Land of thoats

There’s a great expansion in the diversity of horses in the mid-Miocene, especially horses that are adapted to grazing rather than browsing. The shift to grazing is going on world wide among many different groups. In South America the big grazers are the liptoterns, ungulates not closely related to horses that evolve to look a lot like them, with high-crowned grazing teeth, single-toed hoofed feet and legs built for speed. (Edgar Rice Burroughs took the name thoat – what his characters rode around on on Barsoom/Mars — from one genus of liptotern, Thoatherium.)

Thoatherium reconstruction

We often think of evolution as a matter of organisms adapting to their environments, but when the environment is other organisms, each side may be chasing a moving target. Or sometimes the sides may reach an equilibrium. In the case of grazing animals, there’s a process of coevolution that goes on between grazers and grasses. Where grazers are active, the plants that survive are grasses, which keep leaves above the ground but grow from underground. And this works in the other direction: in moderately dry climates, grasses are more productive than taller brushy plants, so it’s when grasses take over that there’s enough food around for grazers – a mutually reinforcing cycle. With drier climates from the mid-Miocene on, grasslands and grazers get to be more and more important.

So a lot of the story of life on Earth is not just the appearance of this or that cool animal, but also the evolution of ecosystems. At the same time grasslands were spreading on land, for example, kelp forests were spreading in coastal oceans. We’ll see how important grasslands are in human evolution and history. And kelp forests, with their rich fish populations, might have been important too, as the highway that the earliest Americans followed along the Pacific coast to the New World.

Planet of the horses

16.7 – 15.8 million years

Horses have probably been the single most important domesticated animal in human history. Also, more than with other livestock, people get attached to horses as individuals. I’m guessing that in history and literature there are more horses with individual names than any other animal. (Alexander the Great’s horse was Bucephalus, “Ox-head”; Muhammed’s was al-Buraq*; Charlemagne’s was Tencendur; Don Quixote’s was Rocinante; Gandalf’s was Shadowfax.) We’ll be hearing a lot more about horses and horse folk on Logarithmic History once we get to human history.

Being so charismatic, horses have featured in a big way in arguments over evolution. Thomas Henry Huxley (1825-1895), “Darwin’s bulldog,” knew he needed to find good evidence for evolution. When he visited the United States in 1876, he was ready to give a lecture based on horse fossils from Europe. But visiting Yale, he was so impressed with O. C. Marsh’s collection of horse fossils from the western United States, that he rewrote his lecture around it.

Henry Fairfield Osborn (1857-1935) was director of the American Museum of Natural History and a huge presence in American paleontology. He was active at a time when most scientists accepted evolution, but many weren’t so keen on Darwin’s theory of natural selection. He thought horses were a fine example of “orthogenesis,” the tendency of species to follow a fixed line of evolution, reflecting internal forces, maybe related to willpower. He thought that humans shared a migratory spirit with horses, so that anywhere horse fossils were found would be a good place to look for human fossils. This theory didn’t pan out too well. A massive AMNH expedition to Central Asia led by Ray Chapman Andrews found all sorts of wonders – dinosaur eggs, baluchitheres – but no fossil “pro-men.” Orthogenesis leant itself naturally to diagrams showing evolution from early to modern horses going in a straight line.

George Gaylord Simpson (1902-1984), paleontologist, was one of the great figures in the evolutionary Modern Synthesis that brought together Darwin’s theory of natural selection and Mendel’s genetics. There was no room for orthogenesis in the Modern Synthesis, and Simpson emphasized that the evolution of horses was a matter of adaptation to a changing environment – especially the spread of grasslands. Also that horse evolution looked more like a bush than a ladder.

