Right now there's a conference going on in Oxford, United Kingdom—that hotbed of Christian apologetics (and Richard Dawkins). John Wilkins is there. One of the topics is defining religion [Ruminations in Oxford]. With an eye to the discussion of the previous chapters, I want to pick out four items or claims that are central to Christian belief—four items that the Christian takes on faith. If you do not believe in these, then you should not call yourself a Christian. First, that there is a God who is creator, "maker of heaven and earth." Second, we humans have duties, moral tasks here on earth, in the execution of which we are going to be judged. Hence, God stands behind morality. Third, Jesus Christ came to earth and suffered because we humans are special, we are worth the effort by God. The usual way of expressing this is to say that we are "made in the image of God." We have "souls." Fourth and finally, there is the promise of "life everlasting." We can go to heaven, what ever that means.Here's my quick take on the four items.
Let me spell out carefully what I see as the task in this and the next chapter. It is not to defend Christianity as a true or compelling belief system. I take it that you can enter these chapters as an agnostic or an atheist and depart in the same frame of mind. I do not want to dissuade people from Christianity, nor do I want to convince them of it. I want to explain in a fair manner what is meant by Christianity in terms of the four points introduced in the last paragraph. I also want to show that you could hold these, if you so wish, in the light of modern science—if you prefer, in the face of modern science. In other words, the Christian's claims are not refuted by modern science—or indeed threatened or made less probable by modern science.
Ward effortlessly flows from one fascinating insight to another about the often contentious relationship between diverse religious views and the new scientific knowledge. Writing with both passion and clarity, he masterfully converys the depth, the difficulty, and the importance of the greatest intellectual and existential questions of the modern age."Clarity"? Don't make me laugh. Keith Ward has never met an example of obscurantism that he doesn't embrace.
[Hat Tip: Clarity - A very nice statement by Dawkins, at RichardDawkins.net.]
Mr. Prime Minister and excellent minister Bev Oda:Did I mention that Denyse is a Roman Catholic? Do you think it's relevant?
Please stand firm against the people who will get money from aborting babies in other countries, if you cave in.
This is for a number of non-religious reasons:
1. There is NO reason to believe abortion will even be voluntary. And what can we do if it isn't? It is better if we Canadians just do not fund it. (If people in other countries want to force women to be aborted, to meet grant-based population reduction quotas, we cannot stop them. But at least we had nothing to do with it, right? It's not like the cheque is stamped 'From a grateful CANADA'. Surely, there are some shames we cannot stoop to.)
2. Contrary to population whackos, most of the world is in steep demographic decline. This is bad news for business, pension plans, etc. Why add to the problem? Right now, YOUR government is advertising for healthy young workers from abroad. So we should kill their successors?
3. Abortion clinics are run by people who do not mind killing babies for a living. Even if you didn't agree that that is a problem, a number of other evils result, including: Teachers molest underage girls and ship them to clinics for discreet abortions, unbeknown to their parents. Abortion clinics may also function on the adoption black market. = Would you keep it for a while instead of killing it, if we get you some money?
4. No one should believe anything an abortion clinic operator says about not killing viable babies. If he really cared about stuff like that, he would not likely do what he does now. So you can assume, for practical purposes, it is unreliable.
5. Some babies may be sold for research that should never be done on a human being, but remember that they do not technically exist.
Stand firm! Most of the criticism I hear about your government comes from NOT standing up for traditional Canadian values. Most of the praise I hear is for doing so.
And REPEAL Section 13 and FIRE Jennifer Lynch. Quit fooling around about that too. People are really angry.
Traditional values and civil rights are important to the people who would re-elect you.
Katarin MacLeod reviews a new book on evolution—one that's intended to educate children who lack an understanding of science [Evolution (Biology)-Juvenile literature]. Katarin MacLeod is an Assistant Professor in Science Education at St. Francis Xavier University in Antigonish, NS. Her areas of interest include physics educational research (PER), and the incorporation of science, technology, society and environment (STSE) outcomes into science courses at all levels to help students understand the relevancy of science, increase scientific literacy, and to promote citizenship.Here's part of her review. You can judge for yourself whether she is competent to teach science education at St. Francis Xavier University.
