Whither HBD: Happy 1,000 posts

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Gratuitous pic of Niels Bohr and Einstein, 1925, because this is my party.

This blog is now 1,000 posts long, which I think calls for a bit of celebration.

I started this blog because I found the idea that evolution–a process normally thought of as turning fins to feet and gills to lungs–could also code for emergent, group-level behavior like the building of termite mounds or nation states fascinating. Could evolution code for other things? Could it give us male and female behavior? Emotions? Political preferences?

I started reading JayMan’s work, then Peter Frost and HBD Chick, and of course Cochran and Harpending. Each of these blogs had new (at least to me) and fascinating ideas about why humans behave the many ways they do. Then came Slate Star Codex and Unqualified Reservations. There were others, of course; a complete listing of one’s intellectual predecessors is always impossible.

Evolution is ultimately a numbers game: if more people who do X have children than people who do Y, then X is likely to become more common than Y–even if we all believe that Y is better than X.

This gets interesting when X is not obviously mediated by genetics–your eye color, sans contacts, is clearly genetic, but the number of years you spend in school is influenced by external factors like whether schools exist in your society. This is where some people get hung up on causation. We don’t need to posit a gene that causes people to get more or less school. Maybe your village has a school because a mountain climber got lost nearby, your village rescued him, and in gratitude, he built you a school, while the village on the other side of the mountain doesn’t have a school because no mountain climber got lost there. Once a school exists, though, it can start having effects, and if those effects are not random, we’ll see genetic correlations.

If people who have more education make more money and end up buying more food and raising more children, then school is exerting a selective effect on society by causing the kids who happened to live near the school to have more children. From an ecological standpoint, the school is operating like a spring in a desert–we get more growth near the spring than far away from it, and whatever traits were common in the village–even ones that have nothing to do with education–will become more numerous in the overall population. If this trend continues, then the cultural habit of “going to school” will continue to proliferate.

We can also posit the opposite case: in the village with the school, kids spend many years at school and end up marrying later and are more educated about things like “birth control” than their neighbors on the other side of the mountain. The kids on the other side of the mountain marry younger and have a bunch of unintended children. In this case, education is suppressing fertility; in this niche, education is like a drought. The educated kids have fewer children of their own, and whatever traits the uneducated kids happen to have spread through society because there are now much more of them (at least as a percent of the total). If this trend continues, then the cultural habit of “going to school” may well die out.

In both of these cases, education caused a change in the distribution of genetic traits in the overall population without requiring any genetic predispositions from the students involved. We are looking at the evolution of the whole society.

But this is a highly constrained example; it is rare in places like the modern US to find areas where one village has a school and the next does not. Once schools are everywhere, they’re not going to select for (or against) “living near a school.” The traits that cause a person to attend more years of schooling or do better in school will be less random–traits like conscientiousness, ability to recognize letters, or family income. In an agricultural society with no schools, raw, physical strength may be at a premium as people must wrest their living from the soil, rocks, trees, and beasts. This selects for physical strength. Once we introduce schools, if the better educated have more children, then physical strength becomes less important, and its prominence in the next generation diminishes. The ability to sit in a chair for long hours may be positively selected, leading to a proliferation of this trait.

This is gene-culture co-evolution–a cultural change can shift the balance of genes in a society, and that in turn can cause further cultural changes, which cause more genetic changes.

I would like to pause and note just how annoying the “but you haven’t proven causation!” crowd is:

Imagine if I said that I thought the blood circulates through the body in a loop instead of being generated anew by the heart with every pump, and someone protested that blood couldn’t possibly circulate because I hadn’t shown any way for blood to get from the arteries to the veins and back to the heart.

This was a real debate in physiology. That the heart pumps is obvious. That veins and arteries carry blood is also obvious. That people die if you cut them open and let the blood drain out, though, mystified doctors for centuries.

Capillaries, unfortunately for many patients, are too small to see with the naked eye. Without any mechanism to return blood from the arteries to the heart, doctors refused to believe that it did. They instead believed that blood was produced anew with every heartbeat and was consumed at our extremities. Bleeding patients, therefore, shouldn’t cause any great difficulties.

The fact that we could not see capillaries before the invention of the microscope should not have caused doctors to reject the theory of circulation, only to say that a mechanism had not yet been found to make it work. The circulation hypothesis did a better job of explaining various facts of human anatomy–like the existence of veins carrying blood to the heart and the habit of patients to die after bleeding–than the heart-generation hypothesis.

The insistence on clinging to the older theory due to the lack of a capillary mechanism lead, of course, to the deaths of thousands of patients. (For more on the history of medicine, anatomy, and circulation, I recommend William Bynum’s A Little History of Science.)

How something works is vastly secondary to the question of whether it works at all in the first place. If it works, it works. If you can’t figure out how, you call it magic admit that you don’t know and hope that someday it’ll be clear. What you don’t do is claim that a thing cannot be true or cannot actually work simply because you don’t understand how it happens.

I don’t understand how airplanes stay in the sky, but that doesn’t make them fall down. Reality doesn’t stop just because we don’t understand it; to think that it does is pure, asinine hubris.

The next objection I commonly hear to the idea that cultural changes (like the proliferation of schools) could trigger changes in the genetic makeup of society is that “evolution doesn’t work that fast.”

This is a funny objection. The speed of evolution depends on the nature of the trait we are discussing. Developing a radically new trait, or greatly modifying an existing one, such as developing the ability to breath air instead of water, does indeed take a long time–sometimes millions or even billions of years. But simply modifying the distribution of existing traits in a population can be done nearly instantly–if an invading army lops the heads off of anyone over 5’9″, the average height of the population will fall immediately. From a genetic perspective, this is “negative selection” against height, and the population has “evolved” to be shorter.

(You might object that this is too artificial an example, so consider the inverse: a situation where everyone over a certain size used to die, but due to environmental changes they now survive. Modern obstetrics and the cesarean section have rescued mothers of large babies from the once-common fate of death in childbirth. This was of course often fatal to the infants, as well, and prevented their parents from producing any further children. Large babies were a serious evolutionary problem for our ancestors, but much less so for us, which has probably contributed to the rise in average heights over the past century.)

Usually selection is less extreme, but the point remains: traits that already exist (and vary) in a population, like height, weight, blood type, or temperament, can be selected for (or against) on very short timescales.

In fact, human societies are always selecting for some traits; this means that we are always evolving. The distribution of traits in humans today is not the same as the distribution of traits in humans 20 years ago, much less 100 years ago.

And we can look at all of the things humans are being selected for (or selecting themselves for) and speculate how this will change society. Religious people have more children than atheists, and some religions produce far more children than other religions. This trend is juxtaposed against the massive rise in atheism over the past few decades. Will atheism continue to spread to the children of the religious, or will the religious “core” be effectively immune and overwhelm the remaining agnostics with numbers?

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Source: Do Schooling and City Living lead to Fewer Babies?

Education (or perhaps it is just a proxy for intelligence) seems to have different effects on different folks and different levels of society. Highschool dropouts have a lot of kids. People with PhDs have a fair number of kids. People who have merely graduated from college, by contrast, have the fewest kids.

Fertility is also different for men and women, with more educated women taking a bigger fertility hit than educated men.

Any discussion of “what’s up with the American middle/working class” has to address facts like these–our country is effectively bifurcating into two “success” models: one very high achieving and one very low achieving. The middle, it seems, is getting cut out.

But we can apply evolutionary theory to much more than humans and their societies. We can analyze ideas, transportation networks, technology, etc.

My first–and probably best–idea in this area was that the idea that the way we transmit ideas influences the nature of our ideas. One of the biggest changes of the past century has been a massive change in the way we communicate, from the rise of mass media to the explosion of social media. Before radio and TV, most people got most of their information from people they knew personally, mostly their families. Today, we get most of our information from total strangers.

Ideas we get from strangers I refer to as meme viruses, (meme as in “unit of idea,” not “funny picture on the internet”) because horizontal transmission resembles the transmission of viruses. Ideas we get from our families I refer to as mitochondrial memes, because vertical transmission resembles the transmission of mitochondrial DNA.

Since the interests of strangers are different from the interests of your close family (your parents are much more interested in you making lots of money, getting married, and making grandbabies than strangers are), they will tend to promote different sorts of ideas. Your parents generally want you to succeed, while strangers would prefer that you do things that help them succeed.

It is this change in the way we communicate, rather than the actions or intentions of any particular group, that I think explains the rise of many modern political trends. (This is the condensed version; I recommend reading one of my posts on memes if you want more.)

I am obviously interested in politics, but not in the conventional sense. I have very little interest in anything associated with particular people in politics, outside of a few historical figures. I have no interest in the latest thing Nancy Pelosi or Emmanuel Macron has been up to. I think people place too much importance on individuals; I am more interested in broad trends (like the spread of technology) that are much bigger and further-reaching than any individual politicians (often their bigger than individual countries).

I’ve come over the years to the conclusion that conventional politics drive people to do (and say) very stupid things. People develop a tribal identity attached to one side or another, and suddenly everything their side does is good and sensible, and everything the other side does is nefarious and dumb. This is not a bad instinct when your enemies have pointy spears and want to turn you into lunch, but it’s terrible when your enemy disagrees with you on optimal interest rates.

