When politicians and journalists declare that the science of global warming is settled, they show a regrettable ignorance about how science works. We were treated to another dose of it recently when the experts of the Intergovernmental Panel on Climate Change issued the Summary for Policymakers that puts the political spin on an unfinished scientific dossier on climate change due for publication in a few months’ time. They declared that most of the rise in temperatures since the mid-20th century is very likely due to man-made greenhouse gases.

The small print explains “very likely” as meaning that the experts who made the judgment felt 90% sure about it. Older readers may recall a press conference at Harwell in 1958 when Sir John Cockcroft, Britain’s top nuclear physicist, said he was 90% certain that his lads had achieved controlled nuclear fusion. It turned out that he was wrong. More positively, a 10% uncertainty in any theory is a wide open breach for any latterday Galileo or Einstein to storm through with a better idea. That is how science really works.

Study: Chimps may have used 'hammers' 4,300 years ago
POSTED: 5:17 p.m. EST, February 12, 2007
Story Highlights
• Stone "hammers" dating back 4,300 years may have been used by chimps
• The hammers, about the size of cantaloupes, were found in West Africa
• Anthropologist skeptical of findings, calls for more evidence
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WASHINGTON (AP) -- Chimpanzees may have been using stone "hammers" as long as 4,300 years ago, an international research team, led by archaeologist Julio Mercader of the University of Calgary, Canada, said Monday.

The researchers uncovered the hammers, in the West African country Ivory Coast. It would be the earliest known use of tools by chimpanzees.

The hammers were used to crack nuts, a behavior still seen in chimps in that area, the researchers said in a paper in the online edition of Proceedings of the National Academy of Sciences.

The finding may indicate that a "chimpanzee stone age" began in ancient times, the researchers say.

The earliest reports of stone tool use by chimpanzees in this area date to the writings of Portuguese explorers in the 1600s.

The stones were about the size of cantaloupes with patterns of wear indicating use to crack nuts. The rocks would have been too large for human hands, but about right for the larger, stronger hands of chimpanzees, the researchers said.

"It's not clear whether we hominins invented this kind of stone technology, or whether both humans and the great apes inherited it from a common forebear," Mercader said in a statement.

But, he added, there were not any farmers living in this region 4,300 years ago, so it is unlikely chimpanzees picked it up by imitating villagers.

Others are not so sure.

The tools may predate farming in the area but not necessarily human contact, said anthropologist Stanley H. Ambrose of the University of Illinois at Urbana-Champaign. There were early human hunter-gatherers in the region at the time, he said.

If chimps and early humans shared this technology with a common ancestor between 5 million and 7 million years ago, there should be sites with chimp debris going back 5 million years and the earliest human stone tool sites should show the kinds of debris found at the chimp sites, Ambrose said: "They absolutely do not."

Some of the hammers also had starch residue on them, mostly from types of nuts that are still eaten by chimpanzees, but not humans. Some of the starch was also associated with tubers but the researchers interpreted that as "background noise" probably picked up in the ground.

Skeptical of the starch findings was anthropologist Jeanne Sept, dean of faculties at Indiana University.

"Their interpretations of the starch grains recovered from the specimens are incomplete, and somewhat circular," she said. "For example, they do not describe which surfaces of the rock fragments the starch grains were obtained from, which makes it difficult to judge whether the grains were left on the tools as a result of tool-use, or if the grains merely naturally stuck to the stones after they became buried in the soil."

"They assert that starch grains from nuts were behaviorally significant, while they decide that starch grains identified as yam roots are 'background noise' but give no justification for that," she added. "They may in fact be dismissing or ignoring evidence that does not match their chimp-nut interpretation of the site."

"It may be premature to accept the range of their claims until further evidence is presented," Sept concluded.

Mercader's research was funded primarily by the Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Canada Research Chairs program, Canada Foundation for Innovation and the University of Calgary.

Also, the chimps used hammers in the past, but they don't do it in the present?

Hunting chimps may change view of human evolution

By Maggie Fox, Health and Science Editor 1 hour, 37 minutes ago

WASHINGTON (Reuters) - Chimpanzees have been seen using spears to hunt bush babies, U.S. researchers said on Thursday in a study that demonstrates a whole new level of tool use and planning by our closest living relatives.
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Perhaps even more intriguing, it was only the females who fashioned and used the wooden spears, Jill Pruetz and Paco Bertolani of Iowa State University reported.

Bertolani saw an adolescent female chimp use a spear to stab a bush baby as it slept in a tree hollow, pull it out and eat it.

Pruetz and Bertolani, now at Cambridge University in Britain, had been watching the Fongoli community of savanna-dwelling chimpanzees in southeastern Senegal.

The chimps apparently had to invent new ways to gather food because they live in an unusual area for their species, the researchers report in the journal Current Biology.

"This is just an innovative way of having to make up for a pretty harsh environment," Pruetz said in a telephone interview. The chimps must come down from trees to gather food and rest in dry caves during the hot season.

"It is similar to what we say about early hominids that lived maybe 6 million years ago and were basically the precursors to humans."

Chimpanzees are genetically the closest living relatives to human beings, sharing more than 98 percent of our DNA. Scientists believe the precursors to chimps and humans split off from a common ancestor about 7 million years ago.

Chimps are known to use tools to crack open nuts and fish for termites. Some birds use tools, as do other animals such as gorillas, orangutans and even naked mole rats.

But the sophisticated use of a tool to hunt with had never been seen.

