Good article about a fascinating study. I'll be looking to follow this work and more about the Bajau.
Thank you, Mr. Zimmer, Ms Ilardo and the other scientists involved.
2
Very interesting. I would also like to know more about the whole process of doing the research. How did the scientist explain her work to the people she wanted to study? What made them agree? Did it make any sense to them? Were they worried that an ultrasound might hurt them? These cross-cultural communications issues would have been interesting to read about too. Thanks!
4
For illustration to non-science people please do the following: People in TIbet and Ethiopia did not develop living at altitude and cattle-herding people in East Africa did not gain a mutation that helps digest milk as an adult- These are mutations that enable the regressive gene variant holder to thrive and reproduce therefore passing on the mutations to offspring who also thrived and reproduced. Non-variant people did not not thrive and reproduce and were taken out of the gene pool via inheritance of the superior functioning DNA holders. The writer's rep of the process really misinterprets the natural selection process. Lamarckian inheritance was proven false thinking centuries ago, yet the writer alludes to it even now.
4
"Gaining a mutation" can be read as shorthand for the genetic process described in four long sentences here. These are a good review of basic genetics but would not have served in the article. The study asks the interesting question about how fast this process can happen.
3
My first class in college was physical anthropology, and there I learned the true definition of evolution - "a change in allele frequencies". It doesn't matter whether these changes are due to cultural or physical advantages, because all evolution comes down to relative reproductive success. The fact that the whole population has enlarged spleens is clearly an indication that a larger spleen has given its owners a reproductive advantage.
Given that "it takes two to tango" in reproduction, and these studies and article are all about inheritance, it is mind-boggling that no mention was made of whether women in this culture dive (the photos and assumption was that they do not), whether children of both sexes dive, whether differences between males and females were seen in the diving-related organs. etc. Answers to such questions would have enormous implications on the research being conducted. It's a sorry reminder that researchers--- including the female ones-- still need to be reminded that women are humans.
3
1 There is a small group of older Japanese women who deep dive for oysters. Comparing their lung capacity, spleen size etc. with the Bajou would be interesting as there is no mention of women Bajou divers. My understanding was that women have a greater capacity for deep diving than men do? Maybe Bayou women were the first to deep dive then came the missionaries and the culture was changed. 2. Physicists are claiming that consciousness is the ground of all being and the material world arises from conscious creation, John Wheeler's "nothing exits until it is observed or registered." And Einstein's "the material world is an illusion albeit a persistent one." Consciousness creates and maintains physicality and our relationship to our environment is always being expressed through our DNA and epigenetic expression. We are spiritual beings on a human journey. Please look to your higher self (consiousness=god) not some creation story diety that is separate from us. There is no separation. We are all one.
5
Interesting article and comments.
The idea that that deep divers were more likely to reproduce due to social and economic factors seems plausible but it assumes that the deep divers didn't share.
It also ignores the possibility that men more likely to live longer would be the preferred (and successful over time) reproductive partner over those who dive. (Diving being inherently risky, even today).
And lastly, don't these people fish? Is deep diving the predominate food/economic source?
They live on the water and dive for a living. They dispose of their waste by throwing it in the water. Maybe the water they're diving in is to account for their enlarged spleens. I wonder what they're life expectancy is.
2
Good observation regarding the Times' selection of the comment. The paper can be heavy handed in pushing their agenda. It would be interesting to know who selects the comments and what guidelines these people are given.
The Muslems have stolen the Bajou's ancestral territory in the Philippines. The Bajau are now living under appalling conditions in the Mega cities like Cebu and Manila.
2
'Even as anthropologists study Bajau culture, biologists have grown curious about them, too. Bajau divers been observed plunging more than 200 feet underwater, their only protection a pair of wooden goggles — a physiological marvel.'
Nope. Wooden goggles would be a pair of wooden encased eyepieces joined together over the bridge of the nose. As the photo shows, the divers wear a wooden face mask — not goggles.
3
'Even as anthropologists study Bajau culture, biologists have grown curious about them, too. Bajau divers been observed plunging more than 200 feet underwater, their only protection a pair of wooden goggles — a physiological marvel.'
Nope. Wooden goggles would be a pair of wooden encased eyepieces joined together over the bridge of the nose. As the photo shows, the duvets were a wooden face mask not goggles.
Nope, check out some other photos, goggles are common. I saw a photo of a child Bajau being towed by some kind of shark, the kid has wooden goggles.
