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Friday, August 08, 2008

How Do Ligands Bind to Proteins?

When glutamine is bound to glutamine-binding protein, the protein is wrapped around the ligand to form a closed binding site that brings more amino acid side chains into contact with the ligand. The unbound protein has a much more open confromation.

The traditional explanations of binding is that the ligand binds to to open form of the protein and causes it to undergo a conformational change creating a closed pocket. The mechanism is called "induced fit." Now, there is evidence that the protein may transiently adopt the closed conformation in the absence of ligand and the ligand binds directly to the closed conformation.

Discount Thoughts reviews a recent paper [Do conformational changes precede or follow binding?]


[Figure credit: Okazaki, K., Takada, S. (2008) Dynamic energy landscape view of coupled binding and protein conformational change: Induced-fit versus population-shift mechanisms. Proc. Nat. Acad. Sci. (USA) 105:11182-11187. [DOI: 10.1073/pnas.0802524105]

The End Is Nigh

 

The Large Hadron Collider is due to be activated on September 10th. Estimates on how long it will take to create a black hole vary from microseconds to about 24 hours. Let's be optimistic and assume that it will take until Thursday morning (September 11th).

I figure the airport (Cointrin) will be sucked in before noon and Geneva should be swallowed up by at least 2pm. France will be gone by 4pm and we in Toronto will encounter the event horizon at midnight.

The good news is that I won't have to buy Ms. Sandwalk a birthday present on Friday. The bad news is that we may be spending an infinite amount of time together as we cross the event horizon so I might wish I had.


nigh: Common Teutonic: OE. néah, néh = OFris. nei, nî, MDutch na, nae (Dutch na), OS. nâh (MLG. nâge, nâ), OHG. nâh adv., nâher adj. (MHG. nâ, nâh-, nâch, G. nah), ONor. ná- (in combs. like ná-búi neighbour; Sw. and Da. na-), Goth. nêhwa (nêhw): the stem appears to be unrepresented outside Teutonic. OHG. is the only one of the older languages in which a fully developed adjectival use of the word exists along with the adverbial. In OE. there are very scanty traces of adjectival inflexion, néah being commonly employed either as a simple adv. or with a dependent dative: in predicative use it may sometimes be taken as an adjective, but it is more probable that in such cases also it is an adverb. It is not till the 14th or 15th cent. that the attributive use becomes common.

The original comparative of néah as an adv. is néar, néor, near adv.1, while the adj. form néarra finally became ner, nar a. The OE. superlative níe(hook)hst(a is latterly represented by next a. and adv. After phonetic changes had obscured the relationship of these forms to the positive, a new compar. and superl., nigher and nighest, were formed, and have been in common use since the 16th cent.

= near adv.2 and a. (which in all senses has taken the place of nigh except in archaic or dialect use). [Oxford English Dictionary]

The Hype About Darwin Continues

 
Let me be clear about one thing. I've said it many times but it bears repeating. In my opinion Charles Darwin is the greatest scientist who ever lived and natural selection is one of the greatest ideas in science.

That should never be an excuse for exaggerating Darwin's contribution to modern evolutionary theory yet that's what we're seeing in the run-up to the 150th anniversary of the publication of On the Origin of Species. I was tremendously disappointed in the Royal Ontario Museum symposium a few weeks ago [Darwinism at the ROM] and in several articles that have been published since then.

I'm going to keep harping on this point until it sinks in. Here's the latest example from TimesOnline in the UK [Darwin's Bulldogs].
Next year marks the 200th anniversary of the birth of Charles Darwin and the 150th anniversary of the publication of his On The Origin of Species. The Natural History Museum and the BBC plan extensive education programmes. Anticipating the anniversaries, Professor Richard Dawkins is presenting a series on Channel 4. These are welcome ventures. On the evidence of its first episode, Professor Dawkins's exposition of Darwinism will be an important public resource.

Darwin founded a branch of learning that has remarkable explanatory power and also grandeur. That the mechanism of evolution is natural selection is one of the great discoveries of science, with implications far beyond evolutionary biology. As Ernst Mayr, the biologist, wrote: “No educated person any longer questions the validity of the so-called theory of evolution, which we now know to be a simple fact.”