My second purpose in founding this blog was to reach out to people who were, as I see it, harmed by the cult-like behavior of modern leftism. When I say “cult-like,” I mean it. Atheism is on the rise, but religious thinking and behavior remains strong. When peoples’ self-identities as “good people” become linked to their membership in political tribes, the threat of excommunication becomes particularly powerful.

Here’s a public example:

… far more unsettling was what happened two weeks later, when knitters who claim to be champions of social justice went after a gay man within the community because he’d written a satirical poem suggesting (correctly) that all the recent anti-racism mobbings might be having a toxic effect on the community. …

The next day, Taylor’s husband Benjamin Till, a composer (who also happens to be Jewish) posted on Sockmatician’s account: “This is Nathan’s husband, Benjamin. At 3 pm today, Nathan was admitted to [the emergency room at] Barnet Hospital. …

Till also wrote on his blog about what had happened:

… Nathan disabled comments when the sheer weight of them became too much, but the following morning, his other Instagram posts, and then his Twitter feed had been hijacked by the haters. The taunts continued. He was a white supremacist, a Nazi apologist…He started obsessively reading the posts but became increasingly worked up, then more and more erratic and then suddenly he snapped, screaming like a terrified animal, smashing boxes and thumping himself. I was forced to wrestle him to the ground and hold onto him for dear life as the waves of pain surged through his body. He made a run for the car keys. He said he wanted to drive at 100 miles per hour until he crashed. I called our doctor and they could hear him screaming in the background and said I was to immediately take him to [the hospital], where he was instantly assessed and put on suicide watch …

This was not the end of Nathan’s ordeal at the hands of people who supposedly believe in “social justice” and helping the powerless, as people continued piling on (yelling at him in public) because of the “harm” he had caused.

I wish I could reach out to everyone like Nathan and tell them that they’re not bad, cults are bad.

The right has its own issues, but I come from a leftist background and so am responding to what I know personally, not abstractly. 

From time to time I get a question about the future of HBD (human bio-diversity). The online HBD community was quite vibrant about a decade ago, but many of the brightest lights have faded. Henry Harpending of Westhunter and co-author of The 10,000 Year Explosion has sadly passed away. HBD Chick and Jayman are both occupied with their own lives.

The future of HBD isn’t in blogs or the internet generally (though we can read about it here). It’s over in real genetics research. Yes, there are some subjects that academics don’t want to touch for fear of losing their jobs, but there are many researchers forging paths into fascinating new territory. The field of ancient DNA is unlocking the story of human migration and dispersal, from Neanderthals to Anglo Saxons. Thanks to aDNA, we’ve discovered a whole new Human species, the Denisovans, that interbred with the ancestors of modern Homo sapiens (as did the Neanderthals). We have also discovered “ghost” species in our DNA that we have no name for.

The field of modern DNA is also advancing; we’re learning new things all the time. CRISPRing humans is just one fascinating possibility.

Imagine the ability to remove simple genetic flaws that cause painful and fatal diseases, make ourselves beautiful or smarter. How much are 20 IQ points worth? One study found that people with IQs of 100 average $58,000 a year, while 120s made $128,000. $70,000 a year, averaged over a few decades of working life, (less intelligent people tend to enter the workforce and start earning younger, so it’s not a simple multiplication problem), adds up quickly.

Let’s imagine a scenario in which CRISPR actually works. Only the wealthy–and perhaps those with genetic diseases willing to shell out thousands or covered by insurance–will be able to afford it. The current bifurcation trend will become even more extreme as the poor continue reproducing normally, while the wealthy make themselves smarter, healthier, and prettier.

But if CRISPR confers advantages to society as a whole–for example, if smarter people make fabulous new inventions that everyone benefits from–then we could see foundations, charities, and even welfare programs aimed at making sure everyone has the CRISPR advantage.

After all, if an extra year in school boosts IQ by 3.4 points (I’m not saying it does, but let’s assume), then 6 extra years in school will give you 20.4 points. We pay about $10,600 per pupil per year for public schools, so those six years are worth $63,600. If you can CRISPR 20 IQ points for less, then it’s a better deal.

Of course, CRISPR might just be a pipe dream that gives people cancer.

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Isaac Newton

Whatever happens, the real future of HBD lies in real labs with real budgets, not online blogs. I’m just here to share, discuss, and think–and hopefully there will be enough interesting ideas to discuss for another thousand posts.

Thanks for being part of all these discussions. Blogs are nothing without readers, after all.

How Tall can Humans Grow

A Twitter friend recently proposed a question:

These skeletons can be divided into two groups: those for whom we have some historical evidence (eg, Goliath, famous literary villain), and those with no evidence except images like this one.

Incidentally, modern man does not average 6 feet tall. The average American man, hailing from a well-fed cohort, is only 5″9′ (you think men are taller than they are because they all lie). The global average is a bit smaller, at about 5’7“.

Historically, people tended to be a bit shorter, probably due to inconsistent food supplies.

I have often seen it claimed that heights fell when people adopted agriculture, but most hunter-gatherers aren’t especially tall. The Bushmen, for example, are short by modern standards; I suspect that the pre-agricultural human norm was more Bushman than Dinka.

If we roll back time to look at our pre-sapiens ancestors, Homo erectus skeletons are estimated to have been between 4″8′ and 6″1′, which puts them about as tall as we are, but with a lot of variation (we also have a lot of variation). Neanderthals are estimated about 5″4′-5″5′; Homo habilis was shorter, at a mere 4″ 3′. Lucy the Australophithecine, while female, was even shorter, similar to modern chimps.

On net, a few food-related hiccups aside, humans seem to have been evolving to be taller over the past few million years (but our male average still isn’t 6 feet.)

But does this mean humans couldn’t be taller?

The trouble with being unusually tall is that, unlike apatosauruses, we humans aren’t built for it. The tallest confirmed human was Robert Wadlow, at 8 feet, 11 inches. According to acromegalic gigantism specialist John Wass, quoted by The Guardian, it would be difficult for any human to surpass 9 feet for long:

First, high blood pressure in the legs, caused by the sheer volume of blood in the arteries, can burst blood vessels and cause varicose ulcers. An infection of just such an ulcer eventually killed Wadlow.

With modern antibiotics, ulcers are less of an issue now, and most people with acromegalic gigantism eventually die because of complications from heart problems. “Keeping the blood going round such an enormous circulation becomes a huge strain for the heart,” says Wass.

Ancient people, of course, did not have the benefit of antibiotics.

What about Bigfoot?

Well, Bigfoot isn’t real, but Gigantopithecus probably was.

Gigantopithecus … is an extinct genus of ape that existed from two million years to as recently as one hundred thousand years ago, at the same period as Homo erectus would have been dispersed,[2] in what is now VietnamChina and Indonesia placing Gigantopithecus in the same time frame and geographical location as several hominin species.[3][4] The primate fossil record suggests that the species Gigantopithecus blacki were the largest known primate species that ever lived, standing up to 3 m (9.8 ft) and weighing as much as 540–600 kg (1,190–1,320 lb),[2][5][6][7] although some argue that it is more likely that they were much smaller, at roughly 1.8–2 m (5.9–6.6 ft) in height and 180–300 kg (400–660 lb) in weight.[8][9][10][11]

They’re related to orangutans; unfortunately it’s difficult to find their remains because the Chinese keep eating them:

Fossilized teeth and bones are often ground into powder and used in some branches of traditional Chinese medicine.[13] Von Koenigswald named the theorized species Gigantopithecus.[8]

Since then, relatively few fossils of Gigantopithecus have been recovered. Aside from the molars recovered in Chinese traditional medicine shops, Liucheng Cave in LiuzhouChina, has produced numerous Gigantopithecus blacki teeth, as well as several jawbones.[14]

Please stop eating fossils. They’re not good for you.

Unfortunately, since we only have teeth and jawbones from this creature, it’s hard to tell exactly how tall it was.

Let’s just estimate, then, a maximum human height around 10 feet. After that, your heart explodes. (Joking. Sort of.)

Let’s start with Goliath.

The Philistines were a real people–one of the “Sea Peoples” who showed up in the Mediterranean during the Bronze Age Collapse:

 In 2016, a large Philistine cemetery was discovered near Ashkelon, containing more than 150 dead buried in oval-shaped graves. A 2019 genetic study found that, while all three Ashkelon populations derive most of their ancestry from the local Levantine gene pool, the early Iron Age population was genetically distinct due to a European-related admixture …According to the authors, the admixture was likely due to a “gene flow from a European-related gene pool” during the Bronze to Iron Age transition…[9]  

The inscriptions at Medinet Habu consist of images depicting a coalition of Sea Peoples, among them the Peleset, who are said in the accompanying text to have been defeated by Ramesses III during his Year 8 campaign. In about 1175 BC, Egypt was threatened with a massive land and sea invasion by the “Sea Peoples,” a coalition of foreign enemies which included the Tjeker, the Shekelesh, the Deyen, the Weshesh, the Teresh, the Sherden, and the PRST. … A separate relief on one of the bases of the Osirid pillars with an accompanying hieroglyphic text clearly identifying the person depicted as a captive Peleset chief is of a bearded man without headdress.[49] This has led to the interpretation that Ramesses III defeated the Sea Peoples including Philistines and settled their captives in fortresses in southern Canaan; another related theory suggests that Philistines invaded and settled the coastal plain for themselves.[53] The soldiers were quite tall and clean shaven. They wore breastplates and short kilts, and their superior weapons included chariots drawn by two horses. They carried small shields and fought with straight swords and spears.[54]

The name “Goliath” is a real Philistine name.