2
It's possible that in a culture of people who dive for a living, genes for better diving, selected by mate selection over many years, led to the changes. It's not clear at what point the mutation appeared; it could have been present in the original population.
"...We are the products of creation, and not just creation that occurred in just the past few thousand years. As theologians peer deeper into their souls, they are accepting instances of human pre-creation from billions of years ago...
Scientist, theologian, diver - or shellfish - all in our DNA...
All God's children - even the atheists...
.....
Perhaps a sequel:
"Minds Remodeled for of a Life of Prayer"
Must be a few tribes somewhere, worth studying...
2
Funny then, they didn't evolve goggles.
1
You can see quite a lot underwater without goggles, if you just open your eyes. But your vision is blurry because the lenses of your eyes don’t properly focus when immersed in water. Evolution would probably operate by increasing the refractive power of the lens instead of constructing an entirely new structure.
2
Over time our eyes have lost their ability to see clearly in the ocean. The salinity of our bodies and our eyes however is still the same as seawater, because that is where eyes first evolved. Fish can still see quite clearly in water.
1
They would have a competitive advantage in sports such as water polo and extreme free diving.
There’s a beautiful film about an elder member of this group called “Jago: A Life Underwater”. Please do see it if you get the chance.
7
This sort of scientific inquiry could really help creationists understand evolution better because of its recency: it doesn’t require them to question their beloved creation myth, so long as you leave out the part about that ice age that ended “thousands of years ago.”
7
Creationists are not scientists, so why would they be interested in any evidentiary case for the truth of evolution? Faith ends questions because it pretends to "answer" them. Science questions everything, always, and every discovery leads to more questions.
Do these guys hold their breath or are they actually exhaling very, very slowly? How long do they typically stay under?
4
The article never mentions how long these people are able to stay underwater. Seems like a deeply salient point.
9
How do they escape the “bends”? The phenomenon where dissolved nitrogen resurfaces as bubbles causing emboli? As a physician, I would really be interested if someone who understands this could explain in this post. What a fascinating article!
4
Maybe they escape the bends by ascending slowly?
You only get the "bends" if you breathe compressed air at depth. If you take air at the surface and hold it, you can go as deep as your body will allow, and then return without decompression sickness, also known as the "bends" and "caisson's disease."
12
La Marquism rises again! This article has so many scientific holes as to make it absurd. First of all the spleen is not an oxygen reservoir its size has nothing to being able to dive longer. The reason these people can dive for such a long time is simple, practice, practice, practice. The more you practice the more the body's metabolism adapts, Greater lung capacity, 2,3DPG dependent oxygen dissociation changes, desensitization of the breath reflex. As in people that live in high altitudes the body adapts. This is an article that has so many holes from the standpoint of fundamental physiology that its essentially worthless. All the genetic babble referred to simply means that the divers in the study were related to each other, not surprising, given that these are small communities that share a strong familial bond and in which extended families and clans participate in the same employment. Utter trash science!
3
Did you not read the part about the spleen injection oxygen rich blood into the blood stream? Why so harsh?
Also, using terms most people don’t know won’t bolster your credibility...most people aren’t stupid and understand what you are trying to do.
11
As a physician I'm well versed on the science involved and the genetics too. La Marque was a 19th century biologist that hypothesized exactly what this article implies that evolution is caused by use or disuse, for example, giraffes got long necks from constantly stretching them. Anyone that has taken a high school biology knows this is essentially scientific garbage. Again as a physiologist the idea that the spleen is a repository of oxygenated blood is preposterous, the spleen like other organs shunt blood to the muscles in periods of high exertion that doesn't make any organ an oxygenation depot.
That doesn't explain the increased spleen size in those who never have dived within this specific population. Nor would it explain why the increase in spleen size correlates with the number of alleles of the PDE10A. That can't be practice related.
Your basic mistake is "claiming the spleen is not an oxygen reservoir its size has nothing to being able to dive longer." Actually the spleen holds a reserve of oxygenated red blood cells so when it contracts it squirts them out effectively bringing oxygen to the tissues. A bigger spleen is in effect a larger tank.
Additionally the Bajau are not a small community; reread the article.
You seem to lack an understanding of Darwinian evolution. Lamarkism helped bring down the USSR as it was mandated to be relied on especially in food production. Didn't work well.
