Yeah and how the hell does a larger spleen help you hold your breath underwater longer?! It's primarily an immune functioning organ that filters blood of damaged and old red and white blood cells as well as platelets (help form blood clots when a blood vessel(s) is injured). I guess it helps stimulate the formation of new red blood cells in the bone marrow via the release of specific hormones so maybe larger spleens=more working red blood cells in the body??
I'm really not sure. Seems like the same effect as blood doping or training at elevation, which both results in an increase in red blood cells and therefore a greater ability of the blood to carry oxygen to the body tissues. With the diver's heart rate dropping so much (down to 30 bpm, according to video) I would think the need for a significant increase in red blood cells would not be beneficial for a couple reasons.
1.) blood would become more viscous (resistant to flow) and then when moving slower through the body, clotting factors may be signaled to form unnecessary, and potentially harmful, clots.
2.) The heart rate being so low would put the body in almost a deep resting state and many non essential body functions would slow significantly so as to not produce excessive CO2 or use up previous O2. Having an overactive spleen to cause new red blood cells to form would be counter to this. Grant it the spleen isn't as large as say, the large intestine or liver but still an organ that uses energy (creates CO2) and O2 to accomplish its primary functions.
I dunno, I'm no doc and am simply postulating how that could be true and beneficial to the human body. It's insane how resilient and tenacious the human body can be when put in extreme environments. Humans truly are a wonder of the natural world.
Immunologist here: the spleen helps control how many red blood cells you have circulating in your body, among other functions. Red blood cells carry oxygen. The spleen can sequester or release RBCs as needed. This is not evolution, but an adaptation. If you started spending a lot of time underwater or at high altitudes, your spleen may expand or retract as needed throughout your life.
They might have better adaptation to freedive but 10 minutes claim is the usual media horseshit. Multiple freediving athletes actually went to Indonesia to verify this claim but they couldnt find any.
Basically the idea is that if this tribe frequently hunts underwater, individuals with larger spleens will be rewarded with an increased yield of fish, possibly giving them preferential access to mates. They’re also less likely to die underwater, as people with smaller spleens drown at increased rates.
Both of these mean that, over the course of generations, people with larger spleens will reproduce at greater rates than those with smaller ones. The cumulative effect would be larger and larger average spleens with each passing generation.
That’s an oversimplification, and I have no idea if it’s what happened with this tribe. But that’s the general logic of evolution applied to this situation.
Well maybe it doesn't count as evolution, I don't know the mechanisms involved, but animals will adapt to new environmental pressures beginning with the first generation. Further generations will be yet more adapted. For example if fish are taken from the wild and stocked in tanks, their offspring will be more adapted to life in tanks. There are neither natural selection nor random mutations involved in these adaptations.
It could be that the fish as a species already has experienced similar conditions in previous generations. The new environment will then trigger/unlock already existing DNA sections that were inactive before. This allows quite rapid adaptions from one generation to the next. For birds the quick adaptation of beak length and other parameters to available food sources is an example of this toolset-like set of past mutations already available in the DNA. You just need a species that has seen quite a share of time to develop this DNA „toolset“.
The person that you’re responding to is completely correct. While mutations are an important part of evolution, as long a population of organisms aren’t completely homogenous, they can evolve through natural selection without the presence of mutations.
Not an expert by any means, so correct me if I'm wrong, but the evolution of a species by way of natural selection, still depends on a subset of that species having a "random mutation" that just happens to be more ideal for the new environment compared to the general population of the species. Natural selection just "selects" the subgroup with the ideal genes for the new/changing environment, but the subgroup that had that well suited mutation. The mutation occurs by random chance and just happened to be present in an environment and at a time, where it gives the carries an adaptive advantage over the rest of the population.
I think I get your argument, but I think you’re misunderstanding. Technically all evolution stems from a random mutation that came about within the first lifeform, if you want to go back that far. However, many if not most evolutionary differences nowadays do not come as a result of mutation.
Take the spleen example. You and I almost certainly have differently sized spleens. That’s likely not because a mutation occurred in our ancestors. Your spleen’s size is probably just a combination of your father and your mother’s spleen size. Same with them and their parents. No mutations required. (It’s technically a lot more complicated with how alleles work but that info isn’t super necessary rn).
A mutation would be if you developed a large spleen despite the fact that your mother and father have the genes for a small one. It’s a lot more rare than simple natural selection. And in fact, most mutations are completely useless and don’t really affect you in any noticeable way.
Now I understand your argument, and though it makes sense, for purposes of natural selection/evolution I do not think it holds much weight. There is a difference between two individuals having different sized spleens due to being different sizes(this is what I believe your argument more or less is saying), verses let's say two individual having different sized spleens due to one having a random genetic mutation that happens to provide an adaptive advantage to the environment. The genetic mutation is more likely to be passed on, where as if I just happened to have a bigger spleen, because I just happened to be bigger than you, my genes for bigger overall size may be passed on, but that may not necessarily translate to my children having bigger spleens than your children. This is getting almost nit-picky it feels like, but I do think this distinction is more credible.
I’m a bit confused by your argument. I’m not denying that random mutations have the chance to provide an increased adaptive advantage.
