Tag Archives: Australia

Australian megafauna and the sixth great extinction

40.1 – 38.0 thousand years ago

The Earth has been through a number of mass extinctions. On Logarithmic History, we covered the five greatest mass extinctions during the month of March, and into early April.

For all these extinctions, the most likely cause is some kind physical catastrophe: either drastic changes in the chemistry of oceans and atmosphere, or extraterrestrial events, like asteroid strikes or, just possibly, gamma ray bursts.

Competition with other organisms is another major cause of extinctions. Usually this is just part of a steady background level of extinction. But occasionally competition – and extinction rates – increase dramatically, as during the Great American Interchange five million years ago, when South American animals were swamped by North American invaders with the establishment of the Isthmus of Panama.

Earth now may be on the edge of another episode of mass extinction, a Sixth Extinction. (although rates of species extinction don’t match those of earlier ME’s. So far). This time the cause is very different: a single species, Homo sapiens, is playing an overwhelming role. Although the pace of extinction has accelerated over the last few centuries, you can make a case that the sixth extinction began a long time ago, with the expansion of modern humans out of Africa. Australia in particular sees the disappearance of a unique fauna that evolved over more than a hundred millions of years of isolation. This fauna included monster wombats, giant kangaroos, huge flightless birds, and a marsupial version of a lion.

All of these – all land mammals, reptiles, and birds with mass of more than 200 pounds – seem to have gone extinct by around 45,000 years ago, after humans crossed the sea to settle the island continent. (Sea levels were lower then, and Australia was connected with New Guinea, but still isolated from mainland Asia.) This is not settled science. Some researchers think climate change was to blame. But I think the evidence in the case of this and later mass extinctions is strongly in favor of humans as the major agent of extinction. This is one more reason to treat the advent of our species as one of the major evolutionary transitions, comparable to the evolution of complex cells, or multi-cellular life.

And then there was one

47.5 – 45.0 thousand years ago.

The broad outlines of the spread of Homo sapiens have been established for several decades now: origins in Africa, expansion out of Africa at least 50-45 thousand years ago. But we’re still arguing about the details. Just recently it was reported that modern humans reached Sumatra 73-63 thousand years ago, and that stone tools in Australia date back 60 thousand years ago.

Also, based on recent recalibrations of DNA mutation rates, it looks like the African/non-African split might have happened more like 100 thousand years ago than 50 thousand years ago. So the ancestors of non-African (or non-sub-Saharan-African) H. sapiens might have occupied a homeland somewhere north of the Sahara between 100 and 50 thousand years ago, before spreading through Eurasia. North Africa is one possibility. The Near East, maybe the Arabian peninsula, is another possibility. The (or “a”) homeland might be (gated, sorry) underwater, under the Persian Gulf (sea levels were lower then). Both possibilities have some archeological support. There might have been multiple homelands, and multiple expansions – south through Arabia and along the shores of the Indian Ocean, and north through the Levant and into Europe.

recent (2015) redating of archeological finds suggests that the Levant-to-Europe corridor was part of the story. A modern stone tool technology, coming from Ksar Akil, just outside Beirut, Lebanon, dates to about 50,000 years ago, a little before much the same technology appears in Europe, in the form of the Upper Paleolithic.

And many other “details” remain to be resolved: What did interbreeding with non-sapiens mean for the evolution of H. sapiens? And just what advantage(s) did H. sapiens have that allowed them (us!) to replace other species? Stay tuned for more on Logarithmic History

Australian megafauna and the Sixth Great Extinction

The Earth has been through a number of mass extinctions. On Logarithmic History, we covered the five greatest mass extinctions during the month of March, and into early April.

For all these extinctions, the most likely cause is some kind physical catastrophe: either drastic changes in the chemistry of oceans and atmosphere, or extraterrestrial events, like asteroid strikes or, just possibly, gamma ray bursts.

Competition with other organisms is another major cause of extinctions. Usually this is just part of a steady background level of extinction. But occasionally competition – and extinction rates – increase dramatically, as during the Great American Interchange five million years ago, when South American animals were swamped by North American invaders with the establishment of the Isthmus of Panama.

Earth now may be on the edge of another episode of mass extinction, a Sixth Extinction. (although rates of species extinction don’t match those of earlier ME’s). This time the cause is very different: a single species, Homo sapiens, is playing an overwhelming role. Although the pace of extinction has accelerated over the last few centuries, you can make a case that the sixth extinction began a long time ago, with the expansion of modern humans out of Africa. Australia in particular sees the disappearance of a unique fauna that evolved over more than a hundred millions of years of isolation. This fauna included monster wombats, giant kangaroos, huge flightless birds, and a marsupial version of a lion.