Pruetz thought it was a fluke when Bertolani saw the adolescent female hunt and kill the bush baby, a tiny nocturnal primate.

But then she saw almost the same thing. "I saw the behavior over the course of 19 days almost daily," she said.

PLANNING AND FORESIGHT

The chimps choose a branch, strip it of leaves and twigs, trim it down to a stable size and then chew the ends to a point. Then they use it to stab into holes where bush babies might be sleeping.

It is not a highly successful method of hunting. They only ever saw one chimpanzee succeed in getting a bush baby once. The apes mostly eat fruit, bark and legumes.

Part of the problem is this group of chimps is shy of humans, and the females, who seem to do most of this type of hunting, are especially wary. "I am willing to bet the females do it even more than we have seen," she said.

Pruetz noted that male chimps never used the spears. She believes the males use their greater strength and size to grab food and kill prey more easily, so the females must come up with other methods.

"That to me was just as intriguing if not even more so," Pruetz said.

The spear-hunting occurred when the group was foraging together, again unchimplike behavior that might produce more competition between males and females, she said.

Maybe females invented weapons for hunting, Pruetz said.

"The observation that individuals hunting with tools include females and immature chimpanzees suggests that we should rethink traditional explanations for the evolution of such behavior in our own lineage," she concluded in her paper.

"The multiple steps taken by Fongoli chimpanzees in making tools to dispatch mammalian prey involve the kind of foresight and intellectual complexity that most likely typified early human relatives."

Scientists have discovered a large area thousands of square kilometres in extent in the middle of the Atlantic where the Earth’s crust appears to be missing. Instead, the mantle - the deep interior of the Earth, normally covered by crust many kilometres thick - is exposed on the seafloor, 3000m below the surface.

Marine geologist Dr Chris MacLeod, School of Earth, Ocean and Planetary Sciences said: "This discovery is like an open wound on the surface of the Earth. Was the crust never there? Was it once there but then torn away on huge geological faults? If so, then how and why?"

When Noah was six hundred years old, the flood started. On the seventeenth day of the second month of the year the underground springs split open, and the clouds in the sky poured out rain.

Study: Dinosaur demise didn't spur species

By MALCOLM RITTER, AP Science Writer 2 hours, 5 minutes ago

NEW YORK - The big dinosaur extinction of 65 million years ago didn't produce a flurry of new species in the ancestry of modern mammals after all, says a huge study that challenges a long-standing theory.
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Scientists who constructed a massive evolutionary family tree for mammals found no sign of such a burst of new species at that time among the ancestors of present-day animals.

Only mammals with no modern-day descendants showed that effect.

"I was flabbergasted," said study co-author Ross MacPhee, curator of vertebrate zoology at the American Museum of Natural History in New York.

At the time of the dinosaur demise, mammals were small, ranging in size between shrews and cats. The long-held view has been that once the dinosaurs were gone, mammals were suddenly free to exploit new food sources and habitats, and as a result they produced a burst of new species.

The new study says that happened to some extent, but that the new species led to evolutionary dead ends. In contrast, no such burst was found for the ancestors of modern-day mammals like rodents, cats, horses, elephants and people.

Instead, they showed an initial burst between 100 million about 85 million years ago, with another between about 55 million and 35 million year ago, researchers report in Thursday's issue of the journal Nature.

The timing of that first period of evolutionary development generally agrees with the conclusions of some previous studies of mammal DNA, which argue for a much earlier origin of some mammal lineages than the fossil record does.

The second burst had shown up in the fossil record, MacPhee said. But he said the new study explains why scientists have been unable to find relatively modern-looking ancestors of the creatures known from that time: without any evolutionary boost from the dinosaur demise, those ancestors were still relatively primitive.

Some experts praised the large scale of the new evolutionary tree, which used a controversial "supertree" method to combine data covering the vast majority of mammal species. It challenges paleontologists to find new fossils that can shed light on mammal history, said Greg Wilson, curator of vertebrate paleontology at the Denver Museum of Nature & Science.

William J. Murphy of Texas A&M University, who is working on a similar project, said no previous analysis had included so many mammal species.

But, "I don't think this is the final word," he said.

The study's approach for assigning dates was relatively crude, he said, and some dates it produced for particular lineages disagree with those obtained by more updated methods.

So as for its interpretation of what happened when the dinosaurs died off, "I'm not sure that conclusion is well-founded," Murphy said.

John Gittleman, a study co-author and director of the University of Georgia Institute of Ecology, said the researchers considered a range of previously reported dates for when various lineages split. They found the overall conclusions of the study were not significantly affected by which dates they chose, he said.

Researchers should now look at such things as the rise of flowering plants and a cooling of the worldwide climate to explain why ancestors of present-day mammals took off before the dinosaurs died out, Gittleman said. The cause of the later boom is also a mystery, he said.

The study's family tree includes 4,510 species, more than 99 percent of mammal species covered by an authoritative listing published in 1993. (Nearly 300 species have since been added to the listing, but the researchers said that doesn't affect their study's conclusions.) To construct it, the researchers combined previously published work that relied on analysis of DNA, fossils, anatomy and other information.

S. Blair Hedges, an evolutionary biologist at Pennsylvania State University, said the new work "pushes the envelope in the methods and data, and that's really important."

He said the demise of the dinosaurs may have affected mammal evolution by influencing characteristics like body size rather than boosting the number of new species created. Such changes wouldn't be picked up by the new study, he noted.

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On the Net:

Nature: http://www.nature.com/nature