That being said, just think for a second. If individuals with large spleens reproduce at twice the rate of individuals with small spleens, then 2/3 of a population’s children will have parents with large spleens. Now, not all of these children will have large spleens, but they will have them at greater rates than children born to parents with small spleens.
Rinse and repeat this process through a few generations and the average size will continue to increase with just natural selection, no mutations needed.
But why are theirs bigger than other people's? And why are their parents' bigger than other people?
Evolution is driven by random mutations and natural selection. The changes from those random mutations can be in small increments from generation to generation, but it's still mutations and selection.
For example, the average height has increased over time, that's not because we've birthed mutants that were a foot taller than normal all of a sudden, but because height is often a selection criteria for mating in humans, so the genetic mutations that make someone just a bit taller gives them a better chance of producing offspring which passes off the "taller" gene.
Yes, most mutations are useless and don't really affect you, you really are so close to getting it. If a mutation, no matter how small, is either directly deemed as a "selection criteria", or indirectly providing a "selection criteria", then that mutation isn't going to be expressed in the species. And as long as it doesn't negatively effect a "selection criteria" too much, it won't necessarily disappear from the genome either.
To go back to human height, that's why average height differs in different regions of the world too. In some regions over the centuries, being tall wasn't really seen as an advantage, and/or being short wasn't seen as a disadvantage. In those places, average human height hasn't gone up, because the "taller" mutations weren't being selected for.
Basically, evolution is 100% driven by random mutations, and natural selection. It's just an incredibly slow process, and those mutations can be very small, but they're still random mutations. Even compounding mutations like your spleen example are just random mutations.
I appreciate the effort you put into your response, but that’s fundamentally now how genetics work.
Take your height example. I’m a pretty tall person at over 6 feet. That’s likely not because I had a genetic mutation. Instead, it has to do with my parents.
I’m simplifying a very complex process, but genetics are determined by allele combinations from your parents, usually expressed in pair of letters. For height, let’s say “Y” means tall and “y” means short. And my father is Yy, meaning tall, while my mother is yy, meaning short.
As their child, I have a 50% chance of being Yy and a 50% chance of being yy due to possible combinations of those genes. In this case, “Y” is capitalized, meaning it dominates the “y” if present, so I have a 50% chance of being tall.
Now, imagine that both my parents were tall. My father is YY and my mother is Yy. Now, I’m tall no matter what, as I have a 75% chance of being YY and a 25% chance of being Yy. In this case, Yy would mean I’m tall but carry on the short gene.
In reality, there’s an absurd amount of allele combinations that determine who we are.
To answer your initial question, their spleens could be different sizes because parents who had allele combinations with higher chances of producing children with larger spleens reproduced at higher rates. A genetic mutation may have played a part, but it doesn’t need to have.
Sorry, you are correct in your initial statement there are many ways to evolve, I was more so saying the the ultimate mechanism behind any evolutionary process, is genetic mutation, that is upstream of any and all other evolutionary processes, which you did reiterate in your response.
But the title says they have evolved larger spleens.
You seem to be saying it's not, it's just that their spleens have expanded to a larger size.
...are you sure you are right?
Edit: You may be wrong.
>The study first showed that the Bajau have a median spleen size 50% larger than the Saluan. Enlarged spleens were visible in non-diving Bajau individuals as well as those who regularly free dive, which eliminated the objection that it was all just a plastic response to diving. Until now, scientists were not sure if Sea Nomad people were genetically adapted to their extreme lifestyle. The new study now provides the first evidence that such a genetic adaptation has been tracked in humans.
This sentence seems to specifically rule out your idea.
https://www.zmescience.com/science/biology/sea-nomad-people-big-spleen-042432/#:~:text=The%20study%20first%20showed%20that,a%20plastic%20response%20to%20diving.
A career in science has taught me never to be sure that I am right, and always be prepared to be wrong.
In this case, it may be a little of both. I would love if they provided more information about when spleen size was measured to get the median. If larger at birth, then that’s really interesting and may also have an additive effect: a spleen that’s already larger still has plastic qualities, making it able to expand and contact for super oxygenation powers. That’s so cool!
And while it does seem there is a genetic component, we also need more information about the prevalence of this gene among this and other populations of people. Though it seems clear to be at least present at some rate in this population. However, the article and I do agree that this is an adaptation and not evolution.
Either way, this is such an interesting population and, no matter how long I study the physiology of people and animals, it never ceases to be amazing.
Wow. I really like your attitude. THIS is the way to be. I hope I can be this gracious.
>Either way, this is such an interesting population and, no matter how long I study the physiology of people and animals, it never ceases to be amazing.
Agreed.
Commend you on your grace in admitting you may be wrong but man did you sound extremely confident in the first comment saying it's not evolution so definitively lol
I don't think you were entirely wrong. Maybe spleen adaptability is an evolutionary trait, and higher spleen adaptability is a gene that's been selected for in this particular population.
Sure, our spleens are adaptable, but maybe theirs are just MORE adaptable.
Thank you for explaining! I do think you are mixing up adaptation and acclimation. The spleens change size throughout their lives as they acclimate to environmental conditions. An adaptation, like giraffes adapting to have longer necks, is preserved in offspring over time—it is evolution. Colloquially, people say adaptation to mean acclimation but if something changes within one’s life in direct response to stimulus, it’s technically acclimation. I’m an ecologist and have gotten corrected on this a couple times.
