Recent Exciting Developments in Human Evolutionary History: Naledi and Flores

A reconstruction of Homo naledi’s head by paleoartist John Gurche, who spent some 700 hours recreating the head from bone scans. Image credit: John Gurche / Mark Thiessen / National Geographic. source:

Continuing with our series on recent exciting discoveries in human genetics/paleo anthropology:

• Ancient hominins in the US?
• Homo naledi
• Homo flores
• Humans evolved in Europe?
• In two days, first H Sap was pushed back to 260,000 years,
• then to 300,000 years!
• Bell beaker paper

One of the most interesting things about our human family tree (the Homo genus and our near primate relatives, chimps, gorillas, orangs, gibbons, etc.) is that for most of our existence, “we” weren’t the only humans in town. We probably coexisted, mated with, killed, were killed by, and at times perhaps completely ignored 7 other human species–Homo erectus, floresiensis, Neanderthals, Denisovans, heidelbergensis, rhodesiensis, and now Naledi.

That said, these “species” are a bit controversial. Some scientists like to declare practically every jawbone and skull fragment they find a new species (“splitters”,) and some claim that lots of different bones actually just represent natural variation within a species (“lumpers.”)

Take the canine family: dogs and wolves can interbreed, but I doubt great danes and chihuahuas can. For practical purposes, though, the behavior of great danes and chihuahuas is similar enough to each other–and different enough from wolves’–that we class them as one species and wolves as another. Additionally, when we take a look at the complete variety of dogs in existence, it is obvious that there is actually a genetic gradient in size between the largest and smallest breeds, with few sharp breaks (maybe the basenji.) If we had a complete fossil record, and could reliably reconstruct ancient hominin behaviors and cultural patterns, then we could say with far more confidence whether we are looking at something like dogs vs. wolves or great danes vs. chihuahuas. For now, though, paleoanthropology and genetics remain exciting fields with constant new discoveries!

Homo naledi and homo Floresiensis may ultimately be small branches on the human tree, but each provides us with a little more insight into the whole.

Naledi’s story is particularly entertaining. Back in 2013, some spelunkers crawled through a tiny opening in a South African cave and found a chamber full of bones–hominin bones.

Anthropologists often have to content themselves with a handful of bones, sometimes just a fragment of a cranium or part of a jaw. (The recent claim that humans evolved in Europe is based entirely on a jaw fragment plus a few teeth.) But in the Rising Star Cave system, they found an incredible 1,500+ bones or bone fragments, the remains of at least 15 people, and they haven’t even finished excavating.

According to Wikipedia:

The physical characteristics of H. naledi are described as having traits similar to the genus Australopithecus, mixed with traits more characteristic of the genus Homo, and traits not known in other hominin species. The skeletal anatomy displays plesiomorphic (“ancestral”) features found in the australopithecines and more apomorphic (“derived,” or traits arising separately from the ancestral state) features known from later hominins.^[2]

Adult males are estimated to have stood around 150 cm (5 ft) tall and weighed around 45 kg (100 lb), while females would likely have been a little shorter and weighed a little less. An analysis of H. naledi‘s skeleton suggests it stood upright and was bipedal.^[2][22][23] Its hip mechanics, the flared shape of the pelvis are similar to australopithecines, but its legs, feet and ankles are more similar to the genus Homo.^[2][24]

I note that the modern humans in South Africa are also kind of short–According to Time, the Bushmen average about 5 feet tall, (that’s probably supposed to be Bushmen men, not the group average,) and the men of nearby Pygmy peoples of central Africa average 4’11” or less.

The hands of H. naledi appear to have been better suited for object manipulation than those of australopithecines.^[2][25] Some of the bones resemble modern human bones, but other bones are more primitive than Australopithecus, an early ancestor of humans. The thumb, wrist, and palm bones are modern-like while the fingers are curved, more australopithecine, and useful for climbing.^[3] The shoulders are configured largely like those of australopithecines. The vertebrae are most similar to Pleistocene members of the genus Homo, whereas the ribcage is wide distally as is A. afarensis.^[2] The arm has an Australopithecus-similar shoulder and fingers and a Homo-similar wrist and palm.^[24] The structure of the upper body seems to have been more primitive than that of other members of the genus Homo, even apelike.^[3] In evolutionary biology, such a mixture of features is known as an anatomical mosaic.

Four skulls were discovered in the Dinaledi chamber, thought to be two females and two males, with a cranial volume of 560 cm³ (34 cu in) for the males and 465 cm³ (28.4 cu in) for females, about 40% to 45% the volume of modern human skulls; average Homo erectus skulls are 900 cm³ (55 cu in). A fifth, male skull found in the Lesedi chamber has a larger estimated cranial volume of 610 cm³ (37 cu in) ^[6]. The H. naledi skulls are closer in cranial volume to australopithecine skulls.^[3] Nonetheless, the cranial structure is described as more similar to those found in the genus Homo than to australopithecines, particularly in its slender features, and the presence of temporal and occipitalbossing, and the fact that the skulls do not narrow in behind the eye-sockets.^[2] The brains of the species were markedly smaller than modern Homo sapiens, measuring between 450 and 610 cm³ (27–37 cu in). The teeth and mandiblemusculature are much smaller than those of most australopithecines, which suggests a diet that did not require heavy mastication.^[2] The teeth are small, similar to modern humans, but the third molar is larger than the other molars, similar to australopithecines.^[24] The teeth have both primitive and derived dental development.^[26]

The overall anatomical structure of the species has prompted the investigating scientists to classify the species within the genus Homo, rather than within the genus Australopithecus. The H. naledi skeletons indicate that the origins of the genus Homo were complex and may be polyphyletic (hybrid), and that the species may have evolved separately in different parts of Africa.^[27][28]

Because caves don’t have regular sediment layers like riverbeds or floodplains, scientists initially had trouble dating the bones. Because of their relative “primitiveness,” that is, their similarity to our older, more ape-like ancestors, they initially thought Homo naledi must have lived a long time ago–around 2 million years ago. But when they finally got the bones dated, they found they were much younger–only around 335,000 and 236,000 years old^,[1][4] which means H naledi and Homo sapiens–whose age was also recently adjusted–actually lived at the same time, though not necessarily in the same place.

(On the techniques used for dating the bones:

Francis Thackeray, of the University of the Witwatersrand, suggested that H. naledi lived 2 ± 0.5 million years ago, based on the skulls’ similarities to H. rudolfensis, H. erectus, and H. habilis, species that existed around 1.5, 2.5, and 1.8 million years ago, respectively.^[35][36] Early estimates derived from statistical analysis of cranial traits yielded a range of 2 million years to 912,000 years before present.^[2][37][38]

Dirks et al. (2017) obtained a much more recent age range of between 335,000 and 236,000 years ago from dating fossil teeth, sediments encasing the fossils and overlying flowstone. They used a variety of dating techniques, including radiocarbon dating of teeth, optically stimulated luminescence of sediment, palaeomagnetic analysis of flowstone, and most conclusively, uranium-thorium dating of cave flowstone and teeth and electron spin resonance dating of teeth.^[1][4] The latter two types of measurements of teeth were performed on blind duplicate samples by two different labs.^[1])

H naledi is unlikely to be a major branch on the human family tree–much too recent to be one of our ancestors–but it still offers important information on the development of “human” traits and how human and ape-like traits can exist side-by-side in the same individual (a theme we will return to later.) (Perhaps, just as we modern Homo sapiens contain traits derived from ancestors who mated with Neanderthals, Denisovans, and others, H naledi owes some of its traits to hybridization between two very different hominins.) It’s also important because it is one more data point in favor of the recent existence of a great many different human varieties, not just a single group.

Flores Hobbit aka Homo floresiensis source

The Flores hominin, (aka the Hobbit,) tells a similar tale, but much further afield from humanity’s evolutionary cradle.

The island of Flores is part of the Indonesian archipelago, a surprisingly rich source of early hominin fossils. Homo erectus, the famous Java Man, arrived in the area around 1.7 million years ago, but to date no erectus remains have been discovered on the actual island of Flores. During the last Glacial Maximum, ocean levels were lower and most of Indonesia was connected in a single continent, called Sundaland. During one of these glacial periods, H erectus could have easily walked from China to Java, but Flores remained an island, cut off from the mainland by several miles of open ocean.

Stone tools appeared on Flores about 1 million years ago, though we don’t know yet who made them, nor how they developed the technology necessary to make the journey.