Although the text is very good in describing the theory of Evolution, there are points in the book where the author makes comments that could imply that Evolution is more than a theory. For example, “…Charles Darwin revealed the solution to the mystery of evolution” (p. 7). He also makes the comment that Evolution is the most important idea in all of biology (p. 7). Such phrases may lead the reader into thinking that scientists completely understand the theory of Evolution which would be incorrect, else Evolution would be a principle or a law and not a theory. As well, it is a bit bold to claim that evolution is the most important idea in all of biology – biology is a huge field of study with other key discoveries.Hint to Professor MacLeod. Before you review your next book on evolution you'd better brush up on the difference between a fact and a theory and learn that a theory can never become a law.
[Hat Tip: Richard B. Hoppe at Panda's Thumb]
The Royal Ontario Museum (ROM) is sponsoring a lecture by Deepak Chopra. You can see for yourself on the ROM website: An Evening with Deepak Chopra.An Evening with Deepak Chopra
Wednesday, June 23, 7:00 - 8:00 pm (Doors Open 6:00 pm)
Status: Registration Starts May 14!
Director's Signature Series
The Warrior Emperor and China's Terracotta Army
World renowned teacher, author and philosopher Deepak Chopra presents his latest concepts in the field of mind-body medicine bridging the technological miracles of the West with the wisdom of the East. He will show you how your highest vision of yourself can be turned into physical reality and discuss how you can become a living cell within the body of a living universe. You don't join the cosmic dance - you become the dance. Deepak will address the deeper meaning of our existence including: What is our true nature? What is the meaning and purpose of our existence? How can I transform myself? How can I make a better world? Deepak explains how the greatest spiritual secrets are tied up in this simple answer: You can't change the body without changing the self, and you can't change the self without bringing in the soul. He explains, "It's all one process, and it begins with knowing that your body exists to mirror who you are and who you want to be."
Deepak Chopra is the author of more than 56 books translated into over 35 languages, including numerous New York Times bestsellers in both the fiction and non-fiction categories. He is a fellow of the American College of Physicians, a member of the American Association of Clinical Endocrinologists, Adjunct Professor at Kellogg School of Management and Senior Scientist with The Gallup Organization. Time magazine heralds Deepak Chopra as one of the top 100 heroes and icons of the century and credits him as "the poet-prophet of alternative medicine." For more information visit: www.deepakchopra.com
Location: Convocation Hall, 31 King’s College Circle, University of Toronto
Cost: Price: Ground VIP: $175, Rise Area: $89, 1st Balcony: $69, 2nd Balcony: $49, Behind Stage: $25
Tickets are non-refundable.
Transcripts from approximately 95% of multi-exon human genes are spliced in more than one way, and in most cases the resulting transcripts are variably expressed between different cell and tissue types. This process of alternative splicing shapes how genetic information controls numerous critical cellular processes, and it is estimated that 15% to 50% of human disease mutations affect splice site selection.I don't object to scientists who hold points of view that are different than mine—even if they're wrong! What I object to is those scientists who promote their personal opinions in scientific papers without even acknowledging that there's a genuine scientific controversy. You have to look very carefully in this paper for any mention of the idea that a lot of alternative splicing could simply be due to mistakes in the splicing machinery. And if that's true, then the "splicing code" that they've "deciphered" is just a way of detecting when the machinery will make a mistake.
Frey compared his computer decoder to the German Enigma encryption device, which helped the Allies defeat the Nazis after it fell into their hands.
“Just like in the old cryptographic systems in World War II, you’d have the Enigma machine…which would take an instruction and encode it in a complicated set of symbols,” he said.
“Well, biology works the same way. It turns out to control genetic messaging it makes use of a complicated set of symbols that are hidden in DNA.”
Given the number of biological activities needed to grow and govern our bodies, scientists had believed humans must have 100,000 genes or more to direct those myriad functions.I wish I had time to present a good review of the paper but I don't. Sorry.
But that genomic search of the 3 billion base pairs that make up the rungs of our twisting DNA ladders revealed a meagre 20,000 genes, about the same number as the lowly nematode worm boasts.