All of these – all land mammals, reptiles, and birds with mass of more than 200 pounds – seem to have gone extinct by around 45,000 years ago, after humans crossed the sea to settle the island continent. (Sea levels were lower then, and Australia was connected with New Guinea, but still isolated from mainland Asia.) This is not settled science. Some researchers think climate change was to blame. But I think the evidence in the case of this and later mass extinctions is strongly in favor of humans as the major agent of extinction. This is one more reason to treat the advent of our species as one of the major evolutionary transitions, comparable to the evolution of complex cells, or multi-cellular life.

Two roads diverged

47.5 – 45.0 thousand years ago.

The broad outlines of the spread of Homo sapiens have been established for several decades now: origins in Africa, expansion out of Africa at least 50-45 thousand years ago. But we’re still arguing about the details. Just recently it was reported that modern humans reached Sumatra 73-63 thousand years ago, and that stone tools in Australia date back 60 thousand years ago.

Also, based on recent recalibrations of DNA mutation rates, it looks like the African/non-African split might have happened more like 100 thousand years ago than 50 thousand years ago. So the ancestors of non-African (or non-sub-Saharan-African) H. sapiens might have occupied a homeland somewhere north of the Sahara between 100 and 50 thousand years ago, before spreading through Eurasia. North Africa is one possibility. The Near East, maybe the Arabian peninsula, is another possibility. The (or “a”) homeland might be (gated, sorry) underwater, under the Persian Gulf (sea levels were lower then). Both possibilities have some archeological support. There might have been multiple homelands, and multiple expansions – south through Arabia and along the shores of the Indian Ocean, and north through the Levant and into Europe.

recent (2015) redating of archeological finds suggests that the Levant-to-Europe corridor was part of the story. A modern stone tool technology, coming from Ksar Akil, just outside Beirut, Lebanon, dates to about 50,000 years ago, a little before much the same technology appears in Europe, in the form of the Upper Paleolithic.

And many other “details” remain to be resolved: What did interbreeding with non-sapiens mean for the evolution of H. sapiens? And just what advantage(s) did H. sapiens have that allowed them (us!) to replace other species? Stay tuned for more on Logarithmic History

Small tools, and dingoes, and Oz

Australia can seem like the Land That Time Forgot. Australian marsupials were largely isolated from competition with placental mammals from other continents. (Although humans seem to have done in a lot of the megafauna when they arrived.) And many discussions of human prehistory assume that outside contact had little effect on Australia from the time of first settlement, before forty thousand years ago, and the English settlement of 1788. Populations just rose and fell with changes in climate and home-grown innovations in technology.

But there have always been hints that the story was more complicated. Some of the evidence comes from language distributions. The distribution of Australian languages is extremely lopsided. There are a lot of language families in and around the northern peninsula of Arnhemland. Then just one family, Pama-Nyungan, (distantly related to some or all of the others) covers about 80% of the continent.

pama nyungan

This sort of distribution is seen with other language families, where it looks like the signature of population spreads. For example, three of four major branches of the Austronesian language family are found only on Taiwan. The fourth branch, Malayo-Polynesian, spans the world from Madagascar, to island Southeast Asia, to Easter Island. The explanation, supported by many lines of evidence, and almost universally accepted, is that Proto-Austronesian first diverged into separate languages on Taiwan. One bunch of Austronesian speakers then sailed to the Philippines, and thence to farther isles, their languages diverging along the way … and the rest is history (actually prehistory). A similar argument roots the Bantu expansion in the Nigeria-Cameroon border area.

So it looks like there was a similar expansion in Australia. Language change is hard to date, but it’s very hard to believe the expansion happened forty thousand years ago. There is other evidence suggesting a recent date. Some time before 2000 BCE, a new archeological culture, the Small Tool Tradition, swept over Australia. At the same time, natives began exploiting a far wider range of habitats and food sources than previously. And – strikingly – a new animal makes its appearance – the dingo, which must have been introduced from overseas. All of this makes it look like some outside contact, jump-started a continent-scale cultural expansion with new technology, and maybe new forms of social organization.

Just published work on Australian genetics suggests a complicated picture. Northeastern and southwestern Australia, separated by the interior desert, are also strongly genetically differentiated, reflecting a split probably going back sometime between 32 and 10 thousand years ago, i.e. well after initial colonization, but well before the spread of the Small Tool Tradition. But there is also evidence that the last 10 thousand years saw a population expansion in the northeast, a population bottleneck in the southwest, and some gene flow between the two. A scenario that fits the data would be Pama-Nyungan speakers expanding in northeast, and then some northeasterners migrating to the southwest, spreading their language and culture, but not arriving in such large numbers as to replace local populations.

