When is similarity homology?
In my last post, I mentioned that two proteins with a sufficiently similar sequence are considered, in many cases, to be homologous—that is, they are derived from the same common ancestor in natural history. Josh had a really good question: why should we assume that sequence homology in molecular biology is evidence for common descent? A designer could just as easily have made organisms filled with genes that are similar in sequence. However, by looking at the divergence of sequence alignments, we can construct family trees that fit to an evolutionary model of natural history that explains the data without the need for a designer and which offers extraordinary predictive power. Any fact from nature that deviates from these predictions would be very strong evidence against an evolutionary model and against the theory of common descent: but no such falsifying evidence has been found. This is an important difference between creationism and evolutionary science. There are many lines of evidence that could refute the theories of evolutionary biology instantly: yes, fossil rabbits in the Precambrian is one famous example that Richard Dawkins often cites (this was originally said by J.B.S. Haldane). But a lot of molecular evidence from the genome sequences of various plants and animals exists which fit perfectly into the predictions made by evolutionary theory.
We Came in Peace For All Mankind
When Megan McArdle calls landing on the moon, “the most magnificent single feat our little tribe of East African Plains Apes has ever managed,” it’s hard to find the hyperbole. And if McArdle’s libertarianism is too squishy for you to give such high praise any merit, consider that Ayn Rand also considered Apollo 11, “the story and the demonstration of man’s highest potential.”
I remember watching Moon Shot leading up to the 25th anniversary; after the last episode, my father took us outside to gaze at the moon. The sky was clear, and the moon was nearly full. It seemed closer than usual, as if I could see its topography in great detail. And yet I knew it was so very far away. When my mind finally wrapped itself around the reality that men had walked on that surface, according to the footage I had just watched, I was filled with such awe and wonder as I don’t believe I have experienced since.
Americans are understandably proud of this achievement, however vicarious our contribution. The problem “of landing a man on the Moon and returning him safely to the Earth,” was largely a technical one: it required a vast collection of brilliant engineers and scientists and the political will to give them virtually unlimited resources. On the first count, this nation’s ability to produce such talent is genuinely impressive. On the second count, it is odd to praise government for opening its purse so widely for a single project, and even odder to see such a boondoggle turn into the most dazzling and successful accomplishment the world has ever witnessed. (It’s also impressive that a nation had such a large purse in the first place.)
The nostalgia for the Apollo program is most prominent in complaints that come in two main varieties. The first are those who cry bitterly that America has lost her nerve for space exploration. They are right. We no longer have the Reds spooking us; manned space exploration turned out to have limited practical value; and the novelty simply wore off. This might be evidence that we do indeed lack imagination, but our pragmatism is commendable. The second complaint is that America, as embodied by her government, has lost her nerve for collective triumph over adversity.
Unfortunately, the spectacle of the moon landing led us to believe that all problems are merely so simple, and all that is required is some intangible political will to create, i.e., fund, technical solutions to all of our ills. This ignores the fact that the moon landing was the exception rather than the rule. Politicians were motivated by a vague but strong worry that the space race had existential implications, and that fear, as much as romantic notions of exploration and adventure, kept political interference to a minimum and the dollars flowing to where they were needed. And at the very least, no politician wanted to be responsible for the very public and visible deaths of the incredibly brave men who volunteered to be our Astronauts. Nothing since has quite so captured the attention of politicians or their constituents.
In Greek mythology, Apollo granted Cassandra the gift of prophecy — yet also cursed her so that no one would believe her predictions. How fitting that our modern would-be Cassandras, like Thomas Friedman, point to the Apollo program as a model of how we can solve their pet problems (the Manhattan Project being another model), and yet that panacea, political will, never materializes.
