Consider her ways

99.9 – 95.6 million years ago.

Here is my obituary for Ed Wilson (1929 – 2021) and below some thoughts about ants.

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 28 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 recent book Genesis: The Deep Origin of Human Societies. 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.”

Other science fiction authors have taken a cheerier view of a world without men.

Your cuisinart, a prehistory

A famous movie cut, from 2001: A Space Odyssey, transitions from a bone club, hurled aloft by an australopithecine 2.5 million years ago, to a spacecraft in the year 2001.

Arthur Clarke and Stanley Kubrick, coming up with the plot for the movie/book, were influenced by the popular author Robert Ardrey. In his book African Genesis, Ardrey casts human evolution as a version of the story of Cain and Abel, except in his version the peaceful vegetarians (robust australopithecines) get clobbered by the club-wielding meat-eaters (gracile australopithecines).

We were born of risen apes, not fallen angels, and the apes were armed killers besides. And so what shall we wonder at? Our murders and massacres and missiles, and our irreconcilable regiments?  Or our treaties whatever they may be worth; our symphonies however seldom they may be played; our peaceful acres, however frequently they may be converted into battlefields; our dreams however rarely they may be accomplished. The miracle of man is not how far he has sunk but how magnificently he has risen. We are known among the stars by our poems, not our corpses.

Ardrey, along with Konrad Lorenz and Desmond Morris, was much in vogue in the 1960s: Sam Peckinpah was another movie director influenced by him. The man could turn a phrase. Unfortunately his speculations on evolution and human behavior are probably not of enduring value: he had the misfortune to take up the topic too early to take on board the sociobiological revolution pioneered by William Hamilton, Robert Trivers, and George Williams, and popularized by E. O. Wilson and Richard Dawkins.

Ardrey may not have been off-base in thinking that weaponry and warfare have been an important motive force in human biological and social evolution (more on this later). But where early stone tools are concerned, a different segue, from Oldowan chopper to Cuisnart may be more appropriate.

Recent research argues that early hominins could have dramatically increased available food energy by pounding vegetables and chopping up meat into more digestible pieces. Tool use may have been an early step in our ancestors’ move to high energy diets. Meat-eating began to be important in human evolution around 2.6 million years ago. Somewhat later we see evidence that some hominins have lighter jaws and aren’t chewing as much. So to celebrate this early dietary revolution, here’s a recipe:

Steak Tartare

Place in a food processor fitted with the metal chopping blade:

1 ½ pounds lean beef (tenderloin, top round, or sirloin) cut into ½ inch cubes

Pulse until meat is coarsely ground, 7-10 seconds. Do not over-process. Remove meat to a chilled platter or individual plates and gently form into 6 individual mounds.

[Optional: Make a spoon shaped indentation on top of each mound and crack into each

1 egg yolk.]

Divide and arrange in small piles around each serving:

½ cup minced onions
½ cup minced shallots
½ cup minced fresh parsley
¼ cup minced drained capers
8-12 anchovies (optional)

Serve immediately and pass separately:

Fresh lemon juice
Worcestershire sauce
Dijon mustard
Hot pepper sauce
Freshly ground black pepper
Salt

From The Joy of Cooking 1997

The monkey’s voyage

35.9 – 34.0 million years ago

The Oligocene (starting today on Logarithmic History) sees a major diversification of anthropoid primates (monkeys, apes, and humans). Among the anthropoids, the major evolutionary split is a geographic one, between platyrrhines (New World monkeys) and catarrhines (Old World monkeys, apes, and humans). Aegyptopithecus is one of the earliest primates that clearly falls on the catarrhine side of that split (although the split must go back earlier).

At Logarithmic History we traffic in Big Questions, and one of the biggest questions of all is the balance of natural law and accident in making our world. Thus physicists have long hoped to find that the laws governing our universe reduce to just a few fundamental equations, but we saw at the beginning of this blog that they are now confronting the possibility that our universe is just one among many, and that the laws of physics in our universe may incorporate a large dose of historical accident. With the discovery of extra-solar planets, we’re just beginning to get an idea of how typical or atypical our solar system is. And we’ll have a lot of opportunities to ask whether there are Laws of History (an old idea now undergoing a revival in the new field of cliodynamics*) when we move into the historical period later in the year.