We can expect that the picture will grow clearer as more data accumulate.

Australian megafauna and the Sixth Great Extinction

The Earth has been through a number of mass extinctions. On Logarithmic History, we covered the five greatest mass extinctions during the month of March, and into early April.

For all these extinctions, the most likely cause is some kind physical catastrophe: either drastic changes in the chemistry of oceans and atmosphere, or extraterrestrial events, like asteroid strikes or, just possibly, gamma ray bursts.

Competition with other organisms is another major cause of extinctions. Usually this is just part of a steady background level of extinction. But occasionally competition – and extinction rates – increase dramatically, as during the Great American Interchange five million years ago, when South American animals were swamped by North American invaders with the establishment of the Isthmus of Panama.

Earth now may be on the edge of another episode of mass extinction, a Sixth Extinction. (although rates of species extinction don’t match those of earlier ME’s). This time the cause is very different: a single species, Homo sapiens, is playing an overwhelming role. Although the pace of extinction has accelerated over the last few centuries, you can make a case that the sixth extinction began a long time ago, with the expansion of modern humans out of Africa. Australia in particular sees the disappearance of a unique fauna that evolved over more than a hundred millions of years of isolation. This fauna included monster wombats, giant kangaroos, huge flightless birds, and a marsupial version of a lion.

All of these – all land mammals, reptiles, and birds with mass of more than 200 pounds – seem to have gone extinct by around 45,000 years ago, after humans crossed the sea to settle the island continent. (Sea levels were lower then, and Australia was connected with New Guinea, but still isolated from mainland Asia.) This is not settled science. Some researchers think climate change was to blame. But I think the evidence in the case of this and later mass extinctions is strongly in favor of humans as the major agent of extinction. This is one more reason to treat the advent of our species as one of the major evolutionary transitions, comparable to the evolution of complex cells, or multi-cellular life.

Two roads diverged

47.5 – 45.0 thousand years ago.

The broad outlines of the spread of Homo sapiens have been established for several decades now: origins in Africa, expansion out of Africa at least 50-45 thousand years ago. But we’re still arguing about the details. Just recently it was reported that modern humans reached Sumatra 73-63 thousand years ago, and that stone tools in Australia date back 60 thousand years ago.

Also, based on recent recalibrations of DNA mutation rates, it looks like the African/non-African split might have happened more like 100 thousand years ago than 50 thousand years ago. So the ancestors of non-African (or non-sub-Saharan-African) H. sapiens might have occupied a homeland somewhere north of the Sahara between 100 and 50 thousand years ago, before spreading through Eurasia. North Africa is one possibility. The Near East, maybe the Arabian peninsula, is another possibility. The (or “a”) homeland might be (gated, sorry) underwater, under the Persian Gulf (sea levels were lower then). Both possibilities have some archeological support. There might have been multiple homelands, and multiple expansions – south through Arabia and along the shores of the Indian Ocean, and north through the Levant and into Europe.

recent (2015) redating of archeological finds suggests that the Levant-to-Europe corridor was part of the story. A modern stone tool technology, coming from Ksar Akil, just outside Beirut, Lebanon, dates to about 50,000 years ago, a little before much the same technology appears in Europe, in the form of the Upper Paleolithic.

And many other “details” remain to be resolved: What did interbreeding with non-sapiens mean for the evolution of H. sapiens? And just what advantage(s) did H. sapiens have that allowed him (us!) to replace other species? Stay tuned for more on Logarithmic History

It’s not just a good idea, it’s the Law

I’m an anthropologist, and I like inflicting kinship on people. Last post was Australian language history; here’s Australian kinship.

Claude Lévi-Strauss thought that the complexities of kinship systems reflect not just adaptation to the physical environment, but also the operation of “fundamental structures of the mind.” (I would agree.) This applies particularly to Australian Aborigines. Lévi-Strauss called them “intellectual aristocrats” of the primitive world, having in mind their complex symbolic life and social organization. Australian Aboriginal systems of kinship and marriage are famously recondite. Generations of anthropology teachers have dragged students through these systems, as earlier generations of Latin teachers dragged their pupils through “amo, amas, amat.” Working out all the details can indeed be tricky. The natives themselves have been known to sketch diagrams, and argue about the correct answers.