Stephen Jay Gould (1941-2002) was the most widely recognized American evolutionary biologist of recent times. (For example had a spot on The Simpson’s — “Lisa The Skeptic,” Season 9.) Gould had his own take on the modern synthesis, taking the “bushes not ladders” theme for horses and other animals (including human ancestors), and pushing it a step further. According to the theory of “punctuated equilibrium” (formulated in collaboration with Niles Eldredge), species mostly change relatively little during the time they exist (evolutionary stasis). Most evolutionary change happens when a small population buds off to form a new species and reproductive isolation allows it to conserve any evolutionary novelties it has developed. This opens up the possibility of “species selection.” Applied to horses, for example, this could mean that horses were evolutionarily successful for some time not so much because individual horses were well-adapted, but because something about horses collectively (their harem mating system, maybe) made one horse species especially likely to generate new species. Both horses and primates seem to be especially prone to bud off new species:

Speciation and chromosomal evolution seem fastest in those genera with species organized into clans or harems (e.g., some primates and horses) or with limited adult vagility and juvenile dispersal, patchy distribution, and strong individual territoriality (e.g., some rodents). This is consistent with the … hypothesis … that population subdivision into small demes promotes both rapid speciation and evolutionary changes in gene arrangement by inbreeding and drift.

 * Richard Dawkins doesn’t believe that Muhammed’s horse, al-Buraq, carried him (i.e. Muhammed) to heaven and back.

Land of thoats

There’s a great expansion in the diversity of horses in the mid-Miocene, especially horses that are adapted to grazing rather than browsing. The shift to grazing is going on world wide among many different groups. In South America the big grazers are the liptoterns, ungulates not closely related to horses that evolve to look a lot like them, with high-crowned grazing teeth, single-toed hoofed feet and legs built for speed. (Edgar Rice Burroughs took the name thoat – what his characters rode around on on Barsoom/Mars — from one genus of liptotern, Thoatherium.)

Thoatherium reconstruction

We often think of evolution as a matter of organisms adapting to their environments, but when the environment is other organisms, each side may be chasing a moving target. Or sometimes the sides may reach an equilibrium. In the case of grazing animals, there’s a process of coevolution that goes on between grazers and grasses. Where grazers are active, the plants that survive are grasses, which keep leaves above the ground but grow from underground. And this works in the other direction: in moderately dry climates, grasses are more productive than taller brushy plants, so it’s when grasses take over that there’s enough food around for grazers – a mutually reinforcing cycle. With drier climates from the mid-Miocene on, grasslands and grazers get to be more and more important.

So a lot of the story of life on Earth is not just the appearance of this or that cool animal, but also the evolution of ecosystems. At the same time grasslands were spreading on land, for example, kelp forests were spreading in coastal oceans. We’ll see how important grasslands are in human evolution and history. And kelp forests, with their rich fish populations, might have been important too, as the highway that the earliest Americans followed along the Pacific coast to the New World.

Planet of the horses

16.3 – 15.5 million years ago

Horses have probably been the single most important domesticated animal in human history. Also, more than with other livestock, people get attached to horses as individuals. I’m guessing that in history and literature there are more horses with individual names than any other animal. (Alexander the Great’s horse was Bucephalus, “Ox-head”; Muhammed’s was al-Buraq*; Charlemagne’s was Tencendur; Don Quixote’s was Rocinante; Gandalf’s was Shadowfax.) We’ll be hearing a lot more about horses and horse folk on Logarithmic History once we get to human history.

Being so charismatic, horses have featured in a big way in arguments over evolution. Thomas Henry Huxley (1825-1895), “Darwin’s bulldog,” knew he needed to find good evidence for evolution. When he visited the United States in 1876, he was ready to give a lecture based on horse fossils from Europe. But visiting Yale, he was so impressed with O. C. Marsh’s collection of horse fossils from the western United States, that he rewrote his lecture around it.

Henry Fairfield Osborn (1857-1935) was director of the American Museum of Natural History and a huge presence in American paleontology. He was active at a time when most scientists accepted evolution, but many weren’t so keen on Darwin’s theory of natural selection. He thought horses were a fine example of “orthogenesis,” the tendency of species to follow a fixed line of evolution, reflecting internal forces, maybe related to willpower. He thought that humans shared a migratory spirit with horses, so that anywhere horse fossils were found would be a good place to look for human fossils. This theory didn’t pan out too well. A massive AMNH expedition to Central Asia led by Ray Chapman Andrews found all sorts of wonders – dinosaur eggs, baluchitheres – but no fossil “pro-men.” Orthogenesis leant itself naturally to diagrams showing evolution from early to modern horses going in a straight line.

