Wednesday, February 18, 2009
World of Warcraft in France
Dear WOW Spammer,
You are spamming my blog with all kinds of links to your websites in France. I don't know what you are trying to achieve because I remove every single one of your comments within a few hours. Please confirm this fact. There's isn't a single link left on Sandwalk.
This is a waste of your time and mine. Please stop.
Tuesday, February 17, 2009
The Modern Synthesis
Most people do not understand current ideas about evolution. The following is a brief summary of the Modern Synthesis of Genetics and Evolution as put forth by evolutionary biologists in the late 1940s.The idea that life on Earth has evolved was widely discussed in Europe in the late 1700s and the early part of the 1800s. In 1859 Charles Darwin supplied a mechanism—namely natural selection—that could explain how evolution occurred. Darwin's theory of natural selection helped to convince most people that life has evolved and this point has not been seriously challenged in the past one hundred and fifty years.
It is important to note that Darwin's book The Origin of Species by Means of Natural Selection did two things. It summarized all of the evidence in favor of the idea that organisms have descended with modification from a common ancestor. Darwin built a strong case for evolution. In addition, Darwin advocated natural selection as a mechanism of evolution.
Biologists no longer question whether evolution has occurred or is occurring. That part of Darwin's book is now considered to be so overwhelmingly demonstrated that is is often referred to as the FACT of evolution. However, the MECHANISM of evolution is still debated [Evolution Is a Fact and a Theory].
During the first part of this century the incorporation of genetics and population genetics into studies of evolution led to a Neo-Darwinian theory of evolution that recognized the importance of mutation and variation within a population. Natural selection then became a process that altered the frequency of genes in a population and this came to be the minimal definition evolution [What Is Evolution?].
The earliest version of this essay appears on the TalkOrigins Archive.
A later version is at Evolution by Accident.This point of view held sway for many decades but by the 1940s the classic Neo-Darwinian view was replaced by a new concept that brought together field biology, paleontology, and population genetics. The new version took pains to exclude all mechanisms except natural selection and random genetic drift. This new version was called The Modern Synthesis after the title of a 1942 book by Julian Huxley.
We have learned much since Darwin's time and it is no longer appropriate to claim that natural selection is the only mechanism of evolution. I can understand why this point may not be appreciated by the average non-scientist because natural selection is easy to understand at a superficial level. It has been widely promoted in the popular press and the image of "survival of the fittest" is too powerful and too convenient.
One of the goals of the Modern Synthesis was to reach consensus on the importance of macroevolution. The founders of the Modern Synthesis insisted that macroevolution could be explained by microevolution and no additional mechanisms—such as the bogeyman of saltation—were required.
Ernst Mayr, one of the original founders of the Modern Synthesis, sums it up this way ...
The term "evolutionary synthesis" was introduced by Julian Huxley in Evolution: The Modern Synthesis (1942) to designate the general acceptance of two conclusions: gradual evolution can be explained in terms of small genetic changes ("mutations") and recombination, and the ordering of the genetic variation by natural selection; and the observed evolutionary phenomena, particularly macroevolutonary processes and speciation, can be explained in a manner that is consistent with the known genetic mechanisms.The original version of the Modern Synthesis included mechanisms other than natural selection, especially random genetic drift. Later on, there was a hardening of the synthesis so that natural selection became the predominant mechanism and drift was relegated to a bit part (see Mayr quotation, above). The original version is described by Douglas Futuyma as ....
