Do You Believe In Science (II)

Back in the heat of the Presidential campaign in Oct 2004 we asked "Do You Believe in Science"?  My launching point was a NY Times magazine article which wondered whether the intersection of race and science (specifically the study of the human genome) was too hot for society to handle.  Here is an illustrative quote:

Some critics worry that the more we find out about genetic differences among people of different racial groups, the more such information will be misinterpreted or abused. Already there are fears that the biological measures of racial differences might lead to pronouncements about inherent differences in such complex traits as intelligence, athletic ability, aggressiveness or susceptibility to addiction. Once such measures are given the imprimatur of science, especially genomic science, loathsome racist stereotypes can take on the sheen of received wisdom.

With that in mind, how will folks react to this latest from the Times?  Its gist - some interesting science suggest that human evolution can be detected as having occurred withing the last ten thousand years, well after different groups had separated into Asia, Africa, and Europe.  And, in a nightmare for the folks worried that this research will be misused by racists, one of the detectable differences involves genes that seem to regulate brain size:

Three populations were studied, Africans, East Asians and Europeans. In each, a mostly different set of genes had been favored by natural selection. The selected genes, which affect skin color, hair texture and bone structure, may underlie the present-day differences in racial appearance.

...Dr. Pritchard also detected selection at work in brain genes, including a group known as microcephaly genes because, when disrupted, they cause people to be born with unusually small brains.

Dr. Bruce Lahn, also of the University of Chicago, theorizes that successive changes in the microcephaly genes may have enabled the brain to enlarge in primate evolution, a process that may have continued in the recent human past.

Last September, Dr. Lahn reported that one microcephaly gene had recently changed in Europeans and another in Europeans and Asians. He predicted that other brain genes would be found to have changed in other populations.

Dr. Pritchard's test did not detect a signal of selection in Dr. Lahn's two genes, but that may just reflect limitations of the test, he and Dr. Lahn said. Dr. Pritchard found one microcephaly gene that had been selected for in Africans and another in Europeans and East Asians. Another brain gene, SNTG1, was under heavy selection in all three populations.

"It seems like a really interesting gene, given our results, but there doesn't seem to be that much known about exactly what it's doing to the brain," Dr. Pritchard said.

Dr. Wells said that it was not surprising the brain had continued to evolve along with other types of genes, but that nothing could be inferred about the nature of the selective pressure until the function of the selected genes was understood.

The four populations analyzed in the HapMap project are the Yoruba of Nigeria, Han Chinese from Beijing, Japanese from Tokyo and a French collection of Utah families of European descent. The populations are assumed to be typical of sub-Saharan Africa, East Asia and Europe, but the representation, though presumably good enough for medical studies, may not be exact.

Well.  I understand that variations within groups are much, much larger than variations across groups.  And I understand that finding race-based differences in brain design is not at all the same as finding that one design is "better".

However - far be it from me to impede the march of science, but this is getting close to the border of "I Don't Want To Know".

MORE:  More on race and ethnicity from the Times; speaking for the "Race is a social construct" crowd:

In articles in the current issue of the journal Nature Genetics, scientists at Howard, a center of African-American scholarship, generally favor the view that there is no biological or genetic basis for race. "Observed patterns of geographical differences in genetic information do not correspond to our notion of social identities, including 'race' and 'ethnicity,' '' writes Dr. Charles N. Rotimi, acting director of the university's genome center.

And for the "Race is a useful proxy for something" view:

But several other geneticists writing in the same issue of the journal say the human family tree is divided into branches that correspond to the ancestral populations of each major continent, and that these branches coincide with the popular notion of race. "The emerging picture is that populations do, generally, cluster by broad geographic regions that correspond with common racial classification (Africa, Europe, Asia, Oceania, Americas)," say Dr. Sarah A. Tishkoff of the University of Maryland and Dr. Kenneth K. Kidd of Yale.