The diminutive Hobbits show up later, around 50,000 to 100,000 years ago, though stone tools recovered alongside their remains have been dated from 50,000 to 190,000 years ago. Homo erectus is generally believed to have lived between 2 million and 140,000 years ago, and Homo sapiens arrived in Indonesia around 50,000 years ago. This places Floresiensis neatly between the two–it could have interacted with either species–perhaps descended from erectus and wiped out, in turn, by sapiens. (Or perhaps floresiensis represents an altogether novel line of hominins who left Africa on a completely separate trek from erectus.)

Unlike H naledi, whose diminutive stature is still within the current human range (especially of humans in the area,) floresiensis is exceptionally small for a hominin. According to Wikipedia:

The first set of remains to have been found, LB1, was chosen as the type specimen for the proposed species. LB1 is a fairly complete skeleton, including a nearly complete cranium (skull), determined to be that of a 30-year-old female. LB1 has been nicknamed the Little Lady of Flores or “Flo”.^[2]

LB1’s height has been estimated at about 1.06 m (3 ft 6 in). The height of a second skeleton, LB8, has been estimated at 1.09 m (3 ft 7 in) based on measurements of its tibia.^[3] These estimates are outside the range of normal modern human height and considerably shorter than the average adult height of even the smallest modern humans, such as the Mbenga and Mbuti (< 1.5 m (4 ft 11 in)),^[32] Twa, Semang (1.37 m (4 ft 6 in) for adult women) of the Malay Peninsula,^[33] or the Andamanese (1.37 m (4 ft 6 in) for adult women).^[34]

By body mass, differences between modern pygmies and Homo floresiensis are even greater. LB1’s body mass has been estimated at 25 kg (55 lb). This is smaller than that of not only modern H. sapiens, but also H. erectus, which Brown and colleagues have suggested is the immediate ancestor of H. floresiensis. LB1 and LB8 are also somewhat smaller than the australopithecines from three million years ago, not previously thought to have expanded beyond Africa. Thus, LB1 and LB8 may be the shortest and smallest members of the extended human family discovered thus far.^{[citation needed]}

Aside from smaller body size, the specimens seem otherwise to resemble H. erectus, a species known to have been living in Southeast Asia at times coincident with earlier finds purported to be of H. floresiensis.^[3]

There’s a lot of debate about whether floresiensis is a real species–perhaps affected by insular dwarfism–or just a hominin that had some severe problems. Interestingly, we have a find from about 700,000 years ago on Flores of another hominin, which we think was also a Hobbit, but is even smaller than Flo and her relatives.

Floresiensis, like Naledi, didn’t contribute to modern humans. Rather, it is interesting because it shows the breadth of our genus. We tend to assume that, ever since we split off from the rest of the great apes, some 7 or 8 million years ago, our path has been ever upward, more complex and successful. But these Hobbits, most likely descendants of one of the most successful human species, (Homo erectus, who mastered fire, was the first to leave Africa, spread across Asia and Indonesia, and lasted for over a million and half years, far longer than our puny 300,000 years,) went in the opposite direction from its ancestors. It became much smaller than even the smallest living human groups. Its brain shrank:

In addition to a small body size, H. floresiensis had a remarkably small brain size. The brain of the holotype LB1 is estimated to have had a volume of 380 cm³ (23 cu in), placing it at the range of chimpanzees or the extinct australopithecines.^[2][40] LB1’s brain size is half that of its presumed immediate ancestor, H. erectus (980 cm³ (60 cu in)).^[40] The brain-to-body mass ratio of LB1 lies between that of H. erectus and the great apes.^[41]

Nevertheless, it still made tools, probably controlled fire, and hunted cooperatively.

Whatever it was, it was like us–and very much not like us.

 

More on Naledi: Another Awesome Twig on our Human Family Tree and Homo Naledi was Chipping its Teeth Amazingly Often.

Gay marriage didn’t win; traditional marriage lost

From the evolutionist point of view, the point of marriage is the production of children.

Let’s quickly analogize to food. Humans have a tremendous variety of customs, habits, traditions, and taboos surrounding foods. Foods enjoyed in one culture, like pork, crickets, and dog, are regarded as disgusting, immoral, or forbidden in another. Cheese is, at heart, rotten vomit–the enzyme used to make cheese coagulate is actually extracted from a calf’s stomach lining–and yet the average American eats it eagerly.

Food can remind you of your childhood, the best day of your life, the worst day of your life. It can comfort the sick and the mourning, and it accompanies our biggest celebrations of life.

Eh, I’d be happy giving him a microstate and seeing how he does running it.

We eat comfort food, holiday food, even sacrificial food. We have decadent luxuries and everyday staples. Some people, like vegans and ascetics, avoid large classes of food generally eaten by their own society for moral reasons.

People enjoy soda because it has water and calories, but some of us purposefully trick our taste buds by drinking Diet Coke, which delivers the sensation of drinking calories without the calories themselves. We enjoy the taste of calories even when we don’t need any more.

But the evolutionary purpose of eating is to get enough calories and nutrients to survive. If tomorrow we all stopped needing to eat–say, we were all hooked into a Matrix-style click-farm in which all nutrients were delivered automatically via IV–all of the symbolic and emotional content attached to food would wither away.

The extended helplessness of human infants is unique in the animal kingdom. Even elephants, who gestate for an incredible two years and become mature at 18, can stand and begin walking around shortly after birth. Baby elephants are not raised solely by their mothers, as baby rats are, but by an entire herd of related female elephants.

Elephants are remarkable animals, clever, communicative, and caring, who mourn their dead and create art:

But from the evolutionist point of view, the point of elephants’ family systems is still the production of elephant children.

Love is a wonderful, sweet, many-splendored thing, but the purpose of marriage, in all its myriad forms–polygamy, monogamy, polyandry, serial monogamy–is still the production of children.

There are a few societies where marriage as we know it is not really practiced because people depend on alternative kin networks or women can largely provide for themselves. For example, 70% of African American children are born out of wedlock; and among the avuncular Apache:

In the Southwest United States, the Apache tribe practices a form of this, where the uncle is responsible for teaching the children social values and proper behavior while inheritance and ancestry is reckoned through the mother’s family alone. (Modern day influences have somewhat but not completely erased this tradition.)

source: BBC News

Despite the long public argument over the validity of gay marriage, very few gay people actually want to get married. Gallop reports that after the Obergefell v. Hodges ruling, the percent of married gay people jumped quickly from 7.9% to 9.5%, but then leveled off, rising to only 9.6% by June 2016.

In contrast, 46% of US adults are married.

Even this number, though, is in sharp decline: in 1960, 72% of adults were married; by 2010, only 51% were.

The situation is similar throughout the Western world. Only 51% of Brits are married. In Italy, the crude marriage rate (the number of new marriages per 1,000 people), has fallen from 7.35 in 1970 to only 4.21 in 2007. Only 58.9% of Japanese are married.

Declining marriage rates across the developed world have been accompanied by declining fertility rates and rising illegitimacy rates:

Graph showing children per woman rate over the years 1960 – 2009 in USA, China, India, Germany, Russia population rates.

H/T: Share of Births to Unmarried Mothers by Race

As Wikipedia notes:

Only 2% of [Japanese] births occur outside of marriage^[35] (compared to 30-60% in Europe and North America) due to social taboos, legal pressure, and financial hurdles.^[32] Half of Japan’s single mothers live below the poverty line, among the highest for OECD countries.^{[36][37][38][39]}

In other words, the Japanese welfare state, while generous, does not encourage single motherhood. Wikipedia also provides a discussion of the causes of declining Japanese marriage rates:

The annual number of marriages has dropped since the early 1970s, while divorces have shown a general upward trend.^{[29] …}

The decline of marriage in Japan, as fewer people marry and do so later in life, is a widely cited explanation for the plummeting birth rate.^{[29][30][31][32]} Although the total fertility rate has dropped since the 1970s (to 1.43 in 2013^[33]), birth statistics for married women have remained fairly constant (at around 2.1) and most married couples have two or more children. Economic factors, such as the cost of raising a child, work-family conflicts, and insufficient housing, are the most common reasons for young mothers (under 34) to have fewer children than desired. …

Between 1990 and 2010, the percentage of 50-year-old people who had never married roughly quadrupled for men to 20.1% and doubled for women to 10.6%.^[41][42] The Welfare Ministry predicts these numbers to rise to 29% of men and 19.2% of women by 2035.^[43] The government’s population institute estimated in 2014 that women in their early 20s had a one-in-four chance of never marrying, and a two-in-five chance of remaining childless.^[44]

Recent media coverage has sensationalized surveys from the Japan Family Planning Association and the Cabinet Office that show a declining interest in dating and sexual relationships among young people, especially among men.^[44][45][46] However, changes in sexuality and fertility are more likely an outcome of the decline in family formation than its cause.^[47][48] Since the usual purpose of dating in Japan is marriage, the reluctance to marry often translates to a reluctance to engage in more casual relationships.^[30]

In other words, marriage is functionally about providing a supportive way of raising children. In a society where birth control does not exist, children born out of wedlock tend not to survive, and people can easily get jobs to support their families, people tended to get married and have children. In a society where people do not want children, cannot afford them, are purposefully delaying childbearing as long as possible, or have found ways to provide for them without getting married, people simply see no need for marriage.