2
Next, we must study the natural selection forces at work on researchers choosing gorgeous tropical locations for their work!
3
Dr Ilardo said: “I would think, as morbid as it is, that if they didn’t have this, it would kill them,”
Yet, of course it killed them, once upon a time, that is how natural selection works. Those ancient Bajau whose spleens did not help them dive, well, they died, enriching the population with people whose spleens DID permit them to do these extreme dives. Natural selection invariably is based on the death of the part of the population that could not stand whatever was mortally challenging the group. Bottlenecks, etc.
7
If by ‘death’ you have in mind an image of a diver making it back to the boat while the his buddy sinks listlessly below the waves that could happen, but it also might be that a diver with a gene that helps him hold his breath longer feeds his children better so he has more children that reproduce themselves. A difference in reproductive success is what really matters.
7
Fascinating. I read this and was reminded of Kevin Costner in Water World, with gills behind his ears. Whether this Bajau genetic adaptation happened after the last ice age or in the past few hundred years, both are very brief periods of time.
3
Charlie-------I believe our ears start out as gills. I think early stages in human embryo's show this. Perhaps we can go backward as well as forward as needed. In fact, maybe our species carry a bigger toolkit than we realize. If this "toolkit" was in us, regardless of when, then we can dodge all the complaining about evolution.
The article is well-written. But the premise, that: mind or decision, or the power of a conscious being ( human or animal ) is of lower - order and subservient, to physical reality: mater- the material aspect of reality, is flawed. What is called 'evolution' is also about changes that arise because of preferences and decisions, by the beings, of before: it's not all about die-off of those without traits; it can also be about something simple: like females preferring hunters to farmers (to co-parent offspring) (Or/and collectively a population wanting to improve on some skill or become o pen to acquiring advantage, too.) . Or- a phenotype (conscious decision based change to the environment) not genotype expressed with decisions to pursue diving.
2
I wonder why they looked at spleen size rather than lung size. It's not like that's the first thing that comes to mind for diving.
7
That's a good point, but it's not lung capacity that determines how long you can go without inhaling. It's a matter of how efficiently you can use the air you take in. The agony you feel when you hold your breath is not your body wanting to inhale; it's your body wanting to exhale.
5
We have known for some time that sea creatures that spend the most time under the surface do have markedly larger spleens.
https://news.nationalgeographic.com/2018/04/bajau-sea-nomads-free-diving...
The amazing people can stay more than ten minutes at depths as deep as 200 feet.
6
Lung volume is irrelevant. Once you're submerged, you're no longer breathing and there's virtually no gas transfer in the alveoli. You're limited to the oxygen already stored in the bloodstream, which obviously continues to circulate. When the blood oxygen is low, hypercapnia takes over and your body makes you desperately want to breathe.
1
So, how did this and other similar adaptations, like for high-altitude living come about? If there was one individual with the mutation, they would be the ancestor of everyone around today. That should be easy to determine. If several people in the population suddenly had the same mutation, then the question becomes how it came about? Was it merely fortuitous, or was Lamarck correct about the inheritance of acquired traits?
1
It's not necessarily a single mutation. And genes react to other genes to activate at different levels. Note that the articla says "A number of genetic variants have become unusually common in the Bajau, she found." and "People with one copy of the mutant gene had bigger spleens than those with none. People with two copies had even bigger spleens." And the noted gene wasn't previously seen to directly affect the spleen, but the thyroid, which could affect the spleen secondarily.
Lamarck was mostly wrong about inheritance of "acquired traits." But modern developments in epigenetics explains how inheritance of gene regulators can pass on traits not directly expressed as genetic change.
10
the misleading word in your question is adaption. No one "adapted", the whole population adapted when the ones who could not stand the diving challenges died. that is how natural selection works: parts of the population that cant cope die, removing their genes from the next generation, and so forth. forget the word "adapt."
4
It's interesting that as the world becomes more globalized and urbanized, people are mixing their genomes more than ever in the past, with inter-raciality becoming more and more common. Which leads me to wonder, if that trend continues, what will happen to these specialized populations in the future. Will their gifts be lost?
16
I remember how astonished I was when my biology professor declared that evolution is a fact, natural selection is the theory (evolution defined as "genetic change" and natural selection is science's current hypothesis on how that change happened). What we have here is a perfect example. The absolute irrefutable fact is that these people are genetically different in a tiny way. It's been scientifically observed and measured. The mystery is how. Evolution has been documented hundreds of times in other species as well, most notably the color changes in peppered moths during industrial revolution London.