The field of biogeography – the study of the geographic distribution of species – has seen some major pendulum swings in this regard. Darwin was intensely interested in questions of biogeography mainly because they could provide support for the theory of evolution. His approach could fairly be called eclectic. From sometime in the second half of the twentieth century however, a lot of biologists thought they could do better than just answering particularistic questions about how species A got to island Z (sometimes disparaged as “stamp collecting”). They wanted to find scientific laws.

Edward O. Wilson was an early pioneer in this area. Along with Robert MacArthur, he developed a theory of island biogeography which was supposed to get the field out of its natural history phase, and turn it into a predictive science. According to MacArthur and Wilson, the number of species on an island is set by a predictable equilibrium between extinction (smaller islands have higher extinction rates) and colonization (remote islands have lower colonization rates). Being a good scientist Wilson actually put this theory to the test by getting an exterminator to “defaunate” (it means what you think it means) some little mangrove islets, and showing that they returned to very close to their predicted equilibrium numbers of animal species after a while.

For the biogeography of continents (and larger islands once part of continents) the quest for scientific laws took a different turn. The discovery of continental drift and plate tectonics encouraged a school of “vicariance biogeography.” Vicariance biogeographers liked to trace current biogeographic distributions to the wanderings of continents. They were highly allergic to explanations involving accidental long-distance dispersal over big stretches of ocean.

Alan de Queiroz, in The Monkey’s Voyage: How Improbable Journeys Shaped the History of Life, provides a highly readable overview of the decline (if not quite the extinction) of the vicariance school in the face of mounting evidence for flukish dispersals as a major factor in biogeography. The dispersal of monkeys to the New World is a dramatic case in point. (Guinea pigs and their relatives are another.) About the only scenario that makes sense involves a raft of trees washing out to sea (most likely from the Congo basin) and eventually delivering a few parched, scared monkeys to the island continent of South America, where they eventually spawned the whole range of species – spider monkeys, squirrel monkeys, howler monkeys, tamarins, marmosets, capuchins – we know today. Sheer accident: change the weather a little, leave the monkeys stranded at sea a little longer, and the whole history of primates in the New World is erased.

* so new my spellchecker doesn’t recognize it.

A famous movie cut, from 2001: A Space Odyssey, transitions from a bone club, hurled aloft by an australopithecine 2.5 million years ago, to a spacecraft in the year 2001.

Arthur Clarke and Stanley Kubrick, coming up with the plot for the movie/book, were influenced by the popular author Robert Ardrey. In his book African Genesis, Ardrey casts human evolution as a version of the story of Cain and Abel, except in his version the peaceful vegetarians (robust australopithecines) get clobbered by the club-wielding meat-eaters (gracile australopithecines).

We were born of risen apes, not fallen angels, and the apes were armed killers besides. And so what shall we wonder at? Our murders and massacres and missiles, and our irreconcilable regiments?  Or our treaties whatever they may be worth; our symphonies however seldom they may be played; our peaceful acres, however frequently they may be converted into battlefields; our dreams however rarely they may be accomplished. The miracle of man is not how far he has sunk but how magnificently he has risen. We are known among the stars by our poems, not our corpses.

Ardrey, along with Konrad Lorenz and Desmond Morris, was much in vogue in the 1960s: Sam Peckinpah was another movie director influenced by him. The man could turn a phrase. Unfortunately his speculations on evolution and human behavior are probably not of enduring value: he had the misfortune to take up the topic too early to take on board the sociobiological revolution pioneered by William Hamilton, Robert Trivers, and George Williams, and popularized by E. O. Wilson and Richard Dawkins.

Ardrey may not have been off-base in thinking that weaponry and warfare have been an important motive force in human biological and social evolution (more on this later). But where early stone tools are concerned, a different segue, from Oldowan chopper to Cuisnart may be more appropriate.