“Marriage” ceases to mean what it once did, reserved for old-fashioned romantics and the few lucky enough to afford it.

Mass acceptance of gay marriage did change how people think of marriage, but it’s downstream from what the massive, societal-wide decrease in child-bearing and increase in illegitimacy have done to our ideas about marriage.

Musical Mystery

Singer Tom Jones, famous recipient of ladies’ panties

There are three categories of supersars who seem to attract excessive female interest. The first is actors, who of course are selected for being abnormally attractive and put into romantic and exciting narratives that our brains subconsciously interpret as real. The second are sports stars and other athletes, whose ritualized combat and displays of strength obviously indicate their genetic “fitness” for siring and providing for children.

The third and strangest category is professional musicians, especially rock stars.

I understand why people want to pass athletic abilities on to their children, but what is the evolutionary importance of musical talent? Does music tap into some deep, fundamental instinct like a bird’s attraction to the courtship song of its mate? And if so, why?

There’s no denying the importance of music to American courtship rituals–not only do people visit bars, clubs, and concerts where music is being played in order to meet potential partners, but they also display musical tastes on dating profiles in order to meet musically-like-minded people.

Of all the traits to look for in a mate, why rate musical taste so highly? And why do some people describe their taste as, “Anything but rap,” or “Anything but country”?

Mick Jagger and Chuck Berry

At least when I was a teen, musical taste was an important part of one’s “identity.” There were goths and punks, indie scene kids and the aforementioned rap and country fans.

Is there actually any correlation between musical taste and personality? Do people who like slow jazz get along with other slow jazz fans better than fans of classical Indian? Or is this all compounded by different ethnic groups identifying with specific musical styles?

Obviously country correlates with Amerikaner ancestry; rap with African American. I’m not sure what ancestry is biggest fans of Die Antwoord. Heavy Metal is popular in Finno-Scandia. Rock ‘n Roll got its start in the African American community as “Race Music” and became popular with white audiences after Elvis Presley took up the guitar.

While Europe has a long and lovely musical heritage, it’s indisputable that African Americans have contributed tremendously to American musical innovation.

Here are two excerpts on the subject of music and dance in African societies:

source: A Voyage to Senegal: The Isle of Goreé, and the River Gambia by  Michel Adanson, Correspondent of the Royal Academy of Sciences

and:

source: Africana: The Encyclopedia of the African and African American Experience Aardvark-Catholic. Vol. 1

Elvis’s pelvis, considered too sexy for TV

Both of these h/t HBD Chick and my apologies in advance if I got the sources reversed.

One of the major HBD theories holds that the three races vary–on average–in the distribution of certain traits, such as age of first tooth eruption or intensity of an infant’s response to a tissue placed over its face. Sub-Saharan Africans and Asians are considered two extremes in this distribution, with whites somewhere in between.

If traditional African dancing involves more variety in rhythmic expression than traditional European, does traditional Asian dance involve less? I really know very little about traditional Asian music or dance of any kind, but I would not be surprised to see some kind of continuum affected by whether a society traditionally practiced arranged marriages. Where people chose their own mates, it seems like they display a preference for athletic or musically talented mates (“sexy” mates;) when parents chose mates, they seem to prefer hard-working, devout, “good providers.”

Natasha Rostova and Andrei Bolkonsky, from War and Peace by Tolstoy

Even in traditional European and American society, where parents played more of a role in courtship than they do today, music still played a major part. Young women, if their families could afford it, learned to play the piano or other instruments in order to be “accomplished” and thus more attractive to higher-status men; young men and women often met and courted at musical events or dances organized by the adults.

It is undoubtedly true that music stirs the soul and speaks to the heart, but why?

 

Is Racism an Instinct?

Everyone is a little bit racist–Hillary Clinton

If everyone in the world exhibits a particular behavior, chances are it’s innate. But I have been informed–by Harvard-educated people, no less–that humans do not have instincts. We are so smart, you see, that we don’t need instincts anymore.

This is nonsense, of course.

One amusing and well-documented human instinct is the nesting instinct, experienced by pregnant women shortly before going into labor. (As my father put it, “When shes starts rearranging the furniture, get the ready to head to the hospital.”) Having personally experienced this sudden, overwhelming urge to CLEAN ALL THE THINGS multiple times, I can testify that it is a real phenomenon.

Humans have other instincts–babies will not only pick up and try to eat pretty much anything they run across, to every parent’s consternation, but they will also crawl right up to puddles and attempt to drink out of them.

But we’re getting ahead of ourselves: What, exactly, is an instinct? According to Wikipedia:

Instinct or innate behavior is the inherent inclination of a living organism towards a particular complex behavior. The simplest example of an instinctive behavior is a fixed action pattern (FAP), in which a very short to medium length sequence of actions, without variation, are carried out in response to a clearly defined stimulus.

Any behavior is instinctive if it is performed without being based upon prior experience (that is, in the absence of learning), and is therefore an expression of innate biological factors. …

Instincts are inborn complex patterns of behavior that exist in most members of the species, and should be distinguished from reflexes, which are simple responses of an organism to a specific stimulus, such as the contraction of the pupil in response to bright light or the spasmodic movement of the lower leg when the knee is tapped.

The go-to example of an instinct is the gosling’s imprinting instinct. Typically, goslings imprint on their mothers, but a baby gosling doesn’t actually know what its mother is supposed to look like, and can accidentally imprint on other random objects, provided they are moving slowly around the nest around the time the gosling hatches.

Stray dog nursing kittens

Here we come to something I think may be useful for distinguishing an instinct from other behaviors: an instinct, once triggered, tends to keep going even if it has been accidentally or incorrectly triggered. Goslings look like they have an instinct to follow their mothers, but they actually have an instinct to imprint on the first large, slowly moving object near their nest when they hatch.

So if you find people strangely compelled to do something that makes no sense but which everyone else seems to think makes perfect sense, you may be dealing with an instinct. For example, women enjoy celebrity gossip because humans have an instinct to keep track of social ranks and dynamics within their own tribe; men enjoy watching other men play sports because it conveys the vicarious feeling of defeating a neighboring tribe at war.

So what about racism? Is it an instinct?

Strictly speaking–and I know I have to define racism, just a moment–I don’t see how we could have evolved such an instinct. Races exist because major human groups were geographically separated for thousands of years–prior to 1492, the average person never even met a person of another race in their entire life. So how could we evolve an instinct in response to something our ancestors never encountered?

Unfortunately, “racism” is a chimera, always changing whenever we attempt to pin it down, but the Urban Dictionary gives a reasonable definition:

An irrational bias towards members of a racial background. The bias can be positive (e.g. one race can prefer the company of its own race or even another) or it can be negative (e.g. one race can hate another). To qualify as racism, the bias must be irrational. That is, it cannot have a factual basis for preference.

Of course, instincts exist because they ensured our ancestors’ survival, so if racism is an instinct, it can’t exactly be “irrational.” We might call a gosling who follows a scientist instead of its mother “irrational,” but this is a misunderstanding of the gosling’s motivation. Since “racist” is a term of moral judgment, people are prone to defending their actions/beliefs towards others on the grounds that it can’t possibly be immoral to believe something that is actually true.

The claim that people are “racist” against members of other races implies, in converse, that they exhibit no similar behaviors toward members of their own race. But even the most perfunctory overview of history reveals people acting in extremely “racist” ways toward members of their own race. During the Anglo-Boer wars, the English committed genocide against the Dutch South Africans (Afrikaners.) During WWII, Germans allied with the the Japanese and slaughtered their neighbors, Poles and Jews. (Ashkenazim are genetically Caucasian and half Italian.) If Hitler were really racist, he’d have teamed up with Stalin and Einstein–his fellow whites–and dropped atomic bombs on Hiroshima. (And for their part, the Japanese would have allied with the Chinese against the Germans.)