Ernst Mayr (1980) "Some Thoughts on the History
of the Evolutionary Synthesis" in The Evolutionary Synthesis,
E. Mayr & W.B. Provine eds. Harvard University Press.
The major tenets of the evolutionary synthesis, then, were that populations contain genetic variation that arises by random (ie. not adaptively directed) mutation and recombination; that populations evolve by changes in gene frequency brought about by random genetic drift, gene flow, and especially natural selection; that most adaptive genetic variants have individually slight phenotypic effects so that phenotypic changes are gradual (although some alleles with discrete effects may be advantageous, as in certain color polymorphisms); that diversification comes about by speciation, which normally entails the gradual evolution of reproductive isolation among populations; and that these processes, continued for sufficiently long, give rise to changes of such great magnitude as to warrant the designation of higher taxonomic levels (genera, families, and so forth).This description would be incomprehensible to Darwin since he was unaware of genes and genetic drift. The Modern Synthesis differed from Darwinism in four important ways:
Futuyma, D.J. in Evolutionary Biology,
Sinauer Associates, 1986; p.12
The Modern Synthesis was a theory about how evolution worked at the level of genes, phenotypes, and populations whereas Darwinism was concerned mainly with organisms, speciation and individuals. This was a major shift in emphasis and those who fail to appreciate it find themselves out of step with the thinking of evolutionary biologists.
- It defined evolution as a change in the frequency of alleles in a population; an idea based on population genetics.
- In addition to natural selection, it recognized random genetic drift as an important mechanism of evolution.
- It recognized that characteristics are inherited as discrete entities called genes. Variation within a population is due to the presence of multiple alleles of a gene. Variation is caused by mutation.
- It postulated that speciation is (usually) due to the gradual accumulation of small genetic changes. This is equivalent to saying that macroevolution is simply a lot of microevolution.
The major controversies among evolutionary biologists today concern the validity of points #2 and #4 (above).
Following the centennial celebrations of the publication of Origin in 1959, there was a gradual hardening of the Modern Synthesis. The 1960s version concentrated almost exclusively on natural selection as a mechanism and random genetic drift was pretty much ignored. Today, there is debate about the relative importance of these two mechanisms and some are calling for an updating of the "hardened" Modern Synthesis.
This update would restore random genetic drift as an important mechanism, recognize neutral theory, and incorporate molecular phylogeny (and the molecular clock).
There are many who believe that the fossil record does not show gradual change but instead long periods of stasis followed by rapid speciation. This model is referred to as Punctuated Equilibrium and it is widely accepted as true, at least in some cases. The debate is over the relative contributions of gradual versus punctuated change, the average size of the punctuations, and the mechanism.
The Modern Synthesis is challenged over the emphasis on gradualism and over the claim that microevolution is sufficient to explain macroevolution. Some evolutionary biologists suggest that evolutionary theory be modified to incorporate mechanisms that occur at levels higher than the population (e.g. species sorting). These scientists advocate an extension called hierarchical theory.
There are other challenges to the Modern Synthesis. Some of them are valid and some of them are silly. But I think it's fair to say that the 50-year old version needs some serious updating to incorporate some of the new concepts.
Some scientists continue to refer to modern evolutionary theory as Neo-Darwinian. In some cases these scientists do not understand that the field has changed but in other cases they are referring to what I have called the Modern Synthesis, only they have retained an old name from the early 1900s.
Monday's Molecule #108: Winner
UPDATE: This week's molecule is the genome of ΦX174, a small bacterial virus. It was the first complete genome to be sequenced (Smith et al., 1977, Sanger et al., 1978, Sanger et al., 1978). The sequencing was done in Fred Sanger's lab and Sanger was awarded the Noble Prize a few year later for developing the dideoxy sequencing technology [The Sanger Method of DNA Sequencing].
ΦX174 is interesting because it has overlapping genes—a feature that we now know to be uncommon.
One of the authors on the papers was Michael Smith. He spent a year in Sanger's lab on sabbatical. In 1978 Smith used the ΦX174 sequence in his experiments to develop site-directed mutagenesis (Hutchison et al. 1978). Smith got the Nobel Prize in 1993. He is this week's Nobel Laureate.
This week's winner is James Fraser of the University of California, Berkeley. We will be meeting for lunch in a few months.
Hutchison, C.A. 3rd, Phillips, S., Edgell, M.H., Gillam, S., Jahnke, P., and Smith, M. (1978) Mutagenesis at a specific position in a DNA sequence. J. Biol. Chem. 253:6551-6560.