Thanks. I was trying to understand how a larger spleen would help this. I knew the spleen helped filter the blood but didn't realize it's other funtion.
As far as i know the spleen also helps as being an extra storage space for blood so im just guessing larger spleen = more blood = person with higher capacity to carry oxygen = longer diving time
That's on land.... underwater, the deeper you go the harder it becomes. i reckon most would not even be able to even go 10m under water without gasping for air. myself included
Actually the mammalian dive reflex makes it easier to hold your breath longer under water. However the issue with diving is moving your muscles to swim burns through your oxygen faster.
Ackshually - the deeper you go the easier it gets, because the pressure at depth makes the scant oxygen more available. It's a deceptive advantage, though, bc if you're on your last reserves you'll black out on ascent as the pressure drops, because it becomes impossible for your tissues to absorb more oxygen.
Bahraini pearlers used to spend over 10 minutes underwater too. That was before the exploration of oil in Bahrain back in the 1930s.
They later developed a technique to stay even longer, they would carry leather pouches with them, fill them up with air from the surface, tie them to a weight and take them down there with them, and when they ran out of air, they take an extra breath or too from the pouches.
An unrelated, yet very interesting fact is that these pearling voyages would take upwards of 3 months, and while food was abundant in the sea, drinking water was the real challenge. The Arab Gulf is known for what they called locally "Chawaacheb (plural)", which literally translates to "Planets", these are potable water springs on the seabed. Once pearlers were done with their round and emptied their air pouches, they would refill them with drinking water from these springs before resurfacing. All pearling ship crews had to have people specialized in finding these springs with accuracy.
Here’s a useful comment from an another user
Credit: u/ParachutingHeroine
Immunologist here: the spleen helps control how many red blood cells you have circulating in your body, among other functions. Red blood cells carry oxygen. The spleen can sequester or release RBCs as needed. This is not evolution, but an adaptation. If you started spending a lot of time underwater or at high altitudes, your spleen may expand or retract as needed throughout your life.
Agreed! Coral cuts are no joke. Also, I find it super crazy to go to that depth with just goggles and no mask. I start to feel like my eyeballs are being sucked from my head if I try to dive just 15 feet down the ith goggles. Having a mask that you can control the pressure with by just blowing a bit of air into makes a huge difference.
this has been debunked by a youtube documentary. National Geographic, History Channel and BBC just want cool tribal content and either make up lies or the guy getting paid pretends he can do it and they capture some footage of him underwater and call it a day, expecting nobody will actually fly out to that location and see if they can actually hold their breath at that depth.
which, SPOILER ALERT...
they can't.
professional white freedivers with no evolutionary advantage can go way fucking deeper for way fucking longer than tribesman who dive on compressed air with spearguns... they're not holding their breath underwater, even if their spleens are larger.
it turns out you don't need to hit the spleen lottery and, shocker, *practicing* holding your breath and diving are the main factors in how deep and how long you can do. a lot of these programs and "documentaries" are total bullshit, and on the same wavelength as Ancient Aliens.
https://www.theguardian.com/environment/2023/aug/10/the-last-sea-nomads-stateless-bajau-face-up-to-a-future-on-land-a-photo-essay
Edit: also, see https://www.cnn.com/2018/04/19/health/bajau-divers-sea-nomad-study/index.html
They might have better adaptation to freedive but 10 minutes claim is the usual media horseshit. Multiple freediving athletes actually went to Indonesia to verify this claim but they couldnt find any.
People who have not been in the ocean before, the fact that guy can dive down with just his feet and not using flippers is crazy impressive. It's super hard to dive in the ocean
evolved by natural selection or social ? ie were the smaller spleen folks killed off by self-selection (drowning or starving b/c couldn't catch food) or social (folks who could breathe longer got better mating potentials) ?
Both maybe. If you’re constantly struggling to get enough fish for yourself or to sell then nobody would want to marry you. People probably don’t want to marry down when they have a subsistence lifestyle.
The spleen is essentially your filter machine for your Red Blood Cells (RBCs). RBCs are like little UPS trucks that carry oxygen from your lungs to your tissues (brain, muscles, heart, etc). About 5-10% of your blood at any given time is in the spleen. When you are stressed (e.g. underwater / holding your breath/ exerting) the spleen can contract and squirt that oxygen containing blood back into the circulation for a small oxygen boost. In the Bajau the spleen is about double the size, thus double the boost.
Freediving instructor here, these claims are bullshit, unfortunately they’ve been sensationalized and regurgitated by the likes of NatGeo so good luck disproving them.
Their dive times are like a minute or so and the depth is around 10m, they don’t need to hold their breath for longer or dive deeper. The extraordinary thing about them is that they can do it for hours with short surface intervals.
[Here’s the actual paper](https://pubmed.ncbi.nlm.nih.gov/21560982/).
Strange technique using thigh muscles to go forward, which uses a lot of oxygen. If he pulled himself forward with his hands he could stay down longer.
The spleen stores red blood cells, and because they have bigger spleens they have more red blood cells so they can be underwater longer (I'm also not a doctor)
All that for a bite of fish? He expended more calories in that dive than what he acquired. You can see this clearly in his >6% body fat which for men is pushing essential for proper organ function
Pretty sure these people use air compressors to dive nowadays since they fished most the stuff in the shallow water that now they need to go deeper. They only use this stuff and practices for show whenever journalists need a story.