Some quotes from the NewScientist article:

The murder victim, a West African chimpanzee called Foudouko, had been beaten with rocks and sticks, stomped on and then cannibalised by his own community. …

“When you reverse that and have almost two males per every female — that really intensifies the competition for reproduction. That seems to be a key factor here,” says Wilson.

Jill Pruetz at Iowa State University, who has been studying this group of chimpanzees in south-eastern Senegal since 2001, agrees. She suggests that human influence may have caused this skewed gender ratio that is likely to have been behind this attack. In Senegal, female chimpanzees are poached to provide infants for the pet trade. …

Early one morning, Pruetz and her team heard loud screams and hoots from the chimps’ nearby sleep nest. At dawn, they found Foudouko dead, bleeding profusely from a bite to his right foot. He also had a large gash in his back and a ripped anus. Later he was found to have cracked ribs. Pruetz says Foudouko probably died of internal injuries or bled out from his foot wound.

Foudouko also had wounds on his fingers. These were likely to have been caused by chimps clamping them in their teeth to stretch his arms out and hold him down during the attack, says Pruetz.

After his death, the gang continued to abuse Foudouko’s body, throwing rocks and poking it with sticks, breaking its limbs, biting it and eventually eating some of the flesh.

“It was striking. The female that cannibalised the body the most, she’s the mother of the top two high-ranking males. Her sons were the only ones that really didn’t attack the body aggressively,” Pruetz says …

Historically, the vast majority of wars and genocides were waged by one group of people against their neighbors–people they were likely to be closely related to in the grand scheme of things–not against distant peoples they’d never met. If you’re a chimp, the chimp most likely to steal your banana is the one standing right in front of you, not some strange chimp you’ve never met before who lives in another forest.

Indeed, in Jane Goodall’s account of the Gombe Chimpanzee War, the combatants were not members of two unrelated communities that had recently encountered each other, but members of a single community that had split in two. Chimps who had formerly lived peacefully together, groomed each other, shared bananas, etc., now bashed each other’s brains out and cannibalized their young. Poor Jane was traumatized.

I think there is an instinct to form in-groups and out-groups. People often have multiple defined in-groups (“I am a progressive, a Christian, a baker, and a Swede,”) but one of these identities generally trumps the others in importance. Ethnicity and gender are major groups most people seem to have, but I don’t see a lot of evidence suggesting that the grouping of “race” is uniquely special, globally, in people’s ideas of in- and out-.

For example, as I am writing today, people are concerned that Donald Trump is enacting racist policies toward Muslims, even though “Muslim” is not a race and most of the countries targeted by Trump’s travel/immigration ban are filled with fellow Caucasians, not Sub-Saharan Africans or Asians.

Race is a largely American obsession, because our nation (like the other North and South American nations,) has always had whites, blacks, and Asians (Native Americans). But many countries don’t have this arrangement. Certainly Ireland didn’t have an historical black community, nor Japan a white one. Irish identity was formed in contrast to English identity; Japanese in contrast to Chinese and Korean.

Only in the context where different races live in close proximity to each other does it seem that people develop strong racial identities; otherwise people don’t think much about race.

Napoleon Chagnon, a white man, has spent years living among the Yanomamo, one of the world’s most murderous tribes, folks who go and slaughter their neighbors and neighbors’ children all the time, and they still haven’t murdered him.

Why do people insist on claiming that Trump’s “Muslim ban” is racist when Muslims aren’t a race? Because Islam is an identity group that appears to function similarly to race, even though Muslims come in white, black, and Asian.

If you’ve read any of the comments on my old post about Turkic DNA, Turkey: Not very Turkic, you’ll have noted that Turks are quite passionate about their Turkic identity, even though “Turkic” clearly doesn’t correspond to any particular ethnic groups. (It’s even more mixed up than Jewish, and that’s a pretty mixed up one after thousands of years of inter-breeding with non-Jews.)

Group identities are fluid. When threatened, groups merged. When resources are abundant and times are good, groups split.

What about evidence that infants identify–stare longer at–faces of people of different races than their parents? This may be true, but all it really tells us is that babies are attuned to novelty. It certainly doesn’t tell us that babies are racist just because they find people interesting who look different from the people they’re used to.

What happens when people encounter others of a different race for the first time?

We have many accounts of “first contacts” between different races during the Age of Exploration. For example, when escaped English convict William Buckley wandered into an uncontacted Aborigine tribe, they assumed he was a ghost, adopted him, taught him to survive, and protected him for 30 years. By contrast, the last guy who landed on North Sentinel Island and tried to chat with the natives there got a spear to the chest and a shallow grave for his efforts. (But I am not certain the North Sentinelese haven’t encountered outsiders at some point.)

But what about the lunchroom seating habits of the wild American teenager?

If people have an instinct to form in-groups and out-groups, then races (or religions?) may represent the furthest bounds of this, at least until we encounter aliens. All else held equal, perhaps we are most inclined to like the people most like ourselves, and least inclined to like the people least like ourselves–racism would thus be the strongest manifestation of this broader instinct. But what about people who have a great dislike for one race, but seem just fine with another, eg, a white person who likes Asians but not blacks, or a black who like Asians but not whites? And can we say–per our definition above–that these preferences are irrational, or are they born of some lived experience of positive or negative interactions?

Again, we are only likely to have strong opinions about members of other races if we are in direct conflict or competition with them. Most of the time, people are in competition with their neighbors, not people on the other side of the world. I certainly don’t sit here thinking negative thoughts about Pygmies or Aborigines, even though we are very genetically distant from each other, and I doubt they spend their free time thinking negatively about me.

Just because flamingos prefer to flock with other flamingos doesn’t mean they dislike horses; for the most part, I think people are largely indifferent to folks outside their own lives.

Antagonistic Selection and Invading Armies

We don’t naturally look like this

Evolution is a fabulous principle, but it can only do so much. It has yet to give us titanium bones or x-ray vision, nor has it solved the problem of death. It even gives us creatures like praying mantises, who eat their mates.

Genetically speaking, men and women are actually quite similar, at least compared to, say, trees. There’s a great deal of overlap between male and female instincts–we both get hungry, we both fall in love, we both think the Ghostbusters remake was an abomination.

While evolution would like* to code for perfect men and perfect women, since we are the same species and ever male has a mom and every female has a dad, genetics ultimately can’t code for perfect men and perfect women. *yes I am anthropomorphizing

Remember, there are only two chromosomes which code for sexual development, the so called XX (female) and XY (male). Both men and women have at least one X, but no women have a Y.

It doesn’t work out that men are, like, expressing half female genes and half male genes, since the Y chromosome blocks the expression of some of the female genes. However, men still have those genes.

Sexual antagonism or “sexual conflict” occurs when a genetic trait that makes one sex better at reproducing makes the opposite sex worse at reproducing:

Interlocus sexual conflict is the interaction of a set of antagonistic alleles at one or more loci in males and females.^[6] An example is conflict over mating rates. Males frequently have a higher optimal mating rate than females because in most animal species, they invest fewer resources in offspring than their female counterparts. Therefore, males have numerous adaptations to induce females to mate with them. Another well-documented example of inter-locus sexual conflict is the seminal fluid of Drosophila melanogaster, which up-regulates females’ egg-laying rate and reduces her desire to re-mate with another male (serving the male’s interests), but also shortens the female’s lifespan reducing her fitness.

From: A recent bottleneck of Y chromosome diversity coincides with a global change in culture

In humans, for example, women benefit from being thin and short, while men benefit from being tall and bulky. But a short, thin woman is more likely to have a short, thin, son, which is not beneficial, and a tall, bulky man is likely to have a tall, bulky daughter–also not beneficial.

Whatever instincts we see in one gender, we likely see–in some form–in at least some members of the opposite gender. So If there is–as some folks around these parts allege–an instinct which makes women submissive to invading armies, then it likely affects some men, too.

For the few men who do survive an invasion, not protesting as your wife is gang raped might keep you alive to later reproduce, too

Hence the recent rise of cuckoldry fetishes.

Cannibalism, Abortion, and R/K Selection.

Reindeer herder, from Quarter of a Million Reindeers to be Butched… after Anthrax Outbreak: “Currently 730,000 animals are being kept in the Yamal Peninsula and the rest of the Yamalo-Nenets region.”