Sanger, F., Air, G.M., Barrell, B.G., Brown, N.L., Coulson, A.R., Fiddes, C.A., Hutchison, C.A., Slocombe, P.M., and Smith, M. (1977) The nucleotide sequence of bacteriophage phiX174. Nature 265:687-695.
Sanger, F., Coulson, A.R., Friedmann, T., Air, G.M., Barrell, B.G., Brown, N.L., Fiddes, J.C., Hutchison, C.A. 3rd, Slocombe, P.M., and Smith, M. (1978) The nucleotide sequence of bacteriophage phiX174. J. Mol. Biol. 125:225-246.
Smith, M., Brown, N.L., Air, G.M., Barrell, B.G., Coulson, A.R., Hutchison, C.A. 3rd, and Sanger, F. (1977) DNA sequence at the C termini of the overlapping genes A and B in bacteriophage phi X174. Nature 265:702-705.
Today's Monday's Molecule really is a molecule. Your task is to identify the molecule from the cartoon shown here. It won't be sufficient to just find the name of the molecule, you will also have to identify the significance behind determining its chemical structure. There's one scientist who was involved in that determination who also did some important work based, in part, on knowing the sequence. This scientist was awarded a Nobel Prize for his work but the prize didn't come until 15 years later. Name this Nobel Laureate.
The first person to identify the molecule and the Nobel Laureate wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first won the prize.
There are eight ineligible candidates for this week's reward: Ramon, address unknown, Jason Oakley of the University of Toronto, John Bothwell from the Marine Biological Association of the UK, in Plymouth (UK), Wesley Butt of the University of Toronto, David Schuller of Cornell University, Nova Syed of the University of Toronto, Dima Klenchin of the University of Wisconsin and undergraduate Alex Ling of the University of Toronto
John, David, and Dima have offered to donate their free lunch to a deserving undergraduate so I'm going to continue to award an additional free lunch to the first undergraduate student who can accept a free lunch. Please indicate in your email message whether you are an undergraduate and whether you came make it for your free lunch (with a friend).
THEME:
Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.
Correct responses will be posted tomorrow. I reserve the right to select multiple winners if several people get it right.
USA Is Ahead of the World in Science Education
This falls into the category of, "Wow, I didn't know that!"1. According to a press release from Michigan State University: College Science Requirements Keep US Ahead Of World, Researcher Argues ...
Despite frequent warnings of the inadequacy of education in the United States, citizens here are still among the world's most scientifically literate, a Michigan State University researcher said.Who would 'av thunk it? American are better at critical scientific reasoning because there are more science-receptive citizens. And it even extends to the law.
You can thank those general education requirements that force English majors to sit through biology classes and budding engineers to read Hemingway, Jon Miller said.
...
Fifty years after English novelist and physicist C.P. Snow warned of a disturbing lack of scientific literacy among the cultural elite and a parallel literary void among Britain's scientists and technologists, little has changed in most of the world, Miller argued. And that's part of what keeps the U.S. at the forefront of scientific endeavor and technological innovation.
"What makes the American market and society different," he said, "is that we have more science- and technology-receptive citizens and consumers, and as a society we're willing to spend money for basic science and have been doing that for years."
Americans as a group tend to be more open-minded about innovations such as genetically modified food, he said. Scientific reasoning also works its way into such disciplines as law, he noted, where facts are routinely marshaled to support or disprove theories.
I guess that's why American courts spend so much time trying to keep superstition out of the science classroom.
1. Personally, I don't think there's all that much difference between science literacy in the USA and other Westeren industrialized nations. However, the idea that the USA is actually superior to other nations does strain belief, somewhat.
Why Are Women Religious?