UPDATE:  Andrew Sullivan is in the mix, twice.  And The Poorman notes that Sully once proudly cited his publication of excerpts from "The Bell Curve" in order to provoke debate.  Hmm, over to Brad DeLong.

Comments

[clarice]

Even if it were true that mankind branched out into three branches only a few thousands of years ago, there is good evidence that there was a great deal of interbreeding among all groups--more than one might imagine if one simply looked at a map of the world. At the same time geneticists are making these discoveries, anthropologists are finding that about 10-12,000 years ago early man traveled further than we'd ever expected. We are finding evidence of Caucasians in the New World, Euroeans in Asia, Asians in South America ..

[Bob in Pacifica]

I found the story of the Flores people, the little home erectuses who survived until maybe 10,000 years ago, to be quite interesting. These people were tiny, but examination of the skull cavities suggest that their brains were organized differently than the average homo sapiens, and fossil evidence suggests that they probably had language skills. So their discovery suggests that the humanity has historically been more intelligent and more plastic in size and brain shape than was ever suspected.

As far as differences between human populations regarding general intelligence, I'll wait to be convinced. Unless there is an advantage to less intelligence, it would be an unlikely evolutionary development in one group over another.

And, of course, racialism is a pretty discounted line of scientific thought. Most of those who propose such differences start with the color of skin and work from there.

[dave]

Well I'll wade in here. Evolution is real but these micro-events are confusing to discuss in the media as evidence of evolution.

Mutation will occur randomly in all genomes over time, including in genes responsible for human brain development (I think people with microcephaly have a primitive brain smaller than a baseball, maybe more like a walnut BTW) but evolution of new species is extremely rare and mysterious. Speciation does seem to be encouraged in small isolated populations on islands like Hawaii or the Galapagos islands.

As I believe the concept of measuring intelligence is fundamentally flawed, the idea of linking subtle gene mutations (mutations in the microcephaly gene that do not cause a full blown microcephaly phenotype for instance) to intelligence or behavior is absurd to me.

There will certainly be mutations affecting health that differ among people, and perhaps the races, and drugs should target these differences - something like 50% of the population is non-responsive to most drugs for this reason.

It is true that everyone's genetics is very much jumbled together these days, particularly in places like the US but not in Iceland and some other places. I hope that with enough info the fear of genetic discrimination might be outweighed by a person's new understanding of their body, new medical options, and their ancestry.

[Rick Ballard]

"Unless there is an advantage to less intelligence, it would be an unlikely evolutionary development in one group over another."

Well, that does account for the diminution in the importance of liberals. Good point.

[Lou Grunt]

You know the small brain gene must be inherent in liberals. (e.g. George Clooney, Barbra Streisand, JOM lefty commenters, etc). As soon as word of this leaks out, the Congressional Dems will insist that all gene research be halted.

[MayBee]

"Unless there is an advantage to less intelligence, it would be an unlikely evolutionary development in one group over another."

Would it not be more likely that less intelligence was not an advantage, but that intelligence wasn't a requirement.
Perhaps a group of humans living in less adverse conditions (more plentiful food, temperatures not requiring the need to learn to build shelter) would not need to develop problem-solving intellectual skills the way humans living in seasonal climates would be. It's that less intelligent people wouldn't have to be selected out of a population where intelligence wasn't as needed.

[reliapundit]

if you asked most people, they'd agree that evolution is a real process, and that humans probably evolved from ancestors who were more ape-like (less "highly evolved" - to use circular reasoning!).

but if you ask these people HOW, most CANNOT explain how evolution works.

they accept that evolution works AS AN ARTICLE OF FAITH.

how ironic.

[Jim Rockford]

There are many different kinds of intelligence, all hard to measure.

There is the ability to quickly process, analyze, and decide near instantaneously thousands of variables and decide what is the best course of action. Fighter pilots, quarterbacks, point guards, rifle company commanders, commercial pilots all have this intelligence.