23
An even more important demonstration of this is in the Andes as well as the Himalayas. Natives there, over millennia, acclimated to the lower oxygen content. Researchers have documented the genetic changes.
12
it happened through natural selection which is empirically observable. Evoultion, not so much. These are refined populations, not evolved members of our species. We are all the same species.
2
Mark from MA said, ".... in the Andes as well as the Himalayas... Natives ... acclimated to the lower oxygen content. Researchers have documented the genetic changes."
As we decrease the oxygen content of our atmosphere through pollution, it will be sweet revenge if the Bolivians and others who are being crushed by our present economic system ultimately turn out to be the survivors; that is, assuming that the world we pass on to them is worth living in.
1
When did they start using the face mask (which seems to be glass, not just wood)?
I'm going to guess that was not available at the last ice age or even in 1600. What were they using before glass?
4
They used nothing. The human eye does operate, though poorly, in water. Both salt and fresh.
4
I seem to recall reading soemthing not that long ago about a small population whose eyes had adapted to water vision. Unfortunately, I cannot remember any more than that. Would be a handy "mutation."
3
There is "natural selection" - but is that the case with the Bajau? If Bajau individuals with large spleens were somehow favored for reproduction over Bajau individuals with normal- or small-sized spleens, then "yes". But, as the researchers found out, the Bajau have large spleens whether or not they are divers, so something else may be going on. What does seem to be the case is that large-spleened humans have an advantage over normal-spleeners when diving, so it's more likely that the Bajau were pre-equipped with the capacity to dive compared to other humans. Some other ecological or biological factor may have given rise to large spleens even while the ancestors of the Bajau were further inland. Then, when the Bajau finally reached the coast, they found their large spleens allowed to perform extended dives.
5
The fact that all Bajau, regardless of whether they currently dive, have large spleens is supportive (or the very least not eliminative) of natural selection. Likewise, what you describe about "pre-equipped" large spleens is also part of natural selection. Natural selection needs at least one person (if there are more, it's even better) with the trait that ends up being fixed the population over time (Darwin didn't really address how these traits arose in the first place in the Origin of Species). The large spleen Bajau did better (in terms of reproduction ultimately) than the smaller spleen ones and therefore it end up being fixed throughout the entire population (not just in the divers).
32
There are most likely a number of factors that work in tandem to effect evolutionary traits beneficial to particular groups of people. One thing I haven't noticed many taking into consideration is social selection. You have a diver who has traits that make him more successful in an occupation (like diving). He/she becomes a better provider and therefore much more desirable as a spouse, passing on the genetic traits that make him/her successful at the given occupation. The next generation sees more people with the genetic adaptation and they are more successful in attracting a mate and reproducing. Each generation sees more people born with the trait. So evolution, natural selection, and social selection work together to ensure that a desirable trait is passed on generation after generation.
3
Doesn't the article suggest that *not* having the larger spleen would likely have resulted in the death of those who dove? It's not like they would have any way of knowing that they had "small" spleens and could consciously make an informed alternative career choice. . .
1
Fascinating article. An interesting linguistic curiosity about the name of this island. Sulawesi or Sulavesi in Finnish means unfrozen water. I would love to research the etymology of that.
19
From a famous on-line encyclopedia: "The name Sulawesi possibly comes from the words sula ("island") and besi ("iron") and may refer to the historical export of iron from the rich Lake Matano iron deposits. The term "sula" also means tines, horn or spikes, derived from Sanskrit, as trishula refer to "trident". Thus "sulawesi" means "iron spikes", which suggested that the island was also a producer of iron edged weapons. The name came into common use in English following Indonesian independence."
2
What about the women divers of Jeju island in South Korea? It would be interesting to learn whether they also have large spleens.
59
One thing missing seems to have been a Y chromosome and mitochondrial DNA study which would have indicated how long ago the selection for these genes took place. I would bet that the entire population descends from a very small set of ancestors.