It is an unfortunate wonder of the modern age that people who are highly educated in some areas may still be resistant to scientific inquiry. We customarily think of objectors to Darwinism as Protestant fundamentalists. There is in fact a worrying trend for Muslim children to be taught the myths of creation, and the pseudoscience of “intelligent design”, as an explanation of the origins of life.
There are three things wrong with this short article.

First, the statement, "That the mechanism of evolution is natural selection is one of the great discoveries of science ..." is just plain wrong. Natural selection is one of the mechanisms of evolution but it is not the only one. Why can't people grasp this simple concept? It does not denigrate Charles Darwin's contribution to point out that we discovered other mechanisms in the 20th century.

Second, Mayr's statement, taken out of context, is misleading. Evolution is a fact but evolutionary theory is not a fact [Evolution Is a Fact and a Theory].

Third, I object to the term "Darwinism" and I am not a Protestant fundamentalist, a Muslim, or an IDiot. I wish journalists would make the effort to realize that modern evolutionary theory is no longer called "Darwinism." [Why I'm Not a Darwinist]. This does not mean that Charles Darwin was wrong. It simply means that the science of evolutionary biology has advanced a smidgen since 1859.


[Hat Tip: RichardDawkins.net]

Amazing Catch by Ball Girl

 
Friday's Urban Legend: FALSE

This video is making the rounds. It shows a ball girl making an amazing catch of a fly ball then casually tossing it to the left fielder. Too bad it's a fake [Ballgirl].




Thursday, August 07, 2008

Are You Disappointed in Barack Obama?

 
I've always been a bit skeptical of Obama. It seemed to me that he wasn't as sincere about his "progressive" stance as, say, Dennis Kucinich. I wondered whether he wasn't playing to a particular audience in order to win the nomination.

Apparently I'm not the only one. There are a group of Americans who have become very nervous about Obama's move to the center. They've written an open letter to Barack Obama that's been published in The Nation [Change We Can Believe In].

The authors of the letter make the important point that the progressives who were attracted to the Obama campaign are the very ones who will ensure a victory in November. They are worried that these progressives will not make the effort to work for Obama if he continues to abandon the core principles that attracted them to the primary campaign.

We urge you, then, to listen to the voices of the people who can lift you to the presidency and beyond.

Since your historic victory in the primary, there have been troubling signs that you are moving away from the core commitments shared by many who have supported your campaign, toward a more cautious and centrist stance--including, most notably, your vote for the FISA legislation granting telecom companies immunity from prosecution for illegal wiretapping, which angered and dismayed so many of your supporters.

We recognize that compromise is necessary in any democracy. We understand that the pressures brought to bear on those seeking the highest office are intense. But retreating from the stands that have been the signature of your campaign will weaken the movement whose vigorous backing you need in order to win and then deliver the change you have promised.
I think they have a point but the more interesting question, from my perspective, is which one is the real Obama? Does he really believe in universal health care but is willing to make compromises for the sake of political expediency, or is he lukewarm on socialized medicine? Does he really believe that the USA needs to get out of Iraq because it never should have been there in the first place, or is he willing to compromise on that stance? What does he really think about the death penalty? Is he opposed on principle, in which case there's no compromise, or are his "principles" negotiable? Does he really expect to change the way things are done in Washington, or is that just something he says in order to get votes?

There's a discussion going on about this on Pharyngula [Progressives put pressure on Obama] but most readers are avoiding the real question. One commenter (Amplexus) said,
My fellow godless hedonists,

Obama is totally on our side. He's just hiding some of his feelings to get elected. We cannot take a stand on principle, we cannot afford to. Obama is blurring his position to win over independents that he sure as hell is going to shake off when he gets elected.
In other words, Obama is a liar and a hypocrite but that's okay because we all know that deep down he's a true believer.

Is that the common point of view among liberal Americans? Won't John McCain exploit this hypocrisy during the campaign?


Evolutionary Psychology: The Capacity for Religion

 
Allen MacNeill has started a new blog called Evolutionary Psychology. Allen teaches introductory biology and evolution at Cornell University (New York, USA). This could be a good addition to the blogosphere since he intends to defend the field. (Good luck!)

The first posting on the new blog is The Capacity for Religious Experience is an Evolutionary Adaptation for Warfare. It starts out well with ...
Recent work on the evolutionary dynamics of religion have converged on a "standard model" in which religions and the supernatural entities which populate them are treated as epiphenomena of human cognitive processes dealing with the detection of and reaction to agents under conditions of stress, anxiety, and perceived threat.
I agree with this. There has been selection in the primate lineages for intelligence and one of the reasons for the fitness advantage may well be the ability to cope with external threats. I think that religion, and many other human behaviors, are epiphenomena that are indirect consequences of intelligent brains.