At my talk last Friday I was asked about the field of evolutionary psychology. This seems to be a popular topic among educated non-scientists. I suppose I shouldn't be surprised that most people are only interested in human evolution—that doesn't mean I can't be disappointed.The person who asked the question wondered why opponents of evolutionary psychology don't get more ink. The implication was clearly that the opponents are in the minority or don't have a very strong case. I should have directed him the the Wikipedia website: Evolutionary psychology controversy. It summarizes the main problems with evolutionary psychology.
Let's look at a recent article by Elisabeth Cornwell, an Assistant Professor of Research at the University of Colorado at Colorado Springs. Her article attempts to explain why women tend to be more religious than men [Why Women Are Bound to Religion: An Evolutionary Perspective]. We may be able to use her article to illustrate some of the problems with explaining human behavior using evolution.
It is because of hormones that male and female brains differ. While there is no evidence for differences in intelligence (as was believed in the nineteenth century and on into the twentieth - women were not even allowed to vote until 1920!), to deny that differences exist is simply wishful thinking. Evolution cares nothing for either misogyny or feminism; it cares not for what is moral or immoral, just or unjust: without caring at all, it builds survival machines to carry genes into the next generation.Emphasizing differences between men and women is a common theme these days. Some of these differences are due to genetic differences between men and women (e.g. hormones) and some are just cultural differences that have no genetic component. The trick is to distinguish between those differences.
But what has this to do with religious beliefs among women? Quite a bit actually. When we look at some of the behavioral and psychological differences between women and men, we can glimpse some of the adaptations necessary for our ancestors' survival.
When it comes to specific behaviors, such as religious belief, we need to be very careful. Is there a gene for "religious belief" or is this an epiphenomenon, or a cultural thing? If there's no gene controlling "religious belief" then we're not talking about evolution or biological adaptation.
With this in mind, we can begin to understand why it is so essential for women to fit into their social group. Exclusion would have meant extinction since those women who could not live in accord with the other members of their group would have had fewer or no descendants. Thus, the evolutionary pressures that shaped the need to live in harmony with the group pressed more strongly on women than on men. This is not to suggest that there were not strong evolutionary pressure for males, too, to conform, indeed there were. However, males who risked upsetting the status quo and did so successfully would have gained an advantage in their own reproductive success. Females who tried the same would not.Like most people who advocate the evolution of specific behaviors, Elisabeth Cornwell is not spelling out the details of her proposal. Let's try and fill in the blanks.
The idea that women might feel the need to belong to a group isn't wrong. There may even be some biological differences between men and women (hormones?) that underlie this preference for belonging. But that's not all that Elisabeth Cornwell is proposing.
What she is suggesting is that there may have been a time in the ancient past when women didn't care about fitting into a social group. Then a new mutation arose that changed this behavior so that women with the mutation wanted to be part of a group. The mutation didn't have the same effect in men even though they must have carried it. Because of "evolutionary pressure" this socialization allele increased in the population until almost everyone had it—but it only worked in women.
Alternatively, women may have elected to form strong social groups because it was a smart thing to do. Over time, women risked being ostracized if they didn't conform to the social norm. (That seems to be a common behavior among women, even today.
)So, we have two competing explanations. One is that there's a gene (allele) for socialization that is responsible for this behavior in women, and that this allele arose during the course of human evolution and became fixed because it conferred selective advantage on women who carried it.
The other possible explanation is that women's biology did not change. The evolution of intelligence in primates, millions of years ago, led to formation of social groups in apes because these groups of women made life easier. It was a deliberate decision, made by intelligent apes. This is not biological evolution.
Religion is a human invention, the gods and goddesses that have come and gone during our short history have all displayed the best and (more often) worst human traits. They fell in love, jealousy was common, revenge, anger and trickery prevailed, the struggle for power was universal, and all could be brought to folly and woe due to excessive hubris, greed, and lust. Soap operas pale in comparison! What concerns me, though, is that religion reflected the culture of the times - and, for better or worse, the religions most prominent today are all rather ancient beasts that grew out of a time when women were subservient to men, and often considered as property to be bartered, battered, and controlled.One of the main criticisms of evolutionary psychology is that its proponents are often guilty of cultural bias. They tend to extrapolate from the culture they know to all of human behavior. This is an important criticism since the stories are not about biological evolution within a small society but about the evolution of human behavior—all humans.