But even if the Cassandras were to prevail, it’s not so clear that any of our problems, e.g., energy, education, health care, etc., can be solved by pointing a fire hose of federal dollars at scientists and engineers, for reasons similar to what Megan McArdle lays out here. In the first place, none of our persistent problems is as simple as putting a man on the moon. This means that its very unclear where, exactly, that fire hose should be aimed. In the second place, there’s no inherent reason why government would be the only provider of these techno-solutions. On the contrary, the intervention of government funding may very well discourage just the sort of innovation we’d like to see. In other words, a modern version of the Apollo program would be more political than technical. I’ve never seen the Cassandras address such concerns, and their call for a blank check from Government to Science is merely a romantic gesture, and as such, hard for any practical man to take seriously.
The Apollo program may not have any larger implications than America is simply a land of talent, ambition, and luck, but I’m not sure what else it need imply. The moon landing deserves to be appreciated as a singular achievement, celebrated by even cynical minarchists. It seems somehow inappropriate to flog it for our current political passions. Alone, it is inspirational and overwhelming. Let that be enough.
By Request: Evolution in the Classroom
Anonymous asks about the Scopes trial and how we should talk about evolution in the classroom. I’m not going to talk about whether the Scopes trial was just in this answer, but I will answer for myself on the later half of the question. And my answer is quite simple: in my hypothetical child’s hypothetical science class, I want my hypothetical child learning science. That is, the way we and the rest of the world understand and do science — empirical research, classroom laboratory experiments, the scientific method, the leading scientific theories of the day, and so on. That means, my child should learn what evolution’s all about and why nearly all scientists accept the theory.
As I understand it, creation science doesn’t “do science” as I’ve defined it above. At its best, creation science critiques existing science work — pointing out where presuppositions are made and evidence is short — but it doesn’t do empirical, falsifiable research of its own. As such, I’d have a difficult time putting creation science or intelligent design (ID) in a junior high or high school classroom right next to regular science work. I want my hypothetical child to learn the tools of science so if she grows up wanting to be a scientist, she’ll have the skills at her disposal to compete in the scientific community.
That said, as a humanities nerd, I’m perfectly ok with creation science or ID making making an appearance in a philosophy class or a philosophy of science unit. That’s because it would contribute to a discussion of epistemology, or the nature of knowledge. How did we arrive at the scientific method and why do we trust it? Are we only justified in believing in things that are scientifically provable? Are the things we call scientific “facts” really the only truths we can get to regarding the human condition? To what extent do our assumptions pour into what we regard as truth?
As for the science classroom, give me the beakers and the bunson burners and the field trips to look for a-million-year-old fossils.
A few other quick hits on the matter:
How nuclear bomb testing enabled obesity research
This is the kind of thing that makes me love science. Derek Lowe has a blog entry about a letter in Nature whose authors figured out a way to determine the number and age of all the fat cells in a person’s body, and tracked that data over a number of years. The results confirm that the number of fat cells you have is set by the time you are an adult, and from then on they merely change size as you gain or lose weight. (I don’t know how this was determined previously, but I’ve heard that fact from a number of different sources.) Even if you undergo liposuction, the cells that get sucked out are replaced after a few years. There is some mechanism that keeps your population of fat cells at a pre-programmed level. They also figured out that about 8% of your fat cells get replaced every year.
So, how did these researchers determine how old a fat cell is? As it turns out, the above-ground nuclear bomb tests in the 50’s and 60’s increased the concentration of radioactive carbon-14 in the atmosphere, and the concentration has been decaying ever since to the natural background level. By measuring the amount of carbon-14 in the DNA of a cell (other parts of a cell are recycled during its lifetime, but the DNA is not) they could determine exactly when that cell was created.
Artificial Resolution
So, does this finally prove intelligent design?
The Weight Loss Post
Apparently, everything we think we knew about weight loss is wrong. Here is Gary Taubes in the New York Magazine:
For the last 60 years, researchers studying obesity and weight regulation have insisted on treating the human body as a thermodynamic black box: Calories go in one side, they come out the other, and the difference (calories in minus calories out) ends up as either more or less fat. The fat tissue, in this thermodynamic model, has nothing to say in the matter. Thus the official recommendations to eat less and exercise more and assuredly you’ll get thinner. (Or at least not fatter.) And in the strict sense this is true — you can starve a human, or a rat, and he will indeed lose weight — but that misses the point. Humans, rats, and all living organisms are ruled by biology, not thermodynamics. When we deprive ourselves of food, we get hungry. When we push ourselves physically, we get tired. Our bodies, like all living organisms, have evolved a fantastically complex web of feedback loops.