Unfortunately, this does not seem to be what MacNeill really means. He goes on to describe behaviors such as religion and warfare as though they were individually selected. He seems to be implying that there are genes for religious behavior and for engaging in warfare. This isn't the same as the "standard" model—unless my interpretation is completely wrong.

Here's how religion evolved, according to MacNeill ...
Wilson (2002) has proposed that the capacity for religion has evolved among humans as the result of selection at the level of groups, rather than individuals. Specifically, he argues that benefits that accrue to groups as the result of individual sacrifices can result in increased group fitness, and this can explain what is otherwise difficult to explain: religiously motivated behaviors (such as celibacy and self-sacrifice) that apparently lower individual fitness as they benefit the group.

At first glance, Wilson's argument seems compelling. Consider the most horrific manifestation of religious warfare: the suicide bomber. A person who blows him or herself up in order to kill his or her opponents has lowered his or her individual fitness. Doesn't this mean that such behavior must be explainable only at the level of group selection? Not at all: the solution to this conundrum is implicit in the basic principles of population genetics. Recall that one of Darwin's requirements for evolution by natural selection was the existence of variation between the individuals in a population. (Darwin, 1859, pp. 7 - 59) Variation within populations is a universal characteristic of life, an inevitable outcome of the imperfect mechanism of genetic replication. Therefore, it follows that if the capacity for religious experience is an evolutionary adaptation, then there will be variation between individuals in the degree to which they express such a capacity.

Furthermore, it is not necessarily true that when an individual sacrifices his or her life in the context of a struggle, the underlying genotype that induced that sacrifice will be eliminated by that act. Hamilton's principle of kin selection (Hamilton, 1964) has already been mentioned as one mechanism, acting at the level of individuals (or, more precisely, at the level of genotypes), by which individual self-sacrifice can result in the increase in frequency of the genotype that facilitated such sacrifice. Trivers (1971) has proposed a mechanism by which apparently altruistic acts on the part of genetically unrelated individuals may evolve by means of reciprocal altruism.

Given these two mechanisms, all that is necessary for the capacity for religious behavior, including extreme forms of self-sacrifice, to evolve is that as the result of such behaviors, the tendency (and ability) to perform them would be propagated throughout a population. The removal of some individuals as the result of suicide would merely lower the frequency of such tendencies and abilities in the population, not eliminate them altogether. If by making the ultimate sacrifice, an individual who shares his or her genotype with those who benefit by that sacrifice will, at the level of his or her genes, become more common over time. (Wilson, 1975, p. 4)
I take issue with this description. When an evolutionary psychologist says that "all that is necessary" for the evolution of a behavior is that it confers some advantage, your adaptationist bullshit detector should hit the red line. That's not all that is necessary. Another, very important, requirement is that there be a genetic component to the behavior. In other words, we need to show that suicide bombers (for example) have different alleles in their genomes than atheists.

I don't believe there's any evidence that such alleles exist.

The idea that there's a specific genetic propensity for religion is difficult to reconcile with our history. If religion alleles have been selected for thousand of years then how come European countries have been becoming secular in the past century? Are Europeans just learning to override the dictates of thei genes?

Or, is religion just an epiphenomenon—one of many cultural ways that a society can encourage cohesiveness? As a way of creating unity—and identifying strangers—religion is no different than patriotism or irrational devotion to a charismatic political leader (Obama as a religion? ). As a matter of fact, it's probably no different than the cliques formed by adolescent girls or the street gangs of teenage boys. They all serve the same purpose, albeit on different scales. They are all learned behaviors. In my opinion, religion is a product of nurture, not nature.



Has Darwinism Been Rejected?

 
A number of misconceptions about evolution are described on the website Understanding Evolution for Teachers. One of them is Misconception: “Most biologists have rejected ‘Darwinism’ (i.e., no longer really agree with the ideas put forth by Darwin and Wallace).
Response: Darwin’s idea that evolution generally proceeds at a slow, deliberate pace has been modified to include the idea that evolution can proceed at a relatively rapid pace under some circumstances. In this sense, “Darwinism” is continually being modified. Modification of theories to make them more representative of how things work is the role of scientists and of science itself.