11
The diving reflex has been well studied in mammals for many years and particularly in seals. One of the physiologic adaptations that has occurred is a marked slowing of the heart rate in response to ice cold water. This is adaptive in the diving seal which with a slower heart rate pumps less blood around its tissues thereby consuming less oxygen. The less oxygen consumed the longer the seal can stay under water. If you went to the emergency room 20 or 30 years ago with an unusual and inappropriately fast heart rate called P.A.T. (T for tachycardia) the doctor would have the nurse bring a basin of ice water to the bedside and he/she would then plunge the patient's face into the water thereby initiating the diving reflex. The heart rate would reflexively slow and return to normal. Nowadays a simple medication given IV generally does the trick but not as dramatic as the former treatment! Thank you seals ... and science!
43
I went to the ER over 40 years ago with a bout of paroxysmal atrial tachycardia. They gave me Valium and told me to go home and take a hot bath.
I like that better than the idea of plunging my face into ice water.
7
The mediation is terrifying and momentarily agonizing. I occasionally suffer from tachycardia and am delighted to dunk my head in ice water! I'm always surprised when it works. Cheaper than a trip to the ER, too.
13
I'd take a bit of fresh, cold water applied externally to any phramaceutical.
2
The spleen acts as a SCUBA tank?! This is one of the coolest things I have heard in a long time.
51
Well ... I guess only the well-spleened will survive if our oceans keep rising.
26
Not necessarily. You could always learn to swim - something entirely different from deep diving.
3
Also the fossil fuel that makes the oceans rise can be used to make synthetic rubber innertubes, so if one is a poor swimmer one can simply float with a glass of global-warming-chilled lemonade and a copy of the Times! (Keep an eye out for the Category 6 storms, though.)
3
Please watch the latest episode of Body Hack on PBS! It's all about the Bajau people and their life on the water. I only hope this attention will not disrupt their lives.
28
Unfortunately commercial fishing, piracy, and conflict in recent decades has resulted in the Bajau abandoning much of their ancestral domain at sea and they have been moving towards being a more land based tribe. In addition, western missionaries have also had a negative effect on their traditions and culture in recent years. Sadly the Bajau and their way of life is slowly disappearing.
2
Fascinating! Thanks, NYT, for supporting and broadcasting pure research like this.
31
Very interesting, and another reason why we should protect our environment. We are specialized to be part of it.
While I was reading this my thoughts kept flashing to my late father. He had webbed toes, which would have been perfect in this water-loving population.
19
It is correct to say that the Bajau have "enlarged" spleens or just larger ones? Enlarged would mean that they started out smaller and their size was increased by an external something -- not a mutation that could be passed on. I think what is meant is that these people are born with larger spleens.
8
Remaking? No exactly what I would call an accurate description of what happens. Evolution does not take an existing person, say myself, and change me. By definition evolution means over successive generations of breeding and survival. More of that fake socialist science to generate click through advertising.
There are a few comments that mention Jean Baptiste Lamarck, and they address your concerns. Lamarck was the guy who postulated that by reaching for the tasty leaves at the top of the tree the giraffe stretched its neck and its giraffelets inherited the stretch. The title of this article does seem to veer disquietingly in that direction. The article itself, however, stays faithful to the idea that first there is an accidental mutation in the DNA, and second the mutation is "selected for" by nature. Nature selects the mutation by killing off critters that don't have it at a faster rate than it kills off creatures that do have it. I suspect that some tender-hearted people who claim they believe in evolution simply to appear educated and liberal don't realize that Darwin ain't pretty, and that they might actually find Genesis more in keeping with their sensibilities. The grim part is that if the big-spleen mutation appeared (at first in the mountains or the desert for all we know) and naturally spread thinly throughout the Asia-Pacific population, it would require the drowning of really a huge number of Bajau divers to concentrate the big-spleen mutation in the Bajau population. Natural history is cruel by my standards, and I don't even like sea cucumbers.
2
At a minimum, I'd think something in you would have to change in order to pass along a somehow "mutated" gene to the next generation. Isn't evolution more of an permanent integration into a population of traits developed by individuals?
I think there's a good chance this is selection coming about through sexual selection. That is, the women prefer deeper diving men. Makes sense in an economy that depends on diving for survival: a man who can dive more successfully can earn more and provide better for his family.
I think it's unlikely there'd be enough dying by diving going on to exert selective pressure towards larger spleens. Presumably most people would start out not having the variant so most people would be dying. That would put a lot of pressure on a population.
It would be interesting to look at it from a cultural perspective to see if mate choice is influenced by diving ability.
65
You got to love it. A change in the sea cucumber market causes evolutionary change.
8
I don't see where this article states that the men are the ones who dive. Perhaps the men prefer deeper diving women? It is interesting from a cultural perspective that you seem to have assumed only men dive.
