Author Archives: logarithmichistory

The worst day in the history of Earth

66.5 million years ago

April 5 on Logarithmic History marks the most famous mass extinction ever, the one that did in the dinosaurs (okay, okay, the non-avian dinosaurs). Here’s a link to a previous year’s post.

And just let year we had news of one of the most extraordinary fossil discoveries ever, in North Dakota: a graveyard of fish piled on one another by a tsunami-like wave, and mixed with burned trees, and the remains of mammals, mososaurs, ammonites, and insects, and a partial triceratops, formed within hours of the asteroid impact that wiped out most life on Earth. Here is a news release, 66 million-year-old deathbed linked to dinosaur-killing meteor, and here is an article from the New Yorker, The Day the Dinosaurs Died.

Leaves of grass

Not as dramatic as the evolution of Triceratops or T. rex, but of more lasting consequence, is the evolution of grasses (Poaceae). We know from coprolites – fossil feces — that grass was around by the Late Cretaceous, so the coevolution of grass and grazers had already begun with dinosaurs. These early grasses were not widespread. It would take climate shifts and more evolution (toward using carbon dioxide more efficiently) to create the sort of grasslands we are familiar with.

Grasses have played a central role in human evolution and human history. Human beings evolved in tropical grasslands, and some evolutionary psychologists think we still have an instinctive affinity for this environment. The domestication of grasses (wheat, barley, oats, millet, rice, corn) was one of the great revolutions in human prehistory, and grasses provided most of the calories people ate for most of recorded history. Contact along the frontier between grasslands supporting pastoralists and grain growing lands supporting peasants is one of the great engines of historical dynamics.

Grasses grow from the base of the leaf, not the tip of the stem, which is what allows them to recover from being grazed. This makes them a recurring symbol both of the transitoriness of life (“All flesh is grass, and all the goodliness thereof is like the flower of the field,” Isaiah 40:6) and its resilience.

Brahms used another verse about grass in the second movement of his German Requiem “For all flesh is as grass, and all the glory of man as the flower of grass. The grass withereth, and the flower thereof falleth away,” 1 Peter1:24. (Here is the German text and English translation.)

And the most famous poem about grass, by Walt Whitman, perhaps strikes the right elegiac note for the dinosaurs, who meet their doom today:

A child said, What is the grass? fetching it to me
with full hands;
How could I answer the child?. . . .I do not know what it
is any more than he.

I guess it must be the flag of my disposition, out of hopeful
green stuff woven.
Or I guess it is the handkerchief of the Lord,
A scented gift and remembrancer designedly dropped,
Bearing the owner’s name someway in the corners, that we
may see and remark, and say Whose?

Or I guess the grass is itself a child. . . .the produced babe
of the vegetation.

Or I guess it is a uniform hieroglyphic,
And it means, Sprouting alike in broad zones and narrow
zones,
Growing among black folks as among white,
Kanuck, Tuckahoe, Congressman, Cuff, I give them the
same, I receive them the same.

And now it seems to me the beautiful uncut hair of graves.
Tenderly will I use you curling grass,
It may be you transpire from the breasts of young men,
It may be if I had known them I would have loved them;
It may be you are from old people and from women, and
from offspring taken soon out of their mother’s laps,
And here you are the mother’s laps.

This grass is very dark to be from the white heads of old
mothers,
Darker than the colorless beards of old men,
Dark to come from under the faint red roofs of mouths.

O I perceive after all so many uttering tongues!
And I perceive they do not come from the roofs of mouths
for nothing.

I wish I could translate the hints about the dead young men
and women,
And the hints about old men and mothers, and the offspring
taken soon out of their laps.

What do you think has become of the young and old men?
What do you think has become of the women and
children?

They are alive and well somewhere;
The smallest sprouts show there is really no death,
And if ever there was it led forward life, and does not wait
at the end to arrest it,
And ceased the moment life appeared.

All goes onward and outward. . . .and nothing collapses,
And to die is different from what any one supposed, and
luckier.