Then there is the intelligence needed to perform say stand-up comedy; or write a novel; or paint a picture. All requiring very different kinds of intelligence.

The intelligence required to engineer a new product; and one required to sell it are very different but are intelligence nevertheless.

Different does not equal better. Just, different. Someone may be gifted in spatial real-time intelligence (and a great fighter pilot like Pappy Boyington) but not say, in focused and tedious analytical skills like say, Turing. Both guys were needed to win WWII. So DIFFERENCES in skills and abilities and advantages are a good thing, if understood and harnessed.

But yes, natural selection means we are affected just like say, finches or starlings. In certain environments different traits will be advantageous and selected for. That's the whole point of natural selection; it's the engine which drives adaptation to the environment.

[Rick Ballard]

Neat, MayBee, that explains why liberals are still around.

For now.

[Robert Speirs]

The correlations between and among brain size, intelligence and things like prosperity, incidence of violent crime and abstract reasoning are too prevalent and effective to be denied. Races are only families. Does anyone not believe in families?

[larwyn]

I began this when only two comments were
posted, chores interrupted. Agree with MayBee and Jim Rockford:

Ironic that this subject would come up with the Solomon Amendment running on another thread.

Evolution is explained as species developing those traits and characteristics that would
enhance their survival.

That is fine in the animal kingdom and seems common sense. But woe to anyone that would apply the same to humans.

Animals instinctively know the most desirable mate, the part of the prey most satisfying, the
cave, cliff, or limb that will provide the best shelter, protection and "nest" to nurture their young.

In regions that provided climates with growing season the full year, there food enough for
an entire chain of species survival, climates that do not require the possession of clothing
or shelter as a life and death issue, the human didn't have to really figure out much. There
was time for play and time for "art" if so inclined but very little challenge to survival.

Then compare what is needed to survive in a less temperate climate -- where winter
comes. Those who do not prepare do not survive. Murray's new book covers man's inventions. It should not be surprising that
the vast majority come from regions where planning is necessary for basic survival.

Of course we now don't give most of them a second thought. Zoning laws would not allow the building of a residence without "necessary" utility hookups.

And no worries that there will be enough food to get thru the winter.

Intelligence? Well, imagine the mad mullahs are successful in wiping out all the electronic
processes in the world. Would not those that still knew how to can/preserve food suddenly
be considered the gurus Vs all those tenured professors?

[Sue]

I have faith that someday it will no longer matter whether we evolved from apes or came from dust. One thing for sure, you won't be going back into your ape form when you die. But dust is likely to occur.

[Rick Ballard]

Worse come to worse, Larwyn, and tenured professors would be referred to as "dietary supplements".

[maryrose]

What about emotional intelligence? The ability to interact and work well and in harmony with others. Sometimes your smartest individuals have a hard time with this kind of reality.
It's all in the genes. mental health and physical well-being.

[clarice]

Maybe we can run one of those little clock thingies--to show how long it's been since the FAIR decision was released until a school turns down the money?

[dave]

It's important to understand that evolution acts over very large time scales, many many generations, and is more likely in very small populations.

All dogs are the same species, though the pure-breads' appearance has been selected by humans - speciation (a mating barrier like an imability to produce any offspring, or fertile offspring) is the significant event of evolution.

If there is a flu pandemic it might turn out that people with certain genetic characteristics are protected, or at more risk. Perhaps the same would occur with other big selective pressures - with chemical or biological weapons, or another huge volcanic or asteroid event.

Big events like this, particualrly if they induced chromosomal mutation could push an isolated community toward speciation (like the Flores people that Bob mentioned above).

[MayBee]

Neat, MayBee, that explains why liberals are still around.
For now

Rick Ballard- do you listen to the Ricky Gervais podcasts? They are hilarious. On one of them their resident off-kilter thinker Karl Pilkington was stating his belief that perhaps we need to re-introduce the tyrannasaurus rex. He thinks we're screwing up the species because we don't allow natural selection and survival of the fittest, so people having to outlive the TRex would put balance back in the world. Hardly anyone dies anymore, he said.