(More on the Bronze Age Collapse: 1177 BC: the Year Civilization Collapsed.)

So there is a decent chance that the Goliath recorded in the Bible was, in fact, a real person.

However, Goliath’s great height may just be… an exaggeration. According to Wikipedia: 

Goliath’s height increased over time: the oldest manuscripts, namely the Dead Sea Scrolls text of Samuel from the late 1st century BCE, the 1st-century CE historian Josephus, and the major Septuagint manuscripts, all give it as “four cubits and a span” (6 feet 9 inches or 2.06 metres)…

It looks like Goliath was tall, but only basketball player tall, not Guinness Book of World Records tall.

Maximinus Thrax:

The shortest guy in the picture, “Maximinus Thrax,” was a real person and emperor of Rome from 235 – 238 AD. 8″6′ is at least within the range of heights humans can achieve, and he was, according to the accounts we have, very tall. Unfortunately, we don’t know how tall he was–the ancient accounts are considered unreliable, the Roman “foot” is not the same as the modern “foot,” and crucially, no one has dug up his skeleton and measured it.

So Maximinus was probably a tall guy, though not 8″6′ (that would require the Roman foot to equal our modern foot).

Og the Rephaim:

Og, King of the Bashan, is only known from the Bible, but might have been an actual king. We don’t have any chronicles from other countries that mention him (kings often show up in such chronicles because they make war, get defeated, send tribute, sign treaties, etc., but there is one Agag of the Amelekites who does have a similar name.

Interestingly, there is one Og attested in archaeology, found in a funerary inscription which appears to say that if the deceased is disturbed, “the mighty Og will avenge me.”

The Bible claims that Og’s bed was 13 feet long. Wikipedia offers us an alternative explanation for this mysterious bed: a megalithic tomb:

It is noteworthy that the region north of the river Jabbok, or Bashan, “the land of Rephaim”, contains hundreds of megalithic stone tombs (dolmen) dating from the 5th to 3rd millennia BC. In 1918, Gustav Dalman discovered in the neighborhood of Amman, Jordan (Amman is built on the ancient city of Rabbah of Ammon) a noteworthy dolmen which matched the approximate dimensions of Og’s bed as described in the Bible. Such ancient rock burials are seldom seen west of the Jordan river, and the only other concentration of these megaliths are to be found in the hills of Judah in the vicinity of Hebron, where the giant sons of Anak were said to have lived (Numbers 13:33).[2]

Og might have actually been a very tall person, though it is doubtful he was 13 feet tall. He might have been a fairly normal-sized person who had a very impressive megalithic tomb which came to be known as “Og’s Bed,” inspiring local legends. He also might not have existed at all. Until someone digs up Og’s body and measures it, we can’t say anything for sure.

French Giants

Interestingly, I found two French giants, though neither of them, as far as I know, near Valence.

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Bones of the giant of Castelnau, plus a normal human humerus.

The Giant of Castlenau is known from three pieces of bone uncovered in 1890. If they are human, they are unusually large, but no research has been done on them since 1894 and even a crack team of Wikipedia editors has failed to uncover anything more recent on the subject.

I’d hold off judgment on these until someone within the past century actually seems them and confirms that they didn’t come from a cow.

Teutobochus, king of the Teutons, was a giant found in 1613, France. Unfortunately, he seems to have been a deinotherium–that is, an extinct variety of elephant.

This is the last of the reasonable skeletons. The rest exist only in graphics like the one at the top of the post and articles discussing them–in other words, there’s more evidence for Paul Bunyan.

So far I’ve found no sources on the 15 foot Turkish giant. Yes, lots of people claiming they exist, eg. No, not one photo of them.

Was a 19’6″ human skeleton found in 1577 A.D. under an overturned oak tree in the Canton of Lucerne? There are no records of it.

Any 23 foot tall skeletons near an unidentified river in Valence, France? Can’t find any.

And what about the 36 foot tall Carthaginian skeletons?

apatosaurus-size
Apatosaurus dimensions

Giraffes, currently the tallest animals on earth, only reach 19 feet. T-rex was 12-20 feet tall. Even the famous Apatosaurus was a mere 30 feet tall (though we don’t know how high he could swing his head).

If you’re talking about humans who were bigger than an Apatosaurus, you’re really going to have to pause and take a biology check–and also check to make sure you aren’t holding an Apatosaurus femur.

Humans could be bigger (or smaller) than they currently are, just as dinosaurs came in many different sizes (some, like hummingbirds, are quite small), but different sizes require different anatomy. That’s why people with giganticism have heart trouble and tall people die younger: we aren’t built for it. Humans aren’t designed to handle Apatosaurus-level weights; our hearts aren’t designed to pump blood that far. A 36 foot tall human couldn’t be a single individual with giganticism, nor even a whole family or tribe of unusually tall people–they’d have to have evolved that way over millions of years. They’d be their own species, and we’d have actual evidence that their bones exist.

Incidentally, most of the sources I found discussing these skeletons, including ones using the graphic above, claim that evidence of these giants is being actively hidden or suppressed or destroyed by The Smithsonian, National Geographic, etc., because they would somehow disprove evolution by showing that humans have gotten shorter instead of taller.

This is absurd. Gigantopithecus is taller than any living ape (including humans) but he doesn’t disprove evolution. He doesn’t even disprove orangutans. A giant human skeleton would simply show that there was once a giant human–not that humans didn’t evolve.

Humans can evolve to be shorter–it has happened numerous times. Pygmies are living human people who are much shorter than average–adult male Pygmies average only 5 feet, one inch tall. Pygmoid peoples are just a little taller, and found in many parts of the world.

Even shorter, though, were Homo floresiensis and Homo luzonensis. The remains we have so far uncovered of H. floresiensis stood a mere 3 feet, 7 inches, and luzonensis was similarly petite. Both of these hominins descended from much taller ancestors.

Evolutionists don’t need to hide the existence of giant skeletons because evolution can’t be disproven by the existence of a tall (or short) skeleton. That’s just not how it works. The Smithsonian would love to display giant skeletons–if it had any. National Geographic would love to run articles on them. They’d make money like hotcakes on such sensational relics.

The problem is that no one can actually find any of these skeletons.

 

Apidima Sapiens?

Two fossil skulls from Apidima, Greece, tell an intriguing story. The first, more than 210,000 years old, appears to be an early Homo sapiens. The second, a younger 170,000 years old, looks like a Neanderthal.

If so, then Homo sapiens moved to Greece, were replaced by Neanderthals, then thousands of years later moved back and replaced the Neanderthals (“replaced” is generally a polite word for “killed.”)

This is consistent with a fair amount of other evidence that Homo sapiens had (at least) two out-of-Africa events, of which the one that killed the Neanderthals was only the most recent. It could also represent the population wave that interbred with Neanderthals, contributing Sapiens DNA to the Neanderthal genome, well before the more famous interbreeding event when Neanderthal DNA entered our modern Homo sapiens genome.

On the other hand, there’s not a whole lot to these fossils. One is just the back of a skull. The back of a skull is more informative than it sounds on first glance because neanderthals have a bump (referred to as a “bun”) on the backs of their skulls that we don’t, but still, we’re not talking about complete skulls. So it could turn out that this was just a funny looking Neanderthal, or a piece that got pressed weirdly by a rock (the first Neanderthal skeleton people found had arthritis, which threw all of the illustrations off for decades, so these things can happen).

But throwing caution to the wind, let’s assume the skulls are correct, and so is the rough timeline I sketched out: Neanderthals inhabit Europe, Sapiens leave Africa, Sapiens push into the Middle East and Greece, Sapiens fail, Neanderthals retake the region, years pass, Sapiens try again and this time succeed, wiping out the Neanderthals.

What changed? What made the first attempt a failure and the second successful?

Aside from Sapiens generally getting smarter, I suggest a humble invention: the sewing needle.

We know from studies of lice (ew, I know) that humans began wearing clothes around 80-170,000 years ago. How do we know? Because the lice that live on our heads and the lice that infect our clothes are different species, and genetics claims that’s when they split.

The earliest known “looks like a needle” comes from Sibudu Cave, South Africa, and dates from about 61,000 years ago, but needles are small and easily broken, so I suspect that plenty were used that we haven’t found.

Neanderthals did not wear clothes–quoting Wikipedia, quoting archaeologist John F. Hoffecker:[102]

Neanderthal sites show no evidence of tools for making tailored clothing. There are only hide scrapers, which might have been used to make blankets or ponchos. This is in contrast to Upper Paleolithic (modern human) sites, which have an abundance of eyed bone needles and bone awls. Moreover, microwear analysis of Neanderthal hide scrapers shows that they were used only for the initial phases of hide preparation, and not for the more advanced phases of clothing production.

— John F. Hoffecker, The Spread of Modern Humans in Europe

Bodyhair_map_according_to_American_Journal_of_Physical_Anthropology_and_other_sourcesIf the Neanderthals did not have clothes, then they had to adapt to the European climate in other ways–probably fur.

(Incidentally, according to the only data I have on the matter, Mediterranean and Nordic peoples are oddly hairy, while Siberian people are weirdly not-hairy. If anyone has any idea why this is I’d love to hear it.)

If the first wave of Sapiens to leave Africa also did not have clothes (or had only very rudimentary clothes) and they lacked the Neanderthals’ fur, then they would have had a very difficult time surviving in the harsh European winters.