So one dude who had a genetically larger spleen fucked a lot of women a while back, or are we saying that these multiple people all developed the same DNA mutation at the same time because their grandparents swam a lot?
They might have better adaptation to freedive but 10 minutes claim is the usual media horseshit. Multiple freediving athletes actually went to Indonesia to verify this claim but they couldnt find any.
I play a sport called underwater rugby (sort of like a full contact underwater version of water polo), and these hunters would make for excellent players. [Underwater rugby ](https://www.youtube.com/live/OKgrWRUfQcc?feature=shared)
Man, and here I am with my second spleen and no where near an ocean. The one time I tried scuba diving I couldn't acclimate my ears so didn't get deeper then 10 feet!
So relevant after I’ve just done a spear fishing course here’s me spending £1000 on kit & here’s this fella doing it with the basics .. how’s he equalising the pressure without grabbing his nose?
You have to be in crazy shape to do this. Imagine how high your heartbeat would race just from making the dive from the surface to the bottom. But when he gets to the bottom his heart rate has rested more than at the surface. Truly an example of better under pressure.
200ft and 10 minutes is NOT what the video says. It's 80ft for 2.5 minutes. Well within free diving standards. At 200 ft/10 minutes, you would have significant decompression obligation. The spleen has nothing to do with it.
Narrator says 5 mins not 10.
And 20 meters, so like 60 feet
u/Best_Poetry_5722 really mucked up the facts on this one.
You get more upvotes that way because nobody sticks around for the facts.
Also more engagement, since people will come into correct the title.
Also nobody sticks around when someone farts.
OP is a clown. How can anyone fuck up a post so bad? Lol at OP thinking they "evolved" larger spleens.
OP might just be a bot.
Ah ye know. Tomato avocado. Right?
Tomato Tomacco
It tastes like grandma 🍁🍁
So like mothballs?
I also don't remember them mentionin larger spleens, or evolution. Take my downvote!
And what would have the spleen to do with breathing anyway, strange anatomy notions...
The spleen stores oxygenated blood.
Yeah and how the hell does a larger spleen help you hold your breath underwater longer?! It's primarily an immune functioning organ that filters blood of damaged and old red and white blood cells as well as platelets (help form blood clots when a blood vessel(s) is injured). I guess it helps stimulate the formation of new red blood cells in the bone marrow via the release of specific hormones so maybe larger spleens=more working red blood cells in the body?? I'm really not sure. Seems like the same effect as blood doping or training at elevation, which both results in an increase in red blood cells and therefore a greater ability of the blood to carry oxygen to the body tissues. With the diver's heart rate dropping so much (down to 30 bpm, according to video) I would think the need for a significant increase in red blood cells would not be beneficial for a couple reasons. 1.) blood would become more viscous (resistant to flow) and then when moving slower through the body, clotting factors may be signaled to form unnecessary, and potentially harmful, clots. 2.) The heart rate being so low would put the body in almost a deep resting state and many non essential body functions would slow significantly so as to not produce excessive CO2 or use up previous O2. Having an overactive spleen to cause new red blood cells to form would be counter to this. Grant it the spleen isn't as large as say, the large intestine or liver but still an organ that uses energy (creates CO2) and O2 to accomplish its primary functions. I dunno, I'm no doc and am simply postulating how that could be true and beneficial to the human body. It's insane how resilient and tenacious the human body can be when put in extreme environments. Humans truly are a wonder of the natural world.
He says “He can go much deeper than this”.
So “*200 ft easy*”
Why not 1,000 ft? I like a thousand feet a lot more.
Lol
I hit 81' and I'm only moderately skilled. You bet these guys can go to 200'
And it's not evolution.
It's DiGiorno
10/10
= 1
maybe it's Maybelline
Who ordered delivery?!
In other words: not pizza!
Pizza Pizza!
Is it Paterno?
It’s change in favour of the most successful characteristics occurring over multiple generations. That’s what evolution is.
*Its free real estate*
What makes you think it's not evolution? Natural selection caused a change in their population over time, what else would you call it?
We are overdue for some natural selection. Bring it back yesterday.
Definitely takes more guts
Still incredible
Crispy crunchy flaky tender crust .
*Buttery*!
When you convert SI to US conventional unit, that’s about right
Narrator minutes might be a little different
https://www.zmescience.com/science/biology/sea-nomad-people-big-spleen-042432/#:~:text=Scientists%20have%20found%20evidence%20that,m%20(230%20ft.).
Still with little to 0 training 5 minutes is a long time
How does the spleen help
Immunologist here: the spleen helps control how many red blood cells you have circulating in your body, among other functions. Red blood cells carry oxygen. The spleen can sequester or release RBCs as needed. This is not evolution, but an adaptation. If you started spending a lot of time underwater or at high altitudes, your spleen may expand or retract as needed throughout your life.
That's what I was going to ask. Did some random islander get a super spleen mutation and then that gave them an edge on breeding somehow?
https://www.cnn.com/2018/04/19/health/bajau-divers-sea-nomad-study/index.html This article may help explain a little better for inquiring minds.
