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TC Tiki Chris Member London Joined: Mar 24, 2002 Posts: 1542	TC Tiki Chris Posted posted on Sat, Oct 30, 2004 3:02 PM Meet cousin Florence Oct 28th 2004 From The Economist print edition A new and diminutive species of human being has been discovered IN THE 1890s, Eugene Dubois, an anatomist working as a doctor in the Dutch army, stunned the scientific world when he found the first fossil human remains outside Europe. Java Man—Homo erectus, as it is now known—threw ideas about human evolution into chaos by suggesting that Europe was not, as most anthropologists had hitherto assumed, the cradle of human evolution. As it turned out, neither was Asia. The evidence now shows that all the important developments in human evolutionary history, from the appearance of Australopithecus (the first species generally regarded as human) to the emergence of Homo sapiens (you and me), happened in Africa. But Asia can still spring the odd surprise in the field. And few finds have been as surprising as that made last year on Java's Indonesian neighbour, Flores, and announced this week in Nature. For Homo floresiensis, as the new species has been dubbed, suggests that the ascent of man is not an evolutionary inevitability. Descent is also possible. That is because Homo floresiensis (whose skull is pictured above, alongside that of a modern human) was but a metre tall, and had a brain not much bigger than an ape's. In a truly ancient fossil human from, say, 3m-4m years ago, those dimensions would not be surprising. But the skeleton found by Peter Brown, of the University of New England, in Armidale, Australia, and his colleagues from the Indonesian Centre for Archaeology in Jakarta, is a mere 18,000 years old. That means it was alive at a time when Homo sapiens had not only come into existence, but had already reached Australia. A little puzzle The species is not, however, a descendant of Homo sapiens. A tooth from a lower soil layer in the cave where the main skeleton was found shows it evolved before modern humans arrived in the area. It was thus one of several species of humanity, such as Neanderthal Man, that were pushed aside by the rise of Homo sapiens. That, in turn, suggests it was descended from Dubois's Homo erectus. But Homo erectus was as big as Homo sapiens—in some cases bigger. And if erectus was not in quite the same intellectual league as modern man, it was certainly no dunce. Its brain could be as big as 1,250cm3 (compared with 1,400cm3 for a modern human). That of Homo floresiensis, by contrast, was a mere 380cm3. Dr Brown knows this because he measured the volume by the delightfully low-tech technique of pouring mustard seeds into the fossil's cranium after he had cleaned the interior. Nor is there any doubt that the skeleton is that of an adult (probably, from the pelvic anatomy, a woman). Her teeth are worn, and some telltale bones in the skull are knitted together in an adult way. On top of that, although they are not described in the paper, Dr Brown's team has now found five more specimens which confirm that she was not an abnormally small member of her species. Of course, a small animal will have a small brain. But what is noticeable about Homo floresiensis is how small the brain is, even in comparison to the diminutive body. The species had regressed, more or less, to the brain/body ratio found in Australopithecus. The question is why. And the answer to that question may shed light on the wider question of how human intelligence arose in the first place. Islands are famous for generating indigenous species from whatever biological material pitches up on them. One frequent trend observed in such island species, at least when they are large mammals, is dwarfism. Elephants seem particularly susceptible. The last mammoths, which lived on an island off the coast of Siberia, were, paradoxically, dwarfs. Similar elephantine examples are known from Malta, Sicily and, indeed, Flores itself. And the same thing has been observed in cattle, too. There seems no reason why it should not happen to hominids. Two evolutionary pressures are thought to drive this process of diminution. One is that islands are often free of large predators (on Flores, the largest were Komodo dragons, a species of large lizard). The other is that they sometimes have a restricted food supply. The result is that you do not need to be big to defend yourself; and if you are big, you may starve. Both of those facts might drive the evolution of smaller brains, too. Brains are expensive in terms of energy consumed, and thus food needed. And an absence of predators would remove at least one reason to have a large brain. In other words, use it or lose it. Why human intelligence evolved in the first place, though, is controversial. Many researchers feel that it was not so much to deal with the non-human world (eg, predators and food-gathering) as to deal with other people. One theory, known as the “Machiavellian mind”, is that intelligence is there to analyse, and thus manipulate, the motives of others. Another, known as the “mating mind”, is that much of human intelligence is about showing off to the opposite sex, in a behavioural equivalent of the peacock's tail. Both could be true. Whether either of these purposes would disappear on an island is moot. All this is speculation, of course. And human fossils are so rare that there is a risk of over-interpreting each new find. What would help is evidence of Homo floresiensis's culture, if any. One possible remnant of that culture is the numerous stone tools in the cave where the skeleton was found. These are small and delicate, which suggests they might have been made and wielded by tiny hands. Nor do they bear much resemblance to the tools of Homo erectus. But they do date from a period when the island could have been inhabited by Homo sapiens. So who made them is unclear. In any case, tool-making is not an exclusive badge of intellectual advancement. Australopithecus used stone tools, and modern chimpanzees make and use tools, too (though admittedly not stone ones). If tools were useful to Homo floresiensis on its island home, natural selection would have retained the ability to make and use them even if other mental faculties dwindled. Regardless of how these questions are settled, what is clear is that Dr Brown's find has changed thinking about the way humanity has evolved. If Homo floresiensis was flourishing 18,000 years ago, the chances are it did not die out until much more recently. Indeed, it is conceivable that it lasted into historical times. Much of Homo sapiens's vision of itself is built around the idea of human uniqueness. That it was not unique until so recently should give pause for thought—and will no doubt spur others to follow Dubois's lead and look for further species of fossil human in previously unexplored places.