In Hunters, Pastoralists, and Ranchers: Reindeer Economies and their Transformations [PDF,] Ingold describes the social distribution of food among hunter-gatherers. In normal times, when food is neither super-abundant nor scarce, each family basically consumes what it brings in, without feeling any particular compulsion to share with their neighbors. In times of super-abundance, food is distributed throughout the tribe, often quite freely:

Since harvested animals, unlike a plant crop, will not reproduce, the multiplicative accumulation of material wealth is not possible within the framework of hunting relations of production. Indeed, what is most characteristic of hunting societies everywhere is the emphasis not on accumulation but on its obverse: the sharing of the kill, to varying degrees, amongst all those associated with the hunter. …

The fortunate hunter, when he returns to camp with his kill, is expected to play host to the rest of the community, in bouts of extravagant consumption.

The other two ethnographies I have read of hunter-gatherers (The Harmless People, about the Bushmen of the Kalahari, and Kabloona, about the Eskimo aka Inuit) both support this: large kills are communal feasts. Hunter gatherers often have quite strict rules about how exactly a kill is to be divided, but the most important thing is that everyone gets some.

And this is eminently sensible–you try eating an entire giraffe by yourself, in the desert, before it rots.

Even in the arctic, where men can (in part of the year) freeze food for the future, your neighbor’s belly is as good as a freezer, because the neighbor you feed today will feed you tomorrow. Hunting is an activity that can be wildly successful one day and fail completely the next, so if hunters did not share with each other, soon each one would starve.

Whilst the successful hunter is required to distribute his spoils freely amongst his camp fellows, he does so with the assurance that in any future eventuality, when through bad luck he fails to find game, or through illness or old age he can no longer provide for himself and his family, he will receive in his turn. Were each hunter to produce only for his own domestic needs, everyone would eventually perish from hunger (Jochelson 1926:124). Thus, through its contribution to the survival and reproduction of potential producers, sharing ensures the perpetuation of society as a whole. …

Yet he is also concerned to set aside stocks of food to see his household through at least a part of the coming winter. The meat that remains after the obligatory festive redistribution is therefore placed in the household’s cache, on which the housewife can draw specifically for the provision of her own domestic group (Spencer 1959:149). After the herds have passed by, domestic autonomy is re-establisheddraws on its own reserves of stored food.

But what happens at the opposite extreme, not under conditions of abundance, but when everyone‘s stocks run out? Ingold claims that in times of famine, the obligation to share what little food one has with one’s neighbors is also invoked:

We find, therefore, that the incidence of generalized reciprocity tends to peak towards the two extremes of scarcity and abundance… The communal feast that follows a successful hunting drive involves the same heightening of band solidarity, and calls into play the same functions of leadership in the apportionment of food, as does the consumption of famine rations.

I am reminded here of a scene in The Harmless People in which there was not enough food to go around, but the rules of distribution were still followed, each person just cutting their piece smaller. Thomas described one of the small children, hungry, trying to grab the food bowl–not the food itself–to stop their mother from giving away their food to the next person in the chain of obligation.

Here Ingold pauses to discuss a claim by Sahlins that such social order will (or should) break down under conditions of extreme hunger:

Probably every primitive organization has its breaking-point, or at least its turning-point. Every one might see the time when co-operation is overwhelmed by the scale of disaster and chicanery becomes the order of the day. The range of assistance contracts progressively to the family level; perhaps even these bonds dissolve and, washed away, reveal an inhuman, yet most human, self-interest. Moreover, by the same measure that the circle of charity is
compressed that of ‘negative reciprocity* is potentially expanded. People who helped each other in normal times and through the first stages of disaster display now an indifference to each others’ plight, if they do not exacerbate a mutual downfall by guile, haggle and theft.

Ingold responds:

I can find no evidence, either in my reading of circumpolar ethnography, or in the material cited by Sahlins, for the existence of such a ‘turning-point’ in hunting societies. On the contrary, as the crisis deepens, generalized reciprocity proceeds to the point of dissolution of domestic group boundaries. ‘Negative reciprocity’, rather than closing in from beyond the frontiers of the household, will be expelled altogether from the wider social field, only to make its appearance within the heart of the domestic group itself.

Thus the women of the household, who are allowed to eat only after the appetites of their menfolk have been satisfied, may be left in times of want with the merest scraps of food. Among the Chipewyan, ‘when real distress approaches, many of them are permitted to starve, when the males are amply provided for’…

In situations of economic collapse, negative reciprocity afflicts not only the domestic relations between husband and wife, but those between mother and child, and between parent and grandparent. If the suckling of children is the purest expression of generalized reciprocity, in the form of a sustained one-way flow, then infanticide must surely represent the negative extreme. Likewise, old or sick members of the household will be the first to be abandoned when provisions run short. Even in normal times, individuals who are past labour have to scavenge the left-overs of food and skins (Hearne 1911:326). In the most dire circumstances of all, men will consume their starving wives and children before turning upon one another.

Drawing on Eskimo material, Hoebel derives the following precepts of cannibal conduct: Not unusually . . . parents kill their own children to be eaten. This act is no different from infanticide. A man may kill and eat his wife; it is his privilege. Killing and eating a relative will produce no legal consequences. It is to be presumed, however, that killing a non-relative for food is murder. (1941:672, cited in Eidlitz 1969:132)

In short, the ‘circle of charity’ is not compressed but inverted: as the threat of starvation becomes a reality, the legitimacy of killing increases towards the centre. The act is ‘inhuman’ since it strips the humanity of the victim to its organic, corporeal substance. If altruism is an index of sociability, then its absolute negation annuls the sodality of the recipient: persons, be they human or animal, become things.

This is gruesome, but let us assume it is true (I have not read the accounts Ingold cites, so I must trust him, and I do not always trust him but for now we will.)

The cold, hard logic of infanticide is that a mother can produce more children if she loses one, but a child who has lost its mother will likely die as well, along with all of its siblings. One of my great-great grandmothers suffered the loss of half her children in infancy and still managed to raise 5+ to adulthood. Look around: even with abortion and birth control widely available, humanity is not suffering a lack of children. ETA: As BaruchK correctly noted, today’s children are largely coming from people who don’t use birth control or have legal access to abortion; fertility rates are below replacement throughout the West, with the one exception AFAIK of Israel.

Furthermore, children starve faster and are easier to kill than parents; women are easier to kill than men; people who live with you are easier to kill than people who don’t.

Before we condemn these people, let us remember that famine is a truly awful, torturous way to die, and that people who are on the brink of starving to death are not right in their minds. As “They’re not human”: How 19th-century Inuit coped with a real-life invasion of the Walking Dead recounts:

“Finally, as the footsteps stopped just outside the igloo, it was the old man who went out to investigate.

“He emerged to see a disoriented figure seemingly unaware of his presence. The being was touching the outside of the igloo with curiosity, and raised no protest when the old man reached his hand out to touch its cheek.

“His skin was cold. …

The figures, of course, were the last survivors of the Franklin Expedition. They had buried their captain. They had seen their ship entombed by ice. They had eaten the dead to survive. …

Inuit nomads had come across streams of men that “didn’t seem to be right.” Maddened by scurvy, botulism or desperation, they were raving in a language the Inuit couldn’t understand. In one case, hunters came across two Franklin Expedition survivors who had been sleeping for days in the hollowed-out corpses of seals. …

The figures were too weak to be dangerous, so Inuit women tried to comfort the strangers by inviting them into their igloo. …

The men spit out pieces of cooked seal offered to them. They rejected offers of soup. They grabbed jealous hold of their belongings when the Inuit offered to trade.

When the Inuit men returned to the camp from their hunt, they constructed an igloo for the strangers, built them a fire and even outfitted the shelter with three whole seals. …

When a small party went back to the camp to retrieve [some items], they found an igloo filled with corpses.

The seals were untouched. Instead, the men had eaten each other. …

In 1854, Rae had just come back from a return trip to the Arctic, where he had been horrified to discover that many of his original Inuit sources had fallen to the same fates they had witnessed in the Franklin Expedition.

An outbreak of influenza had swept the area, likely sparked by the wave of Franklin searchers combing the Arctic. As social mores broke down, food ran short.

Inuit men that Rae had known personally had chosen suicide over watching the slow death of their children. Families had starved for days before eating their dog teams. Some women, who had seen their families die around them, had needed to turn to the “last resource” to survive the winter.

Infanticide, cannibalism, and human sacrifice were far more common prior to 1980 or so than we like to think; God forbid we should ever know such fates.