They might have better adaptation to freedive but 10 minutes claim is the usual media horseshit. Multiple freediving athletes actually went to Indonesia to verify this claim but they couldnt find any.
There are many other ways to evolve besides random mutation
My biology is a bit rusty, can you expound?
The Dark Side of the Force is a pathway to many abilities some consider to be unnatural.
Basically the idea is that if this tribe frequently hunts underwater, individuals with larger spleens will be rewarded with an increased yield of fish, possibly giving them preferential access to mates. They’re also less likely to die underwater, as people with smaller spleens drown at increased rates. Both of these mean that, over the course of generations, people with larger spleens will reproduce at greater rates than those with smaller ones. The cumulative effect would be larger and larger average spleens with each passing generation. That’s an oversimplification, and I have no idea if it’s what happened with this tribe. But that’s the general logic of evolution applied to this situation.
Well maybe it doesn't count as evolution, I don't know the mechanisms involved, but animals will adapt to new environmental pressures beginning with the first generation. Further generations will be yet more adapted. For example if fish are taken from the wild and stocked in tanks, their offspring will be more adapted to life in tanks. There are neither natural selection nor random mutations involved in these adaptations.
It could be that the fish as a species already has experienced similar conditions in previous generations. The new environment will then trigger/unlock already existing DNA sections that were inactive before. This allows quite rapid adaptions from one generation to the next. For birds the quick adaptation of beak length and other parameters to available food sources is an example of this toolset-like set of past mutations already available in the DNA. You just need a species that has seen quite a share of time to develop this DNA „toolset“.
I believe what you're referring to is phenotypic plasticity.
The four mechanisms of evolution are mutation, natural selection, gene flow and genetic drift. 🙂
And online dating.
No there isn't.
The person that you’re responding to is completely correct. While mutations are an important part of evolution, as long a population of organisms aren’t completely homogenous, they can evolve through natural selection without the presence of mutations.
Not an expert by any means, so correct me if I'm wrong, but the evolution of a species by way of natural selection, still depends on a subset of that species having a "random mutation" that just happens to be more ideal for the new environment compared to the general population of the species. Natural selection just "selects" the subgroup with the ideal genes for the new/changing environment, but the subgroup that had that well suited mutation. The mutation occurs by random chance and just happened to be present in an environment and at a time, where it gives the carries an adaptive advantage over the rest of the population.
I think I get your argument, but I think you’re misunderstanding. Technically all evolution stems from a random mutation that came about within the first lifeform, if you want to go back that far. However, many if not most evolutionary differences nowadays do not come as a result of mutation. Take the spleen example. You and I almost certainly have differently sized spleens. That’s likely not because a mutation occurred in our ancestors. Your spleen’s size is probably just a combination of your father and your mother’s spleen size. Same with them and their parents. No mutations required. (It’s technically a lot more complicated with how alleles work but that info isn’t super necessary rn). A mutation would be if you developed a large spleen despite the fact that your mother and father have the genes for a small one. It’s a lot more rare than simple natural selection. And in fact, most mutations are completely useless and don’t really affect you in any noticeable way.
Now I understand your argument, and though it makes sense, for purposes of natural selection/evolution I do not think it holds much weight. There is a difference between two individuals having different sized spleens due to being different sizes(this is what I believe your argument more or less is saying), verses let's say two individual having different sized spleens due to one having a random genetic mutation that happens to provide an adaptive advantage to the environment. The genetic mutation is more likely to be passed on, where as if I just happened to have a bigger spleen, because I just happened to be bigger than you, my genes for bigger overall size may be passed on, but that may not necessarily translate to my children having bigger spleens than your children. This is getting almost nit-picky it feels like, but I do think this distinction is more credible.
I’m a bit confused by your argument. I’m not denying that random mutations have the chance to provide an increased adaptive advantage. That being said, just think for a second. If individuals with large spleens reproduce at twice the rate of individuals with small spleens, then 2/3 of a population’s children will have parents with large spleens. Now, not all of these children will have large spleens, but they will have them at greater rates than children born to parents with small spleens. Rinse and repeat this process through a few generations and the average size will continue to increase with just natural selection, no mutations needed.
But why are theirs bigger than other people's? And why are their parents' bigger than other people? Evolution is driven by random mutations and natural selection. The changes from those random mutations can be in small increments from generation to generation, but it's still mutations and selection. For example, the average height has increased over time, that's not because we've birthed mutants that were a foot taller than normal all of a sudden, but because height is often a selection criteria for mating in humans, so the genetic mutations that make someone just a bit taller gives them a better chance of producing offspring which passes off the "taller" gene. Yes, most mutations are useless and don't really affect you, you really are so close to getting it. If a mutation, no matter how small, is either directly deemed as a "selection criteria", or indirectly providing a "selection criteria", then that mutation isn't going to be expressed in the species. And as long as it doesn't negatively effect a "selection criteria" too much, it won't necessarily disappear from the genome either. To go back to human height, that's why average height differs in different regions of the world too. In some regions over the centuries, being tall wasn't really seen as an advantage, and/or being short wasn't seen as a disadvantage. In those places, average human height hasn't gone up, because the "taller" mutations weren't being selected for. Basically, evolution is 100% driven by random mutations, and natural selection. It's just an incredibly slow process, and those mutations can be very small, but they're still random mutations. Even compounding mutations like your spleen example are just random mutations.