15
Meg, point taken about Ed Op's assumption, but if you know anything about the Bajau you know the men dive. Your final statement is itself interesting from a cultural perspective.
8
That's impossible. The GOP and every Republican Presidential hopeful for the last decade and the Church and most other religions have proven that evolution simply does not exist. It' so fake the lying science of Darwin was removed from textbooks of those advanced Republican states like Kansas, Kentucky and Mississippi, that as we know, are the bastions of education, research and scientific advancement.
132
All locations destined to become seafloor in the semi-near future, as God intended.
2
The majority of Republicans I know believe in evolution at least as firmly as you do. I don’t know what the majority of Republicans you know believe. Perhaps you should ask him.
Nevertheless, many Republicans deny that evolution has been happening. lronically, many Democrats presume that evolution has stopped.
If God really is watching, he/she may be smiling indulgently at you. If Darwin is watching, he/he may be doing the same. Regarding the subject of human origins and human differences, however, you need not be careful what you wish for. It won’t change anything.
Actually, Ben makes a good, rarely expressed point. Even those of us who've understood evolution from early childhood tend to wander on to connected issues without ever having the epiphany that evolution continues nonstop, and will eventually change everything with which we are familiar into other things, with greater or lesser similarity to what we know today. It's a process, not a cosmic bus stop.
2
I hope scientists the world over do lots of these types of studies (respectfully) with isolated and indigenous populations. Our human biodiversity is fascinating!
39
Very interesting and well written article.
As for a sea based diet, I recall reading indigenous Arctic peoples took in plant products by including the stomach contents of marine mammals in their diets. Evolutionary theory would say, given sufficient time and population pressure, adaptations will occur to the food stuffs available in any given environment.
Compared to Eskimos, the Bajau are blessed with a tropical climate and the lush vegetation seen in the picture of their beach within wading distance of their boats and they have been traders at least since the 1600's. I'll bet you they have access to fresh fruit and tubers (maybe for the picking, digging) and they can trade their sea food for the products of local gardens.
Restrictive diets? Look at out diets of fast foods (e.g.hot dogs, ketchup, fried meats by the pound, topped with bacon and cheese), no veggies unless you count in french fries. Maybe we too will adapt to these junk foods, but it will take several generations of deaths from cardiovascular disease, obesity, diabetes.
12
Another interesting example of natural selection to look for over time.
1
This is a fascinating study.
Natural selection for deep-diving ability would not have been benign. Those with smaller spleens were more likely to starve to death.
7
Interesting to see the NYT speaking frankly about the recent evolutionary adaptations of a human population. Does this mean we're finally ready to quit pretending there's no obvious genetic explanation for (to take a couple easy examples) east African people winning most of our marathons, or Ashkenazi Jews having consistently high IQs?
That kind of pretense is culturally toxic in several ways. This article is a good example of how the science can be done and talked about without the sky falling.
93
We may soon be able to answer questions like yours but for now, there's often too much of a rush to explain any differences as being genetic, and not due to cultural differences. For instance, social attitudes towards academic achievement vary wildly even within this country. Especially these days, when expertise gained through years of study and research, can be disdained as "elitism".
And either argument - genetics or culture - can explain East African runners. Their prodigious abilities might rise from adaptation due to living at high altitudes, or it may be that there is little opportunity for advancement in their own countries and the prize money offered by marathons provides a strong incentive for ambitious, athletic people.
41
It's important to distinguish between physical adaptations, such as the ability of Inuit peoples to synthesize vitamin C (making them immune to scurvy), verses "high IQs" and other forms of presumed mental superiority.
The former is directly based on genes in a demonstrable way. The latter is mainly the result of experience -- at least according to extensive neurological studies which have shown than roughly 99% of the wiring in an adult brain happens after birth in response to experience -- a phenomenon known as "neural plasticity".
Put another way, suggesting that a specific people group has a higher average IQ independently of culture/experience is deeply racist. This pernicious idea literally declares one group of people to be mentally superior to the rest of us at the genetic level, which in turn directly implies that all other people groups are inferior. This idea also indirectly implies that, if some people groups are mentally superior to the human average, then other people groups might be mentally inferior to the average.
In short, it's one thing for science to study minor physical differences between ethnic groups which result from relatively short-term natural selection. It's quite another thing to study, or even suggest, the existence of genetically-based mental/behavioral differences between ethnic groups.