George Gaylord Simpson (1902-1984), paleontologist, was one of the great figures in the evolutionary Modern Synthesis that brought together Darwin’s theory of natural selection and Mendel’s genetics. There was no room for orthogenesis in the Modern Synthesis, and Simpson emphasized that the evolution of horses was a matter of adaptation to a changing environment – especially the spread of grasslands. Also that horse evolution looked more like a bush than a ladder.

Stephen Jay Gould (1941-2002) was the most widely recognized American evolutionary biologist of recent times. (For example had a spot on The Simpson’s — “Lisa The Skeptic,” Season 9.) Gould had his own take on the modern synthesis, taking the “bushes not ladders” theme for horses and other animals (including human ancestors), and pushing it a step further. According to the theory of “punctuated equilibrium” (formulated in collaboration with Niles Eldredge), species mostly change relatively little during the time they exist (evolutionary stasis). Most evolutionary change happens when a small population buds off to form a new species and reproductive isolation allows it to conserve any evolutionary novelties it has developed. This opens up the possibility of “species selection.” Applied to horses, for example, this could mean that horses were evolutionarily successful for some time not so much because individual horses were well-adapted, but because something about horses collectively (their harem mating system, maybe) made one horse species especially likely to produce new species. Both horses and primates seem to be especially prone to bud off new species:

Speciation and chromosomal evolution seem fastest in those genera with species organized into clans or harems (e.g., some primates and horses) or with limited adult vagility and juvenile dispersal, patchy distribution, and strong individual territoriality (e.g., some rodents). This is consistent with the … hypothesis … that population subdivision into small demes promotes both rapid speciation and evolutionary changes in gene arrangement by inbreeding and drift.

 * Richard Dawkins doesn’t believe that Muhammed’s horse, al-Buraq, carried him (i.e. Muhammed) to heaven and back.

Horse clans

3912 – 3588 BCE

The Botai culture (3700 – 3100 BCE), in present-day Kazakhstan, represents an uncommon mode of subsistence: equestrian hunting. The fact that the Botai folk have domesticated horses makes them different from most hunters and gatherers, while the fact that they depend heavily on hunting makes them different from later herders in the region.

The most famous equestrian hunters are the American Plains Indians of the seventeenth to nineteenth centuries. These were a varied assortment of tribes, with origins among more settled Indian groups, who took up riding after Spaniards reintroduced the horse (which had gone extinct in North America, along with other megafauna, twelve thousand years earlier). Plains Indians depended on hunting bison for most of their diet. The Botai folk were not hunting bison, of course, but wild horses. Horses supplied the overwhelming part of their diet; 90% of animal bones in their settlements come from horses. There was an argument for a while about whether the Botai folk really had domesticated horses. However, this has been settled by the discovery of pottery containing residues of mare’s milk; obviously no one is arguing that they were milking wild horses. So unlike American Indians, Botai folk milked their horses.  It is also likely that they were riding horses and using them for traction. There is evidence for bit wear on the teeth of some of their horses, and it’s hard to see how they could have gotten whole wild horse carcasses back home (as they did) without having tame horses to pull the carcasses, probably on sledges.

The fact that the Botai folk had horse milk in their diet, along with lots of horse meat, is interesting. Horse milk is sweet (6.3% lactose vs. 1.3% fat, close to human milk), sweeter than cow’s milk (4.6% lactose vs. 3.4% fat). Any Botai individual who carried the lactase persistence allele, which allows carriers to digest lactose (milk sugar) past infancy and into adulthood, would presumably have had a strong fitness advantage. The ability to digest lactose might have been particularly important for kids making the transition from mother’s milk to horse meat. However, it took a long time – millennia – for the lactase gene to get really frequent.