Recent research argues that early hominins could have dramatically increased available food energy by pounding vegetables and chopping up meat into more digestible pieces. Tool use may have been an early step in our ancestors’ move to high energy diets. Meat-eating began to be important in human evolution around 2.6 million years ago. Somewhat later we see evidence that some hominins have lighter jaws and aren’t chewing as much. So to celebrate this early dietary revolution, here’s a recipe:

Steak Tartare

Place in a food processor fitted with the metal chopping blade:

1 ½ pounds lean beef (tenderloin, top round, or sirloin) cut into ½ inch cubes

Pulse until meat is coarsely ground, 7-10 seconds. Do not over-process. Remove meat to a chilled platter or individual plates and gently form into 6 individual mounds.

[Optional: Make a spoon shaped indentation on top of each mound and crack into each

1 egg yolk.]

Divide and arrange in small piles around each serving:

½ cup minced onions
½ cup minced shallots
½ cup minced fresh parsley
¼ cup minced drained capers
8-12 anchovies (optional)

Serve immediately and pass separately:

Fresh lemon juice
Worcestershire sauce
Dijon mustard
Hot pepper sauce
Freshly ground black pepper
Salt

From The Joy of Cooking 1997

The monkey’s voyage

35.9 – 34.0 million years ago

The Oligocene (starting today on Logarithmic History) sees a major diversification of anthropoid primates (monkeys, apes, and humans). Among the anthropoids, the major evolutionary split is a geographic one, between platyrrhines (New World monkeys) and catarrhines (Old World monkeys, apes, and humans). Aegyptopithecus is one of the earliest primates that clearly falls on the catarrhine side of that split (although the split must go back earlier).

At Logarithmic History we traffic in Big Questions, and one of the biggest questions of all is the balance of natural law and accident in making our world. Thus physicists have long hoped to find that the laws governing our universe reduce to just a few fundamental equations, but we saw at the beginning of this blog that they are now confronting the possibility that our universe is just one among many, and that the laws of physics in our universe may incorporate a large dose of historical accident. With the discovery of extra-solar planets, we’re just beginning to get an idea of how typical or atypical our solar system is. And we’ll have a lot of opportunities to ask whether there are Laws of History (an old idea now undergoing a revival in the new field of cliodynamics*) when we move into the historical period later in the year.

The field of biogeography – the study of the geographic distribution of species – has seen some major pendulum swings in this regard. Darwin was intensely interested in questions of biogeography mainly because they could provide support for the theory of evolution. His approach could fairly be called eclectic. From sometime in the second half of the twentieth century however, a lot of biologists thought they could do better than just answering particularistic questions about how species A got to island Z (sometimes disparaged as “stamp collecting”). They wanted to find scientific laws.

Edward O. Wilson was an early pioneer in this area. Along with Robert MacArthur, he developed a theory of island biogeography which was supposed to get the field out of its natural history phase, and turn it into a predictive science. According to MacArthur and Wilson, the number of species on an island is set by a predictable equilibrium between extinction (smaller islands have higher extinction rates) and colonization (remote islands have lower colonization rates). Being a good scientist Wilson actually put this theory to the test by getting an exterminator to “defaunate” (it means what you think it means) some little mangrove islets, and showing that they returned to very close to their predicted equilibrium numbers of animal species after a while.

For the biogeography of continents (and larger islands once part of continents) the quest for scientific laws took a different turn. The discovery of continental drift and plate tectonics encouraged a school of “vicariance biogeography.” Vicariance biogeographers liked to trace current biogeographic distributions to the wanderings of continents. They were highly allergic to explanations involving accidental long-distance dispersal over big stretches of ocean.