According to Wikipedia:

“Many Neolithic groups routinely resorted to infanticide … Joseph Birdsell believed that infanticide rates in prehistoric times were between 15% and 50% of the total number of births,^[10] while Laila Williamson estimated a lower rate ranging from 15% to 20%.^{[6]:66 …} Comparative anthropologists have calculated that 50% of female newborn babies were killed by their parents during the Paleolithic era.^[12] Decapitated skeletons of hominid children have been found with evidence of cannibalism.^[13] …

“Three thousand bones of young children, with evidence of sacrificial rituals, have been found in Sardinia. Pelasgians offered a sacrifice of every tenth child during difficult times. Syrians sacrificed children to Jupiter and Juno. Many remains of children have been found in Gezer excavations with signs of sacrifice. Child skeletons with the marks of sacrifice have been found also in Egypt dating 950-720 BCE. In Carthage “[child] sacrifice in the ancient world reached its infamous zenith.”^[11]:324  …

“According to Shelby Brown, Carthaginians, descendants of the Phoenicians, sacrificed infants to their gods.^[25] Charred bones of hundreds of infants have been found in Carthaginian archaeological sites. One such area harbored as many as 20,000 burial urns.^[25] …

Plutarch (c. 46–120 AD) mentions the practice, as do Tertullian, Orosius, Diodorus Siculus and Philo. The Hebrew Bible also mentions what appears to be child sacrifice practiced at a place called the Tophet (from the Hebrew taph or toph, to burn) by the Canaanites. Writing in the 3rd century BCE, Kleitarchos, one of the historians of Alexander the Great, described that the infants rolled into the flaming pit. Diodorus Siculus wrote that babies were roasted to death inside the burning pit of the god Baal Hamon, a bronze statue.

“… the exposure of newborns was widely practiced in ancient Greece, it was even advocated by Aristotle in the case of congenital deformity — “As to the exposure of children, let there be a law that no deformed child shall live.”^[30] …

“The practice was prevalent in ancient Rome, as well. … A letter from a Roman citizen to his sister, or a pregnant wife from her husband,^[35] dating from 1 BC, demonstrates the casual nature with which infanticide was often viewed:

“I am still in Alexandria. … I beg and plead with you to take care of our little child, and as soon as we receive wages, I will send them to you. In the meantime, if (good fortune to you!) you give birth, if it is a boy, let it live; if it is a girl, expose it.” ^[36][37]

“In some periods of Roman history it was traditional for a newborn to be brought to the pater familias, the family patriarch, who would then decide whether the child was to be kept and raised, or left to die by exposure.^[39] The Twelve Tables of Roman law obliged him to put to death a child that was visibly deformed. …

“According to William L. Langer, exposure in the Middle Ages “was practiced on gigantic scale with absolute impunity, noticed by writers with most frigid indifference”.^{[47]:355–356} At the end of the 12th century, notes Richard Trexler, Roman women threw their newborns into the Tiber river in daylight.^[48]” …

“Philosopher Han Fei Tzu, a member of the ruling aristocracy of the 3rd century BC, who developed a school of law, wrote: “As to children, a father and mother when they produce a boy congratulate one another, but when they produce a girl they put it to death.”^[63] …

“Buddhist belief in transmigration allowed poor residents of the country to kill their newborn children if they felt unable to care for them, hoping that they would be reborn in better circumstances. Furthermore, some Chinese did not consider newborn children fully “human”, and saw “life” beginning at some point after the sixth month after birth.^[65]

“Contemporary writers from the Song dynasty note that, in Hubei and Fujian provinces, residents would only keep three sons and two daughters (among poor farmers, two sons and one daughter), and kill all babies beyond that number at birth.^[66]”

Sex Ratio at birth in the People’s Republic of China

“It was not uncommon that parents threw a child to the sharks in the Ganges River as a sacrificial offering. The British colonists were unable to outlaw the custom until the beginnings of the 19th century.^[82]:78

“According to social activists, female infanticide has remained a problem in India into the 21st century, with both NGOs and the government conducting awareness campaigns to combat it.^{[83] …}

“In the Eastern Shoshone there was a scarcity of Indian women as a result of female infanticide.^[100] For the Maidu Native Americans twins were so dangerous that they not only killed them, but the mother as well.^[101] In the region known today as southern Texas, the Mariame Indians practiced infanticide of females on a large scale. Wives had to be obtained from neighboring groups.^[102]”

Meanwhile in the Americas:

In 2005 a mass grave of one- to two-year-old sacrificed children was found in the Maya region of Comalcalco. The sacrifices were apparently performed for consecration purposes when building temples at the Comalcalco acropolis.^{[2] …}

Archaeologists have found the remains of 42 children sacrificed to Tlaloc (and a few to Ehecátl Quetzalcóatl) in the offerings of the Great Pyramid of Tenochtitlan. In every case, the 42 children, mostly males aged around six, were suffering from serious cavities, abscesses or bone infections that would have been painful enough to make them cry continually. Tlaloc required the tears of the young so their tears would wet the earth. As a result, if children did not cry, the priests would sometimes tear off the children’s nails before the ritual sacrifice.^[7]

And don’t get me started on cannibalism.

James Cook witnessing human sacrifice in Tahiti

It is perhaps more profitable to ask which cultures didn’t practice some form of infanticide/infant sacrifice/cannibalism than which ones did. The major cases Wikipedia notes are Ancient Egypt, Judaism, Christianity, and Islam (we may note that Judaism in many ways derived from ancient Egypt, and Christianity and Islam from Judaism.) Ancient Egypt stands out as unique among major the pre-modern, pre-monotheistic societies to show no signs of regular infanticide–and even in the most infamous case where the Egyptian pharaoh went so far as to order the shocking act, we find direct disobedience in his own household:

³ And when she [Jochebed] could not longer hide him [the baby], she took for him an ark of bulrushes, and daubed it with slime and with pitch, and put the child therein; and she laid it in the flags by the river’s brink.⁴ And his sister stood afar off, to wit what would be done to him.

⁵ And the daughter of Pharaoh came down to wash herself at the river; and her maidens walked along by the river’s side; and when she saw the ark among the flags, she sent her maid to fetch it.

⁶ And when she had opened it, she saw the child: and, behold, the babe wept. And she had compassion on him, and said, “This is one of the Hebrews’ children.”

⁷ Then said his sister to Pharaoh’s daughter, “Shall I go and call to thee a nurse of the Hebrew women, that she may nurse the child for thee?”

⁸ And Pharaoh’s daughter said to her, “Go.” And the maid went and called the child’s mother.

⁹ And Pharaoh’s daughter said unto her, “Take this child away, and nurse it for me, and I will give thee thy wages.” And the women took the child, and nursed it.

¹⁰ And the child grew, and she brought him unto Pharaoh’s daughter, and he became her son. And she called his name Moses: and she said, “Because I drew him out of the water.”

–Exodus 2:3-10

I don’t know the actual infanticide numbers in modern Muslim countries (le wik notes that poverty in places like Pakistan still drives infanticide) but it is officially forbidden by Islam.

According to Abortions in America:
• Black women are five times more likely to abort than white women.
• 69% of pregnancies among Blacks are unintended, while that number is 54% among Hispanics and 40% of pregnancies among Whites.
• Planned Parenthood, … has located 80% of its abortion clinics in minority neighborhoods

Today, between the spread of Abrahamic religions, Western Values, and general prosperity, the infanticide rate has been cut and human sacrifice and cannibalism have been all but eliminated. Abortion, though, is legal–if highly controversial–throughout the West and Israel.

According to the CDC, the abortion rate for 2013 was 200 abortions per 1,000 live births, or about 15% of pregnancies. (The CDC also notes that the abortion rate has been falling since at least 2004.) Of these, “91.6% of abortions were performed at ≤13 weeks’ gestation; … In 2013, 22.2% of all abortions were early medical abortions.”

To what can we attribute this anti-infanticide sentiment of modern monotheistic societies? Is it just a cultural accident, a result of inheritance from ancient Egypt, or perhaps the lucky effects of some random early theologian? Or as the religious would suggest, due to God’s divine decree? Or is it an effect of the efforts parents must expend on their few children in societies where children must attend years of school in order to succeed?

According to Wikipedia:

In ecology, r/K selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus upon either increased quantity of offspring at the expense of individual parental investment of r-strategists, or reduced quantity of offspring with a corresponding increased parental investment of K-strategists, varies widely, seemingly to promote success in particular environments. …

In r/K selection theory, selective pressures are hypothesised to drive evolution in one of two generalized directions: r– or K-selection.^[1] These terms, r and K, are drawn from standard ecological algebra as illustrated in the simplified Verhulst model of population dynamics:^[7]

d N d t = r N ( 1 − N K )

where r is the maximum growth rate of the population (N), K is the carrying capacity of its local environmental setting, and the notation dN/dt stands for the derivative of N with respect to t (time). Thus, the equation relates the rate of change of the population N to the current population size and expresses the effect of the two parameters. …

As the name implies, r-selected species are those that place an emphasis on a high growth rate, and, typically exploit less-crowded ecological niches, and produce many offspring, each of which has a relatively low probability of surviving to adulthood (i.e., high r, low K).^[8] A typical r species is the dandelion Taraxacum genus.