Wacky, but not wacky, all at the same time.

[JM Hanes]

Oddly enough, I was commenting on brains & evolution in an entirely different context over at Quasiblog a mere few days ago (just scroll down a bit).

I tried to read the NYT's Genome in Black & White but just gave up in disgust when I read this reiteration (or perhaps preiteration) of your opening quote:

Pharmacogenomics has for years been touted as the ultimate benefit of the genomics revolution. But to many, this revolution has a troubling side. For race-based niche marketing to work, drug developers first will have to explore the ways that blacks, whites, Asians and Native Americans are biologically different. And the more they explore and describe such differences, critics say, the more they play into the hands of racists. Even the broad-minded might inadvertently use such information to stigmatize, isolate or categorize the races. Could it be that this terrain is too dangerous to let anyone, no matter how well meaning, try to navigate it?

Has anyone else noticed how consistently anonymous such "critics" seem to be? And does anyone else think that journalists covering genetics may actually be the ones who feel compelled to pose those questions? Most of evolution's real critics are creationists, not racists, yet we still see this tired old frame hauled out nearly every time genetics are explored outside of dedicated science/tech columns.

Is evolution the root cause of racism? Let's be kind, call this a rhetorical question (or academic if you prefer), and give public discourse a chance to move forward instead of yawningly back.

So, now that I've gotten that off my chest, I'll go check out what Andrew Sullivan has to say on the topic...

[Rick Ballard]

Well, a T-Rex with a sweet tooth for tenured professors would be neat. No harm done, either.

[clarice]

Hmmmmmmmmmespecially peace and ethnic studies profs...

[Rick Ballard]

Maybe breed'em on the basis of sensitivity to the smell of Birkenstocks - or mocha latte.

[dave]

"Is evolution the root cause of racism?" I'm not sure what you're saying here, there are many possible interpretations.

I think it's necessary for journos to remind people of the dangers involved in research identifying genetic groups (these most likely won't be "races"), early in the last century a lot of harm was done in the name of genetics and evolution. These same events would never occur today but there are reasonable fears of discrimination by insurance companies and employers.

[MayBee]

Michael Moore: slow, filling, and nicely marbled

[Gaucho]

"My daddy says longnecks have small brains."

[JM Hanes]

dave

"These same events would never occur today but there are reasonable fears of discrimination by insurance companies and employers."

And the way to combat that is to fight discrimination, not science, which was where the kind of warnings you describe ended up last time. Anyone who even hinted at a genetic component in a whole roster of human activity was just kissing their funding and their colleagues goodbye.

[gh]

scientific progress unfolds new truths, not always as we like it but it needs to be accepted or questioned, based not on our preconceived notions and PC but on whether the biology math science and logic were correct or incorredct

and perhaaps "truths' is not the right word to use, new information unfolds that leads to a better, albeit always incomplete understanding of reality.

the question is are we to be luddites denying the revolution in biology taking place within our midst, or are we going to embrace new data and adapt to it in a humane ethical manner

[Neo]

This turf is so easily tread by demagogues, so I shall go no further.

[gh]

here is a more detailed analysis of the paper

http://scienceblogs.com/gnxp/2006/03/the_morphing_man_evolution_hap.php

[dave]

I agree about targeting discrimination, I'd support a Genetic Discrimination Act that prevented discrimination by sex, race, disablilty, even age (which now can be roughly defined genetically). This idea rattled around the Senate a few years ago and, most likely, got buried by a cabal of various lobbyists.

I still think there's a very large separation between a genetic mutation and human behavior, with some notable exceptions like microcephaly. I'm also completely disillusioned with academia, sorry about the funding difficulties etc....