Alan de Queiroz, in The Monkey’s Voyage: How Improbable Journeys Shaped the History of Life, provides a highly readable overview of the decline (if not quite the extinction) of the vicariance school in the face of mounting evidence for flukish dispersals as a major factor in biogeography. The dispersal of monkeys to the New World is a dramatic case in point. (Guinea pigs and their relatives are another.) About the only scenario that makes sense involves a raft of trees washing out to sea (most likely from the Congo basin) and eventually delivering a few parched, scared monkeys to the island continent of South America, where they eventually spawned the whole range of species – spider monkeys, squirrel monkeys, howler monkeys, tamarins, marmosets, capuchins – we know today. Sheer accident: change the weather a little, leave the monkeys stranded at sea a little longer, and the whole history of primates in the New World is erased.

* so new my spellchecker doesn’t recognize it.

Edward O. Wilson, 1929-2021

I met Ed Wilson once. He was going to give a plenary talk at a conference I was at, and I was doing liaison with the people who were going to record the talk. I joked with him that there would be both Christian anti-evolutionists and Marxist anti-sociobiologists trying to get a hold of the recording so they could play it backward looking for hidden Satanic messages. He laughed at that. That was years ago, and back then I expected that the furor over Wilson and his work would die down over time. But now here’s this.

Wilson’s work has come up frequently on this blog. Here are some reflections.

Isaiah Berlin divided writers into foxes who know many things and hedgehogs who know one big thing. He called Tolstoy a fox who wanted to be a hedgehog. That fits Wilson too. He was an incredibly prolific and successful scientist and intellectual. He was also always on the look out for the big idea(s) that would pull everything together. He scored a great early success on those lines with his work on island biogeography. He teamed up with the mathematical ecologist Robert MacArthur to develop a formal theory of the topic, and then did some actual experiments where he wiped out the invertebrate fauna of little mangrove islets and then showed that they returned to predicted equilibrium species numbers. Here I write about this work, and also about the more recent turn in biogeography away from grand theory to more particularist explanations. 

In his scientific work, Wilson is above all an ant guy. But at the end of his book The Insect Societies, Wilson called for a new science of sociobiology, and then wrote a whole book about Sociobiology: The New Synthesis. The book is a rich mine of information. Running throughout is a hope that we might get beyond the topics in particular chapters to produce something like a Grand Unified Theory of social evolution, maybe something like a periodic table or a low dimensional space of social variation that would organize and explain the multifarious variation that we see in animal societies. So far this hasn’t quite panned out. Even in the limited domain of primates, although we’ve learned a lot about socioecology, early hopes for a straightforward theory along the lines of “You tell me the ecology, I’ll tell you the social organization” haven’t quite panned out. Things are messier than that.

And Wilson also aimed to extend sociobiology to humans.  His role here is interesting. He is hugely important as an inspiration, and as a defender of the field. But none of the various schools of evolution and human behavior – human behavioral ecology, evolutionary psychology, gene-culture coevolution – descend very directly from Wilson. His big theoretical effort, Genes, Mind, and Culture, coauthored with Charles Lumsden, fell with a thud and inspired very little followup. (Worth noting, in light of his later advocacy of group selection: L&W’s model of gene-culture coevolution makes no room for cultural group selection. If, as in their model, the probability of a kid in Pennsylvania being Amish depends only on the overall frequency of Amish in the population, and not on what her parents are, then CGS for Amishness is not going to get off the ground.)

More recently he stirred up a fuss by arguing that the theory of kin selection is overrated, and advocating for a version of group selection. I have partial sympathy with this. It isn’t always appreciated by people who know the popular version of the theory that you can’t always just plug in Hamilton’s formula for inclusive fitness and off you go. I suspect that some of what makes human kinship special comes from the way that human societies use norms and third-party interventions to beat Hamilton’s rule. And not just Wilson, but a lot of folks, think that some version of group selection may operate in our species. But Wilson, ever after the big picture, goes further, trying hard to connect eusociality in insects with human hypersociality (Well, ants have nests, so do people, sort of …). I think it’s hard to make that fly.

But whatever the fate of his particular theories, Wilson stands out as a great defender of consilience, of the unity of the sciences, of the sciences and the humanities, and particularly of biology and the social sciences. Several books cover the sociobiology wars and Wilson’s role in them. And these bring out another quality of the man. If he is not quite the hedgehog that Darwin was, he is, very like Darwin, an exemplar of humanity and grace under pressure.