Like the Roanoke colony, the survivors may have happily gone over to the Neanderthal side.

By the time the second wave of Sapiens showed up, however, they had invented clothes–and had other elements of a more advanced cultural/technological toolkit that let them conquer the elements–and the ‘Thals.

Let’s Talk about Music, Baby

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There has been a lot of chatter lately about whether the development of human musical abilities can be explained via some form of sexual selection. Most of this debate has been needlessly heated/involved more insults than it warrants, so I don’t want to pick on any particular people, but all of it seems to have overlooked some basic facts:

  1. Musical success–at least as expressed in our culture–is strongly dimorphic in favor of men.
  2. Music groupies–that is, fans who want to have sex with musicians–are strongly dimorphic in favor of women (especially teens).
  3. Successful musicians have tons of sex.

Let’s run through a little evidence on each of these points. First, talent: 

Wikipedia has a nice list of musicians/bands by # of albums sold. It probably doesn’t include folks like Beethoven, but that’s for the best since it would muck up the data to have artists whose work has been for sale for so long.

The top selling artists, with 250 million or more record sales, are:

The Beatles
Elvis
Micheal Jackson
Madonna
Elton John
Led Zeppelin
Rhianna
Pink Floyd

If this list surprises you, you might want to listen to more music.

Men dominate women here 3:1.

I’m not going to list the rest of the top-selling artists on the page, but if we total them up,  I count 27 women/female bands (including two bands that are half women) and 83 male (including the two half-male bands).

Remarkably, 83:27 (and 89:29) is almost exactly 3:1.

Now, some people object that “people liking their music enough to fork over money for it” is not a good measure of “musical talent,” but it is definitely a measure of musical success. If someone is super talented but no one wants to listen to them, well, I am a bit skeptical of the claim that they are talented.

The other common response I get to this runs along the lines of “But we tested musical ability in a lab, and in our experiments, men and women did equally well.”

So?

All that shows is that you got different results; it doesn’t explain why the dimorphism exists in the real world. There are exceedingly few top-selling musicians in the world (118 on Wikipedia’s list, plus or minus a few deaths,) and it’s highly doubtful that anyone of this caliber wandered into a university music lab. It may be that musicians of average quality show no dimorphism at all (or are even biased toward women) while exceptional musicians are disproportionately male, just because there is no particular reason to assume that two different groups of people have the same range of abilities even if they have the same average. In fact, men have a greater range than women in many documented areas, like height and IQ–that is, while there are more men than women in Mensa, there are also more boys than girls in Special Ed.

Second, groupies: 

The first time Scottish concert promoter Andi Lothian booked the Beatles, in the frozen January of 1963, only 15 people showed up. The next time he brought them north of the border… it was as if a hurricane had blown into town.

The night almost unravelled when nervous local police insisted Lothian bring the Beatles on early to satisfy rowdily impatient fans, even though his bouncers were still in the pub. “The girls were beginning to overwhelm us,” remembers Lothian, now 73 and a business consultant. “I saw one of them almost getting to Ringo’s drumkit and then I saw 40 drunk bouncers tearing down the aisles. It was like the Relief of Mafeking! It was absolute pandemonium. Girls fainting, screaming, wet seats. The whole hall went into some kind of state, almost like collective hypnotism. I’d never seen anything like it.”

A Radio Scotland reporter turned to Lothian and gasped, “For God’s sake Andi, what’s happening?” Thinking on his feet, the promoter replied, “Don’t worry, it’s only… Beatlemania.” — Beatlemania: The Screamers and other Tales of Fandom

normal_fans_21.jpg.w300h282As for Elvis:

Gone are all the jerky body movements that once earned Elvis Presley the nickname of ‘The Pelvis’. Gone are all the actions that were dubbed vulgar by his critics. Presley’s stage performance is now restrained. But that did not stop 5,500 wildly excited spectators at the Bloch Arena, Pearl Harbour, Hawaii from going outrageously wild with unreserved enthusiasm last Saturday night. Never have I heard anything like it. Their enthusiasm was fever-pitch, and they were screaming non-stop from start to finish, making it impossible to identify some of the songs he sang. Whether he was talking, singing, raising his eyebrows or just breathing, it was a signal for the volume of excitement to rise higher and higher throughout this fantastic concert.

Hundreds of naval police at this U.S. Navy fortress were detailed to restrain fanatical fans from invading the stage, and they were kept busy for the entire show. …

The climax came when he closed with the all-out rocker ‘Hound Dog’, the signal for the greatest bout of unlimited pandemonium, many of the younger girls going completely berserk! Then came the trickiest part of all – ‘Operation Exit Elvis’ – to get Presley out of the building before the crowd could tear him apart from sheer adoration.

More about the screaming.

Why all of the screaming?

“Screaming girls”—that was a recurring theme in newspaper reviews of Elvis’s stage shows in 1956 and 1957. At almost every stop, the girls screamed so loud that no one could hear Elvis sing. Even the musicians on stage had trouble hearing each other. … Elvis himself explained that at times in 1957 he had to cover his ears with his hands so that he could hear himself sing. …

When I spoke with some women who had attended an Elvis concert back in 1957, most of them admitted they had screamed. …

“We screamed when he came out. I didn’t know I was going to yell and scream. I’d never done that in my whole life. It was spontaneous. …  He could excite you with his music so much. My mom’s gone; I guess she wouldn’t care if I said it now … it was like a sexual experience. It went through your body kind of like that.”

Kurt Cobain’s suicide sent weeping girls into the streets:

A rumor went around in ninth grade English class. We went home and turned on MTV to find out for sure. I remember girls crying in the hallway. …

I was watching the news when I heard, and cried. It was believable and unbelievable, all at the same time. It’s our generation’s “Where were you…?” moment. My husband, our friends, all remember where we were when we heard the news and how devastated we were. …

I was in the bathroom getting ready for school, and my dad yelled “Hey, some guy from that band you like is dead.”

I walked into the living room and saw them playing footage from one of their performances on the TV. And then they said his name. I immediately started bawling. I don’t think my mom made me go to school that day.

In Seattle:

Seattle bid goodbye to Kurt Cobain on April 10 in true grunge-rock style, bursting the ranks of a quickly organized public vigil and leaping into the nearby international fountain, a giant, water-spouting structure some 50 yards wide and ten feet deep that flanks the Flag Pavilion. … Weeping girls wore beauty pageant banners around their middles, made out of the plastic yellow, “POLICE LINE DO NOT CROSS” tape, the same kind of tape which, three days earlier, had criss-crossed the driveway to Cobain and Courtney Love’s home.

At this point, denying that women (especially teen girls) seem to have some sort of thing for rock stars is right up there with denying that men have a thing for fertile young women with hourglass figures.

Third, the sex:

Chuck-Berry-and-Mick-Jagger
Mick Jagger and Chuck Berry

Groupie sex, oh groupie sex. How many groupies have rockstars actually boned?

Vice has an article titled Elvis was the King of Treating Women like Shit and Luring 14 Year Olds into Bed. Elvis had sex with a lot of teenagers (including Priscilla Marie, who was 14 when they met).

Cracked has a pretty good overview if you’ve never heard of groupies before:

We’ve already written about the sex tents that Van Halen’s Sammy Hagar had installed wherever he performed so that he could disappear mid-solo and indulge himself in a groupie or nine. But that’s not the only way Van Halen was entrepreneurial with his young fans. Let’s take a minute and discuss how original frontman David Lee Roth amused his roadies by sending them out on groupie scavenger hunts.

From his lofty position on the stage, Roth would instruct his roadies to dive into the crowd and collect very specific girls for him to have sex on. The lucky girl would be given a special backstage pass with the initials of the roadie who approached her written in the top corner. If that pass was then among the ones strewn on his floor the next morning, Roth would reward the roadie with a $100 bonus at breakfast the next morning, because exchanging money for sex works up an appetite.

Motley Crue came up with the, uh, creative solution of rubbing burritos on their crotches so their girlfriends wouldn’t smell the scents of groupie sex on them:

He tells Hustler magazine, “We were always f**king other chicks at the studio and backstage… We would take Tommy’s (Lee) van to a restaurant called Noggles to buy these egg burritos and then rub them on our crotches to cover the smell of the girls we had just f**ked.

Let’s hear some more about these “sex tents”:

Before they became a quartet of endless punchlines, Van Halen used to be one of the coolest bands in the world, and they demonstrated their status by having sex with every female who wandered within one mile of their powerful aura. Their career is a filthy memorial to how being in a band is a more powerful aphrodisiac than things like “not looking completely ridiculous,” …

One tour saw the band build a tent directly beneath the stage specifically for Sammy Hagar’s erection. During the mid-show 20-minute guitar solos Eddie Van Halen would launch into each night, Hagar would disappear to the tent and discover a group of naked fans waiting to swallow his penis.

Mick Jagger, by the way, has (at least) eight children via five different women.

Look, I feel a little silly having to spell out in great detail the fact that rock stars get laid a lot. You probably feel a little silly reading it, yet there are people who seem hellbent on arguing that there’s no particular evidence in favor of sexual selection for musical talent.

And no, you can’t explain this away by saying that musicians are “famous” and that women want to have sex with all sorts of famous people. Donald Trump is famous, but he doesn’t have sex tents. Leonardo diCaprio is famous and has legions of fans, but as far as I know, he also doesn’t have sex tents.