Here are two general principles that help understand what’s going on. Both principles are found widely, but not universally, in Australia. Outside Australia, the first principle is widespread (but not familiar to most Westerners), the second is rare (but found a few other places, like western Amazonia, an independent reinvention).

1) Most Aborigines, when they label their kin, and divide them into marriageable and non-marriageable, follow a version of so-called Dravidian rules. (As the name suggests, these are common in southern India, but this isn’t strong evidence for an Australia-India historical connection, because Dravidian rules are found all over the place.) According to the rules, Father’s Brother = Father (i.e. Father’s Brother is called by the same term as Father), but Mother’s Brother gets a different term, which we could translate “uncle”. Mother’s Sister = Mother (i.e. Mother’s Sister is called by the same term as Mother), but Father’s Sister gets a different term, which we could translate “aunt”. With perfect consistency, these equations are carried over to their children. Father’s Brother’s Child = Father’s Child = Sibling, and Mother’s Sister’s Child = Mother’s Child = Sibling. (There may be further distinctions, like breaking down Sibling into Brother and Sister, but I ignore these here.) On the other hand, Mother’s Brother’s Child and Father’s Sister’s Child are not equated with siblings. Very commonly, these principles are used to determine who can marry whom. Parallel cousins (those classified as Sibling, related through parents who are same-sex siblings) are covered by the incest taboo, and off limits for marriage. Cross cousins (those not classified as Sibling, related through parents who are opposite-sex siblings) aren’t covered by the taboo, and may be preferred spouses.

(The Yanomamö of the Orinoco basin are one of many groups that follow – and sometimes break – these rules. Generations of students learned about them from one or another edition of this classic study, by Napoleon Chagnon, who died last year.)

2) Aborigines do something unusual with Dravidian rules in the children’s generation. For us, the important distinction in the Child category is the sex of the child: is he or she female (daughter) or male (son)? But for Aborigines, the important distinction is the sex of the child’s parent: fathers and mothers generally classify their children differently, with one or more terms covering Man’s Child and one or more different terms covering Woman’s Child. So a woman and her husband use different kin terms for their kids. We could call these kin types “fatherling” (the children to whom one is father = Man’s Child) and “motherling” (the children to whom is mother = Woman’s Child.) These terms are commonly extended to other kin. Ask a man who his fatherlings are and he will name his own children, then his brothers’ children (after all, they call him father). Ask a woman who her motherlings are and she will label her own children, then her sisters’ children (after all, they call her mother). But … this is the tricky bit … Ask a man who his motherlings are, and he will name his sister’s children (the children to whom he is Mother’s Brother). Ask a woman who her fatherlings are, and she will name her brother’s children (the children to whom she is Father’s Sister).

This means that the classification of kin in the children’s generation is a mirror image of classification in the parents’ generation. And at some point some clever Aborigine noticed that under this system all relatives fall into just four super-classes – anthropologists call them sections – and everyone can agree on where to draw the boundaries between them. (This is not the case in more standard Dravidian systems, which, like most Western systems, don’t distinguish Man’s Child from Woman’s Child.) So you can go ahead and assign names to these sections, give them totemic animals, and so on. For any individual there will be

a) his or her own section (which also includes Siblings, and some grandkin: Fathers’ Fathers, Mothers’ Mothers, Fatherlings’ Fatherlings, and Motherlings’ Motherlings),

b) a section for his/her Fathers (and Fathers’ Sisters, and Fatherlings), a

c) a section for his/her Mothers (and Mothers’ Brothers, and Motherlings), and

d) a section for his/her potential Spouses (and Siblings-in-law, and some grandkin: Fathers’ Mothers, Mothers’ Fathers, Fatherlings’ Motherlings, and Motherlings’ Fatherlings)

There’s a lot of variation on basic themes across Australia (e.g. systems where sections are further subdivided, yielding eight subsections). It’s likely (but not certain) the kinship terms came first, and the division into recognized sections came later. Not everybody does sections. And some groups have adopted the section system even thought they don’t have the corresponding terms.

If you just skimmed through the part above (that’s OK, it’s not on the exam) here’s an analogy. We (at least most readers of this blog) aren’t used to sorting out kin the way Aborigines do, but we’re used to the idea of voting for candidates supported by different political parties. And we’re also used to the idea that different voting rules have different consequences: a first-past-the-post rule favors a two party system; proportional representation favors many parties. This is the stuff of politics in democratic societies, but imagine how confusing it would be to anyone not used to voting at all . By the same token, odd quirks in the way people categorize kin can have important consequences. Human beings, even in technologically simple societies, don’t just adapt to their natural environment, but also navigate a universe of social rules – what Aborigines call “the Law”.