“The nematode has about 1,000 cells, and we have at least 1,000 different neuron (cells) in our brains alone,” said Benjamin Blencowe, a U of T biochemist and the study’s co-senior author.
To achieve this huge complexity, our genes must be monumental multi-taskers, with each one having the potential to do dozens or even hundreds of different things in different parts of the body.
And to be such adroit role switchers, each gene must have an immensely complex set of instructions – or a code – to tell them what to do in any of the different tissues they need to perform in.
Barash, Y., Calarco, J.A., Gao, W., Qun Pan, Q., Wang, X., Shai, O., Benjamin J. Blencowe, and Frey, B.J. (2010) Deciphering the splicing code. Nature 465: 53–59. [doi:10.1038/nature09000] [Supplementary Information]
This is the fourth in a series of postings by guest blogger, Arlin Stoltzfus. You can read the introduction to the series at: Introduction to "The Curious Disconnect". The first part is at: The "Mutationism" Myth I. The Monk's Lost Code and the Great Confusion. The second installment is: Theory vs Theory.Our journey to map out the Curious Disconnect— the gap between how we think about evolution and how we might think if we were freed from historical baggage— began with The Mutationism Myth, part 1. Then, in Theory vs Theory, we took a brief detour to distinguish theory1 (grand conjecture) from theory2 (body of abstract principles). Today we are back to the Mutationism Myth and our goal is to probe its claim that the scientific community rejected Darwin's ideas on erroneous grounds.1
The Mutationism Myth is a story told in the literature of neo-Darwinism, regarding the impact of the (re)discovery of Mendelian genetics a century ago. In this story, the discoverers of genetics (characterized as laboratory-bound geeks) misinterpret their discovery, thinking it incompatible with natural selection; the false gospel of these "mutationists" brings on a dark period that lasts until the 1930s, when theoretical population geneticists prove that genetics is the missing key to Darwinism; Darwinism is restored, and there is peace and unity in the land.
In typical versions of the mutationism story that we reviewed in part 1, the Mendelians cast a spell on the scientific community, convincing it of a false belief that either
For instance, Eldredge (2001) writes:
Many early geneticists at the dawn of the 20th century, thought their discoveries of the fundamental principles of genetics somehow cast doubt [on], or rendered obsolete, the concept of natural selection
As noted earlier, a myth is not necessarily false. Some parts of the Mutationism Myth reflect history accurately, and others do not. An underlying truth in the Mutationism Myth is that, as a direct result of the re-discovery of Mendelian genetics, leading geneticists— Bateson, Johannsen, de Vries, Morgan, Punnett, and others— rejected Darwin's theory for how evolution works.
Our goal is to understand why. We must begin with heredity, the heart of the issue.
The re-discovery of Mendel's principles of heredity was nothing short of a revolution, and if you were trained in 19th-century views of heredity, this would be obvious, and there would be no need for me to explain it.
Unfortunately, the chances are good that you, dear reader, have been trained in the principles of Mendelism, and that puts us at a disadvantage. Once we can imagine the purity of hereditary factors, and we learn Johannsen's genotype-phenotype distinction, these principles seem to change our view of the world irreversibly, and its hard to understand what came before. Johannsen's quantitative-genetics experiments on seed weights of the Princess bean, conducted in the first decade of the 20th century, appear to have had more impact on evolutionary thinking than any single study conducted before or since. In the figure below, Johanssen (1903) shows the distribution of weights of beans from a plot planted with a mixture of seeds from pure self-fertilizing lines (the legend says "The variation of the weight of 5494 beans from the 1902 harvest, descendants of all weight classes in 1901") (online source):
The beans from the mixed plot show a nice bell-shaped distribution (figure). Similarly, the beans harvested from pure lines grown in separate garden plots also show nice bell-shaped distributions, though the means differ for each pure line. The key difference is in the results of selective breeding for heavier (or lighter) beans, i.e., planting a new crop using only the heaviest (or lightest) beans: selection shifts the distribution of seed weights in the mixed plot, but has no significant effect on the distribution of seed weights produced by a pure line.