I agree that we can’t definitively prove how musical talent evolved among the first humans, (because we don’t have time machines,) but the correlation between sex and music today, in our own society, is overwhelming. A claim that it didn’t have similar effects on our ancestors needs to explain what changed so radically between then and now.

Likewise, we can’t assume that just because music works like this in our own society, it must also work this way in every other society. But conversely, just because something doesn’t work in one society doesn’t imply it doesn’t work in every society. There are a lot of groups out there, and some of them are obviously weird in ways that are’t relevant to everyone else. Some people, for example, like to dress up like anthropomorphic animals and go to conventions. We should be cautious about over-generalizing from small examples. Sure, there might be a random tribe somewhere that with weird traditions like killing any women who see a musical instrument being played, but these tribes generally have fewer people in them than one concert’s worth of screaming Elvis fans.

The Evolution of Horses

lascaux-chinese-horseThe ancestors of horses–small, multi-toed quadrupeds–emerged around 50 million years ago, but horses as we know them (and their wild cousins) evolved from a common ancestor around 6 million years ago. Horses in those days were concentrated in North America, but spread via the Bering land bridge to Eurasia and Africa, where they differentiated into zebras, asses, and “wild” horses.

When humans first encountered horses, we ate them. American horses became extinct around 14,000-10,000 years ago, first in Beringia and then in the rest of the continent–coincidentally about the time humans arrived here. The first known transition from hunting horses to herding and ranching them occurred around 6,000 years ago among the Botai of ancient Kazakhstan, not far from the proto-Indo European homeland (though the Botai themselves do not appear to have been pIEs). These herds were still managed for meat, of which the Botai ate tons, until some idiot teenager decided to impress his friends by riding one of the gol-dang things. Soon after, the proto-Indo-Europeans got the idea and went on a rampage, conquering Europe, Iran, and the Indian subcontinent, (and then a little later North and South America, Africa, Australia, and India again). Those horses were useful.

Oddly, though, it appears that those Botai horses are not the ancestors of the modern horses people ride today–but instead are the ancestors of the Przewalski “wild” horse. The Przewalski was though to be a truly wild, undomesticated species, but it appears to have been a kind of domesticated horse* that went feral, much like the mustangs of the wild west. Unlike the mustang, though, the Przewalski is a truly separate species, with 66 chromosomes. Domesticated horses have 64, so the two species cannot produce fertile hybrids. When exactly the Przewalski obtained their extra chromosomes, I don’t know.

*This, of course, depends on the assumption that the Botai horses were “domesticated” in the first place.

Instead, modern, domesticated horses are believed to have descended from the wild Tarpan, though as far as I know, genetic studies proving this have not yet been done. The Tarpan is extinct, but survived up to the cusp of the twentieth century. (Personally, I’m not putting odds on any major tarpan herds in the past couple thousand years having had 100% wild DNA, but I wouldn’t classify them as “feral” just because of a few escaped domestics.)

Thus the horse was domesticated multiple times–especially if we include that other useful member of the equus family, the ass (or donkey, if you’d prefer). The hardworking little donkey does not enjoy its cousin’s glamorous reputation, and Wikipedia reports,

Throughout the world, working donkeys are associated with the very poor, with those living at or below subsistence level.[45] Few receive adequate food, and in general donkeys throughout the Third World are under-nourished and over-worked.[68]

The donkey is believed to have been domesticated from the wild African ass, probably in ancient Nubia (southern Egypt/northern Sudan). From there it spread up the river to the rest of Egypt, where it became an important work animal, and from there to Mesopotamia and the rest of the world.

Wild African asses still exist, but they are critically endangered.

All of the different species within the equus genus, except the domesticated donkey and its wild African cousins, have different numbers of chromosomes:

przewalski: 66
Horse: 64
Donkey: 62
Onager (Persian wild ass): 56
Kulan: 54/55 (??)
Kiang (Asian wild ass): 51/52 (??)
Grevy’s zebra: 46
common zebra: 44
mountain zebra: 42

As far as I know, they can all cross and make mules, but all of these hybrids are infertile except domestic donkey/wild African donkey crosses. (Your only limit is African wild donkeys being endangered.)

I have no idea while equines have so much chromosomal diversity; dogs have been domesticated for much longer than horses, but are still interfertile with wolves and even coyotes (tbf, maybe horses could breed with tarpans.)

Interestingly, domestication causes a suit of changes to a species’ appearance that are not obviously useful. Recently-domesticated foxes exhibit pelt colors and patterns similar to those of domesticated dogs, not wild foxes. We humans have long hair, unlike our chimp-like ancestors. Horses also have long manes, unlike wild zebras, asses, and tarpans. Horses have evolved, then, to look rather like humans.

Also like humans, horses have different male and female histories. Male horses were quite difficult to tame, and so early domesticators only obtained a few male horses. Females, by contrast, were relatively easy to gentle, so breeders often restocked their herds with wild females. As a result, domesticated horses show far more variation in their mitochondrial DNA than their Y chromosomes. The stocking of herds from different groups of wild horses most likely gave rise to 17 major genetic clusters:

From these sequences, a phylogenetic network was constructed that showed that most of the 93 different mitochondrial (mt)DNA types grouped into 17 distinct phylogenetic clusters. Several of the clusters correspond to breeds and/or geographic areas, notably cluster A2, which is specific to Przewalski’s horses, cluster C1, which is distinctive for northern European ponies, and cluster D1, which is well represented in Iberian and northwest African breeds. A consideration of the horse mtDNA mutation rate together with the archaeological timeframe for domestication requires at least 77 successfully breeding mares recruited from the wild. The extensive genetic diversity of these 77 ancestral mares leads us to conclude that several distinct horse populations were involved in the domestication of the horse.

The wild mustangs of North America might have even more interesting DNA:

The researchers said four family groups (13.8%) with 31 animals fell into haplogroup B, with distinct differences to the two haplogroup L lineages identified.

The closest mitochondrial DNA sequence was found in a Thoroughbred racing horse from China, but its sequence was still distinct in several areas.

The testing also revealed links to the mitochondrial DNA of an Italian horse of unspecific breed, the Yunnan horse from China, and the Yakutia horse from central Siberia, Russia.

Haplogroup B seems to be most frequent in North America (23.1%), with lower frequencies in South America (12.68%) and the Middle East (10.94%) and Europe (9.38%).

“Although the frequency of this lineage is low (1.7%) in the Asian sample of 587 horses, this lineage was found in the Bronze Age horses from China and South Siberia.”

Westhunter suggests that this haplogroup could have originated from some surviving remnant of American wild horses that hadn’t actually been completely killed off before the Spanish mustangs arrived and bred with them. I caution a more prosaic possibility that the Russians brought them while colonizing Alaska and the coast down to northern California. Either way, it’s an intriguing finding.

The horse has been man’s companion for thousands of years and helped him conquer most of the Earth, but the recent invention of internal and external combustion engines (eg, the Iron Horse) have put most horses out to pasture. In effect, they have become obsolete. Modern horses have much easier lives than their hard-working plow and wagon-pulling ancestors, but their populations have shrunk enormously. They’re not going to go extinct, because rich people still like them (and they are still useful in parts of the world where cars cannot easily go,) but they may suffer some of the problems of inbreeding found in genetically narrow dog breeds.

Maybe someday, significant herds of wild horses will roam free again.

 

Out of Africa revisited? pt 2

nature-siberian-neanderthals-17.02.16-v2The out-of-Africa theory basically says that humans evolved in Africa, then spread in several pulses across the rest of the planet. The first hominin to leave Africa–as far as we know–was Erectus, followed by the Neanderthals/Denisovans, and finally Sapiens. Where exactly smaller, less well-known hominins like Homo Floresiensis fit into the picture we don’t know, yet.)

One of the incredible things about human evolution is just how many other human species we used to co-exist with. We shared this earth with at least 8 other species of human, met and mated with at least 4 of them. Before us came a proliferation of australopithecines.

Today, there is only us. This stunning diversity of upright apes has been winnowed to a single line. Species that had survived for thousands if not millions of years disappeared, either because they died out or were wiped out. We, sapiens, are the last ones standing.

Humans met Neanderthals. We interbred, briefly. Then the Neanderthals died out. Humans met Denisovans. We interbred, briefly. Then the Denisovans disappeared. Humans met so-called “Ghost populations” in west and southern Africa and interbred. The ghosts then disappeared. It’s all very mysterious how every other species of hominin and australopithecine seems to have died out immediately after we sapiens arrived in the area.

This implies, then, that sapiens didn’t live in these areas during the thousands or so years before we wiped out the locals (though some small exceptions may exist.)

So where did we live?

The West African Ghost Population contributed a big chunk of DNA to modern humans a mere 50,000 years ago–around the same time as sapiens were mating with Neanderthals. This seems to have been a much more significant encounter than the one with Neanderthals–perhaps many of these “ghosts” joined the sapiens who moved into their area.

So west Africa was likely not inhabited by modern humans before 50,000 years ago.

Homo naledi is too small to have co-existed with us, effectively ruling out their part of South Africa during that period, and the Pygmies probably interbred with their mystery hominin around 35,000 years ago, so that rules out the Congolese forest area.