Horses and horse riding and horse traction play an enormous role in Eurasian history. They are probably a major factor in the expansion of speakers of Indo-European languages. However, the Botai folk were almost certainly not the original Proto-Indo-European (PIE) speakers – the PIE vocabulary doesn’t fit – and Indo-European origins probably lie somewhere to the West, Ukraine, South Russia, or the Caucasus.

Land of throats

16.3-15.6 million years ago

There’s a great expansion in the diversity of horses in the mid-Miocene, especially horses that are adapted to grazing rather than browsing. The shift to grazing is going on world wide among many different groups. In South America the big grazers are the liptoterns, ungulates not closely related to horses that evolve to look a lot like them, with high-crowned grazing teeth, single-toed hoofed feet and legs built for speed. (Edgar Rice Burroughs took the name thoat – what his characters rode around on on Barsoom/Mars — from one genus of liptotern, Thoatherium.)

Thoatherium reconstruction

We often think of evolution as a matter of organisms adapting to their environments, but when the environment is other organisms, each side may be chasing a moving target. Or sometimes the sides may reach an equilibrium. In the case of grazing animals, there’s a process of coevolution that goes on between grazers and grasses. Where grazers are active, the plants that survive are grasses, which keep leaves above the ground but grow from underground. And this works in the other direction: in moderately dry climates, grasses are more productive than taller brushy plants, so it’s when grasses take over that there’s enough food around for grazers – a mutually reinforcing cycle. With drier climates from the mid-Miocene on, grasslands and grazers get to be more and more important.

So a lot of the story of life on Earth is not just the appearance of this or that cool animal, but also the evolution of ecosystems. At the same time grasslands were spreading on land, for example, kelp forests were spreading in coastal oceans. We’ll see how important grasslands are in human evolution and history. And kelp forests, with their rich fish populations, might have been important too, as the highway that the earliest Americans followed along the Pacific coast to the New World.

Planet of the horses

18.3 – 17.4 million years ago

We’re now running through Big History at the rate of 1 million years per day.

Horses have probably been the single most important domesticated animal in human history. Also, more than with other livestock, people get attached to horses as individuals. I’m guessing that in history and literature there are more horses with individual names than any other animal. (Alexander the Great’s horse was Bucephalus, “Ox-head”; Muhammed’s was al-Buraq*; Charlemagne’s was Tencendur; Don Quixote’s was Rocinante; Gandalf’s was Shadowfax.) We’ll be hearing a lot more about horses and horse folk on Logarithmic History once we get to human history.

Being so charismatic, horses have featured in a big way in arguments over evolution. Thomas Henry Huxley (1825-1895), “Darwin’s bulldog,” knew he needed to find good evidence for evolution. When he visited the United States in 1876, he was ready to give a lecture based on horse fossils from Europe. But visiting Yale, he was so impressed with O. C. Marsh’s collection of horse fossils from the western United States, that he rewrote his lecture around it.

Henry Fairfield Osborn (1857-1935) was director of the American Museum of Natural History and a huge presence in American paleontology. He was active at a time when most scientists accepted evolution, but many weren’t so keen on Darwin’s theory of natural selection. He thought horses were a fine example of “orthogenesis,” the tendency of species to follow a fixed line of evolution, reflecting internal forces, maybe related to willpower. He thought that humans shared a migratory spirit with horses, so that anywhere horse fossils were found would be a good place to look for human fossils. This theory didn’t pan out too well. A massive AMNH expedition to Central Asia led by Ray Chapman Andrews found all sorts of wonders – dinosaur eggs, baluchitheres – but no fossil “pro-men.” Orthogenesis leant itself naturally to diagrams showing evolution from early to modern horses going in a straight line.

George Gaylord Simpson (1902-1984), paleontologist, was one of the great figures in the evolutionary Modern Synthesis that brought together Darwin’s theory of natural selection and Mendel’s genetics. There was no room for orthogenesis in the Modern Synthesis, and Simpson emphasized that the evolution of horses was a matter of adaptation to a changing environment – especially the spread of grasslands. Also that horse evolution looked more like a bush than a ladder.

