeting of the Linnean Society in London on July 1, , and published together later that summer. Wallace, then on an island in what is now Indonesia, wouldn't find out about the joint publication until October. Carroll, a biologist and author of books on evolution.

He was honored that his work was considered worthy" to be included alongside that of Darwin, whom he greatly admired. This first public airing of Darwinian evolution caused almost no stir whatsoever. But when Darwin published his ideas in book form the following year, the reaction was quite different. On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life soon sold out its first press run of 1, copies, and within a year some 4, copies were in circulation.

Legend has it that Darwin was converted to the theory of evolution, eureka-like, during his visit to the islands. How could he not have been? In retrospect, the evidence for evolution seems so compelling. I owe this historical insight to a curious fact—Darwin was a lousy speller. We know, moreover, from the complete record of his unpublished scientific notes that he was personally dubious about evolution.

According to creationist theory, species were a bit like elastic bands. He and his servant did take back to England, as pets, two baby tortoises. Those juvenile tortoises further misled Darwin, because differences among subspecies are evident only in adults. Not realizing the importance of tortoises for the theory he would eventually develop about the origins and diversity of living things, Darwin and his fellow shipmates ate their way through 48 adult tortoise specimens and threw their shells overboard.

They have become one of the most famous cases of species adapting to different ecological niches. For example, Darwin thought the cactus finch, whose long, probing beak is specialized for obtaining nectar from cactus flowers and dodging cactus spines , might be related to birds with long, pointed bills, such as meadowlarks and orioles. He also mistook the warbler finch for a wren. Not realizing that all of the finches were closely related, Darwin had no reason to suppose that they had evolved from a common ancestor, or that they differed from one island to another.

One of my most unexpected discoveries in the Darwin archives was the piece of paper on which Darwin recorded his crucial meeting with Gould.

Stunned by the realization that evolving varieties could break the supposedly fixed barrier that, according to creationism, prevents new species from forming, he quickly sought to rectify his previous collecting oversights by requesting island locality information from the carefully labeled collections of three Beagle shipmates. The birth of the Darwinian revolution was a highly collaborative enterprise.

The case for evolution presented by this shared ornithological evidence nevertheless remained debatable for nearly a decade. Darwin was not entirely convinced Gould was right that all the finches were separate species, or even that they were all finches.

Darwin also knew that, without specimens in hand, island-to-island differences among the tortoises were contestable, even though a French herpetologist told a delighted Darwin in that at least two species of tortoise existed in the islands.

Unlike the birds, the plants all had accurate localities attached to them—not because Darwin had collected the plants with evolutionary theory in mind, but because plants have to be preserved in plant presses shortly after being collected. Hence the specimens from each island had all been pressed together, rather than being intermixed.

That came later, with the discovery of how genes encode different biological or behavioral traits, and how genes are passed down from parents to offspring. The incorporation of genetics into Darwin's theory is known as "modern evolutionary synthesis. The physical and behavioral changes that make natural selection possible happen at the level of DNA and genes within the gametes, the sperm or egg cells through which parents pass on genetic material to their offspring.

Such changes are called mutations. Mutations can be caused by random errors in DNA replication or repair, or by chemical or radiation damage.

Usually, mutations are either harmful or neutral, but in rare instances, a mutation might prove beneficial to the organism. If so, it will become more prevalent in the next generation and spread throughout the population. In this way, natural selection guides the evolutionary process, preserving and adding up the beneficial mutations and rejecting the bad ones. But natural selection isn't the only mechanism by which organisms evolve, she said.

For example, genes can be transferred from one population to another when organisms migrate or immigrate — a process known as gene flow. And the frequency of certain genes can also change at random, which is called genetic drift. The reason Lamarck's theory of evolution is generally wrong is that acquired characteristics don't affect the DNA of sperm and eggs.

A giraffe's gametes, for example, aren't affected by whether it stretches its neck; they simply reflect the genes the giraffe inherited from its parents. But as Quanta reported , some aspects of evolution are Lamarckian. For example, a Swedish study published in in the European Journal of Human Genetics found that the grandchildren of men who starved as children during a famine passed on better cardiovascular health to their grandchildren.