The Neanderthal ancestry is in pretty much everyone not in Africa, (and a little in Africa due to recent back-migration) which is pretty strong support for the out-of-Africa theory. The most parsimonious explanation is that a single population split, and half of that population, as it entered Eurasia, encountered Neanderthals, while the other half traveled deeper into Africa and encountered African hominins.

East Africa/the horn of Africa region remains, therefore, the most logical spot to locate Homo sapiens immediately before this splitting phase, but I wouldn’t rule out the Middle East.

On the other hand, Homo sapiens’s ancestor, Homo heidelbergensis, lived in Africa, Europe, and the Middle East for thousands, possibly a million years (depending on how we classify the similar bones of Homo antecessor, who lived near Norfolk, England, about 950,000 years ago. Homo heidelbergensis’s (probable) ancestor, Homo erectus, lived in Africa, Europe, and Asia for over a million years.

Here’s where it gets complicated, because while species like the little hobbits from Flores are clearly different from other varieties of Homo, there are no clear dividing lines between folks like erectus, heidelbergensis, and ergastor. We have a bunch of bones, a few nice skulls, scattered across continents and centuries, from which we try to derive a vague sense of whether this population and that population were similar enough to consider them a single species. Quoting Wikipedia:

Although “Homo ergaster” has gained some acceptance as a valid taxon since its proposal in 1975, ergaster and erectus since the 1980s have increasingly come to be seen as separate (that is, African or Asian) populations of the larger species H. erectus. … The question was described as “famously unresolved” as of 2003.[10] Sura et al (2007) concluded that Homo erectus “was a likely source of multiple events of gene flow to the Eurasian continent”.[11]

The discoveries of the Dmanisi skulls in the South Caucasus since 2005 have re-opened this question. Their great morphological diversity suggests that the variability of Eurasian H. erectus already includes the African fossils dubbed H. ergaster. The discovery of Dmanisi skull 5 in 2013, dated to 1.8 million years ago, now dates evidence of H. erectus in Eurasia as of virtually the same age as evidence for H. ergaster in Africa, so that it is unclear if the speciation of H. erectus/ergaster from H. habilis took place in Africa or Asia.[12] This has reinforced the trend of considering H. ergaster as synonymous with H. erectus, a species which would have evolved just after 2 million years ago, either in Africa or West Asia, and later dispersed throughout Africa and Eurasia.[13][14]

Homo habilis, by contrast, is (so far) only found in east Africa.

What does it mean to evolve in a place? Habilis, as far as we know, actually did evolve in Africa. It didn’t leave Africa; neither did the australopithecines (unless one of those little hobbity folks out in the Philippines turn out to be australopiths, but that would be very remarkable). But after that, “humans” spread from Africa to Europe and Asia with remarkable speed. They lived in England almost a million years ago. And within this range, we seem to have become repeatedly isolated, speciated, and then met back up again when the weather improved.

Personally, I wouldn’t say that the out of Africa theory is wrong. It is still the most parsimonious explanation of human evolutionary history. However, I would say that it simplifies a huge chunk of our history, since for most of our time on this earth, our range has been quite a bit larger than Africa.

Why do Women have breasts?

the_paps_of_dana-01
Paps Anu, Ireland (If you look closely, someone put nipples on top.)

Well, there’s a clickbaity title if ever I wrote one.

Nevertheless, human breasts are strange. Sure, all females of the class mammalia are equipped with mammary glands for producing milk, but humans alone posses permanent, non-functional breasts.

Yes, non-functional: the breast tissue that develops during puberty and that you see on women all around you is primarily fat. Fat does not produce milk. Milk ducts produce milk. They are totally different things.

Like all other mammals, the milk-producing parts of the breasts only activate–make milk–immediately after a baby is born. At any other time, milk production is a useless waste of calories. And when mothers begin to lactate, breasts noticeably increase in size due to the sudden production of milk.

A woman’s normal breast size actually tells you nothing at all about her ability to make milk–if anything, the correlation is the opposite, with obese women (with correspondingly large breasts) having a more difficult time nursing and producing milk:

A number of factors associated with low milk supply have been identified, such as nipple pain, ineffective nursing, hormonal disorders, breast surgery, certain medications, and maternal obesity. …  Research into breast size and milk production shows that milk supply is not dependent on breast size, but rather on the amount of epithelial tissue contained in a breast that is capable of making milk …

However, in addition to baby attachment issues, accumulating evidence shows that a major factor preventing overweight and obese mothers to breastfeed is the inability of their breast epithelial cells to start producing copious amounts of milk after birth. This is often referred to as unsuccessful initiation of lactation. …

a recent study took advantage of breast epithelial cells non-invasively isolated from human milk. In these cells, certain genes are turned on, which enable the cells to gradually make milk as the breast matures during pregnancy, and then deliver it to the baby during breastfeeding.

The study reported a negative association between maternal BMI (body mass index), and the function of a gene that represents the milk-producing cells. This suggested that the breast epithelial tissue is not as mature and ready to make copious amounts of milk in mothers with higher BMI. Most likely, the large breasts of overweight or obese mothers contain more fat cells than milk-making cells, which can explain the low milk supply of many of these mothers.

Therefore, breast size does not necessarily translate to more milk-producing cells or higher ability to make milk.

More fat=less room for milk production.

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original source (colors have been changed.)

Interestingly, average cup size varies by country.  Of course the data may not be 100% accurate, and the lumping of everyone together at the national level obscures many smaller groups, like Siberians, but it otherwise still indicates some general trends that we can probably trust.

If breasts don’t actually make milk, then why on Earth do we have them? Why are women cursed with lumpy fat blobs hanging off their chests that have to be carefully smushed into specialized clothing just so we can run without them flopping around painfully?

And for that matter, why do we think they look nice?

One reasonable theory holds that breasts are really just front-butts. Our apish ancestors, like modern chimpanzees, most likely not copulate ad libitum like we do, but only when females were fertile. Female fertility among our chimpish relatives is signaled via a significant swelling and reddening of their rear ends, a clear signal in a species that wears no clothes and often walks on four limbs.

peter-paul-rubens-portrait-of-susanna-fourment-le-chapeau-de-paille
Le Chapeau, Peter Paul Rubens’s portrait of Susanna Fourmer

When humans began walking consistently on two legs, wearing clothes, and looking at each other’s faces, this obvious signal of female fertility was lost, but not our desire to look at rear-ends. So we simply transferred this desire to women’s fronts and selectively had more children with the women who piqued our interests by having more butt-shaped cleavage.

In support of this theory, many women go to fair lengths to increase the resemblance between their ample bosoms and an impressive behind; against this theory is the fact that no other bottom-obsessed species has accidentally evolved a front-butt.

I realized yesterday that there is an even simpler potential explanation: humans are just smart enough to be stupid.

Most of us know that breasts produce milk. Few of us really understand the mechanism of how they produce milk. I had to explain that fat lumps don’t produce milk at the beginning of this post because so few people actually understand this. Far more people think “Big breasts=lots of milk” than think “big breasts=lactation problems.” Humans have probably just been accidentally selecting for big breasts for millennia while trying to select for milk production.

Our breast obsession is cargo-cult lactation.

 

When we become our own worst enemies

In times of danger, tribes merge; in times of peace, they split.

From Scientific Reports, De novo origins of multicellularity in response to predation:

Here we show that de novo origins of simple multicellularity can evolve in response to predation. We subjected outcrossed populations of the unicellular green alga Chlamydomonas reinhardtii to selection by the filter-feeding predator Paramecium tetraurelia. Two of five experimental populations evolved multicellular structures not observed in unselected control populations within ~750 asexual generations. Considerable variation exists in the evolved multicellular life cycles, with both cell number and propagule size varying among isolates. Survival assays show that evolved multicellular traits provide effective protection against predation. These results support the hypothesis that selection imposed by predators may have played a role in some origins of multicellularity.

If we evolve multicellularity in response to predation, then the inverse–a loss of multicellularity, a splitting apart, can happen when predation is removed. 

The Democrats have faced a bit of controversy lately over the comments of Ilhan Omar (for the non-Americans in the audience, Ilhan Omar is a recently elected representative of Somali Muslim origins.) As Politico reports: 

Then, after being seated on the House Foreign Affairs Committee, Omar was lampooned for a 2012 tweet in which she wrote during an Israeli military campaign in the Gaza Strip, “Israel has hypnotized the world, may Allah awaken the people and help them see the evil doings of Israel.”  

Omar then made an idiotic non apology — “she claimed ignorance of the anti-Semitic trope that conceives of Jewish hypnosis.” 

Whether Omar knew it is a trope or not is irrelevant to the question of whether or not Omar was saying something anti-semitic–and even that is not necessarily grounds for an apology, because people apologize when they actually feel contrite about something. Omar most likely doesn’t.

Muslims have their interests; Jews have different interests. The existence of Israel is a big deal for Jews–it helps ensure that nasty incidents like the Holocaust don’t repeat. The existence of Israel is also a big deal for Palestinians, many of whom, I assume, would be living in the area if Jews weren’t. 

Conflicts over land are nothing new in human history, and it doesn’t require a degree in astrophysics to realize that sometimes groups have conflicting interests. Americans of the non-Jewish or Muslim variety also have their own interests (many desire, for example, that Israel continue existing for their own religious reasons–not hypnosis.) 