Griffinoceratops

Blog about dinosaurs and you also end up blogging about the great age of dinosaur discovery that began almost 200 years ago. But dinosaurs hunting didn’t begin with the Victorians. Adrienne Mayor wrote a great book called The First Fossil Hunters, about how many of the monsters of ancient Greek and Roman myth were based on the discovery of the bones of extinct species, from mammoths (likely basis for the legend of Cyclops) to dinosaurs.

The griffin is a fine example. The Greeks from the 7th century BCE picked up stories from the Scythian nomads of the Eurasian steppe about griffins far to the east who guarded treasures of gold. These griffins were supposed to be “four-legged birds” with feathers, wings, eagle-like beaks, and clawed feet. The legendary homeland of the griffins was explored in 1922 by the great fossil-hunting expedition of Ray Chapman Andrews, which discovered abundant remains of the late Cretaceous (about 83 million years ago) Protoceratops, along with dinosaur eggs. The resemblance to the legendary griffins is striking.

griffinceratops copy

Mayor argues that Scythian discoveries of ceratopsian skeletons inspired the story of the griffin. The main difference is the griffin’s wings, which might have been a misreading of ceratopsian collar bones. Remarkably, the ancient idea of the griffin is close to recent reconstructions of feathered agile dinosaurs. The word “dinosaur” literally means “terrible lizard,” but many dinosaurs really were closer to “four-legged birds.”

Dino habilis

84.5 – 80 million years ago

When Jane Goodall reported in 1960 that chimpanzees at her field site in Gombe, Tanzania, were making tools, she made headlines. The discovery toppled a supposed pillar of human uniqueness, enshrined in the catchphrase “Man the Toolmaker.” Louis Leakey, upon getting the news from a telegram sent by Goodall, wrote “Now we must redefine tool, redefine Man, or accept chimpanzees as humans.”

We’ve grown more blasé since then, and the gradually accumulating evidence for dinosaur tool use has attracted a lot less attention. The evidence is similar to what we find for early human ancestors, Homo habilis and earlier. It takes the form of manuports, stones that have been transported a long way out of their geological context. Although the inference was resisted at first, it now looks almost certain that they were picked up and carried, probably by dinosaurs who used them as hammers to smash bones (or, less plausibly, to attract mates). Most suspected manuports weigh just a few pounds (a kilogram or two), and the most likely tool users in this case are the various raptors. A small fraction of manuports are much larger – up to fifty pounds (over twenty kilograms) – and may have been carried by larger dinosaurs like Tyrannosaurus rex. T. rex was clearly a carnivore, but people have long wondered how she got her meat, whether by hunting or scavenging. The latest finds raise the possibility that she was a specialized predator, dropping rocks from above to smash armored prey like tortoises and ankylosaurs.

Tool use is sometimes taken as evidence of sophisticated cognition. With dinosaurs, however, we may be seeing something different, the evolution of complex tool-using instincts over many tens of millions of years, no more indicative of high intelligence than honeybee dances or spider webs. If there is a parallel with human evolution it is not that dinosaurs were especially smart, but that the process of evolution, given as a starting point a pair of forelimbs not being used for locomotion, is likely to find (or exapt) some new function for them.

The suggested evolutionary scenario for instinctive tool use in dinosaurs is supported by findings regarding another group of organisms, still abundant today: ethologists discovered decades ago that complex tool using abilities without a high level of intelligence are present among some varieties of gull. More recently, these gull abilities have turned out to be widespread.

Slime had they for mortar

“And slime had they for mortar” Genesis 11:3

The last post was about a major transition in evolution, the origin of social insect colonies, in which individual ants and bees work together to make up something like a superorganism. Around the same time that this was happening we find evidence for another venture in higher-level evolution, the slime molds. (The evidence is in the form of a recently discovered 100 million year old fossil, although slime molds were probably around long before this.)