Thus far, however, there have been no credible challenges to the basic Darwinian principles that evolution proceeds primarily by the mechanism of natural selection acting upon variation in populations and that different species share common ancestors. Scientists have not rejected Darwin’s natural selection, but have improved and expanded it as more information has become available. For example, we now know (although Darwin did not) that genetic mutations are the source of variation acted on by natural selection, but we haven’t rejected Darwin’s idea of natural selection—we’ve just added to it.

Here's how I would re-word the first sentence of the second paragraph.
We now know that natural selection is just one of several mechanisms of evolution. One of the others is random genetic drift where variants can become established in a species purely by chance. There is clear evidence that variants that are neither harmful or beneficial can contribute to evolution and, in fact, the evidence suggests strongly that this is the most common form of evolution. However, there have been no credible challenges to the basic Darwinian principles that adaptive evolution proceeds exclusively by the mechanism of natural selection acting upon variation in populations and that different species share common ancestors.
I realize that my version is more complicated but it is also more accurate. This is a case where over-simplification comes at the expense of accuracy and I don't think the spin framing version is worth the sacrifice. There's nothing wrong with informing the general public (and teachers) that Darwinism remains true even though modern evolutionary theory covers much more than just Darwin's central ideas.

Ironically, the Understanding Evolution website has a good description of Genetic Drift, which they describe as "one of the basic mechanisms of evolution." I don't know why don't mention these other mechanisms on the page where they discuss Darwinism.

Now, look at the first paragraph of the website version. I think they're referring to punctuated equilibria. In this case, the extra complication isn't worthwhile because it doesn't really represent a significant change from Darwin's idea of evolution by natural selection. As a matter of fact, the description is downright misleading. The key concept in punctuated equilibria is that evolutionary change is associated with speciation by cladogenesis and the idea that evolution can occur rapidly isn't all that significant.


Missing Pieces of the Puzzle

 
Understanding Evolution for Teachers is a website run by the University of California Museum of Paleontology (UCMP) in Berkeley.

Part of the website addresses a number of misconceptions about evolution and one of them is: Misconception: “Evolutionary theory is incomplete and is currently unable to give a total explanation of life”.

What I particularly like about their explanation is the "jigsaw puzzle analogy" that they use to illustrate the concept. Looking at the figure, you can immediately see the relevance—the fact that a few pieces are missing does not mean that we can't see the big picture.

There is no doubt about the general structure of evolutionary theory in spite of the fact that some pieces of the puzzle haven't been put in their proper place. There is no doubt about the fact that neither creationism nor any other explanation fits the scientific data.

I don't know who first came up with the jigsaw puzzle analogy. I first heard about it on talkorigins many years ago but I've forgotten who the author was. Please let me know if you remember. This figure needs to be widely disseminated because it makes an important point. I hope the University of California and the Understanding Evolution website won't object as long as we attribute it to them.


[Hat Tip: John Dennehy]

Wednesday, August 06, 2008

Tangled Bank #111

 
The latest issue of Tangled Bank has been published on denialism blog [Tangled Bank #111].
Welcome to Tangled Bank #111! Today's entries are presented without comment, but with poetry, a truly remarkable natural, albeit human, phenomenon, or to quote Love and Rockets:

You can't go against nature
Because when you do
Go against nature
It's part of nature too.


If you want to submit an article to Tangled Bank send an email message to host@tangledbank.net. Be sure to include the words "Tangled Bank" in the subject line. Remember that this carnival only accepts one submission per week from each blogger. For some of you that's going to be a serious problem. You have to pick your best article on biology.

On this day in 1945 ...

 
(reposted from August 6, 2007)

At 8:15 AM on August 6, 1945 an atomic bomb was detonated over Hiroshima, Japan. Approximately 78,000 civilians were killed on that day. Six months later the death toll had risen to about 140,000 people.

There are many arguments in favor of dropping the bomb just as there are many arguments against it. What's clear is that in the context of 2007 we are not in a good position to judge the actions of countries that had been at war for many years.

The most important lesson of Hiroshima is that war is hell and many innocent people die. It's all very well to enter into a war with the best of intentions—as the Japanese did on December 7, 1941—but it's foolish to pretend that when you start a war there won't be any suffering. When you do that you can really say that the victims of Hiroshima died in vain.