Your cuisinart, a prehistory

A famous movie cut, from 2001: A Space Odyssey, transitions from a bone club, hurled aloft by an australopithecine 2.5 million years ago, to a spacecraft in the year 2001.

Arthur Clarke and Stanley Kubrick, coming up with the plot for the movie/book, were influenced by the popular author Robert Ardrey. In his book African Genesis, Ardrey casts human evolution as a version of the story of Cain and Abel, except in his version the peaceful vegetarians (robust australopithecines) get clobbered by the club-wielding meat-eaters (gracile australopithecines).

We were born of risen apes, not fallen angels, and the apes were armed killers besides. And so what shall we wonder at? Our murders and massacres and missiles, and our irreconcilable regiments?

Ardrey, along with Konrad Lorenz and Desmond Morris, was much in vogue in the 1960s: Sam Peckinpah was another movie director influenced by him. Unfortunately his speculations on evolution and human behavior are probably not of enduring value: he had the misfortune to take up the topic too early to take on board the sociobiological revolution pioneered by William Hamilton, Robert Trivers, and George Williams, and popularized by E. O. Wilson and Richard Dawkins.

Ardrey may not have been off-base in thinking that weaponry and warfare have been an important motive force in human biological and social evolution (more on this later). But where early stone tools are concerned, a different segue, from Oldowan chopper to Cuisnart may be more appropriate.

Recent research argues that early hominins could have dramatically increased available food energy by pounding vegetables and chopping up meat into more digestible pieces. Tool use may have been an early step in our ancestors’ move to high energy diets. Meat-eating began to be important in human evolution around 2.6 million years ago. Somewhat later we see evidence that some hominins have lighter jaws and aren’t chewing as much. So to celebrate this early dietary revolution, here’s a recipe:

Steak Tartare

Place in a food processor fitted with the metal chopping blade:

1 ½ pounds lean beef (tenderloin, top round, or sirloin) cut into ½ inch cubes

Pulse until meat is coarsely ground, 7-10 seconds. Do not over-process. Remove meat to a chilled platter or individual plates and gently form into 6 individual mounds.

[Optional: Make a spoon shaped indentation on top of each mound and crack into each

1 egg yolk.]

Divide and arrange in small piles around each serving:

½ cup minced onions
½ cup minced shallots
½ cup minced fresh parsley
¼ cup minced drained capers
8-12 anchovies (optional)

Serve immediately and pass separately:

Fresh lemon juice
Worcestershire sauce
Dijon mustard
Hot pepper sauce
Freshly ground black pepper
Salt

From The Joy of Cooking 1997

The monkey’s voyage

34.5-32.7 million years ago

The Oligocene (starting today on Logarithmic History) sees a major diversification of anthropoid primates (monkeys, apes, and humans). Among the anthropoids, the major evolutionary split is a geographic one, between platyrrhines (New World monkeys) and catarrhines (Old World monkeys, apes, and humans). Aegyptopithecus is one of the earliest primates that clearly falls on the catarrhine side of that split (although the split must go back earlier).

At Logarithmic History we traffic in Big Questions, and one of the biggest questions of all is the balance of natural law and accident in making our world. Thus physicists have long hoped to find that the laws governing our universe reduce to just a few fundamental equations, but we saw at the beginning of this blog that they are now confronting the possibility that our universe is just one among many, and that the laws of physics in our universe may incorporate a large dose of historical accident. With the discovery of extra-solar planets, we’re just beginning to get an idea of how typical or atypical our solar system is. And we’ll have a lot of opportunities to ask whether there are Laws of History (an old idea now undergoing a revival in the new field of cliodynamics*) when we move into the historical period later in the year.

The field of biogeography – the study of the geographic distribution of species – has seen some major pendulum swings in this regard. Darwin was intensely interested in questions of biogeography mainly because they could provide support for the theory of evolution. His approach could fairly be called eclectic. From sometime in the second half of the twentieth century however, a lot of biologists thought they could do better than just answering particularistic questions about how species A got to island Z. They wanted to find scientific laws.