After decades of being told that the relevant factors are diet and exercise, it seems instead that twin pillars of weight regulation are appetite and metabolism.
Unfortunately, these two factors are inside that black box. We don’t fully understand them, but we do know that diet and exercise can influence them in counterproductive ways. Taubes spends much of his article detailing how exercise can not makes us thin. Part of the reason is our metabolism does not respond to exercise in ways that sustain caloric losses. Another is that vigorous exercise increases our appetite: the more one works out, the hungrier one becomes.
For its part, there is now considerable evidence that diets don’t work; initial losses are small, and in the long-term, dieters even end up gaining. Diet has complex interactions with both appetite and metabolism, as Gina Kolata explains in an excerpt from her new book, reprinted here in the New York Times. Kolata endorses the view that every individual has a set range of weight, 10-20 pounds, in which they will normally fluctuate. This range acts like a thermostat, and when pushed outside that range, the “complex web of feedback loops” will return a person to his normal weight through metabolism and appetite.
We can work down to the lower end of each of our ranges, so it is possible to lose 10 lbs. with some self-discipline. But even this expenditure of will-power takes a lot of effort, and remember, will-power is a limited resource. How much harder must it be for the obese, who must push far below their range to fall into what our culture deems normal? Their conscious expenditure of will-power must overcome crippling biological impulses. Their bodies are sending out every signal that they are starving, metabolism slows, and appetite skyrockets. Kolata summarizes research with weight loss subjects:
The Rockefeller subjects also had a psychiatric syndrome, called semi-starvation neurosis, which had been noticed before in people of normal weight who had been starved. They dreamed of food, they fantasized about food or about breaking their diet. They were anxious and depressed; some had thoughts of suicide. They secreted food in their rooms. And they binged . . .
Eventually, more than 50 people lived at the hospital and lost weight, and every one had physical and psychological signs of starvation. There were a very few who did not get fat again, but they made staying thin their life’s work, becoming Weight Watchers lecturers, for example, and, always, counting calories and maintaining themselves in a permanent state of starvation.
In light of these findings, it is absurd to ascribe obesity to sloth or gluttony. Likewise is it wrong to think lean people simply have an excess of will-power. Taubes explains:
They are people whose bodies are programmed to send the calories they consume to the muscles to be burned rather than to the fat tissue to be stored — the Lance Armstrongs of the world. The rest of us tend to go the other way, shunting off calories to fat tissue, where they accumulate to excess.
We are bound by our biology. Kolata reports that our weight ranges have many determinants, but genetics may account for up to 70% of the variation. That’s rather discouraging, especially since it is unknown what comprises the other 30% (obviously, some sort of environmental factors — here are some obscure ones). And yet I share Jane Galt’s skepticism about genetic determinants, since inheritance cannot adequately explain the weight gain epidemic. It will be interesting to see how malleable appetite and metabolism are.
And so we have a new frontier in weight regulation research. Hopefully, science will follow where fads have gone before. The Atkins Diet is a theoretical approach to changing metabolism, but it ultimately fails (among other reasons) because it is not sustainable. For whatever reason, we have an innate appetite for carbohydrates. Seth Roberts’ Shangri-La Diet is an interesting stab from the other direction; it claims to be able to perpetually lower appetite. In a world of hundreds of diets, I suppose it’s natural that at least two would have stumbled on the new insights. But maybe now we can stop groping in the dark.
Cybersquatting for Darwin?