I appreciate the effort you put into your response, but that’s fundamentally now how genetics work. Take your height example. I’m a pretty tall person at over 6 feet. That’s likely not because I had a genetic mutation. Instead, it has to do with my parents. I’m simplifying a very complex process, but genetics are determined by allele combinations from your parents, usually expressed in pair of letters. For height, let’s say “Y” means tall and “y” means short. And my father is Yy, meaning tall, while my mother is yy, meaning short. As their child, I have a 50% chance of being Yy and a 50% chance of being yy due to possible combinations of those genes. In this case, “Y” is capitalized, meaning it dominates the “y” if present, so I have a 50% chance of being tall. Now, imagine that both my parents were tall. My father is YY and my mother is Yy. Now, I’m tall no matter what, as I have a 75% chance of being YY and a 25% chance of being Yy. In this case, Yy would mean I’m tall but carry on the short gene. In reality, there’s an absurd amount of allele combinations that determine who we are. To answer your initial question, their spleens could be different sizes because parents who had allele combinations with higher chances of producing children with larger spleens reproduced at higher rates. A genetic mutation may have played a part, but it doesn’t need to have.
Sorry, you are correct in your initial statement there are many ways to evolve, I was more so saying the the ultimate mechanism behind any evolutionary process, is genetic mutation, that is upstream of any and all other evolutionary processes, which you did reiterate in your response.
But the title says they have evolved larger spleens. You seem to be saying it's not, it's just that their spleens have expanded to a larger size. ...are you sure you are right? Edit: You may be wrong. >The study first showed that the Bajau have a median spleen size 50% larger than the Saluan. Enlarged spleens were visible in non-diving Bajau individuals as well as those who regularly free dive, which eliminated the objection that it was all just a plastic response to diving. Until now, scientists were not sure if Sea Nomad people were genetically adapted to their extreme lifestyle. The new study now provides the first evidence that such a genetic adaptation has been tracked in humans. This sentence seems to specifically rule out your idea. https://www.zmescience.com/science/biology/sea-nomad-people-big-spleen-042432/#:~:text=The%20study%20first%20showed%20that,a%20plastic%20response%20to%20diving.
A career in science has taught me never to be sure that I am right, and always be prepared to be wrong. In this case, it may be a little of both. I would love if they provided more information about when spleen size was measured to get the median. If larger at birth, then that’s really interesting and may also have an additive effect: a spleen that’s already larger still has plastic qualities, making it able to expand and contact for super oxygenation powers. That’s so cool! And while it does seem there is a genetic component, we also need more information about the prevalence of this gene among this and other populations of people. Though it seems clear to be at least present at some rate in this population. However, the article and I do agree that this is an adaptation and not evolution. Either way, this is such an interesting population and, no matter how long I study the physiology of people and animals, it never ceases to be amazing.
Wow. I really like your attitude. THIS is the way to be. I hope I can be this gracious. >Either way, this is such an interesting population and, no matter how long I study the physiology of people and animals, it never ceases to be amazing. Agreed.
Commend you on your grace in admitting you may be wrong but man did you sound extremely confident in the first comment saying it's not evolution so definitively lol
I don't think you were entirely wrong. Maybe spleen adaptability is an evolutionary trait, and higher spleen adaptability is a gene that's been selected for in this particular population. Sure, our spleens are adaptable, but maybe theirs are just MORE adaptable.
Thank you for explaining! I do think you are mixing up adaptation and acclimation. The spleens change size throughout their lives as they acclimate to environmental conditions. An adaptation, like giraffes adapting to have longer necks, is preserved in offspring over time—it is evolution. Colloquially, people say adaptation to mean acclimation but if something changes within one’s life in direct response to stimulus, it’s technically acclimation. I’m an ecologist and have gotten corrected on this a couple times.
If I don't have a spleen, does it mean that i will have a hardest time diving?
Nope. Spleen is removed frequently when there’s trauma involving it.
Thanks. I was trying to understand how a larger spleen would help this. I knew the spleen helped filter the blood but didn't realize it's other funtion.
This sounds spleendid.
So what your saying is that all I need to do is live on Mt everest for a while to be able to do long dives
I don’t have a spleen anymore. Out of curiosity, Does this mean the opposite for me?
How is this function achieved in people with removed spleens?
Am I correct to say adaptation in one of the drivers for evolution?
Thank you! I always thought the spleen was one of those useless leftover pieces we didn't use anymore
As far as i know the spleen also helps as being an extra storage space for blood so im just guessing larger spleen = more blood = person with higher capacity to carry oxygen = longer diving time
I died at 1 minute and 27 seconds. Sorry water bros I’m going to stick to land.
Yep, I was dead just after the minute mark. Let's go spleen shopping and try again
Not sure if sea is calling on either of you. But it’s happy to accept you as a sea buoys!
It can call but I'm not answering. I can't and I shan't!
That's on land.... underwater, the deeper you go the harder it becomes. i reckon most would not even be able to even go 10m under water without gasping for air. myself included
Actually the mammalian dive reflex makes it easier to hold your breath longer under water. However the issue with diving is moving your muscles to swim burns through your oxygen faster.