Within just a few decades, neo-Darwinians such as Ford (1938) dismissed Johannsen's results as a logical necessity, as though the experiments proved nothing. Johannsen's studies had changed our understanding so profoundly that Ford was unable to imagine how scientists (mis)understood the world before.
I won't ask you to do what Ford could not, which is to forget genetics.
Instead, I would like to ask you to join me in imagining a different world— one in which particulate inheritance of pure hereditary factors does not apply.
We have been sent to this alien world as evolutionary experts, to consult with its scientists about how evolution might work on their planet. The alien scientists explain that, in their world, the bodies of organisms have differentiated organs composed of diverse cell-like units (CLUs), which swell, fuse, split and exchange material. The CLUs don't seem to have nuclei or central control centers. Instead, they are composed of substances that interact productively and grow, crystal-like (possibly some kind of prion-like protein, we think to ourselves). Different CLUs have different compositions, and thus have different developmental tendencies, e.g., some CLUs have a tendency to aggregate and interact to form a differentiated organ.
We are skeptical of the alleged lack of nuclei, so we explain the "nucleus" concept to the aliens and propose that CLUs actually have a spatially localized store of information that controls growth and development. The aliens listen carefully and ask clarifying questions in order to understand our hypothesis. Then they tell us that they know we are wrong. Alien scientists long ago developed a method of splitting CLUs which showed that the separated parts of CLUs largely retain their potential for growth and development, even if the CLUs are cut in multiple pieces. Thus, the alien scientists had demonstrated that CLUs and their substances have a hereditary aspect, but the potential for heredity seems to be dispersed in the substances, not centralized in a nucleus.
During the life of an organ, CLUs may come and go. CLUs circulating in the body are harvested continually in the reproductive organs, where substances are extracted to form minute reproductive corpuscles, RCs, whose role in reproduction is similar to gametes. However, the RCs or reproductive corpuscles don't have the 1-copy-of-each-factor neatness of earthly Mendelian gametes. The growable substances in the RCs are variable in amount, thus RCs vary in hereditary potencies. Furthermore, the composition of CLUs circulating in the body reflects the totality of what is happening in the body: because the body is continually growing and reacting and changing, the RCs are changing, too. In particular, the composition of the RCs tends to deviate more strongly when the organisms are stressed or face unusual conditions.
While some of the alien organisms are asexual, others have tri-parental reproduction that involves mixing of RCs from different parents. Each of the 3 parents makes a contribution of RCs, typically equal in size, though in some species, one type of parent contributes much more than the other two. When the parental RCs come together, the substances in them seem to mix or blend.
The alien scientists have outlined the basis of heredity on their planet, and they are looking to us expectantly for ideas about how evolution is going to work. We were hoping to gather more facts, and particularly to hear from other experts about the diversity of life, and so on, but the aliens are eager for our ideas right away. What can we infer about evolution in a bottom-up manner, from an understanding of heredity?
We see immediately that it will be possible to apply some concept of "selection" in this world, but its going to be awfully slippery. We reach into our conceptual toolbox, and the first thing we find is the concept of "selection coefficient". But thats not useful on the alien planet, because there is no stable genetic entity to which one may apply the selection coefficient— everything in the alien world with a bearing on heredity seems to be variable in potency and to be subject to blending. Heredity depends on the differential growth of continuous substances, modulated by their differential incorporation into RCs due to conditions of life, and so on. The alien world lacks the algebraic neatness of pairwise combinations and pure factors.
In fact, our hearts sink as we realize that, because of this blending-together, it might be impossible for evolution to start from a single hereditary variant, as would be possible on earth starting with a single Mendelian mutant. The distinctive features of the individual variant would simply diffuse and blend.
But our discouragement is only temporarily. Yes, it would have been simple and easy if hereditary factors emerged discretely, combined in simple ratios, and maintained their purity during reproduction— but who said science was supposed to be simple and easy?
We are undaunted. We are determined to discover some way to apply the principle of selection. In fact, given that the RCs deviate more strongly under unusual conditions, we note with enthusiasm that extra hereditary variation will emerge just when it would be helpful to provide fuel for adaptation to new conditions! Due to hereditary blending, one variant individual, with a variation in a favorable direction, would not be enough.