Stephen Jay Gould (1941-2002) was the most widely recognized American evolutionary biologist of recent times. (For example had a spot on The Simpson’s — “Lisa The Skeptic,” Season 9.) Gould had his own take on the modern synthesis, taking the “bushes not ladders” theme for horses and other animals (including human ancestors), and pushing it a step further. According to the theory of “punctuated equilibrium” (formulated in collaboration with Niles Eldredge), species mostly change relatively little during the time they exist (evolutionary stasis). Most evolutionary change happens when a small population buds off to form a new species and reproductive isolation allows it to conserve any evolutionary novelties it has developed. This opens up the possibility of “species selection.” Applied to horses, for example, this could mean that horses were evolutionarily successful for some time not so much because individual horses were well-adapted, but because something about horses collectively (their harem mating system, maybe) made one horse species especially likely to produce new species. Both horses and primates seem to be especially prone to bud off new species:

Speciation and chromosomal evolution seem fastest in those genera with species organized into clans or harems (e.g., some primates and horses) or with limited adult vagility and juvenile dispersal, patchy distribution, and strong individual territoriality (e.g., some rodents). This is consistent with the … hypothesis … that population subdivision into small demes promotes both rapid speciation and evolutionary changes in gene arrangement by inbreeding and drift.

 * Richard Dawkins doesn’t believe that Muhammed’s horse, al-Buraq, carried him (i.e. Muhammed) to heaven and back.

The sheep and the horses

By today’s date, the speakers of Proto-Indo-European are probably well-ensconced in their homeland, either Anatolia/the Caucasus/Northern Iran or (more likely according to the DNA evidence) the steppes north of the Black Sea. Nobody was writing the language down, but scholars have reconstructed a lot of it based on its daughter languages, which include English, Irish, Latin, Greek, Polish, Sanskrit, and Hittite, among many others. In 1868, August Schleicher wrote a little tale in reconstructed Proto-Indo-European. Here’s his version

Avis akvāsas ka

Avis, jasmin varnā na ā ast, dadarka akvams, tam, vāgham garum vaghantam, tam, bhāram magham, tam, manum āku bharantam. Avis akvabhjams ā vavakat: kard aghnutai mai vidanti manum akvams agantam. Akvāsas ā vavakant: krudhi avai, kard aghnutai vividvant-svas: manus patis varnām avisāms karnauti svabhjam gharmam vastram avibhjams ka varnā na asti. Tat kukruvants avis agram ā bhugat.

And the English translation

The Sheep and the Horses

A sheep that had no wool saw horses, one of them pulling a heavy wagon, one carrying a big load, and one carrying a man quickly. The sheep said to the horses: “My heart pains me, seeing a man driving horses.” The horses said: “Listen, sheep, our hearts pain us when we see this: a man, the master, makes the wool of the sheep into a warm garment for himself. And the sheep has no wool.” Having heard this, the sheep fled into the plain.

And here’s a sound file of the tale, based on more than a century’s linguistic work post-Schleicher, read aloud by linguist Andrew Bird.

Here’s a transcription of this version

 H₂óu̯is h₁éḱu̯ōs-k^we

h₂áu̯ei̯ h₁i̯osméi̯ h₂u̯l̥h₁náh₂ né h₁ést, só h₁éḱu̯oms derḱt. só g^wr̥h_xúm u̯óǵ^hom u̯eǵ^hed; só méǵh₂m̥ b^hórom; só d^hǵ^hémonm̥ h₂ṓḱu b^hered. h₂óu̯is h₁ék^woi̯b^hi̯os u̯eu̯ked: “d^hǵ^hémonm̥ spéḱi̯oh₂ h₁éḱu̯oms-k^we h₂áǵeti, ḱḗr moi̯ ag^hnutor”. h₁éḱu̯ōs tu u̯eu̯kond: “ḱlud^hí, h₂ou̯ei̯! tód spéḱi̯omes, n̥sméi̯ ag^hnutór ḱḗr: d^hǵ^hémō, pótis, sē h₂áu̯i̯es h₂u̯l̥h₁náh₂ g^whérmom u̯éstrom u̯ept, h₂áu̯ib^hi̯os tu h₂u̯l̥h₁náh₂ né h₁esti. tód ḱeḱluu̯ṓs h₂óu̯is h₂aǵróm b^huged.