The killing and maiming of civilians is an inevitable outcome of war, no matter how hard you might try to restrict your targets to military objectives. Before going to war you need to take the consequences into account and decide whether the cost is worth it.

One of the many mistakes in Iraq was the naive assumption that it would be a clean war with few casualties and no long-term consequences for the Iraqi people. Yet today, the numbers of innocent lives lost in Iraq is comparable to the numbers lost in Hiroshima and Nagasaki. And what is the benefit for Iraq that outweighs the cost in human lives? Is it "freedom" and "democracy"?

Hiroshima was not a glorious victory. It was ugly, heartbreaking, and avoidable. War is not an end in itself, it is the failure of peace. War is not an instrument of your foreign policy—it is an admission that you don't have a foreign policy.

[The top photograph shows the mushroom cloud over Hiroshima on the morning of August 6, 1945 (Photo from Encyclopedia Britanica: Hiroshima: mushroom cloud over Hiroshima, 1945. [Photograph]. Retrieved August 7, 2007, from Encyclopædia Britannica Online. The bottom image is taken from a Japanese postcard (Horoshima and Nagassaki 1945). It shows victims of the attack on Hiroshima.]


Nobel Laureates: Karl von Frisch, Konrad Lorenz, Nikolaas Tinbergen

 

The Nobel Prize in Physiology or Medicine 1973.
"for their discoveries concerning organization and elicitation of individual and social behaviour patterns"

Karl von Frisch (1886 - 1982), Konrad Lorenz (1903 - 1989), and Nikolaas Tinbergen (1907 - 1988) received the Nobel Prize in Physiology or Medicine for their work on animal behavior. This is the most biological of all Nobel Prizes that have been awarded and, at the time, it suggested that the Nobel Committee was prepared to consider a wider view of "physiology." That turned out to be optimistic. Subsequent prizes have failed to recognize advancements in evolution and ecology, to name just two disciplines that have been ignored.

The presentation speech was delivered in Swedish by Professor Börje Cronholm of the Karolinska Medico-Chirurgical Institute.

THEME:
Nobel Laureates
Your Majesty, Your Royal Highnesses, Ladies and Gentlemen,

Animal behavior has fascinated man since time immemorial as can be witnessed by the important role of animals in myths, fairy-tales and fables. However, for too long man has tried to understand it from his own experiences, from his own way of thinking, feeling and acting. Descriptions along these lines may be quite poetic, but they do not lead to any increase in knowledge. Various pre-scientific ideas have been especially tenacious in this field. Thus, it is not long ago that the vitalists maintained that the instincts bore witness of a wisdom that was inherent in the organism and could not be further analyzed. It was not until behavior problems were studied by means of scientific methods, by systematic observation and by experimentation, that real progress was made. Within that research field this year's Nobel prize laureates have been pioneers. They have collected numerous data about animal behavior both in natural settings and in experimental situations. Being biological scholars they leave also studied the functions of behavior patterns, their role in the individual struggle for life and for the continuation of the species. Thus, behavior patterns have stood out as results of natural selection just as morphological characteristics and physiological functions.

It is of fundamental importance that some behavior patterns evidently are genetically programmed. The so-called fixed action patterns do not request any previous experience and they will be automatically elicited by definite key stimuli. They proceed in a mechanical, robot-like way, and when they have started they are no more influenced by external circumstances. In insects, fishes and birds, such important procedures as courtship, nesting and taking care of the brood, to a large extent consist in fixed action patterns. With development of the brain hemispheres, behavior has become increasingly modifiable and dependent on learning in mammals and especially in man, but fixed action patterns still play an important role.

For more than sixty years: Karl von Frisch has devoted himself to studies of the very complicated behavior of honeybees. Above all, he has elucidated what has rightly been called 'the language of bees'. When a bee has found flowers containing nectar, it performs a special dance when returning to the hive. The dance informs the bees in the hive of the existence of food, often also about the direction where the flowers will be found and about the distance to them. The foraging bee is able to indicate the direction of the food source in relation to the sun by means of analyzing polarized, ultraviolet light from the sky, light that is invisible to us. The honeybees do not learn, either to dance or to understand the message of the dance. Both the dancing and the appropriate reactions to it are genetically programmed behavior patterns.