But thats not a problem. In fact, to treat it as a "problem" is wrong-headed, because this alien world is not a world of discrete heredity anyway! Instead, on the alien planet, heredity is a bulk process, like the flow and mixing of liquids. The hereditary substances flow (metaphorically) in new directions every generation, and selection can get some leverage from these fluctuations of hereditary potency, even if there is not any single discrete particle to grasp. Selection would guide these fluctuations, building them smoothly from generation to generation. Possibly we could develop a mathematical formalism for this process by adapting the breeder's equation of quantitative genetics, although the shifting of hereditary potencies from one generation to the next would be problematic. An even more radical thought occurs to us: Lamarckian evolution can't happen in our world, but in the alien world, it just might be possible due to the way the RCs reflect what is going on in the body as it experiences its environment.
If you have followed me thus far, congratulations! You are one of the re-discoverers of Darwin's lost theory of evolution!
Sadly, when I refer to a "lost theory", its not a joke, because Darwin's "Natural Selection Theory" (not to be confused with the principle of natural selection2) is largely unknown to contemporary scientists. During the Darwin bicentennial last year, I lost track of how many times "Darwin's theory" was explained by reference to "selection and random mutation" or some such anachronism.
Darwin had no such theory. Given Darwin's assumptions that inheritance is blending (not particulate), that the germ-line is responsive to external conditions (not isolated), and that hereditary potencies shift gradually every generation (not rarely and abruptly, from one pure, stable state to another), it is physically impossible for a rare trait, having arisen by some process, and conferring a fitness advantage of (for example) 2 %, to be passed on to offspring by a stable non-blended hereditary factor, thus conferring on the offspring a 2 % advantage, and for such a process to continue for thousands of generations until the previously rare trait prevails. We may think of evolution in this way: Darwin did not.
Instead, Darwinism 1.0 (Darwin's conception of evolution) is an automatic process of adjustment to altered conditions, dependent on a rampant process of "fluctuation" yielding abundant "infinitesimally small inherited modifications" in response to the effect of altered "conditions of life" on the "sexual organs" (Chs. 1, 2, 4 and 5 of Darwin 1859). Fluctuation was not rare and discrete, but shifted hereditary factors continuously and cumulatively each generation, producing visible effects in "several generations" (Ch. 1 of Darwin 1859). Muller (1956) referred to Darwinian fluctuation as "creeping variation". I have called it "variation on demand", and I also think that, to understand Darwin's view, its helpful to think of heredity and variation as processes mediated by fluids (liquids or gases). Darwin's critics, and quite a few of his friends such as Huxley and Galton, believed that individual "sports" (mutants) could be the start of something new in evolution, but this was not part of Darwin's theory, which invoked blending inheritance and held fast to natura non facit salta.
For those who would like to get more of a flavor of Darwin's view from his own writings, I have included a few passages below in an appendix. Readers may wish to go further by browsing online sources via the links provided. Others may wish to take a colorful look at Darwin's laws of variation from the Virtual Museum of the Origin of Species.To account for his principles or "laws"3 of variation, Darwin proposed a "gemmule" theory for the mechanism of heredity, where "gemmules" are somewhat like the RCs or "reproductive corpuscles" in the fictional alien world described above.
Although Darwin's "Natural Selection" theory invoked Lamarckian effects, the fluctuation-selection process that Darwin called "Natural Selection" was recognized immediately as its mechanistic core. Only this core mechanism remains in the reformed view of Weismann and Wallace— "Darwinism 1.2" for our purposes—, which expunged Lamarckism and relied on selection of ever-present fluctuations, a process understood (in Darwinism 1.2) as the exclusive and all-powerful driving force of evolution.
In fact, the "Mendelians" did not reject the principle of selection. Instead, they rejected "fluctuation" as the basis of evolutionary change for exactly the reason we would expect, namely that these fluctuations are not heritable. Johannsen's experiments were influential because they suggested that the fluctuations that emerge reliably every generation, i.e., Darwin's "endless slight peculiarities which distinguish the individuals of the same species and which cannot be accounted for by inheritance from either parent or from some more remote ancestor", are non-heritable and cannot be the basis for evolution by natural selection.