John Tyler Bonner, who died just last year, spent 70 years of a very long life studying cellular slime molds. Here are some weirdly beautiful movies he made. Cellular slime molds switch between being single cell organisms and multicellular organisms. Most of the time they live alone, looking and acting much like non-social amoebae. But when times get tough, and local food resources are exhausted, the cells start sending out chemical signals indicating they are ready to shift to another state. Individual cells aggregate to form a mass, which is capable of moving around, seeking out new food sources, even learning. (In cellular slime molds, cells retain their identity as separate cells. In plasmodial slime molds, the cells merge to form one super cell.) The mass may raise up a fruiting body atop a stem. The spores in the fruiting body may blow away, perhaps being carried some distance to a better home, where the survivors disperse and feast as the cycle begins again. There is an interesting sociobiological puzzle here: the cells forming the stalk are sacrificing themselves for the sake of the spore cells. This is probably an instance of kin selection.

Both social insects and slime molds may carry lessons for human social life, which, on a large scale, is radically different from the social life of our primate near relations. Both social insects and humans commonly build enormous social organizations with high levels of cooperation. These organizations are too large for their members to recognize one another as individuals. Instead they rely on signals to show others that they are the right sort. With social insects, these are mostly chemical signals. With humans these are the various insignia – letters of commission, uniforms, shibboleths, etc. – that mark the bearer as the occupant of a particular social role, independently of his personal character. (“You salute the uniform, not the man.”) For more on this topic, check out Mark Moffett’s The Human Swarm: How Our Societies Arise, Thrive, and Fall.

And, as with slime molds, humans seem to go through characteristic alternations in their social lives, on a time scale of multiple generations. With slime molds there is an alternation between solitary and social phases. With humans there is an alternation between phases of lesser and greater social solidarity (asabiya). Borrowing from Max Weber, we might call this an alternation between routine and charisma. In phases of routine, people learn the rules of their society, and do their best to get ahead by following the rules, or working around them. But in times of crisis, the old ways no longer serve. While slime molds secrete pheromones to instigate aggregation in hard times, humans secrete cosmologies. Prophets arise, with visions of a new order, taking their cues from divine visions, or the Book of Daniel or Revelations, or theories of political economy or race science. The great majority of such projects are stillborn, but occasionally one succeeds, subduing doubters and infidels, overthrowing the established order or leading a chosen people to a new land. The world we live in – the civilizational landscape of Eurasia, the cultural geography of the United States (I write this in Salt Lake City, Utah) – is in some degree the legacy of such projects.

The quotation above from Genesis 11:3 was used by Eric Hoffer in his book The True Believer: Thoughts on the Nature of Mass Movements, published in the early years of the Cold War, still worth reading today.

Related, here’s me on the sociobiology of “ethnic group selection.”

Consider her ways

106-100 million years ago.

There are some pieces of paleontology that really stand out in the popular imagination. Dinosaurs are so cool that even if they hadn’t existed we would have invented them. (Maybe we did, in the form of dragons. And look ahead (or back) to early April for the dinosaur-griffin connection.) Also, as I suggested in a previous post, transitions from one form of locomotion to another – flightless dinosaurs to birds, fish to tetrapods, land mammals to whales – really grab the imagination (and annoy creationists) because the largest and most distinctive named folk categories of animals (snakes, fish, birds) are built around modes of locomotion.

Evolutionary biologists tend to see things differently. Turning fins into legs, legs into wings, and legs back into flippers is pretty impressive. But the really major evolutionary transitions involve the evolution of whole new levels of organization: the origin of the eukaryotic cell, for example, and the origin of multicellular life. From this perspective, the really huge change in the Mesozoic – sometimes called the Age of Dinosaurs – is the origin of eusociality among insects like ants and bees. An ant nest or a bee hive is something like a single superorganism, with most of its members sterile workers striving – even committing suicide — for the colony’s reproduction, not their own. (100 million years ago – corresponding to March 29 in Logarithmic History — is when we find the first bee and ant fossils, but the transition must have been underway before that time.)

Certainly the statistics on social insects today are impressive.