In this case, Elisabeth Cornwell is talking about cultures that date back only 3,000 or 4,000 years. They are the cultures that produced Judaism, Christianity, and Islam. They are not relevant when it comes to discussions about human evolution.
Another criticism of evolutionary psychology is related to the previous one. It's the premise that evolutionary psychologists know enough about pre-historic societies to be able to make reliable statements about evolutionary pressures. As a matter of fact, we simply don't know how our hunter-gatherer ancestors behaved. We don't know if women formed tight-knit social groups that excluded men, or if women living 50,000 years ago tended to be more "religious." Maybe women were smarter than men and they didn't believe the crap that male shamans1 were spouting!
So we are back to our original question: Why do women today continue to fall victim to an archaic system of beliefs that foster misogynistic behavior? Why are women even more likely to be religious than men? The simple answer is that it is safe. Please don't take this as a slight against women -- it isn't. Male/female differences exist, but I'm certainly not suggesting that risk taking is a better option than playing it safe. After all, women are less likely than men to die doing incredibly stupid things (check out the Darwin Awards it is nearly exclusively male 'winners'). But the fact that women are less likely to push the status quo for fear of social exclusion and even retribution makes a lot of evolutionary sense.Actually it doesn't make a lot of sense from an evolutionary perspective except as an epiphenomon. Female ape brains may be biologically different from male ape brains and those differences may make it easier for females to form groups. The fact that, today, women in Western industrialized nations tend to be more religious than men could be entirely due to culture.
In other cultures, and other times, it might be men who are more devoted to religion. I don't believe that a woman's brain is hard-wired to be more susceptible to superstition than a man's. Nor do I believe that humans evolved a propensity to be superstitious over being rational.
1. shamans is the correct plural of shaman.
[Hat Tip: RichardDawkins.net]
For more, see Pop Evolutionary Psychology, Modern women are excellent gatherers, Changing Your Mind About Evolutionary Psychology, Please Tell Me This Is a Joke, and Changing Your Mind: Are Humans Evolving?.
Junk DNA Is "Dead as a doornail"?
I just received an email message from András Pellionisz informing me that in America the concept of junk DNA is "dead as a doornail." He "proves" his case in an article on his website [HoloGenomics].A Eureka Moment concerning the fractal character of neurons led in turn to a novel picture of genomics where protein structures act back recursively upon their DNA code -- in outright contradiction to prevailing orthodoxy. A household name in neuroscience for his tensor network theory, Dr. András Pellionisz has recently had another far-reaching discovery borne out. This insight has now received striking confirmation in stunning results from the new field of epigenetics -- promising a whole raft of novel medical diagnoses and therapies.THEME
Sunnyvale, Calif. (PRWEB) July 16, 2008 -- A landmark article on "The Principle of Recursive Genome Function" (received December 7, accepted December 18, 2007) by András J. Pellionisz appears online in Springer's e-Journal Cerebellum.
The paper marks the first anniversary of an historic event--the release of pilot results for ENCODE, the Encyclopedia of DNA Elements project. Building on the results of the Human Genome Project, the ENCODE effort revealed a far more complex DNA coding sequence than was ever previously imagined. "There's a lot more going on than we thought," said Collins, who was director of the National Human Genome Research Institute (NHGRI). Dr. Collins issued a mandate a year ago "the scientific community will need to rethink some long-held views".
A happy few did not need to rethink either the "central dogma of molecular biology" (Crick, 1956) or the misnomer of "junk" DNA (Ohno 1972), since they never believed them in the first place. The dictum claiming that a flow of information from proteins back to DNA "never happens" or the idea that 98.7% of the human genome should be disregarded as junk was never very believable.