This is precisely the reason that geneticists gave, explicitly, for rejecting Darwin's view. For instance, in his 1911 book Mendelism, Punnett (of the "Punnett square" one studies in Genetics 101) explains the new "basis of evolution":
"The distinction between these two kinds of variation, so entirely different in their causation, renders it possible to obtain a clearer view of the process of evolution than that recently prevalent. . . Evolution only comes about throught the survival of certain variations and the elimination of others. But to be of any moment in evolutionary change a variation must be inherited. And to be inherited it must be represented in the gametes. This, as we have seen, is the case for those variations which we have termed mutations. For the inheritance of fluctuations, on the other hand, of the variations which result from the direct action of the environment upon the individual, there is no indisputable evidence. Consequently we have no reason for regarding them as playing any part in the production of that succession of temporarily stable forms which we term evolution. In the light of our present knowledge we must regard the mutation as the basis of evolution— as the material upon which natural selection works. For it is the only form of variation of whose heredity we have any certain knowledge.
It is evident that this view of the process of evolution is in some respects at variance with that generally held during the past half century. " (Punnett, 1911, p. 139-140; online source)
Punnett rejects "fluctuations", defined as "the variations which result from the direct action of the environment upon the individual".
It wasn't about rejecting natural selection: Punnett identifies mutation as the "basis" of evolution precisely on the grounds that it provides "the material on which selection works". While TH Morgan (1916) often avoided the phrase "natural selection", as in the following passage, he clearly is not rejecting a role for differential effects of fitness
"evolution has taken place by the incorporation into the race of those mutations that are beneficial to the life and reproduction of the organism" (p. 194) (online source)
This "mutationist" view was merely the start of a new way of looking at evolution. In the next installment, we'll find out what sort of understanding of evolution emerged among this new generation of evolutionists inspired by Mendelian principles. We'll see that, contrary to the Mutationism Myth, the period between the discovery of genetics and the origin of the Modern Synthesis in the 1930s was not a dark period of confusion at all, but a period of innovation that gave rise to key elements of the genetics-based understanding of evolution that persists today, including new ways of understanding selection.
This post raises several issues that will receive attention in future posts of The Curious Disconnect. For instance, the mutationists rejected "Natural Selection", the theory1 of Darwin, but not the "concept of selection" (as mistakenly asserted by Eldredge, above). In a later post, we will explore how the ambiguity in "natural selection" covers a multitude of sins (e.g., Charlesworth, 2005), and we'll consider ways to speak (and think) more clearly.
A second issue is the cult of personality that has developed around Darwin, which instills in so many scientists the desire to align themselves with Darwin and label themselves "Darwinists" while ignoring Darwin's actual views. Rather than reject or defend Darwin's actual theory, the cultists make personal excuses for Darwin ("he couldn't have known!"), as though science were about judging persons rather than evaluating theories. In a future post, we'll explore the distorting influence of the Darwin Fetish.
A third issue has to do with the structure of Darwin's theory, and more generally, how we determine the structure of a theory, and how the parts fit together. This will become important when we evaluate the deeply problematic claim of the Modern Synthesis to have reconciled Darwin's view with genetics. In essence, the architects of the Modern Synthesis will claim that "the maintenance of abundant infinitesimal variation in the gene pool" replaces "fluctuation" while leaving the rest of Darwin's theory unchanged.
Darwin espoused a theory of evolution, not merely a principle of selection. If this theory merely asserted the principle of selection, then no possible finding in genetics could contradict it. In fact, Darwin's theory invoked the principle of selection, in the context of a mechanism he called "fluctuation", to account for most of the actual facts of evolution, leaving a residue to be explained by other means (Lamarckian and Buffonian effects)— other means that Darwin's followers soon rejected as untenable, leaving only the fluctuation-selection process.