The recent discussion of evolution here reminded me of something I noticed a few weeks ago. What side of the creation/evolution debate would you expect to find at a website called AntiEvolution.org or TalkDesign.org? If you said Creationism or Intelligent Design, you’d be wrong. Both of these web sites are devoted to criticism of Creationism and ID.
Both of these sites are apparently run by the same folks who run TalkOrigins.org. And neither site is very active (6 posts in the last year on one, none in the last 8 months on the other). It’s pretty clear they were started simply to snatch up a domain name that some critic of evolution might want to use, and to confuse a few people Googling for information on the controversy.
So what of it? Some might say that this little prank does not reflect well on a group of people who purport to represent a portion of the scientific enterprise. I say let them have their fun–but they better make sure they renew their registration on time!
Evening Power Usage Time
The early onset of Daylight Savings Time in the United States this year may have been for naught.
The move to turn the clocks forward by an hour on March 11 rather than the usual early April date was mandated by the U.S. government as an energy-saving effort.
But other than forcing millions of drowsy American workers and school children into the dark, wintry weather three weeks early, the move appears to have had little impact on power usage.
“We haven’t seen any measurable impact,” said Jason Cuevas, spokesman for Southern Co., one of the nation’s largest power companies, echoing comments from several large utilities.
That may come as no surprise to the Energy Department, which last year predicted only modest energy savings because the benefits of the later daylight hour would be offset.
For example, households may draw less electricity for lights at night, but will use more power early in the day as they wake to darker and chillier mornings.
Residential lighting comprises only about 10 percent of the average homeowner’s electricity use, while air conditioners, heaters and refrigerators consume much more power. Washers, dryers and plasma televisions are also bigger users of electricity than lighting . . .
Perhaps the biggest impact was felt by the computer users and Blackberry addicts who had to scramble for software patches to keep their digital devices on the right time.
[Emphasis added]
Thankfully, this idiotic piece of legislation contains a provision for Congress to revert to a “normal” DST schedule based upon a Department of Energy study of the impact, which isn’t likely to be positive. Sadly, I doubt any Congressman, including the sponsors of the extended DST, Ed Markey (D-MA) and Fred Upton (R-MI), will learn that good intentions (and complete disregard for evidence) don’t make for good legislation.
Now, how about a provision allowing for the abolition of any DST based upon a full study of its impacts?
Previously by the author:
“Morning Darkness Saving Time”
“A Bad Plan for Indiana”
“DST and Broken Hearts”
“No, This is NOT Happening”
“Grrrrr“
…and the delegate from Mother Nature agrees?
On the same day that the Intergovernmental Panel on Climate Change released its report agreeing that anthropogenic global warming is occurring, Punxsutawney Phil failed to see his shadow for the first time since 1999, heralding an early spring. Coincidence?
Gratuities Accepted
Scientists and economists have been offered $10,000 each by a lobby group funded by one of the world’s largest oil companies to undermine a major climate change report due to be published today.
Letters sent by the American Enterprise Institute (AEI), an ExxonMobil-funded thinktank with close links to the Bush administration, offered the payments for articles that emphasise the shortcomings of a report from the UN’s Intergovernmental Panel on Climate Change (IPCC).
Buying dissent is a perversion of the scientific process, and that certainly seems to be what is going on here. There is an alternative explanation, more charitable but highly unlikely, I would offer less than seriously.
Suppose you are a scientist with a quibble about the report (and at this point, I think the only thing a serious scientist would come up with is a quibble). However, there are social and/or professional costs associated with raising this quibble too loudly: your department chair will put a black mark on your file, your colleagues won’t let you sit at their lunch table, people at conferences will give you that “why are you being a smart-ass” look, and reporters will ask you for quotes in an annoyed tone of voice. Is it all really worth it? What if someone intended to compensate you for those costs?
Would $10,000 change your mind? I highly doubt it, and I agree with Kevin Drum that, “For this level of simpering I recommend holding out for at least $50,000. That’s the minimum it would take to buy a congressman, after all.” (Explanation of of why congressmen come so cheap here.)