Genomes & Junk DNA
There are some interesting scientific debates about the role of noncoding DNA in large genomes. Much of it is junk but there's lot of other functions that we've known about for decades. Many respectable scientists dispute the notion that most of our genome is junk.
Unfortunately, very little of that interesting scientific debate can be seen on András Pellionisz's website. Instead, I direct you to the site in order to see a classic example of a modern kook in action. The site has all of the characteristics of kookdom (see crank) and serves as a self-evident answer to the question Is András Pellionisz a Kook?.
Monday, February 16, 2009
I Wish My Country's Leader Could Say This!
I don't think Prime Minister Stephen Harper believes any of the things that Barack Obama says in this video. My country is cutting back on science at the very time when science needs all the support it can get.
[Hat Tip: Pharyngula]
Monday's Molecule #108
Today's Monday's Molecule really is a molecule. Your task is to identify the molecule from the cartoon shown here. It won't be sufficient to just find the name of the molecule, you will also have to identify the significance behind determining its chemical structure. There's one scientist who was involved in that determination who also did some important work based, in part, on knowing the sequence. This scientist was awarded a Nobel Prize for his work but the prize didn't come until 15 years later. Name this Nobel Laureate.
The first person to identify the molecule and the Nobel Laureate wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first won the prize.
There are eight ineligible candidates for this week's reward: Ramon, address unknown, Jason Oakley of the University of Toronto, John Bothwell from the Marine Biological Association of the UK, in Plymouth (UK), Wesley Butt of the University of Toronto, David Schuller of Cornell University, Nova Syed of the University of Toronto, Dima Klenchin of the University of Wisconsin and undergraduate Alex Ling of the University of Toronto
John, David, and Dima have offered to donate their free lunch to a deserving undergraduate so I'm going to continue to award an additional free lunch to the first undergraduate student who can accept a free lunch. Please indicate in your email message whether you are an undergraduate and whether you came make it for your free lunch (with a friend).
THEME:
Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.
Correct responses will be posted tomorrow. I reserve the right to select multiple winners if several people get it right.
Comments will be blocked for 24 hours.
IDiots and the Genetic Fallacy.
The term Genetic Fallacy is used to describe fallacious arguments that attack an idea based on its origins (genesis) and not its current validity. The most common (but not the only) examples are attempts to discredit someone's idea by impugning the character of the person who originated the idea. For example, you could try to cast doubt on Thomas Jefferson's views about freedom by attacking his morality. Same with Benjamin Franklin, who, we all know, wasn't a very nice person. That has no bearing on the truth of his ideas or his work on electricity.
In the battle between rationalism and superstition, we can always count on the Intelligent Design Creationists to give us examples of every single logical fallacy. They are very good at irrational thinking.
Here's the latest from Denyse O'Leary: If you accept the argument in Descent of Man, you accept a racist argument. Some of her arguments against science are so classic I wouldn't be surprised if they enter the philosophy textbooks as examples of the important logical fallacies.
Quite honestly, I find current Darwinist efforts to get the old Brit toff off the hook for racism embarrassing. Far from differing from his generation's racist beliefs, Darwin wanted to provide solid scientific support for them. And to the extent that anyone accepts the argument in Descent of Man, they accept a racist argument.
Has anyone noticed how Darwinists carefully protect themselves from having the issue framed bluntly in those terms?
[Image Credit: ThadGuy.com]
Chuck Lorre on How to Become an Atheist
Chuck Lorre is a TV producer. One of his shows is Two and a half men, another is The Big Bang Theory. Chuck Lorre has a blog but it's a strange kind of blog—no comments allowed and the titles of each posting are just numbers. Many (all?) of them appear in the credits at the end of his shows. Here's #240, posted on Feburary 2, 2009.