Konrad Lorenz has studied among many other things the fixed action patterns of various birds. His experiments with inexperienced animals, e.g. young birds from an incubator, are of great importance in this context. In these young birds he observed behavior patterns that could not reasonably have been learnt but were to be interpreted as being genetically programmed. He also found that experiences of young animals during a critical period could be decisive for their future development. Newborn ducks and geese follow the first moving object that they catch sight of, and later on they will follow those particular objects only. Normally, they will follow their mother, but they may be seduced to follow almost any moving object or creature. This phenomenon has been called 'imprinting'.

While Konrad Lorenz has above all been a systematic observer of animal behavior, Nikolaas Tinbergen has to a large extent tested various hypotheses by means of comprehensive, careful, and quite often ingenious experiments. Among other things, he has used dummies to measure the strength of different key stimuli as regards their ability to elicit corresponding fixed action patterns. He made the important observation that 'supranormal' stimuli eliciting more intense behavior than those of natural conditions, may be produced by exaggerating certain characteristics.

The discoveries made by this year's Nobel prize laureates were based on studies of insects, fishes and birds and might thus seem to be of only minor importance for human physiology or medicine. However, their discoveries have been a prerequisite for the comprehensive research that is now pursued also on mammals. Studies are devoted to the existence of genetically programmed behavior patterns, their organization, maturation and their elicitation by key stimuli. There are also studies concerning the importance of specific experiences during critical periods for the normal development of the individual. Research into the behavior of monkeys have demonstrated that serious and to a large extent lasting behavior disturbances may be the result when a baby grows up in isolation without contact with its mother and siblings or with adequate substitutes. Another important research field concerns the effects of abnormal psychosocial situations on the individual. They may lead not only to abnormal behavior but also to serious somatic illness such as arterial hypertension and myocardial infarction. One important conclusion is that the psychosocial situation of an individual cannot be too adverse to its biological equipment without serious consequences. This holds true for all species, also for that which in shameless vanity has baptized itself 'Homo sapiens'.

Karl von Frisch, Konrad Lorenz, Nikolaas Tinbergen,

According to an old fable, cited by one of you, king Solomon is said to have been the owner of a ring that had the mystical power to give him the gift of understanding the language of animals. You have been the successors of king Solomon in the respect that you have been able to decode the information that animals pass to each other, and also to elucidate the meaning of their behavior to us. Your ability to find general rules underlying the confusing manifold of animal behavior makes us sometimes believe that king Solomon's ring has in fact been available also to you. But we know that you have been working in an empirical way, collecting data and interpreting it according to hard and fast scientific rules.

Aside from their value in themselves, your discoveries have had a farreaching influence on such medical disciplines as social medicine, psychiatry and psychosomatic medicine. For that reason it was very much in agreement with the spirit of Alfred Nobel's will when the medical faculty of the Karolinska Institute awarded you this year's Nobel Prize.

We are proud to have two of you, professor Konrad Lorenz and professor Nikolaas Tinbergen, with us today, and we are also grateful to professor Karl von Frisch that he has sent his son, professor Otto von Frisch, to represent him here.

On behalf of the Karolinska Institute I wish to convey to you the warmest congratulations and I now ask you to receive your prize from the hands of His Majesty the King.


Epigenetics in 1952-53

 
This week's Citation Classics are, indeed, classics [This Week's Citation Classics: Host Induced Variation]. They were the first papers to describe a new form of non-Mendelian inheritance that eventually became well-understood at the molecular level. Today, scientists working on animal development think they have independently discovered this concept. They call it epigenetics.

As John Dennehy says,
Today epigenetics is all the rage, but it has its roots in a pair of papers appeared nearly simultaneously in 1952-1953.


John Hawks and Comments

John Hawks is writing a series on blogging and tenure. In the last installment, How to blog, get tenure and prosper: A very useful engine, he discusses reasons for blogging. You should read the whole thing, but I'd like to focus on one small part.

John Hawks does not allow comments on his blog. It's the only science blog that I know of with a no-comment policy.1 Here's why, according to Hawks,
For some people, the most rewarding part about a blog is the immediate feedback from comments. Others dislike the comment section, whether it’s the constant battle against spam, or the trolls, or the pressure to respond to comments.