Researchers hypothesize that although experiences such as food deprivation don't change the DNA sequences in the gametes, they may result in external modifications to DNA that turn genes "on" or "off.

For instance, a chemical modification called methylation can affect which genes are turned on or off. Such epigenetic changes can be passed down to offspring. In this way, a person's experiences could affect the DNA he or she passes down, analogous to the way Lamarck thought a giraffe craning its neck would affect the neck length of its offspring. Even though scientists could predict what early whales should look like, they lacked the fossil evidence to back up their claim.

Creationists viewed this absence, not just with regard to whale evolution but more generally, as proof that evolution didn't occur, as pointed out in a Scientific American article. But since the early s, scientists have found evidence from paleontology, developmental biology and genetics to support the idea that whales evolved from land mammals.

These same lines of evidence support the theory of evolution as a whole. The critical piece of evidence was discovered in , when paleontologists found the fossilized remains of Ambulocetus natans , which means "swimming-walking whale," according to a review published in the journal Evolution: Education and Outreach.

And then there is Jerry Fodor, the American philosopher. I started reading What Darwin Got Wrong, the new book he has co-authored with the cognitive scientist Massimo Piattelli-Palmarini, one morning, along with that day's first coffee. A few pages later, as the coffee kicked in, I grasped with astonishment what Fodor had done. He hadn't just identified evidence that natural selection was more complicated than previously thought — he'd uncovered a glaring flaw in the whole notion!

Natural selection, he explains, simply "cannot be the primary engine of evolution". I got up and refilled my cup. But by the time I returned, his argument had slipped from my grasp. Suddenly, he seemed obviously wrong, tied up in philosophical knots of his own creation.

I alternated between these two convictions. Was Fodor's critique so devastatingly correct that his critics — Dawkins, Dennett, the Cambridge philosopher Simon Blackburn, and many others — simply couldn't see it? Had he actually managed to. I called Fodor and asked him to explain his point in language an infant school pupil could understand. If we're right that Darwin and Darwinists have missed the point we've been making for years, that's not because it's a simple point and Darwin was stupid.

It's a really complicated issue. Fodor's objection is a distant cousin of one that rears its head every few years: doesn't "survival of the fittest" just mean "survival of those that survive", since the only criterion of fitness is that a creature does, indeed, survive and reproduce? The ones who survive! The 'survival of the fittest' would be a joke if it weren't part of the belief system of a fanatical cult infesting the Scientific Community.

This argument, perhaps uniquely among all arguments ever made by Coulter, feels persuasive, not least because it is a reasonable criticism of some pop-Darwinism.

In fact, though, it's entirely possible for scientists to measure fitness using criteria other than survival, and thus to avoid circular logic. For example, you might hypothesise that speed is a helpful thing to have if you're an antelope, then hypothesise the kind of leg structure you'd want to have, as an antelope, in order to run fast; then you'd examine antelopes to see if they do indeed have something approximating this kind of leg structure, and you'd examine the fossil record, to see if other kinds of leg died out.

Fodor's point is more complex than this, although it's also possible that it is not really a point at all: several reviews of the book by professional evolutionary theorists and philosophers have concluded that it is, indeed, nonsense. As far as I can make out, it can be summarised in three steps. Step one: Fodor notes — undeniably correctly — that not every trait a creature possesses is necessarily adaptive.

Some just come along for the ride: for example, genes that express as tameness in domesticated foxes and dogs also seem to express as floppy ears, for no evident reason. Other traits are, as logicians say, "coextensive": a polar bear, for example, has the trait of "whiteness" and also the trait of "being the same colour as its environment".

Yes, that's a brain-stretching, possibly insanity-inducing statement. Take a deep breath. Step two: natural selection, according to its theorists, is a force that "selects for" certain traits. Floppy ears appear to serve no purpose, so while they may have been "selected", as a matter of fact, they weren't "selected for". And polar bears, we'd surely all agree, were "selected for" being the same colour as their environment, not for being white per se: being white is no use as camouflage if snow is, say, orange.

Step three is Fodor's coup de grace: how, he says, can that possibly be? The whole point of Darwinian evolution is that it has no mind, no intelligence. But to "select for" certain traits — as opposed to just "selecting" them by not having them die out — wouldn't natural selection have to have some kind of mind?