A wise man once told me that we are all God in drag. I like that. Sometimes when I'm in a public place or sitting at a stop light, I'll watch people walking by and I'll silently say to myself, "He's God. She's God. He's God. She's God." Before long I always find myself feeling a warm sense of affinity for these strangers. The experience is even more powerful when I do this while observing a person who is clearly suffering. On occasion I'll test my little spiritual practice by turning on Fox News. Within minutes I become an atheist.
[Photo Credit: Could Chuck Lorre Be the Smartest Person in Television?]
[Hat Tip: Carmi's Art Life World: Chuck Lorre Makes Me Laugh]
In Praise of Jodrell Bank
Jodrell Bank was one of the instruments that excited my imagination back when I was a junior member of the astronomical society. Ms. Sandwalk and I are thinking of visiting the Lake District in England. She would be delighted to take a side trip to see Jodrell Bank.
The photos of the main telescope almost convinced me to be an astronomer—but then I found out that biology was much more challenging!
Mark has posted an article In Praise of Jodrell Bank on Cosmic Variance.
Variation and Natural Selection
Here's a photograph of many varieties of hybrid radish. It's from the Botany Photo of the Day posted on Darwin's birthday by Nhu Nguyen to illustrate speciation in action.
Please visit the UBC website to see the entire posting. I'd like to comment on one particular statement. Nhu Nguyen writes,
This is a weedy species that grows in coastal (and some central) areas of California. According to research by Norman Ellstrand's group at UC Riverside, this species is evolving in a quantifiable manner. It is a hybrid between Raphanus sativus, the common radish, and Raphanus raphanistrum.What is the evidence that natural selection is acting one these variants? I doubt that there's any evidence at all.
Curiously, the same hybrid occurs elsewhere in similar climates such as that of South Africa, but something special about ecosytems in California allowed it to proliferate. It is now different enough from either of its parents that Ellstrand's group is considering describing this as a new species. This has occurred within the timespan that the two parents were brought together by humans in California."
There are many color variations of this evolving species. It is exactly through this variation that the process of natural selection works. If allowed to go its own way, some of these color morphs may persist, others may perish, all depending on the selective forces present where they occur. Eventually, each of these via time and selection could become a species of its own. California thus would be the center of diversity for a new group of Raphanus species.
While it's true that evolution may result in many of these variants becoming separate species, there's no reason to suppose that there are "selective forces" working on different colored flowers. It could just as easily happen that one or more colored variations could become fixed in a new species by random genetic drift.
I'm not sure what the problem is here. Is it just sloppy language on the part of some botanists? Do they use the words "natural selection" as a synonym for "evolution" without thinking about it? Or, are they confirmed adaptationists who actually believe that all visible phenotypes must be subject to selection?
There seem to be a large number of scientists who think that all speciation events are driven by natural selection. This was (mostly) what Darwin thought but I was previously under the impression that this had changed in the 20th century to recognize that random genetic drift plays an important role in speciation.
Does This Look Designed?
Check out today's Botany Photo of the Day from the University of British Columbia Botanical Garden and Centre for Plant Research. The species is Euphorbia caput-medusae L. from South Africa.It's an example of a strange-looking species that most of us are not familiar with. We need to keep in mind that life is complicated and weird.
Sunday, February 15, 2009
Literary Darwinism
A reader tells me that Trent University (Peterborough, Ontario, Canada) celebrated Darwin's birthday with a talk by Joseph Carroll on The Historical Position of Literary Darwinism. She asked me what I thought of Literary Darwinism.
I had never heard of it so I asked my good friend "Google" and he (she?) didn't disappoint. There's a Wikipedia entry on Darwinian Literary Studies (aka Literary Darwinism).