Thus, prior to the discovery of genetics, Darwin's theory was understood correctly to rely on continuous hereditary variation that Darwin called "fluctuation", and that was induced by environmental conditions, not inherited from parents. The Mendelians argued that, if we wish to understand the "the basis of evolution— the material on which selection works", we must look to mutation, not to Darwin's "fluctuations", because variations induced by conditions are not heritable.
Little of this is understood today, because "Darwinism" or "Darwin's theory" has been redefined, and the original meaning of "Darwin's theory" has gone done the proverbial memory hole.
Charlesworth, B. 2005. On the Origins of Novelty and Variation. Science 310:1619-1620.
Darwin, C. 1859. On the Origin of Species. John Murray, London.
Darwin, C. 1883. Variation of Animals and Plants under Domestication. D. Appleton & Co., New York.
Eldredge, N. 2001. The Triumph of Evolution and the Failure of Creationism. W H Freeman & Co.
Ford, E. B. 1938. The Genetic Basis of Adaptation. Pp. 43-56 in G. R. de Beer, ed. Evolution. Clarendon Press, Oxford.
Johannsen, W. L. 1903. Erblichkeit in Populationen und in reinen Linien. Gustav Fischer, Jena.
Morgan, T. H. 1916. A Critique of the Theory of Evolution. Princeton University Press, Princeton, NJ.
Muller, H. J. 1956. On the Relation between Chromosome Changes and Gene Mutation. Brookhaven Symposia in Biology 8:126-147.
Punnett, R. C. 1911. Mendelism. MacMillan.
Three passages below illustrate Darwin's view of the emergence of hereditary variation. The first indicates that the emergence of hereditary variation occurs on the scale of a few generations— no waiting around for mutations— and that the fluctuations build up cumulatively:
"It seems clear that organic beings must be exposed during several generations to new conditions to cause any great amount of variation; and that, when the organisation has once begun to vary, it generally continues varying for many generations." (Darwin, 1859, Ch. 1; online source
Darwin knew that "sports" (mutants) could have heritable effects, but he imagined that infinitesimal fluctuations were even more likely to be heritable:
"If strange and rare deviations of structure are really inherited, less strange and commoner deviations may be freely admitted to be heritable. Perhaps the correct way of viewing the whole subject would be, to look at the inheritance of every character whatever as the rule, and non-inheritance as the anomaly" (Darwin, 1859, Ch. 1; online source).
Darwin learned about heredity the hard way: by exchanging hand-written letters with hobbyists and stockmen who bred pigeons, sheep, dogs, and so on. Below he is describing an experiment in domestication of ducks from wild eggs, based on information provided by Mr. Hewitt, a source referenced by Darwin many times in his works:
"Mr. Hewitt found that his young birds always changed and deteriorated in character in the course of two or three generations; notwithstanding that great care was taken to prevent their crossing with tame ducks. After the third generation his birds lost the elegant carriage of the wild species, and began to acquire the gait of the common duck. They increased in size in each generation, and their legs became less fine. The white collar round the neck of the mallard became broader and less regular, and some of the longer primary wing-feathers became more or less white. When this occurred, Mr. Hewitt destroyed nearly the whole of his stock and procured fresh eggs from wild nests; so that he never bred the same family for more than five or six generations. His birds continued to pair together, and never became polygamous like the common domestic duck. I have given these details, because no other case, as far as I know, has been so carefully recorded by a competent observer of the progress of change in wild birds reared for several generations in a domestic condition. "(Darwin, 1883, p. 293; online source)
Thus, Darwin is describing subtle variations that emerge in response to new conditions, and that emerge immediately or, at least, within a few generations. He saw hereditary fluctuation as an effectively continuous process, i.e., a process that can be subdivided arbitrarily in time and in outcome because it is the summation of infinitesimal increments. Adaptation can happen rapidly and reliably because organisms start to vary immediately upon encountering new conditions. Similar variations will be manifested in many individuals (as in the case of the ducks above), so that multiple members of a "race" may emerge and interbreed simultaneously with, or prior to, selection. This avoids the problems posed by the swamping effect of blending inheritance (Darwin did not believe that a solitary variant could begin an evolutionary change). Darwin's principles of variation are roughly that
1 An updated version of this post will be available at http://www.molevol.org/cdblog/mutationism_myth2
2 Don't blame me for this egregious ambiguity, which we will address in a future post.
3 Today we would call these laws "principles" or "generalizations". "Laws" in 19th century science are empirical generalizations, reached by the method of Baconian induction: collect lots of facts and distill them into generalizations.