Horse clans

3913 – 3589 BCE

The Botai culture (3700 – 3100 BCE), in present-day Kazakhstan, represents an uncommon mode of subsistence: equestrian hunting. The fact that the Botai folk have domesticated horses makes them different from most hunters and gatherers, while the fact that they depend heavily on hunting makes them different from later herders in the region.

The most famous equestrian hunters are the American Plains Indians of the seventeenth to nineteenth centuries. These were a varied assortment of tribes, with origins among more settled Indian groups, who took up riding after Spaniards reintroduced the horse (which had gone extinct in North America, along with other megafauna, twelve thousand years earlier). Plains Indians depended on hunting bison for most of their diet. The Botai folk were not hunting bison, of course, but wild horses. Horses supplied the overwhelming part of their diet; 90% of animal bones in their settlements come from horses. There was an argument for a while about whether the Botai folk really had domesticated horses. However, this has been settled by the discovery of pottery containing residues of mare’s milk; obviously no one is arguing that they were milking wild horses. So unlike American Indians, Botai folk milked their horses.  It is also likely that they were riding horses and using them for traction. There is evidence for bit wear on the teeth of some of their horses, and it’s hard to see how they could have gotten whole wild horse carcasses back home (as they did) without having tame horses to pull the carcasses, probably on sledges.

The fact that the Botai folk had horse milk in their diet, along with lots of horse meat, is interesting. Horse milk is sweet (6.3% lactose vs. 1.3% fat, close to human milk), sweeter than cow’s milk (4.6% lactose vs. 3.4% fat). Any Botai individual who carried the lactase persistence allele, which allows carriers to digest lactose (milk sugar) past infancy and into adulthood, would presumably have had a strong fitness advantage. The ability to digest lactose might have been particularly important for kids making the transition from mother’s milk to horse meat. However, it took a long time – millennia – for the lactase gene to get really frequent.

Horses and horse riding and horse traction play an enormous role in Eurasian history. They are probably a major factor in the expansion of speakers of Indo-European languages. The Botai folk were almost certainly not the original Proto-Indo-European (PIE) speakers – the PIE vocabulary doesn’t fit – but they or people like them might have played some role in Indo-European origins, even if their language didn’t prevail.

Land of the thoats

16.3-15.6 million years ago

There’s a great expansion in the diversity of horses in the mid-Miocene, especially horses that are adapted to grazing rather than browsing. The shift to grazing is going on world wide among many different groups. In South America the big grazers are the liptoterns, ungulates not closely related to horses that evolve to look a lot like them, with high-crowned grazing teeth, single-toed hoofed feet and legs built for speed. (Edgar Rice Burroughs took the name thoat – what his characters rode around on on Barsoom/Mars — from one genus of liptotern, Thoatherium.)

We often think of evolution as a matter of organisms adapting to their environments, but when the environment is other organisms, each side may be chasing a moving target. Or sometimes the sides may reach an equilibrium. In the case of grazing animals, there’s a process of coevolution that goes on between grazers and grasses. Where grazers are active, the plants that survive are grasses, which keep leaves above the ground but grow from underground. And this works in the other direction: in moderately dry climates, grasses are more productive than taller brushy plants, so it’s when grasses take over that there’s enough food around for grazers – a mutually reinforcing cycle. With drier climates from the mid-Miocene on, grasslands and grazers get to be more and more important.

So a lot of the story of life on Earth is not just the appearance of this or that cool animal, but also the evolution of ecosystems. At the same time grasslands were spreading on land, for example, kelp forests were spreading in coastal oceans. We’ll see how important grasslands are in human evolution and history. And kelp forests, with their rich fish populations, might have been important too, as the highway that the earliest Americans followed along the Pacific coast to the New World.