As Leda Cosmides and John Tooby indicate in their essay "The Psychological Foundations of Culture," scientific models and theories allow us to sense abstract objects and relationships just as our eyes and ears allow us to sense concrete ones. In Darwinian literary studies, as in evolutionary psychology, "[t]he tools of evolutionary functional analysis function as an organ of perception, bringing the blurry world of human psychological and behavioral phenotypes into sharp focus and allowing one to discern the formerly obscured level of our richly organized species-typical functional architecture."[2] In other words, since the human mind is embodied in evolving organic structures such as the brain, researchers should be able to explain aspects--not only of cognitive systems such as language ability, but of cultural systems such as art and literature--in terms of the environmental factors, or selection pressure, that give rise to them. A chief goal of Darwinian literary studies is to show how the reading and writing of literature contributes to the inclusive fitness of the human organism. In this sense the discipline relates closely to adaptationism, and it shares with the adaptationist social sciences the ultimate goal of understanding human nature.So it's closely related to adaptationism and evolutionary psychology, eh? I don't think I'm going to like literary Darwinism. Sounds like just another misinterpretation of evolution by a bunch of non-scientists.
Let's look at an example.
A good example of applied Darwinian criticism is Joseph Carroll's reading of Pride and Prejudice, which shows how the fundamental biological problem of mate choice informs the plot of Austen's novel[3]. In this view, the novel narrates a social order in which males compete on the basis of socioeconomic attributes such as money and rank, whereas females compete according to 'personal' attributes such as youth and beauty. The story of Darcy and Elizabeth's courtship establishes a model for partial subversion of this social order, since the couple manage to abide by it even though the proximate causes of their mutual attraction have more to do with the conventionally undervalued attributes of dignity, honesty, kindness, and intelligence. A Darwinian critic might argue that the whole book functions as a tool for humans to perceive, order, and make sense of the conflicting impulses that characterize romantic relationships.I don't know whether I count as a "Darwinian critic" or not but it seems to me that Austen is pointing out that women can be either smart or stupid when it comes to choosing a mate and so can men. Jane Austin is describing the breakdown of an English social order that existed prior to the nineteenth century. That social order is very different than those in other societies at the same time (e.g. India, China, North American natives), which, in turn, is probably nothing like the society of our ancestors 50,000 years ago. I don't see what this has to do with human evolution—or whatever these English scholars mean by "Darwinism."
Dan Falk Gets It Right!
Dan Falk is a Toronto-based science writer and winner of 2002 Canadian Science Writers’ Association Science in Society Journalism Award. He writes for major Canadian newspapers and is a frequent contributer to the CBC television program Quirks and Quarks. He is the author of In Search of Time: Journeys Along a Curious Dimension, which I have not read—an oversight I plan to correct as soon as possible.I'm critical of many science writers for misrepresenting science in their articles appearing in newspapers or magazines. It's even worse when ordinary journalists attempt to write about science [The Ottawa Citizen Should Be Ashamed of David Warren].
Today I'm deligheted to bring to your attention an excellent article by Dan Falk in today's Toronto Star "[You are here: Your microspot in the universe: What Galileo and Darwin should really be remembered for: making us feel smaller"].
You really should follow the link and read the whole article. Here's the conclusion—I hope it will tempt you.
As physicist Steven Weinberg famously said, "The more the universe seems comprehensible, the more it also seems pointless."Thank-you Dan Falk. It's refreshing to see that kind of writing in a major newspaper. I'm looking forward to the letters to the editor, especially from those who haven't yet swallowed the bitter pill.
Both Galileo and Darwin showed us that our place in the cosmos is less central – perhaps less special – than we had imagined. For some it has been a bitter pill to swallow. But there is also every reason to rejoice in their discoveries. We are indeed animals, but we are animals that can comprehend the structure of DNA and the unity of life.
And yes, we live in one remote corner of the galaxy, itself one of billions of galaxies, but from this outpost we have probed the fabric of the universe, from the smallest quark to the most distant quasars.
Galileo and Darwin broadened our horizons, perhaps to a greater degree than any other two thinkers in history. As a result of their vision, we live in a larger, richer and more wonderful universe.
[Photo Credit: The photograph of Dan Falk on the University of Toronto campus is from his article, TIME TRAVEL AND THE DOWNING STREET DILEMMA, on the pagebooks.ca website.]
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