[James B. Shearer]

Bob in Pacifica, the advantage to less intelligence is that intelligence doesn't come for free. It is costly for the body to support a large brain. At equilibrium genes providing additional IQ have compensating disadvantages and so don't increase in frequency. The location of the equilibrium (and hence the average IQ of a population) will vary depending on the relative value of IQ and the accompanying disadvantages in the local environment. I see no reason to expect it to be the same everywhere.

[Bob in Pacifica]

Mr. Shearer,

I doubt that you can produce any studies to show a difference in energy use by brains of smart or stupid people, or brain energy use by race.

IQ is based on testing. You can take the son of highland tribesman from New Guinea at birth and put him in America he'll do just fine if he's loved and lives in a happy, monied family and is loved and is free from discrimination.

A big brain is useless for a shark, but we're not talking about various species and their need for energy conservation versus the size of a brain. An IQ test hasn't been devised for the many kinds of intelligence that are used by humanity. The average New Guinean highlander has an incredible knowledge of the flora and fauna in their environment because it's essential for their survival. People like Rick Ballard, for example, would probably die in that environment in 72 hours without the kindness of a stranger because Ballard, for ex, is incompetent in what would pass for nominal intelligence there.

[Sylvia]

I'm trying to picture the species in the animal world and how different they are. I know that if members of an animal species becomes too from each other, they can no longer mate. That has the effect of keeping the members of most species relatively similar. The ones who are similar breed among each other, and if they aren't similar enough they become their own species and then that new species breeds among itself, etc. The fact that all human species can easily breed among each other, and have for thousands of years, means that any differences between the races is slight. So I doubt any future genetics study will uncover any real dramatic or controversial differences.

[wickedpinto]

"Brain Size" granted, it is necessary to have a large enough container, but brain size as an exclusive indicator of "intelligence" strikes me as silly, and has for a while because I BELIEVE! (not a scientist, and wouldn't mind a correction and reference if I am wrong) that Downs babies tend to have large cranium capacity, and a more significant brain mass mass.

Most of the arguments about how this is a silly statement revolve around "theres different kinds of smart" but smart is smart, the "different kinds of smart" is based on disciplines rather than genetic capacity. I DO believe it is necessary to have sufficient capacity within the brain, but there are people who are missing portions of their brain and are smarter than people who aren't. I believe I heard, read, saw once that there is an opinion that smarts are actually based on the ability of the human brain to communicate with itself, so it is less important to have a big brain, than it is to have an efficient brain with more neurotransmitters and receptors. The more ACTIVE the brain, the smarter the brain.

The truth is that there hasn't been much truth in most of these hypotheses forwarded to the public to predict a brave new world. Over population, global cooling, global warming, super-flu, frankenfoods, AIDS, triple black belt ninja west nile engineered arian mosquitoes. The TRUTH is the media cares about hyperbole not truth.

[Daddy]

To restate an old but a relevant question in this debate: "Who's side are you on here, the Ape's, or the Angels?"

Worth remembering that this discussion pretty much started back about 1870, when it became the falling out point between Darwin and Wallace, the co-discoverers of Evolutionary Adaption through Natural Selection.

If I remember correctly, Wallace gradually became convinced that pretty much everything was explainable via Natural Selection, except for the relatively large size of the human brain. Focusing on this as an aberration, he increasingly came to believe that there was no reason why the process of Natural Selection would have endowed us with brains any larger than those of a common gorilla. His reasoning was that us just being another Primate cousin, significantly less than our current cranial capacity would have been all we would have needed to survive as a well adapted species.

Unable to move beyond that conclusion, Wallace eventually veered off into religion and spiritualism, leaving Chuck bummed but resiliant in carrying on the theory by his lonesome, and postulating Sexual Selection in addition to Natural Selection as the potential problem solver for Wallace's dilemma.

Personally I'm pulling for the Ape's.