Edward O. Wilson was an early pioneer in this area. Along with Robert MacArthur, he developed a theory of island biogeography which was supposed to get the field out of its natural history phase, and turn it into a predictive science. According to MacArthur and Wilson, the number of species on an island is set by a predictable equilibrium between extinction (smaller islands have higher extinction rates) and colonization (remote islands have lower colonization rates). Being a good scientist Wilson actually put this theory to the test by getting an exterminator to “defaunate” (it means what you think it means) some little mangrove islets, and showing that they returned to very close to their predicted equilibrium numbers of animal species after a while.

For the biogeography of continents (and larger islands once part of continents) the quest for scientific laws took a different turn. The discovery of continental drift and plate tectonics encouraged a school of “vicariance biogeography.” Vicariance biogeographers liked to trace current biogeographic distributions to the wanderings of continents. They were highly allergic to explanations involving accidental long-distance dispersal over big stretches of ocean.

Alan de Queiroz, in The Monkey’s Voyage: How Improbable Journeys Shaped the History of Life, provides a highly readable overview of the decline (if not quite the extinction) of the vicariance school in the face of mounting evidence for flukish dispersals as a major factor in biogeography. The dispersal of monkeys to the New World is a dramatic case in point. (Guinea pigs and their relatives are another.) About the only scenario that makes sense involves a raft of trees washing out to sea (most likely from the Congo basin) and eventually delivering a few parched, scared monkeys to the island continent of South America, where they eventually spawned the whole range of species – spider monkeys, squirrel monkeys, howler monkeys, tamarins, marmosets, capuchins – we know today. Sheer accident: change the weather a little, leave the monkeys stranded at sea a little longer, and the whole history of primates in the New World is erased.

* so new my spellchecker doesn’t recognize it.

The modern synthesis and the blank slate

August 1938 – November 1943

We’re now dividing time finely enough to include months as well as years.

For most of the later nineteenth century after the publication of On the Origin of Species. biologists were skeptical of Darwin’s proposed mechanism of evolutionary change – natural selection. It was only in the twentieth century that this began to change. When Mendel’s work on heredity was rediscovered in 1900, it was originally seen by many as antithetical to Darwinism. But with the pioneering theoretical work of Fisher, Haldane, and Wright, and the subsequent empirical work of Mayr, Dobzhansky, Simpson, Huxley, Stebbins, and others, Darwin’s theory of natural selection and Mendel’s theory of heredity were combined in what came to be called “the modern synthesis.” Julian Huxley’s book Evolution: The Modern Synthesis marked the coming of age of the theory.

In an earlier post I noted how Lyell’s and Darwin’s embrace of gradualism in explaining the past (as well as George Eliot’s celebration of Dorothea Brooke’s “unhistoric acts” and “hidden life”) had something to do with the political climate in England in the years after the French Revolution and Napoleon. Evolution: The Modern Synthesis was first published in 1942. It’s no surprise that the modern synthesis too was a product of its time, when Nazi Germany and the Soviet Union offered gruesome antithetical demonstrations of how not to think about evolution, genes, and behavior.

Not coincidentally, at the same time that biologists in England and the United States were advancing the modern synthesis, social scientists – cultural anthropologists, behaviorist psychologists – were coming to embrace a strong blank slate view of human nature. (Carl Degler tells the American side of the story in In Search of Human Nature: The Decline and Revival of Darwinism in American Social Thought.) There grew up something amounting to a peace treaty between evolutionary biology and the social sciences, with the two fields agreeing to respect each others’ spheres of influence. Social scientists would leave biology to the biologists, accepting, for example, that neither a good upbringing nor acquired skills can improve your genes. Biologists in turn would largely steer clear of addressing social behavior. For example, the theory of sexual selection, which Darwin developed, and Fisher elaborated, was mostly dropped from the modern synthesis as it matured. Huxley argued (pretty unconvincingly in retrospect) that the elaborate mating dances and ornaments found in so many species were not a product of sexual selection, but merely helped to get individuals to choose the right species of mate. Westermarck’s pioneering work on the evolutionary psychology of incest avoidance and the incest taboo was largely shelved in favor of the shakier theories of Freud and Lévi-Strauss. Even Darwin’s work on emotional expression, which might have seemed fairly anodyne politically, was largely rejected by anthropologists. And the study of prehistory was affected as well.