Meet cousin Florence

Oct 28th 2004
From The Economist print edition

A new and diminutive species of human being has been discovered

IN THE 1890s, Eugene Dubois, an anatomist working as a doctor in the Dutch army, stunned the scientific world when he found the first fossil human remains outside Europe. Java Man—Homo erectus, as it is now known—threw ideas about human evolution into chaos by suggesting that Europe was not, as most anthropologists had hitherto assumed, the cradle of human evolution.

As it turned out, neither was Asia. The evidence now shows that all the important developments in human evolutionary history, from the appearance of Australopithecus (the first species generally regarded as human) to the emergence of Homo sapiens (you and me), happened in Africa. But Asia can still spring the odd surprise in the field. And few finds have been as surprising as that made last year on Java's Indonesian neighbour, Flores, and announced this week in Nature. For Homo floresiensis, as the new species has been dubbed, suggests that the ascent of man is not an evolutionary inevitability. Descent is also possible. That is because Homo floresiensis (whose skull is pictured above, alongside that of a modern human) was but a metre tall, and had a brain not much bigger than an ape's.

In a truly ancient fossil human from, say, 3m-4m years ago, those dimensions would not be surprising. But the skeleton found by Peter Brown, of the University of New England, in Armidale, Australia, and his colleagues from the Indonesian Centre for Archaeology in Jakarta, is a mere 18,000 years old. That means it was alive at a time when Homo sapiens had not only come into existence, but had already reached Australia.

A little puzzle
The species is not, however, a descendant of Homo sapiens. A tooth from a lower soil layer in the cave where the main skeleton was found shows it evolved before modern humans arrived in the area. It was thus one of several species of humanity, such as Neanderthal Man, that were pushed aside by the rise of Homo sapiens.

That, in turn, suggests it was descended from Dubois's Homo erectus. But Homo erectus was as big as Homo sapiens—in some cases bigger. And if erectus was not in quite the same intellectual league as modern man, it was certainly no dunce. Its brain could be as big as 1,250cm3 (compared with 1,400cm3 for a modern human). That of Homo floresiensis, by contrast, was a mere 380cm3. Dr Brown knows this because he measured the volume by the delightfully low-tech technique of pouring mustard seeds into the fossil's cranium after he had cleaned the interior.

Nor is there any doubt that the skeleton is that of an adult (probably, from the pelvic anatomy, a woman). Her teeth are worn, and some telltale bones in the skull are knitted together in an adult way. On top of that, although they are not described in the paper, Dr Brown's team has now found five more specimens which confirm that she was not an abnormally small member of her species.

Of course, a small animal will have a small brain. But what is noticeable about Homo floresiensis is how small the brain is, even in comparison to the diminutive body. The species had regressed, more or less, to the brain/body ratio found in Australopithecus. The question is why. And the answer to that question may shed light on the wider question of how human intelligence arose in the first place.

Islands are famous for generating indigenous species from whatever biological material pitches up on them. One frequent trend observed in such island species, at least when they are large mammals, is dwarfism. Elephants seem particularly susceptible. The last mammoths, which lived on an island off the coast of Siberia, were, paradoxically, dwarfs. Similar elephantine examples are known from Malta, Sicily and, indeed, Flores itself. And the same thing has been observed in cattle, too. There seems no reason why it should not happen to hominids.

Two evolutionary pressures are thought to drive this process of diminution. One is that islands are often free of large predators (on Flores, the largest were Komodo dragons, a species of large lizard). The other is that they sometimes have a restricted food supply. The result is that you do not need to be big to defend yourself; and if you are big, you may starve.

Both of those facts might drive the evolution of smaller brains, too. Brains are expensive in terms of energy consumed, and thus food needed. And an absence of predators would remove at least one reason to have a large brain. In other words, use it or lose it.

Why human intelligence evolved in the first place, though, is controversial. Many researchers feel that it was not so much to deal with the non-human world (eg, predators and food-gathering) as to deal with other people. One theory, known as the “Machiavellian mind”, is that intelligence is there to analyse, and thus manipulate, the motives of others. Another, known as the “mating mind”, is that much of human intelligence is about showing off to the opposite sex, in a behavioural equivalent of the peacock's tail. Both could be true. Whether either of these purposes would disappear on an island is moot.

All this is speculation, of course. And human fossils are so rare that there is a risk of over-interpreting each new find. What would help is evidence of Homo floresiensis's culture, if any.

One possible remnant of that culture is the numerous stone tools in the cave where the skeleton was found. These are small and delicate, which suggests they might have been made and wielded by tiny hands. Nor do they bear much resemblance to the tools of Homo erectus. But they do date from a period when the island could have been inhabited by Homo sapiens. So who made them is unclear. In any case, tool-making is not an exclusive badge of intellectual advancement. Australopithecus used stone tools, and modern chimpanzees make and use tools, too (though admittedly not stone ones). If tools were useful to Homo floresiensis on its island home, natural selection would have retained the ability to make and use them even if other mental faculties dwindled.

Regardless of how these questions are settled, what is clear is that Dr Brown's find has changed thinking about the way humanity has evolved. If Homo floresiensis was flourishing 18,000 years ago, the chances are it did not die out until much more recently. Indeed, it is conceivable that it lasted into historical times. Much of Homo sapiens's vision of itself is built around the idea of human uniqueness. That it was not unique until so recently should give pause for thought—and will no doubt spur others to follow Dubois's lead and look for further species of fossil human in previously unexplored places.

Post #122755 by Tiki Chris on Sat, Oct 30, 2004 3:02 PM