[kim]

It is patently absurd that all men are created equal. The cultural point is that all men are equal before the law. Extending that to biology has caused serious confusion.
==============================

[boris]

Once humans became their own natural enemy, large brains were inevitable. Why are murder mysteries, crime capers and war stories so popular? Because that's what humans evolved to survive.

[JM Hanes]

TM

I'm not sure why anyone would be beating up on Andrew Sullivan here. The Bell Curve was incredibly unPC when if first came out, and I'll give him props for publishing. Brad DeLong snidely points out that Thomas Sowell disagreed with the BC's authors as though it were a gotcha moment, when it really only proves Sullivan's point about the controversy. It wasn't exeactly hard to find Herrnstein and Murray critics -- in fact, Sullivan says he published a collection of 'em himself.

These days it's not hard to find Sullivan critics either; let's give the guy a break where we can.

[clarice]

I have a lot of respect for Sowell. but reading his critique of the Bell Curve, I think he made a fatal error, assuming as he does that the early IQ tests were similar to those in use now. They weren't. Immigrants were asked questions that only someone who lived in America could answer--in other words, it was far more loaded with cultural literacy matters than would be done today.

[cathyf]

"These same events would never occur today but there are reasonable fears of discrimination by insurance companies and employers."

But what's "discrimination"? Is it discrimination to have an insurance company rule that says that they will pay for annual mammograms starting at 45 for caucasian women, 40 for black and hispanic women, and 50 for asian women? It would save a lot of black and hispanic women's lives. Approximately 20% of the population lacks the gene to metabolize codeine. Is it discrimination for an insurance company not to pay for more expensive painkillers in the 80% of the population where codeine works great?

And a lot of it depends on how you phrase the question:

Is it ok to charge people with the gene for a disease higher insurance premiums?

Is it ok to give people without unhealthy genes a discount on their insurance premiums?

Because it's going to be phrased as the second question, not the first.

And furthermore, understand that in the policy debate where you bring in "market forces" and "choice" to the health insurance market, when you combine this with our accelerating genetic knowledge, "choice" means the ability of healthy people to prevent less-healthy people from getting health insurance.

cathy :-)

[clarice]

Actually, I foresee a time in the not so distant future where we will be able to tailor the types of medicine and dosages more specifically suited to each person. Size, metabolic factors, age etc probably are more significant factors than race.

[larwyn]

There is some INTELLIGENCE in Higher Education - DrSanity linked to this via the Corner:

Disingenuous Free Speech Claims
Contact: Stephen H Balch, President (609) 683-7878
PRINCETON, NJ -- 7 March 2006 -- The National Association of Scholars applauded the Supreme Court's dismissal yesterday of the disingenuous free speech claims put forward by a coalition of law schools in Rumsfeld v Forum for Academic and Institutional Rights.

"While we have generally been wary of the use of government power to coerce private higher education institutions," said Stephen H. Balch, president of the National Association of Scholars, "we are pleased that in this instance the bien pensants of academe have been hoist with their own petards. Having long been complicit or acquiescent in the enforcement of speech codes, and supportive of regulatory policies promoting ethnic and gender quotas, they here tried to torture the concept of free speech to cover their pet practice of excluding military recruiters from campus. The Court has rightly and unanimously rebuked their sophistry." "A sensible and consistent commitment to intellectual freedom," observed Dr. Balch, "ought to allow military recruiters open access to campus. Students should be at liberty to learn about the opportunities for serving their country through the armed forces, along with other career possibilities, whatever the administrations of their institutions may think about the wisdom of specific military policies. It is embarrassing that so many legal scholars, and other academic leaders, cannot bring themselves to recognize such a simple fact."
The National Association of Scholars is America's foremost higher education reform group. Located in Princeton, it has forty-six state affiliates and more than four thousand professors, graduate students, administrators, and trustees as members.

NAS Press Release Supreme Ct Allows DoD Recruiting
http://www.nas.org/print/pressreleases/hqnas/releas_07mar06.htm

[ajacksonian]

Well, geography is certainly *one* factor that plays a role, but when considering environment as a whole there are other things that are also geographically limited, but not to varieties of mankind, generally heaped into races.