The twenty thousand known species of eusocial insects, mostly ants, bees, wasps and termites, account for only 2 percent of the approximately one million known species of insects. Yet this tiny minority of species dominate the rest of the insects in their numbers, their weight, and their impact on the environment. As humans are to vertebrate animals, the eusocial insects are to the far vaster world of invertebrate animals. … In one Amazon site, two German researchers … found that ants and termites together compose almost two-thirds of the weight of all the insects. Eusocial bees and wasps added another tenth. Ants alone weighed four times more than all the terrestrial vertebrates – that is, mammals, birds, reptiles, and amphibians combined. E. O. Wilson pp 110-113

E. O. Wilson, world’s foremost authority on ants, and one of the founders of sociobiology, thinks that the origin of insect eusociality might have lessons for another major evolutionary transition, the origin of humans (and of human language, technology, culture, and complex social organization). In his book The Social Conquest of Earth he argues that a key step in both sets of transitions was the development of a valuable and defensible home – in the case of humans, a hearth site. Wilson returns to this argument in his book Genesis: The Deep Origin of Human Societies, just published, which I’ll get around to saying more about here eventually. On the same topic, Mark Moffett’s book The Human Swarm: How Human Societies Arise, Thrive, and Fall,  asks how it is that we somehow rival the social insects in our scale of organization.

One trait found in both ants and humans is large-scale warfare. Wilson gives an idea of the nature of ant warfare in fictional form in his novel Anthill. It’s an interesting experiment, but also disorienting. Because individual recognition is not important for ants, his story of the destruction of an ant colony reads like the Iliad with all the personal names taken out. But Homer’s heroes fought for “aphthiton kleos,” undying fame (and got some measure of it in Homer’s poem). The moral economy of reputation puts human cooperation in war and peace on a very different footing from insect eusociality. (Here’s my take on “ethnic group selection,” which depends on social enforcement, perhaps via reputation.)

Consider her ways” is the title of a short story by John Wyndham, about a woman from the present trapped in a future ant-like all-female dystopia. It was made into an episode of Alfred Hitchcock Presents. The title is from Proverbs 6:6, “Go to the ant, thou sluggard, consider her ways and be wise.”

The People of the Wind

140-133 million years ago

John W. Campbell, the editor of Astounding Science Fiction magazine, used to challenge writers with new premises. One of his challenges was to imagine an alien that is to mammals as mammals are to reptiles. Science fiction writer Poul Anderson took up this challenge by inventing the Ythri, flying intelligent aliens of the planet Avalon, for his novel The People of the Wind. The Ythri were able to support the high metabolisms necessary for flight because they had a special system for supercharging their bloodstreams with extra oxygen.

Since Anderson’s time, we’ve learned that birds – and some dinosaurs – are actually somewhat Ythri-like. To begin with, consider non-dinosaur reptiles, like lizards: their sprawling posture means that their legs compress and expand their lungs as they run, so they can’t run and breathe at the same time. (David Carrier, a biologist at the University of Utah, was a main guy to figure this out.) If you had traveled back in time to the Paleozoic, before the dinosaurs took over, and if you had had good endurance training, you would have found the hunting easy, because the sprawling reptiles of the time would not have been able to run away for more than a short sprints. The predators to worry about would have been ambush hunters, not endurance hunters.

Dinosaurs got around these constraints in the first place by running bipedally (although some later reverted to quadrupedalism). And it now looks like at least some of them also had the sort of respiration we find in birds. Lungs are only part of birds’ respiratory systems. Birds also have an extensive network of air sacs running through their bodies, and even air passages in their bones. Air moves in both directions, in and out, like a bellows, through the air sacs, but only one direction through the lungs. This allows for more efficient circulation than mammalian lungs, where air has to move both in and out of the lungs. Just recently (2008), it’s been shown that Allosaurus, only distantly related to birds, had the same system, so it was probably widespread among dinosaurs. This breathing system may have helped dinosaurs to survive low-oxygen crises at the end of the Triassic, and flourish in the low oxygen Jurassic and Cretaceous. It may also have helped one group of dinosaurs to evolve into birds.

Anderson’s book isn’t just about respiratory physiology. It’s also about perennial issues of loyalty and identity. Avalon also has human settlers, who have so absorbed Ythri values — some of them even yearning, impossibly, to be Ythri — that they fight for an independent Avalon against an expanding Terran Empire. (Compare the movie Avatar.)

We’ll have more to say about bipedalism and breathing — and language — when human evolution comes up.