The left’s coalition requires different groups to work together (to ally) in their own self-interest, which works if they have bigger enemies to fear. It doesn’t work if they are strong enough to stand on their own feet (or if someone is too dumb to recognize the value of teamwork.) The ideological justification for allying is “intersectionality,” a term which has been bastardized well beyond its original meaning, but is now used to mean “all forms of oppression are really the same thing, so if you oppose one oppression, you must oppose them all.” So if you are against wife beating, you must also be vegan; if you are opposed to the police shooting unarmed black men, you must also be in favor of hijabs. “Interlocking systems of oppression” work to identify a single enemy, a necessary component for unifying people into something like a voting block or a military. 

And it works as long as there actually is a single enemy. 

It falls apart when you don’t have a single enemy, which is of course the world as it actually stands, because lots of groups have different interests and would like each other’s stuff. There isn’t actually anything magically special about cis-hetero-white-Christian-omnivorous-etc-men that makes them any more or less the oppressors of others. Over in Africa, Africans get oppressed by their fellow Africans. In Islamic countries, chickens get eaten by Muslims. In China, Christianity isn’t even remotely significant. 

In a related story, some British schools have recently seen their pro-LGBT curricula attacked by Muslim parents, who are, despite intersectionalist theory, actually pretty anti-homosexuality.

There is no real way to decide between these two points of view. The vast, vast majority of Muslims believe that homosexuality is a sin, and a school that goes out of its way to teach something counter to that is obviously running up against the students’ and parents’ right to their beliefs. Yet gay people also believe, with equal fervor, that homosexuality is morally respectable and they have a right to advocate on their own behalf and have a perfectly sensible desire to reach out to gay Muslims. 

The difficulty with victory is you don’t need your allies anymore; like the US and the USSR at the end of WWII, victorious allies are apt to turn on each other, fighting for what remains of the spoils. This is true of everyone, not just the left–it is just more interesting when it happens on the left because I’ve been pointing out that this would happen for years. 

Of course, some people react to this and say, “clearly the solution to our group splitting apart is to split our group apart; once our group is split, we will all have the same interests and no one will ever fight, just as children never fight with their siblings–hey knock it off in there STOP PUNCHING YOUR BROTHER you have to SHARE THAT TOY–“

Lack of predation => splitting doesn’t just stop at any particular level. 

297px-world_population_v3-svgThe other difficulty with splitting is that we live in a shrinking world. Up until the 1950s, the entire world had fewer than 3 billion people; today we have more than twice that many, and we’re still growing. Our cities are bigger, communities are expanding, transportation is better and faster, and more people have the money necessary to move to new places. More people than ever before are on the internet, watching TV, or otherwise interacting. 

Devour, get devoured, or make something new?

Links Post: Evolution and More

road-to-bigger-brains
From State of the Science: Finding Human Ancestors in New Places

The Puerto Rican rainforest is beautiful and temporarily low on bugs. (Bugs, I suspect, evolve quickly and so can bounce back from these sorts of collapses–but they are collapses.)

More evidence for an extra Neanderthal or Denisovan interbreeding event in East Asians and Melanesian genomes:

 In addition to the reported Neanderthal and Denisovan introgressions, our results support a third introgression in all Asian and Oceanian populations from an archaic population. This population is either related to the Neanderthal-Denisova clade or diverged early from the Denisova lineage.

(Congratulations to the authors, Mondal, Bertranpetit, and Lao.)

Really interesting study on gene-culture co-evolution in Northeast Asia:

Here we report an analysis comparing cultural and genetic data from 13 populations from in and around Northeast Asia spanning 10 different language families/isolates. We construct distance matrices for language (grammar, phonology, lexicon), music (song structure, performance style), and genomes (genome-wide SNPs) and test for correlations among them. … robust correlations emerge between genetic and grammatical distances. Our results suggest that grammatical structure might be one of the strongest cultural indicators of human population history, while also demonstrating differences among cultural and genetic relationships that highlight the complex nature of human cultural and genetic evolution.

I feel like there’s a joke about grammar Nazis in here.

Why do we sleep? No one knows.

While humans average seven hours, other primates range from just under nine hours (blue-eyed black lemurs) to 17 (owl monkeys). Chimps, our closest living evolutionary relatives, average about nine and a half hours. And although humans doze for less time, a greater proportion is rapid eye movement sleep (REM), the deepest phase, when vivid dreams unfold.

Sleep is pretty much universal in the animal kingdom, but different species vary greatly in their habits. Elephants sleep about two hours out of 24; sloths more than 15. Individual humans vary in their sleep needs, but interestingly, different cultures vary greatly in the timing of their sleep, eg, the Spanish siesta. Our modern notion that people “should” sleep in a solid, 7-9 hour chunk (going so far as to “train” children to do it,) is more a result of electricity and industrial work schedules than anything inherent or healthy about human sleep. So if you find yourself stressed out because you keep taking a nap in the afternoon instead of sleeping through the night, take heart: you may be completely normal. (Unless you’re tired because of some illness, of course.)

Interestingly:

Within any culture, people also prefer to rest and rise at different times: In most populations, individuals range from night owls to morning larks in a near bell curve distribution. Where someone falls along this continuum often depends on sex (women tend to rise earlier) and age (young adults tend to be night owls, while children and older adults typically go to bed before the wee hours).

Genes matter, too. Recent studies have identified about a dozen genetic variations that predict sleep habits, some of which are located in genes known to influence circadian rhythms.

While this variation can cause conflict today … it may be the vestige of a crucial adaptation. According to the sentinel hypothesis, staggered sleep evolved to ensure that there was always some portion of a group awake and able to detect threats.

So they gave sleep trackers to some Hadza, who must by now think Westerners are very strange, and found that at any particular period of the night, about 40% of people were awake; over 20 nights, there were “only 18 one-minute periods” when everyone was asleep. That doesn’t prove anything, but it does suggest that it’s perfectly normal for some people to be up in the middle of the night–and maybe even useful.

Important dates in the evolution of human brain genes found:

In May, a pair of papers published by separate teams in the journal Cell focused on the NOTCH family of genes, found in all animals and critical to an embryo’s development: They produce the proteins that tell stem cells what to turn into, such as neurons in the brain. The researchers looked at relatives of the NOTCH2 gene that are present today only in humans.

In a distant ancestor 8 million to 14 million years ago, they found, a copying error resulted in an “extra hunk of DNA,” says David Haussler of the University of California, Santa Cruz, a senior author of one of the new studies.

This non-functioning extra piece of NOTCH2 code is still present in chimps and gorillas, but not in orangutans, which went off on their own evolutionary path 14 million years ago.

About 3 million to 4 million years ago, a few million years after our own lineage split from other apes, a second mutation activated the once non-functional code. This human-specific gene, called NOTCH2NL, began producing proteins involved in turning neural stem cells into cortical neurons. NOTCH2NL pumped up the number of neurons in the neocortex, the seat of advanced cognitive function. Over time, this led to bigger, more powerful brains. …

The researchers also found NOTCH2NL in the ancient genomes of our closest evolutionary kin: the Denisovans and the Neanderthals, who had brain volumes similar to our own.

And finally, Differences in Genes’ Geographic Origins Influence Mitochondrial Function:

“Genomes that evolve in different geographic locations without intermixing can end up being different from each other,” said Kateryna Makova, Pentz Professor of Biology at Penn State and an author of the paper. “… This variation has a lot of advantages; for example, increased variation in immune genes can provide enhanced protection from diseases. However, variation in geographic origin within the genome could also potentially lead to communication issues between genes, for example between mitochondrial and nuclear genes that work together to regulate mitochondrial function.”

Researchers looked at recently (by evolutionary standards) mixed populations like Puerto Ricans and African Americans, comparing the parts of their DNA that interact with mitochondria to the parts that don’t. Since mitochondria hail from your mother, and these populations have different ethnic DNA contributions along maternal and paternal lines. If all of the DNA were equally compatible with their mitochondria, then we’d expect to see equal contributions to the specifically mitochondria-interacting genes. If some ethnic origins interact better with the mitochondria, then we expect to see more of this DNA in these specific places.

The latter is, in fact, what we find. Puerto Ricans hail more from the Taino Indians along their mtDNA, and have relatively more Taino DNA in the genes that affect their mitochondria–indicating that over the years, individuals with more balanced contributions were selected against in Puerto Rico. (“Selection” is such a sanitized way of saying they died/had fewer children.)

This indicates that a recently admixed population may have more health issues than its parents, but the issues will work themselves out over time.

Notes from E. O. Wilson’s Sociobiology

 

a-giraffe-walks-behand-a-termite-mound-in-the-bushland-of-the-okavango-delta-in-botswana-1600x1066-1024x682
Termite Mound aka Termitary

I recently came across a copy of E. O. Wilson’s Sociobiology (the textbook, 1977 edition) at the secondhand shop.

In The Blank Slate, Steven Pinker gives about the best recommendation I can think of for Wilson’s book:

At Harvard there were leaflets and teach-ins, a protester with a bullhorn calling for Wilson’s dismissal, and invasions of his classroom by slogan-shouting students. When he spoke at other universities, posters called him the “Right-Wing-Prophet of Patriarchy” and urged people to bring noisemakers to his lectures. Wilson was about to speak at a 1978 meeting of the American Association for the Advancement of Science when a group of people carrying placards (one with a swastika) rushed onto the stage chanting, “Racist Wilson, you can’t hide, we charge you with genocide.” One protester grabbed the microphone and harangued the audience while another doused Wilson with a pitcher of water.