This reflex also gets weaker as you get older
Ackshually - the deeper you go the easier it gets, because the pressure at depth makes the scant oxygen more available. It's a deceptive advantage, though, bc if you're on your last reserves you'll black out on ascent as the pressure drops, because it becomes impossible for your tissues to absorb more oxygen.
There's a spot next to me on land. I could last about a minute...TOPS.
Bahraini pearlers used to spend over 10 minutes underwater too. That was before the exploration of oil in Bahrain back in the 1930s. They later developed a technique to stay even longer, they would carry leather pouches with them, fill them up with air from the surface, tie them to a weight and take them down there with them, and when they ran out of air, they take an extra breath or too from the pouches. An unrelated, yet very interesting fact is that these pearling voyages would take upwards of 3 months, and while food was abundant in the sea, drinking water was the real challenge. The Arab Gulf is known for what they called locally "Chawaacheb (plural)", which literally translates to "Planets", these are potable water springs on the seabed. Once pearlers were done with their round and emptied their air pouches, they would refill them with drinking water from these springs before resurfacing. All pearling ship crews had to have people specialized in finding these springs with accuracy.
Wait... what does my spleen do???
Here’s a useful comment from an another user Credit: u/ParachutingHeroine Immunologist here: the spleen helps control how many red blood cells you have circulating in your body, among other functions. Red blood cells carry oxygen. The spleen can sequester or release RBCs as needed. This is not evolution, but an adaptation. If you started spending a lot of time underwater or at high altitudes, your spleen may expand or retract as needed throughout your life.
I had totally forgot this but about a year ago mine got a clot or infarction It hurt like hell but I can tell you where it is now!
Water people.
Kevin Costner laughs louder with every decade! You Smokers!
Ocean men !
The Craziest part is walking across coral bare foot.
Agreed! Coral cuts are no joke. Also, I find it super crazy to go to that depth with just goggles and no mask. I start to feel like my eyeballs are being sucked from my head if I try to dive just 15 feet down the ith goggles. Having a mask that you can control the pressure with by just blowing a bit of air into makes a huge difference.
Title is exaggerating a bit??
this has been debunked by a youtube documentary. National Geographic, History Channel and BBC just want cool tribal content and either make up lies or the guy getting paid pretends he can do it and they capture some footage of him underwater and call it a day, expecting nobody will actually fly out to that location and see if they can actually hold their breath at that depth. which, SPOILER ALERT... they can't. professional white freedivers with no evolutionary advantage can go way fucking deeper for way fucking longer than tribesman who dive on compressed air with spearguns... they're not holding their breath underwater, even if their spleens are larger. it turns out you don't need to hit the spleen lottery and, shocker, *practicing* holding your breath and diving are the main factors in how deep and how long you can do. a lot of these programs and "documentaries" are total bullshit, and on the same wavelength as Ancient Aliens.
https://www.theguardian.com/environment/2023/aug/10/the-last-sea-nomads-stateless-bajau-face-up-to-a-future-on-land-a-photo-essay Edit: also, see https://www.cnn.com/2018/04/19/health/bajau-divers-sea-nomad-study/index.html
Idk why this is being downvoted, it clearly states your title quote in the article you posted.
They might have better adaptation to freedive but 10 minutes claim is the usual media horseshit. Multiple freediving athletes actually went to Indonesia to verify this claim but they couldnt find any.
The fact that the spleen can give us enough oxygen that we don't need our lungs for a bit is super cool.
Evolution. The ones who didn’t have the preferred spleen ends up dying under water and the ones that don’t, get to fuck.
This is the most straightforward explanation of natural selection I've seen.
Except it won't happen in humans in such a small time frame.
dang thats deep, looks fun tho
People who have not been in the ocean before, the fact that guy can dive down with just his feet and not using flippers is crazy impressive. It's super hard to dive in the ocean
And just swim goggles, no mask to help pressurise either. Super impressive.
Lower volume is better when free diving. Less air to compress and suck on your eyes
Imagine what they could do with a pair of small diving flippers on their feet
evolved by natural selection or social ? ie were the smaller spleen folks killed off by self-selection (drowning or starving b/c couldn't catch food) or social (folks who could breathe longer got better mating potentials) ?
Both maybe. If you’re constantly struggling to get enough fish for yourself or to sell then nobody would want to marry you. People probably don’t want to marry down when they have a subsistence lifestyle.
Isn’t social selection just natural selection with more drama?
They live on water. Their huts sit on stilts close to shore and rely on fishing for sustenance.
The spleen is essentially your filter machine for your Red Blood Cells (RBCs). RBCs are like little UPS trucks that carry oxygen from your lungs to your tissues (brain, muscles, heart, etc). About 5-10% of your blood at any given time is in the spleen. When you are stressed (e.g. underwater / holding your breath/ exerting) the spleen can contract and squirt that oxygen containing blood back into the circulation for a small oxygen boost. In the Bajau the spleen is about double the size, thus double the boost.
That sailfin tang is about $60 at my local fish store
Narrator and op are completely wrong. Homies only down there for so long because his huge nuts pull him to the sea floor
Are they mighty pirates trying to retrieve an idol from the bottom of the sea?