65
Tom is incorrect. There is now near-universal consensus among the relevant scientists that intelligence (aka "IQ" or "G") is heavily heritable. We don't know yet just how much is genetic and how much is environmental, but a pretty common shorthand number among scientists at the moment is ~50/50.
For Tom and all others inclined to disagree, I invite you to browse the scientific literature. A good place to start would be this meta-study published in Nature a couple years ago, which determined that traits of cognition are in fact more heavily gene-determined than traits of skin or bone.
https://www.nature.com/articles/ng.3285
15
It sounds as if the reasoning on this is backwards. The most likely cause for the selection of the genes in question is that the divers who had would be more successful fishing than the normals, so would be more attractive sexual partners.
29
The reasoning is not backward, you are defining evolution. Mate selection (paired with lower odds of death limiting procreation) is the main driver of evolution.
9
Great article!!!
8
So, Carl, how long can these divers stay underwater? And how does that compare with non-islanders?
20
I'm confused. Does the article suggest that the Bajau are genetically passing along the seemingly acquired ability to dive deeper? Or, are those Bajau who happen to have that innate ability more likely to produce offspring and hence, pass along that trait to their children? The former (Lamarckian theory) was, I thought, discredited. The latter would tend to conform more to the generally accepted Darwinian theory of natural selection. Am I wrong? Please discuss.
5
Recent discoveries of "Lamarkian" type adaptations seem to be attributable to to epigenetics -- a heritable shift in the expression of a particular gene caused by the experiences of a parent.
3
The article is suggesting that parents with a greater fitness had more offspring, so normal evolution, not Lamarkian.
1
Spleens yes, but other organs and circumstances need exposure:
Just a few...
Is their lung vital capacity greater?
Are hemoglobins higher- increased oxygen carrying capacity.
Is their blood volume greater?
Do they smoke or engage in other such behaviors?
19
Did diving promote large spleens or were people with large more successful at diving and therefore more likely to dive for a living?
10
If evolution affects the spleen, it also affects the brain. Researchers should be able to measure group differences in brain structure and function. But that's verboten in our toxic, politically correct universities. Chairman Mao would be so proud.
5
Dear Noodles,
Evolutionary pressure on one organ does NOT necessarily affect any other organ, particularly the brain. The clearest example of this is lactose tolerance which developed in northern Europe populations only with the introduction of domesticated cattle perhaps 10,000 years ago, maybe a little bit later. This trait did not change eyes, hair, heart or anything else, just the ability to digest primary milk products in adulthood. As for the difference between brain structure and brain function, perhaps you should do a little more reading.
15
Interesting that they are noting changes in the actual genes. I wonder if there are epigenetic changes as well?
13
Please. Nobody "gains" a mutation. The lifestyle selects out those who don't have it, or can't develop the physical requirements some other way. When you look at a group of people with some physical feature that sets them apart, remember that they are the survivors and everybody else in their lineage died without offspring.
Evolution is the outcome of a lot of death.
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Actually - people do 'gain' mutations.
Natural selection is indeed the 'outcome of a lot of death', but evolution is: mutations + natural selection. Mutations are spontaneously acquired - and then natural selection determines whether or not those mutations are advantageous enough to be passed down.
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"... remember that they are the survivors and everybody else in their lineage died without offspring.
Evolution is the outcome of a lot of death."
Not necessarily. Evolution is the outcome of differential reproduction. A genetic variant may be eliminated from a population because all organisms with it die before they can reproduce--- i.e., your assertion. But others may be eliminated or just reduced because they don't reproduce as successfully as those without the variant, i.e., they don't produce as many descendants, the descendants begin reproducing later in their lives, descendants are adapted to fewer environments, etc.
And yes, organisms do gain mutations.
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For instance, we are selecting for people who want children by the voluntary use of contraceptives by people who don't want children. No extra deaths required.
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What does it mean to eat a diet primarily of seafood? As a stranger to the land do they eat plants? It doesn't sound healthy to have such a restrictive diet. Pass the hot dogs and ketchup please.
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Consider it a marine ketogenic diet.
They also eat different varieties of seaweed.
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My husband and I spent a little time with the Bajau in Sulawesi about 13 years ago. We learned they also trade with land people for veggies and other needs. (Fun fact:They can get “land sick” when on land.) They seemed to be really healthy to me!
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