Pretty intense for a guy whose career is mostly about ants.

Since it is easier to remember what you have read if you take notes and then transcribe them, and this thing is 574 pages long, I’ll be transcribing some of my notes here as I go along.

The book gives lots of interesting examples of different concepts. For example, in the section on parasitism, there’s an example of a variety of termite that moves into and eats the nests of other termites, thus making a termite mound-in-a-mound, I suppose. To be fair, some termite mounds are about as big as a house and so this is a totally reasonable thing for termites to do.

Chapter 1: The morality of the Gene

Camus said that the only serious philosophical question is suicide.

That is wrong even in the strict sense intended. …

From now on, let’s use “” instead of blockquotes.

Chapter 2: Elementary Concepts

“Genes, like Leibnitz’s monads, have no windows; the higher properties of life are emergent. To specify an entire cell, we are compelled to provide not only the nucleotide sequences but also the identity and configuration of other kinds of molecules placed in and around the cells. To specify an organism requires still more information about both the properties of the cells and their spacial positions. And once assembled, organisms have no windows. A society can be described only as a set of particular organisms, and even then it is difficult to extrapolate the joint activity of this ensemble from the instant of specification, that is, to predict social behavior. …

“Society: a group of individuals belonging to the same species and organized in a cooperative manner. … Yet aggregation, sexual behavior, and territoriality are important properties of true societies, and they are correctly referred to as social behavior. … Since the bond of the society is simply and solely communication, its boundaries can be defined in terms of the curtailment of communication.”

EvX: I have been thinking for a long time about language as effective barriers of culture. Not that culture can’t cross language barriers (movies get dubbed all the time,) but it’s much harder. And since some languages are easier to learn than others, (eg, Finnish is harder than German if you speak English,) cross-language communication is probably easier between some groups than others. The Finns (and a few other European groups) speak non-Indo-European languages, which might make them more functionally isolated within the European context than, say, their neighbors in Sweden.

Back to Wilson:

“Individual: Any physically distinct organism… The distinction between the individual and the colony can be especially baffling in the sponges. … [Hah.]

“Population: A set of organisms belonging to the same species and occupying a clearly delimited area at the same time. This unit… is defined in terms of genetic continuity. In the case of sexually reproducing organisms, the population is a geographically delimited set of organisms capable of freely interbreeding with one another under natural conditions. …

“In sexually reproducing forms, including the vast majority of social organisms, a species is a population or set of populations within which the individuals are capable of freely interbreeding under natural conditions. By definition the members of the species do not interbreed freely with those of other species, however closely related they may be genetically. … In establishing the limits of a species it is not enough merely to prove that genes of two or more populations can be exchanged under experimental conditions. The population must be demonstrated to interbreed fully in the free state.”

[Example: Lions and Tigers can interbreed, yet even in places where their ranges historically overlapped, no one ever reported finding wild ligers or tigons. While they can interbreed in zoos, their behavior is different enough in the wild that it doesn’t happen.]

EvX: And here’s where people ask about Sapiens and Neanderthals. Yes, they interbred. But it looks like they didn’t interbreed much (while they bred plenty with their own,) and it also looks like there’s been a fair amount of selection against Neanderthal DNA in modern humans, winnowing down the genes passed on to us. For example, there’s pretty much no Neanderthal DNA on the Y chromosome, suggesting that any sons of Neanderthal-Sapiens unions were infertile (or didn’t make it at all.) There’s also no (known) Neanderthal mtDNA, suggesting that the matings that did happen involved Neanderthal men with Sapiens women–or if the opposite pairing happened, those children were brought into Neanderthal tribes. At any rate, the pattern is far from complete interfertility.

Back to Wilson:

“A population that differs significantly from other populations belonging to the same species is referred to as a geographic race or subspecies. Subspecies are separated from other subspecies by distance and geographic barriers that prevent the exchange of individuals, as opposed to the genetically based “intrinsic isolating mechanisms” that hold species apart. Subspecies, insofar as they can be distinguished with any objectivity at all, show every conceivable degree of differentiation from other subspecies. At one extreme are the populations that fall along a cline–a simple gradient in the geographic variation of a given character. In other words, a character that varies in a clinal pattern is one that changes gradually over a substantial portion of the entire range of the species. At the other extreme are subspecies consisting of easily distinguished populations that are differentiated from one another by numerous genetic traits and exchange genes across a narrow zone of intergradation.

The main obstacle in dealing with the population as a unit… is the practical difficulty of deciding the limits of particular populations.”

EvX: I would like to point out that humans made up these words to carve up a part of reality that doesn’t always carve that easily. For example, it may be obvious that a wolf species that ranges over thousands of miles is pretty different at the far east and far western extent of its range, but there may be no exact spot in between where the eastern type ends and the western type begins. By contrast, sometimes in human societies you have groups of genetically and culturally distinct people separated for centuries by little more than a road, a wall, a religion, or a language. There is no a priori reason to think that one of these cases fits the definition and the other does not.

But the language we use to delineate groups of ants or wolves or fungi is not the language we use to delineate humans, not just because we wish to be inaccurate, but also because we generally wish to show each other respect. We do so by avoiding language normally reserved for non-humans and using special terms for humans, eg, my offspring are normally referred to as my “children.”

Back to Wilson.

“What is the relation between the population and the society? Here we arrive unexpectedly at the crux of theoretical sociobiology. The distinction between the two categories is essentially as follows: the population is bounded by a zone of sharply reduced gene flow, while the society is bounded by a zone of sharply reduced communication. Often the two zones are the same…

The Multiplier Effect

Social organization is the class of phenotypes furthest removed from the genes. It is derived jointly from the behavior of the individuals and the demographic properties of the population… A small evolutionary change in the behavior pattern of individuals can be amplified into a major social effect by the expanding upward distribution of the effect into multiple facets of life. …

“Even stronger multiplier effects occur in the social insects. … The structure of nests alone can be used to distinguish species within the higher termites.”

EvX: There follows an interesting description of how termites build their mounds, also known as “termitaries.”

“Multiplier effects can speed social evolution still more when an individual’s behavior is strongly influenced by the particularities of its social experience. This process, called socialization, becomes increasingly becomes increasingly prominent as one moves upward phylogenetically into more intelligent species, and it reaches its maximum influence in the higher primates. Although the evidence is still largely inferential, socialization appears to amplify phenotypic differences among primate species.

S”ocialization can also amplify genetically based variation of individual behavior within troops. The temperament and rank of a higher primate is strongly influenced by its early experiences with its peers and its mother.”

EvX: This is a really interesting idea. We hear constantly that ideas like race and gender are social constructs, but what exactly a social construct is we hear far less often. The implication–at least as the phrases are employed–is that they are not real at all, that they are make believe, that we have chosen some random and arbitrary place to carve up reality and that we could use some other random place just as well, but Wilson provides a much better conception: “social constructs” are really amplified ideas about the world around us. In other words, they’re exaggerated stereotypes.

For example, let’s imagine a world in which the average male is taller than the average female, but there’s a lot of variety in height and so there are many individual men who are shorter than a good chunk of women, and likewise many women who are taller than a decent chunk of men. The idea that “men are taller than women” is of course true on average, but also an exaggeration. Men who are particularly short and women who are particularly tall may dislike the fact that they don’t match this Platonic ideal.

Back to Wilson:

“The Evolutionary Pacemaker and Social Drift

“…when evolution involves both structure and behavior, behavior should change first and then structure. In other words, behavior should be the evolutionary pacemaker. … Social behavior also frequently serves as an evolutionary pacemaker. The entire process of ritualization, during which a behavior is transformed by evolution into a more efficient signaling device, typically involves a behavioral change followed by morphological alterations that enhance the visibility and distinctiveness of the behavior.

“The relative lability of behavior leads inevitably to social drift, the random divergence in the behavior and mode of organization of societies or groups of societies. …

“The amount of variance within a population of societies is the sum of the variations due to genetic drift, tradition drift, and their interaction. … Even if the alteration to social structure of a group is due to a behavioral change in a key individual, we cannot be sure that this member was not predisposed to the act by a distinctive capability or temperament conferred by a particular set of genes …

“…Cavalli-Sforza and Feldman (1973) have suggested that in human social evolution the equivalent of an important mutation is a new idea. If it is acceptable and advantageous, the idea will spread quickly. If not, it will decline in frequency and he forgotten. Tradition drift in such instances, like purely genetic drift, has stochastic properties amenable to mathematical analysis.”

EvX: Good old memes. How I love them.

Adaptive Demography

“All true societies are differentiated populations. When cooperative behavior evolves it is put to service by one kind of individual on behalf of another, either unilaterally or mutually…

“The proportions of the demographic classes [like old and young people] also affect the fitness of the group and, ultimately, of each individual member… a deviant population allowed to reproduce for one to several generations will go far to restore the age distribution of populations normal for the species.”

EvX: By “deviant population” he means a population that has more or less of a particular class than is ideal, like if an ant colony lost half of its workers in an accident or a plague wiped out most of the children in a society.

Nature_trees_dark_night_forest_moon_1920x1200“Only if its growth is zero when averaged over many generations can the population have a chance of long life. There is one remaining way to be a success. A population headed for extinction can still possess a high degree of fitness if it succeeds in sending out propagules and creates new populations elsewhere.”

EvX: Your destiny is the stars.

And with that, I’m taking off for the evening.