In unstable or unpredictable environments, r-selection predominates due to the ability to reproduce quickly. There is little advantage in adaptations that permit successful competition with other organisms, because the environment is likely to change again. Among the traits that are thought to characterize r-selection are high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely. …

By contrast, K-selected species display traits associated with living at densities close to carrying capacity, and typically are strong competitors in such crowded niches that invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood (i.e., low r, high K). In scientific literature, r-selected species are occasionally referred to as “opportunistic” whereas K-selected species are described as “equilibrium”.^[8]

In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant in number and close to the maximum that the environment can bear (unlike r-selected populations, where population sizes can change much more rapidly).

Traits that are thought to be characteristic of K-selection include large body size, long life expectancy, and the production of fewer offspring, which often require extensive parental care until they mature.

Of course you are probably already aware of Rushton’s R/K theory of human cultures:

Rushton’s book Race, Evolution, and Behavior (1995) uses r/K selection theory to explain how East Asians consistently average high, blacks low, and whites in the middle on an evolutionary scale of characteristics indicative of nurturing behavior. He first published this theory in 1984. Rushton argues that East Asians and their descendants average a larger brain size, greater intelligence, more sexual restraint, slower rates of maturation, and greater law abidingness and social organization than do Europeans and their descendants, who average higher scores on these dimensions than Africans and their descendants. He theorizes that r/K selection theory explains these differences.

I’d be remiss if I didn’t also mention that the article states, “Rushton’s application of r/K selection theory to explain differences among racial groups has been widely criticised. One of his many critics is the evolutionary biologist Joseph L. Graves, who has done extensive testing of the r/K selection theory with species of Drosophila flies. …”

Genetics or culture, in dense human societies, people must devote a great deal of energy to a small number of children they can successfully raise, leading to the notion that parents are morally required to put this effort into their children. But this system is at odds with the fact that without some form of intervention, the average married couple will produce far more than two offspring.

Ultimately, I don’t have answers, only theories.

Source: CDC data, I believe

Creationism, Evolutionism, and Categories

I’ve been thinking about the progression of ideas about natural categories, such as “men” and “women,” “cows” and “mules,” “English” and “Polynesian.” Not exactly our high philosophical progression, but a somewhat commoner one.

It seems that 100 years or so ago, most people would have explained the differences between things with a simple, “Because God wanted them to be that way.” And if God wants it that way, then the way they are is good and you should leave them alone.

I have heard my [sibling] wax practically poetic about the way God made mules and horses for farm work, and why you should not yoke together an ox and a donkey. (One of the interesting parts of meeting my siblings for the first time as an adult was realizing that dorkiness is genetic.)

The evolutionary perspective is that evolution created things (or, as we like to call it around here, GNON, the God of Nature and Nature’s God.) Gnon and God are functionally rather similar, for Gnon also made things in natural categories, and while we may refrain from deeming them “good” in quite the same way as religious people, we certainly believe that each group’s features serve purposes that have helped members of that group survive where others did not.

The conservative creationist denies the role of evolution, but he does not deny that categories exist. He merely disputes their method of creation. To quote Answers in Genesis:

So, a good rule of thumb is that if two things can breed together, then they are of the same created kind. …

As an example, dogs can easily breed with one another, whether wolves, dingoes, coyotes, or domestic dogs. When dogs breed together, you get dogs; so there is a dog kind. It works the same with chickens. There are several breeds of chickens, but chickens breed with each other and you still get chickens. So, there is a chicken kind. The concept is fairly easy to understand.

But in today’s culture, where evolution and millions of years are taught as fact, many have been led to believe that animals and plants (that are classed as a specific “species”) have been like this for tens of thousands of years and perhaps millions of years. So, when they see things like lions or zebras, they think they have been like this for an extremely long time.

From a biblical perspective, though, land animals like wolves, zebras, sheep, lions, and so on have at least two ancestors that lived on Noah’s Ark, only about 4,300 years ago. These animals have undergone many changes since that time. But dogs are still part of the dog kind, cats are still part of the cat kind, and so on. God placed variety within the original kinds, and other variation has occurred since the Fall due to genetic alterations.

For all that people accuse the Answers in Genesis folks of being crazy, and for all that they are trying awfully hard to re-invent the wheel, this is an unobjectionable approach to species and hybridization.

By contrast, the liberal creationist, since she cannot fall back on God in his rejection of Gnon, asserts that the categories themselves do not exist. “Race is a social construct. Gender is a social construct.” etc. Dr. Zuleyka Zevallos, who is definitely not a crazy Creationist with no respect for science, writes:

When people talk about the differences between men and women they are often drawing on sex – on rigid ideas of biology – rather than gender, which is an understanding of how society shapes our understanding of those biological categories.

Gender is more fluid – it may or may not depend upon biological traits. [bold mine.] More specifically, it is a concept that describes how societies determine and manage sex categories; the cultural meanings attached to men and women’s roles; and how individuals understand their identities including, but not limited to, being a man, woman, transgender, intersex, gender queer and other gender positions. …

The sociology of gender examines how society influences our understandings and perception  of differences between masculinity (what society deems appropriate behaviour for a “man”) and femininity (what society deems appropriate behaviour for a “woman”). We examine how this, in turn, influences identity and social practices. We pay special focus on the power relationships that follow from the established gender order in a given society, as well as how this changes over time.

And the New York Times writes:

Race is not biological. It is a social construct. There is no gene or cluster of genes common to all blacks or all whites. Were race “real” in the genetic sense, racial classifications for individuals would remain constant across boundaries. Yet, a person who could be categorized as black in the United States might be considered white in Brazil or colored in South Africa.

Answers in Genesis understands genetics better than the New York times or people with doctorates from actual universities. That is pretty damn pathetic.

crayon map of racial distribution. Not guaranteed correct

Of course, some of our ideas about what “men” and “women”  or “blacks” and “whites” are like are cultural (especially any that involve technology, since technology has changed radically over the past 100 years.) As an amateur anthropologist, I am quite aware that different cultures have different ideas on these subjects. This does not negate the fact that “maleness” and “femaleness” are basically biologically-driven. Female interest in babies and male interest in violence has its roots in biology, not culture. Genetics have a huge effect on personality. Likewise, races are absolutely real, biological categories, which no doctor attempting an organ transplant can afford to ignore.

The idea that races don’t exist in some kind of genetic way is absurd. Let’s just take the EDAR gene:

Ectodysplasin A receptor (EDAR) is a protein that in humans is encoded by the EDAR gene. EDAR is a cell surface receptor for ectodysplasin A which plays an important role in the development of ectodermal tissues such as the skin.^{[3][4][5] …}

A derived G-allele point mutation (SNP) with pleiotropic effects in EDAR, 370A or rs3827760, found in most modern East Asians and Native Americans but not common in African or European populations, is thought to be one of the key genes responsible for a number of differences between these populations, including the thicker hair, more numerous sweat glands, smaller breasts, and dentition characteristic of East Asians.^[7]… The 370A mutation arose in humans approximately 30,000 years ago, and now is found in 93% of Han Chinese and in the majority of people in nearby Asian populations. ^… The derived G-allele is a mutation of the ancestral A-allele, the version found in most modern non-East Asian and non-Native American populations.

Most East Asians and Native Americans (that is, the greater Asian Race,) have the G-allele of EDAR. Most non-Asians have the A-allele.

World map of Y-DNA Haplotypes

If you don’t have some form of causality to explain how the world’s variation came to exist, I guess you fall back on “it’s totally random and meaningless.”

Noah’s Twitter Deluge

To be alive today is to drown in data…

Noah’s Ark by Edward Hicks, 1846

Now the earth was corrupt in GNON’s sight and was full of violence. So GNON said to Noah, “I am going to put an end to all people, for the earth is filled with violence because of them. So make yourself an ark of cypress wood; make rooms in it and coat it with pitch inside and out. Make a roof for it, leaving below the roof an opening one cubit high all around. Put a door in the side of the ark and make lower, middle and upper decks, and make it immune to Twitter, Facebook, and cable TV.  I am going to bring a deluge of information, unending news, tweets, and endless status updates on the earth to distract all life under the heavens, every creature that has the breath of life in it, until they fade from existence.