Philip Ball is a freelance science writer based in London (UK). He frequently writes for Nature. His latest article is a review of a recently published paper by John Avise [What a shoddy piece of work is man]. Apparently Avise has just published a paper in PNAS where he points out that our genome does not look like it was designed. It's an attack on Intelligent Design Creationism and Adaptationism. However — although heaven forbid that this should seem to let ID off the hook — it is worth pointing out that some of the genomic inefficiencies Avise lists are still imperfectly understood. We should be cautious about writing them off as 'flaws', lest we make the same mistake evident in the labelling as 'junk DNA' genomic material that seems increasingly to play a biological role. There seems little prospect that the genome will ever emerge as a paragon of good engineering, but we shouldn't too quickly derogate that which we do not yet understand.THEME
My point is that it's extremely misleading to suggest that our identification of junk DNA is based on a lack of understanding. That's simply not true. There are some very good scientific reasons for maintaining that most of our DNA is junk based on over 40 years of work on genome organization. 
At least they weren't the only ones. The Toronto Star is a perfectly respectable newspaper. It's not one of those tabloids that publish anything in order to pander to the lowest common denominator.
Sometimes you discover that you're related to people you'd rather not be related to. Here's a valid relationship between me and Richard Nixon. 
Biologists often make a distinction between the fact of evolution (all living things are cousins) and the theory of what drives it (they usually mean natural selection, and they may contrast it with rival theories such as Lamarck's theory of 'use and disuse' and 'the inheritance of acquired characteristics'). ... Nowadays it is no longer possible to dispute the fact of evolution itself—it has graduated to become a theorum or obviously supported fact—but it could still bedoubted (just) that natural selection is its major driving force.The distinction is important. Things like common descent and the history of life are the facts that demonstrate evolution. Evolutionary theory offers a solid, widely-accepted, explanation of how evolution happens.
Douglas Futuyma has written one of the most respected textbooks on evolution. He agrees with this distinction—as do all other textbook authors that I know of. Here's what Futuyma says in Evolution 2nd ed. p. 4.The explanation of how modification occurs and how ancestors gave rise to diverse descendants constitutes the theory of evolution. We now know that Darwin's hypothesis of natural selection on hereditary variation was correct, but we also know that there are more causes of evolution than Darwin realized, and that natural selection and hereditary variation themselves are more complex than he imagined. A body of ideas about the causes of evolution, including mutation, recombination, gene flow, isolation, random genetic drift, the many forms of natural selection, and other factors, constitute our current theory of evolution or "evolutionary theory." Like all theories in science, it is a work in progress, for we do not yet know the causes of all of evolution, or all the biological phenomena that evolutionary biology will have to explain. Indeed, some details may turn out to be wrong. But the main tenets of the theory, as far as it goes, are so well supported that most biologists confidently accept evolutionary theory as the foundation of the science of life.No doubt you're puzzled about the purpose of this posting. You are probably saying to yourself. "So what? We all know that, already."
Apparently, not all of us agree. In an otherwise excellent review of Richard Dawkin's book, Jerry Coyne says the following [see: The Improbability Pump].Demonstrating the truth of natural selection is just one of Dawkins's aims, for the theory of evolution is composed of several more or less independent parts, which I like to describe in one longish sentence: "Life on earth evolved gradually, beginning with one primitive species; it then branched out over time, throwing off many new and diverse species--and the process producing the illusion of design in organisms is natural selection." This sentence constitutes a scientific theory, which is not just a guess but an informed statement about the general principles that explain many observations about nature.I think that's very wrong. First, it's wrong because it states that the history of life is a theory. Second, it's wrong because it states that the "illusion of design" is part of modern evolutionary theory (it isn't). Third, it's wrong because it only mentions natural selection and modern evolutionary theory is much more than that.