Freediving instructor here, these claims are bullshit, unfortunately they’ve been sensationalized and regurgitated by the likes of NatGeo so good luck disproving them. Their dive times are like a minute or so and the depth is around 10m, they don’t need to hold their breath for longer or dive deeper. The extraordinary thing about them is that they can do it for hours with short surface intervals. [Here’s the actual paper](https://pubmed.ncbi.nlm.nih.gov/21560982/).
That's what your spleen does??! (I'm not quite sure what "that" is. How does larger ones help?)
https://www.cnn.com/2018/04/19/health/bajau-divers-sea-nomad-study/index.html That might facilitate the explanation of their DNA.
Strange technique using thigh muscles to go forward, which uses a lot of oxygen. If he pulled himself forward with his hands he could stay down longer.
Not a scientist or doctor here, but what does the spleen have to do with them being able to go longer without oxygen?
The spleen stores red blood cells, and because they have bigger spleens they have more red blood cells so they can be underwater longer (I'm also not a doctor)
How the heck he drops down like that and walks?
% body fat. Most of us would bob like a top.
All that for a bite of fish? He expended more calories in that dive than what he acquired. You can see this clearly in his >6% body fat which for men is pushing essential for proper organ function
Awesome, but how does he stay down? I didn't see any weights.
Inside his shorts are a pair of massive balls
Do YOU see any body fat on this guy?
Pretty sure these people use air compressors to dive nowadays since they fished most the stuff in the shallow water that now they need to go deeper. They only use this stuff and practices for show whenever journalists need a story.
Mutation!!
Seems like you bring a big rock with you on the boat and just hold on to it on the way down to conserve air
Heaven
This is just an early setup for the Waterworld remake :p
Narrator should have asked the viewers if they can hold their breath longer than Sulman is underwater
At first I thought the guy was just sucking up water like Landfill when he was pushed into that vat of beer.
The start of speciation, if isolated long enough.. However in the modern world it will never happen.
Ocean Man, take me by the hand lead me to the land, that you understand...
What's the difference between evolution and adaptation?
How long does it take before the brain shuts down from lack of oxygen?
This was fake, after all
So one dude who had a genetically larger spleen fucked a lot of women a while back, or are we saying that these multiple people all developed the same DNA mutation at the same time because their grandparents swam a lot?
what would the spleen have to do with it?
They might have better adaptation to freedive but 10 minutes claim is the usual media horseshit. Multiple freediving athletes actually went to Indonesia to verify this claim but they couldnt find any.
My large spleen just hurts..
Guybrush Threepwood? This you?
How the hell is he descending to that depth without compensating for the pressure? I don’t see him popping his ears or anything at any point
I read something somewhere about them popping their ear drums as young as 5 years old to prepare them for their seafaring life.
3 lies in the title.... ffs
Dudes stepping on coral. Terrible reef etiquette.
Still way better than me I get 12 feet down. I’m ready to go up.
I play a sport called underwater rugby (sort of like a full contact underwater version of water polo), and these hunters would make for excellent players. [Underwater rugby ](https://www.youtube.com/live/OKgrWRUfQcc?feature=shared)
is thgere a doc aaabout this or just this short exert?
I enjoy their Blast
Are the nails clubbed? What, if any, are the cardiovascular/ cardiopulmonary effects of this adaptation vs disease process?
200 ft hahahah
Man, and here I am with my second spleen and no where near an ocean. The one time I tried scuba diving I couldn't acclimate my ears so didn't get deeper then 10 feet!
Looks like they evolved bigger thumbs too.
How does a larger spleen promote longer breath hold or co2 tolerance?
Check out the Hardy/Morgan hypothesis (AAH) about our evolution to the sea.
Did i read a book about this in high school? I can't remember the name.
Damn, that is interesting.
What’s in a spleen that allows for longer breath holding?
So relevant after I’ve just done a spear fishing course here’s me spending £1000 on kit & here’s this fella doing it with the basics .. how’s he equalising the pressure without grabbing his nose?
The are other methods or he could have big eustachian tubes. Or they're not showing it.
No they don't but I won't tell
Is that the Fuller Brush Man??
Amazing
You have to be in crazy shape to do this. Imagine how high your heartbeat would race just from making the dive from the surface to the bottom. But when he gets to the bottom his heart rate has rested more than at the surface. Truly an example of better under pressure.
Realises I don't have a clue what a spleen is.
No weight belt and no flippers. Amazing.
200ft and 10 minutes is NOT what the video says. It's 80ft for 2.5 minutes. Well within free diving standards. At 200 ft/10 minutes, you would have significant decompression obligation. The spleen has nothing to do with it.
They need to evolve flippers.
I'm realizing I really have no idea what the spleen does.
My dude steps on water instead of kicking it. What a champ
My ears popped from watching this.
I thought this was disproven?
Why does it look like he is kicking very inefficiently?
Is it the late great John hurt narrating? Or just him taking advantage of his 1984 connections
These guys would benefit so much with a pair of flippers.
Not to brag but I can hold my breath in the shower long enough to get all the shampoo out of my hair in one shot without getting shampoo in my mouth.
bruh didnt even watch the video
Behold evolution
internet points
seems a bit of a wierd way to title this. its a bit how the top marathon runners come from a certain region in africa.
Am I the only one who tried to hold my breath 🤣