…modernity is selecting for those who resist modernity.

Why are Mammals Brown? (pt. 2)

Rainbow leaf beetle

As I was saying in part 1, compared to colorful fish, lizards, birds, and even ladybugs, we mammals are downright drab. Blue and purple fur are non-existent because these colors are difficult to produce as pigments, and so most animals with these colors produce them structurally rather than chemically, but hair is not a good medium for structural color. We are limited to pigments.

But this only explains blue and purple. Why are there so few mammals with bright red, pink, orange, or green fur? Wouldn’t green offer convenient camouflage for tree-dwelling sloths or lemurs? So on to the second reason we’re drab:

2. Compared to other animals, mammals have bad color perception.

For example, according to the guy who writes The Oatmeal, which is totally a reputable scientific source, dogs can only see two colors, blue and green. Humans can see three colors–green, blue, and red–which we combine to make the rest of the colors we see. Butterflies, non-mammals, can perceive 5 colors–we have no idea what that actually means, since we can’t even imagine the colors they see. And the mantis shrimp perceives an incredible 16 different colors.

The majority of mammals run closer to dogs than humans in color-perception.

But this only inspires a new question: why do we have bad eyesight?

The original mammals were small, shrew-like creatures that tried to avoid being eaten by dinosaurs back in the Triassic, about 200 million years ago.

Read the full comic over at The Oatmeal

Lizards, being mostly cold-blooded, are forced to be active primarily during the day, when it’s warm. Our warm-blooded ancestors therefore probably found it easy to avoid reptilian predators by doing their hunting and foraging at night.

According to Wikipedia:

The nocturnal bottleneck hypothesis is an hypothesis to explain several mammal traits. The hypothesis states that mammals were mainly or even exclusively nocturnal through most of their evolutionary story, starting with their origin 225 million years ago, and only ending with the demise of the dinosaurs 65 millions years ago. While some mammal groups have later evolved to fill diurnal niches, the 160 million years spent as nocturnal animals has left a lasting legacy on basal anatomy and physiology, and most mammals are still nocturnal.^[1]

Between the nocturnal and the crepuscular, most mammals are only awake at times when color isn’t particularly relevant. Most mammals, therefore, have evolved eyes that aren’t very good at perceiving color, in order to optimize for seeing in dim light.

We have more rods, which perceive light; diurnal animals have more cones, which perceive colors.

Animals use their colors for three main purposes: to signal to each other, to hide, and to signal to predators.

Since most mammals can’t see many colors, even if they had a peacock’s spots, they couldn’t use them for mate selection. Few mammals are poisonous (if any,) so we don’t have the poison dart frog’s use for bright color. And you might want to be green to blend in with the trees during the day, but at night, trees are dark.

In short, we are optimized for the dark.

So even though we humans like being awake during the day, we’re unlikely to trade in our drab pelts for the macaw’s rainbow hues anytime soon.

 

Why are Mammals Brown? (pt. 1)

We don’t naturally look like this

Compared to colorful fish, lizards, birds, and even ladybugs, we mammals are downright drab. I see no particular environmental reason for this–plenty of mammals live in areas with trees or grass where green fur or spots might help them blend in, or have such striking patterns–like a zebra–that I hardly think a blue stripe would result in more lion attacks.

I think there are two main reasons mammals are mostly brown, instead of showing the vibrant colors of other species:

1. Some colors are difficult to produce.

Blue, for example. Walk into the forest or a meadow on an average day, and you’ll see a lot of green. Anything not green is likely brown. Outside a garden, there are very few naturally blue or purple plants.

This guy, however, does

It’s no coincidence that early human art uses colors that could be easily produced from the natural environment, like brown, black, (charcoal,) and yellow. By the Roman era, we could produce purple dye, but it was so hard to obtain from such rare sources (shells) that it was prohibitively expensive for mere mortals, hence why it was called “royal purple.” The European tradition of painting the Virgin Mary’s cloak blue also hails from the days when blue pigments were expensive, and thus a sign of exalted status.

A purple dye cheap enough for average people to buy and wear wasn’t invented until 1856, by William Henry Perkin.

I’m not sure exactly why blue and purple are so hard to produce, but I think it’s because light toward the violent end of the spectrum is higher energy than light toward the red end. As Bulina et al state:

Pigments in nature play important roles ranging from camouflage coloration and sunscreen to visual reception and participation in biochemical pathways. Considering the spectral diversity of pigment-based coloration in animals one can conclude that blue pigments occur relatively rare (as a rule blue coloration results from light diffraction or scattering rather than the presence of a blue pigment). At least partially this fact is explained by an inevitably more complex structure of blue pigments compared to yellow-reds. To appear blue a compound must contain an extended and usually highly polarized system of the conjugated π-electrons.

Okay… So, because blue and purple are more energetic, they require molecules that have more double bonds and are less common in nature. (Why double bonds are less common is a matter I’ll leave for a chemistry discussion.)

You’re probably used to thinking of color as an inherent property of the objects around you–that a green leaf is green, or a red bucket is red, in the same way that the leaf and bucket have a particular mass and are made of their particular atoms.

Low energy to the left, high to the right

But turn off the lights, and suddenly color goes away. (Mass doesn’t.)

The colors we see are created by light “bouncing” (really, being absorbed and then re-emitted) off objects. Within the visible spectrum, red light requires the least energy to produce (because it has the widest wavelength,) and violent takes the most energy.

But nature, being creative, has come up with alternative way to produce blues and purples that doesn’t depend on electron energy levels: structure.

Unless you are a color scientist you are probably accustomed to dealing with chemical colors. For example, if you take a handful of blue pigment powder, mix it with water, paint it onto a chair, let it dry, then scrape it off the chair, and grind it back into powder, you expect it to remain blue at all stages in the process (except if you get a bit of chair mixed in with it.)

Blue Morpho butterfly

By contrast, if you scraped the scales off a blue morpho butterfly’s wings, you’d just end up with a pile of grey dust and a sad butterfly. By themselves, blue morpho scales are not “blue,” even under regular light. Rather, their scales are arranged so that light bounces between them, like light bouncing from molecule to molecule in the air. Or as Ask Nature puts it:

Many types of butterflies use light-interacting structures on their wing scales to produce color. The cuticle on the scales of these butterflies’ wings is composed of nano- and microscale, transparent, chitin-and-air layered structures. Rather than absorb and reflect certain light wavelengths as pigments and dyes do, these multi scale structures cause light that hits the surface of the wing to diffract and interfere.

The same process is at work in the peacock’s plumage and bluebird’s blue:

Male eastern bluebird

Soft condensed matter physics has been particularly useful in understanding the production of the amorphous nanostructures that imbue the feathers of certain bird species with intensely vibrant hues. The blue color of the male Eastern bluebird (Sialia sialis), for example, is produced by the selective scattering of blue light from a complex nanostructure of b-keratin channels and air pockets in the hairlike branches called feather barbs that give the quill its lift. The size of the air pockets determines the wavelengths that are selectively amplified.

When the bluebird’s feathers are developing, feather barb cells known as medullary keratinocytes expand to their boxy final shape and deposit solid keratin around the periphery of the cell—essentially turning the walled-in cells into soups of ß-keratin suspended in cytoplasm. Next, b-keratin filaments free in the cytoplasm start to bind to each other to form larger bundles. As these filaments become less water-soluble, they begin to come out of solution—a process known as phase separation—ultimately forming solid bars that surround twisted channels of cytoplasm. These nanoscale channels of keratin remain in place after the cytoplasm dries out and the cell dies, resulting in the nanostructures observed in the feathers of mature adults.

“The bluebird doesn’t lay down a squiggly architecture and then put the array of the protein molecules on top of it,” Prum explains. “It lets phase separation, the same process that would occur in oil and vinegar unmixing, create this spatial structure itself.”

The point at which the phase separation halts determines the color each feather produces.

Decades old Pollia fruit retains its structural brilliance

This kind of structural color works great if your medium is scales, feathers, carapaces, berries, or even CDs, but just doesn’t work with hair, which we mammals have. Unlike the carefully hooked together structure of a feather or the details of a butterfly’s scales, hair moves. It shakes. It would have to be essentially solid to create structural color, and it’s not.

So for the most part, bright colors like green, blue, and purple are expensive, energy-wise, to produce chemically, and mammals don’t have the option birds, fish, lizards, and insects have of producing them structurally.

To be continued…