A gene that offers resistance to malaria can occur in different populations and arise from separate genetic occurances. However, such changes also carry a price of having deficeits in the organism carrying them. So, widely variant populations exposed to the same endemic disease will show differing responses due to genetic variation. While the original disease will be resisted, the allele that confers resistance may also cause other problems in the body, thus lowering overall longevity. But if those carrying it are able to reproduce and pass on their genetic resistance while those without, proportionately, are unable to, the resultant generations will trend towards the gene expression as it is preferred due to the offering of resistance. So while envrionments are similar for two populations the response is different. But, it should be noted that the gene suite conferring the resistance naturally occurs in other populations and is usually selected against due to limited life span compared to the population. So the endemic disease presence is a selector. Thalassemia, then, is located within populations exposed to malaria that have a common suite of genes to provide resistance and that suite is not geographically centralized. Sickle cell disease, while offering a similar resistance to malaria, arises from a mutation and it confers resistance to malaria, but generally shortens life span.

This is a sieving process of which disease, genetic commonality of ancestral populations, geographic isolation and mutation will all play a role or *not* as the case may be.

Now island populations suffer two common problems: large creatures get smaller over generations and small creatures get larger with succeeding generations over time. This is a well known effect of limited environment and the Square-Cube Law playing out which is better codified under Bergmann's Rule. Here the limitation of habitat to body size is of prime importance along with efficient use of caloric intake. Also note that this effect speaks to island isolation in general, so that a series of connected lakes that lose their connections are considered to be 'islands' for the aquatic cultures within each one. This geographic isolation and change in dietary structure will preferentially select smaller and more efficient body sizes for larger creatures to adjust mass to limited diet and larger, more efficient body sizes for smaller creatures so that they use fewer calories by preserving heat due to larger mass but only moderate increase in surface area.

Once one begins to understand the role isolation plays, geography plays, disease plays and other factors such as general climactic condition for any geographic region, then reproductive success becomes a multivariate problem that needs to be examined in many different ways. Genetic heritage and mutation play their roles, and the ancestor effect via limiting an available gene pool due to number of ancestors to found a population, will also play its role.

Finally, extinction events mark extreme change in climactic and other conditions in which there is no real set rule for survival and it is often by happenstance that one genetically isolated part of a larger population will survive while the rest dies out. During the last major extinction event at 65 MYA foraminifera were of a widely divers population globally exhibiting a large number of different body types adapted to differing climates. The extinction event wiped all of them out, save for one type that had seasonal hibernation period due to its living in arctic conditions. This one body plan and lifestyle type in the foram population survived and is the sole founder of the modern foram population. A more interesting example is population diversity of brachiopods and bivalves before the Permo-Triassic extinction. Both body plans use similar feeding styles but have different overall characteristics. Before the P-T event brachiopods were highly diverse throughout the warm near shore waters and bivalves were a few paltry species existing in niche territories. After the extinction event the situation reversed over time as bivalves turned into many different populations while brachiopods became a few species in niche environmental zones. Something in that event favored the general reproductive rate of one over the other for a similar environment and allowed bivalves to proliferate and speciate while brachiopods could not compete to do so.

So, my understanding of evolution is that one may not consider just one factor in isolation, but must consider numerous factors and conditions to understand why populations drift within and amongst species. Once all the conditions are examined, along with all other competitors for similar ecozones and niches, can success be measured via differential survival according to genetic changes.

Studies such as those cited? Nice, but only a small part of any puzzle. Diversity of life is a difficult thing to understand, but has basic rules with which it can be understood, although they are complex in their enaction.

[noah]

Actually if you are "healthy" it makes no sense at all to purchase health insurance. Accident insurance? Yes.

The unhealthy and neurotic will bankrupt us all.