It was only beginning in the 1960s and 1970s, with the rise of sociobiology, that evolutionary biologists returned to seriously addressing social behavior. Sociobiology: The New Synthesis (1975), by E. O Wilson, made a nod to Huxley in its subtitle. It also announced the end of an intellectual peace treaty, and the opening of an intellectual war that persists up to the present.

The monkey’s voyage

33.9-32.1 million years ago

The Oligocene (starting today on Logarithmic History) sees a major diversification of anthropoid primates (monkeys, apes, and humans). Among the anthropoids, the major evolutionary split is a geographic one, between platyrrhines (New World monkeys) and catarrhines (Old World monkeys, apes, and humans). Aegyptopithecus is one of the earliest primates that clearly falls on the catarrhine side of that split (although the split must go back earlier).

At Logarithmic History we traffic in Big Questions, and one of the biggest questions of all is the balance of natural law and accident in making our world. Thus physicists have long hoped to find that the laws governing our universe reduce to just a few fundamental equations, but we saw at the beginning of this blog that they are now confronting the possibility that our universe is just one among many, and that the laws of physics in our universe may incorporate a large dose of historical accident. With the discovery of extra-solar planets, we’re just beginning to get an idea of how typical or atypical our solar system is. And we’ll have a lot of opportunities to ask whether there are Laws of History (an old idea now undergoing a revival in the new field of cliodynamics*) when we move into the historical period later in the year.

The field of biogeography – the study of the geographic distribution of species – has seen some major pendulum swings in this regard. Darwin was intensely interested in questions of biogeography mainly because they could provide support for the theory of evolution. His approach could fairly be called eclectic. From sometime in the second half of the twentieth century however, a lot of biologists thought they could do better than just answering particularistic questions about how species A got to island Z. They wanted to find scientific laws.

Edward O. Wilson was an early pioneer in this area. Along with Robert MacArthur, he developed a theory of island biogeography which was supposed to get the field out of its natural history phase, and turn it into a predictive science. According to MacArthur and Wilson, the number of species on an island is set by a predictable equilibrium between extinction (smaller islands have higher extinction rates) and colonization (remote islands have lower colonization rates). Being a good scientist Wilson actually put this theory to the test by getting an exterminator to “defaunate” (it means what you think it means) some little mangrove islets, and showing that they returned to very close to their predicted equilibrium numbers of animal species after a while.

For the biogeography of continents (and larger islands once part of continents) the quest for scientific laws took a different turn. The discovery of continental drift and plate tectonics encouraged a school of “vicariance biogeography.” Vicariance biogeographers liked to trace current biogeographic distributions to the wanderings of continents. They were highly allergic to explanations involving accidental long-distance dispersal over big stretches of ocean.

Alan de Queiroz, in The Monkey’s Voyage: How Improbable Journeys Shaped the History of Life, provides a highly readable overview of the decline (if not quite the extinction) of the vicariance school in the face of mounting evidence for flukish dispersals as a major factor in biogeography. The dispersal of monkeys to the New World is a dramatic case in point. (Guinea pigs and their relatives are another.) About the only scenario that makes sense involves a raft of trees washing out to sea (most likely from the Congo basin) and eventually delivering a few parched, scared monkeys to the island continent of South America, where they eventually spawned the whole range of species – spider monkeys, squirrel monkeys, howler monkeys, tamarins, marmosets, capuchins – we know today. Sheer accident: change the weather a little, leave the monkeys stranded at sea a little longer, and the whole history of primates in the New World is erased.

* so new my spellchecker doesn’t recognize it.