If you want even more, the AustKin database and websites provides access to kinship terminologies and social category systems from published and archival sources for over 607 Australian Aboriginal languages.

Small tools, and dingoes, and Oz

2158 – 1959 BCE

Australia can seem like the Land That Time Forgot. Australian marsupials were largely isolated from competition with placental mammals from other continents. (Although humans seem to have done in a lot of the megafauna when they arrived.) And many discussions of human prehistory assume that outside contact had little effect on Australia from the time of first settlement, before forty thousand years ago, and the English settlement of 1788. Populations just rose and fell with changes in climate and home-grown innovations in technology.

But there have always been hints that the story was more complicated. Some of the evidence comes from language distributions. The distribution of Australian languages is extremely lopsided. There are a lot of language families in and around the northern peninsula of Arnhemland. Then just one family, Pama-Nyungan, (distantly related to some or all of the others) covers about 80% of the continent.

pama nyungan

This sort of distribution is seen with other language families, where it looks like the signature of population spreads. For example, three of four major branches of the Austronesian language family are found only on Taiwan. The fourth branch, Malayo-Polynesian, spans the world from Madagascar, to island Southeast Asia, to Easter Island. The explanation, supported by many lines of evidence, and almost universally accepted, is that Proto-Austronesian first diverged into separate languages on Taiwan. One bunch of Austronesian speakers then sailed to the Philippines, and thence to farther isles, their languages diverging along the way … and the rest is history (actually prehistory). A similar argument roots the Bantu expansion in the Nigeria-Cameroon border area.

So it looks like there was a similar expansion in Australia. Language change is hard to date, but it’s very hard to believe the expansion happened forty thousand years ago. There is other evidence suggesting a recent date. Some time before 2000 BCE, a new archeological culture, the Small Tool Tradition, swept over Australia. At the same time, natives began exploiting a far wider range of habitats and food sources than previously. And – strikingly – a new animal makes its appearance – the dingo, which must have been introduced from overseas. All of this makes it look like some outside contact, jump-started a continent-scale cultural expansion with new technology, and maybe new forms of social organization.

Just published work on Australian genetics suggests a complicated picture. Northeastern and southwestern Australia, separated by the interior desert, are also strongly genetically differentiated, reflecting a split probably going back sometime between 32 and 10 thousand years ago, i.e. well after initial colonization, but well before the spread of the Small Tool Tradition. But there is also evidence that the last 10 thousand years saw a population expansion in the northeast, a population bottleneck in the southwest, and some gene flow between the two. A scenario that fits the data would be Pama-Nyungan speakers expanding in northeast, and then some northeasterners migrating to the southwest, spreading their language and culture, but not arriving in such large numbers as to replace local populations.

We can expect that the picture will grow clearer as more data accumulate.

Australian megafauna and the Sixth Great Extinction

46.6 – 44.1 thousand years ago

The Earth has been through a number of mass extinctions. On Logarithmic History, we covered the five greatest mass extinctions during the month of March, and into early April.

For all these extinctions, the most likely cause is some kind physical catastrophe: either drastic changes in the chemistry of oceans and atmosphere, or extraterrestrial events, like asteroid strikes or, just possibly, gamma ray bursts.

Competition with other organisms is another major cause of extinctions. Usually this is just part of a steady background level of extinction. But occasionally competition – and extinction rates – increase dramatically, as during the Great American Interchange five million years ago, when South American animals were swamped by North American invaders with the establishment of the Isthmus of Panama.

Earth now may be on the edge of another episode of mass extinction, a Sixth Extinction. (although rates of species extinction don’t match those of earlier ME’s). This time the cause is very different: a single species, Homo sapiens, is playing an overwhelming role. Although the pace of extinction has accelerated over the last few centuries, you can make a case that the sixth extinction began a long time ago, with the expansion of modern humans out of Africa. Australia in particular sees the disappearance of a unique fauna that evolved over more than a hundred millions of years of isolation. This fauna included monster wombats, giant kangaroos, huge flightless birds, and a marsupial version of a lion.

All of these – all land mammals, reptiles, and birds with mass of more than 200 pounds – seem to have gone extinct by around 45,000 years ago, after humans crossed the sea to settle the island continent. (Sea levels were lower then, and Australia was connected with New Guinea, but still isolated from mainland Asia.) This is not settled science. Some researchers think climate change was to blame. But I think the evidence in the case of this and later mass extinctions is strongly in favor of humans as the major agent of extinction. This is one more reason to treat the advent of our species as one of the major evolutionary transitions, comparable to the evolution of complex cells, or multi-cellular life.