Personally, I can let a question sit in my inbox for a long time (as some of you know!), but I wouldn’t tolerate it sitting unanswered on my site. That’s my most important reason for not having a comments section: I think about posts, and I think about replies, and comments don’t generally give much time for thinking. The sites I like the best take a hybrid approach: They include questions or comments from readers, but do not have a “comments section” for each post. That kind of full-moderation, indirect feedback still can provide the sense of interaction and community, but without the repetition, trolling, and off-topic digressions that often emerge in comments sections. That’s only my preference, though—you may feel differently.

Will your commenters hurt your tenure case? I don’t think it really matters whether you have comments or not, assuming that you keep out the spam and discourage bad behavior. Probably the most important thing, as I’ll describe in the next installment, is that you mind your university’s use guidelines. As long as you follow the rules, your readers and evaluators are almost certainly smart enough to understand that your commenters are not you.

A healthy, lively comment ecosystem will add to the value of your blog. Your regular commenters help to give your site an identity by giving it a sense of community. Pointing to the community element can help to sell your site to your committee. University mission statements often include ideas like “building learning communities,” or “providing to underserved communities” (more on this in part 4 of the series). A healthy comments section is evidence that you are indeed serving a community.

An anemic comment ecosystem, mostly a monoculture invaded by the occasional weed, will subtract value from your blog. Imagine that someone visited one of your classes. Would you want to show a class where the students just wouldn’t participate? Or where one student always stood up after the lecture and announced that your ideas were garbage? You don’t want to say you’re serving an active community, while your blog comments appear to give concrete evidence that you’re not.

As you approach your tenure review, you have to think carefully about how to sell your blog to a committee. Then take action: Shut down your comments for a while, or put them on full moderation, encourage your e-mailers to submit comments, or make a concerted effort to draw comments from students or people in your field. As you plan ahead, you can think of the best way to accentuate the positives, and a small force applied early may save a lot of explaining later.
Since you can't discuss these ideas on John's blog, I'm giving you the chance here. From my prespective, comments are the most fun part of blogging. I love the discussions that go on in the comments and I love to provoke debate by posting on controversial topics. It's what science is all about, as far as I'm concerned. I've learned a lot from commenters who disagree with what I write.

I don't ever want to censure anyone who comments on my blog—although there are one or two who test my patience. Personally, I don't think the downside of commenting is all that bad and it does very little to diminish the upside. On the other hand, there are blogs where the chaff is much more obvious than the wheat and I don't even bother reading the comments. I don't know how you would prevent that.


1. It's also one of the few blogs from a university professor with a disclaimer at the bottom of each posting. I wonder if this is a special rule at the University of Wisconsin?

Chance and Necessity

 
Thanks to Ryan Gregory [Blogs by Scientists], I've just added a new blog Chance and Necessity to my list of must-reads. As you might guess from the title, this blog is devoted to evolution. It's published by a "faculty member in the South"—presumably this means southern USA and not Australia or Chile.

Here are two teasers to tempt you to follow Ryan's suggestion and read Chance and Necessity. The first is Increasing neurogenesis in the adult mammalian brain ...
The conventional wisdom is that we are born with all the brain cells we’re ever going to have, and it’s all downhill from there—as we age, we lose brain cells, never to replace them. This, of course, explains why teenagers are so much smarter than their parents. Unfortunately for the conventional wisdom, it’s wrong.
The second is a posting on the debate over the significance of evo-devo; especially the claim that most morphological changes in animals are due to change in regulatory sequences and not in coding regions of protein [Incorporating evo-devo and the genetics of morphology].
Scientific controversies typically consist of vigorous exchanges of ideas with periodic injections of new data that may shape the debate. Personalities can certainly influence the path these controversies take, but the ultimate arbiter is data, not drama. In the field of evolutionary developmental biology (evo-devo) we can witness just such a lively situation, both in the literature and at meetings.
Read the comments to this posting. You'll find intelligent people discussing whether natural selection or random genetic drift accounts for morphological change. This is such a refreshing change from blogs where any challenge to adaptationist explanations is viewed as extreme heresy.


This Is Not a Spider

 
It's not a spider but I'm not going to tell you what it is. In order to find out, you'll have to go to Catalogue of Organisms and read up on these species. At the same time you'll discover why Christopher Taylor posts an article with the title: In Which I Reveal Just How Much of a Freak I Am.

Good luck Christopher, I don't think that's a freaky thing to do. I think it's cool.