7. Scientists Get Inside the Mind (and Genes) of the Neanderthal
For a span of 200,000 years or more, Neanderthals thrived from Gibraltar to Uzbekistan. Big-brained and robust, they weathered the depths of the last ice age, only to vanish around 30,000 years ago, about when modern humans entered Europe. Did the new arrivals annihilate the natives, or were Neanderthals absorbed by interbreeding? Two studies offer new perspectives on the nature and fate of the Neanderthals. One is a project devoted to analyzing Neanderthal DNA; the other is a reconstruction of hunting strategies that suggests the Neanderthals were not slow-witted brutes unable to compete with modern humans.
Archaeologist Daniel Adler from the University of Connecticut, working with David Lordkipanidze and Nikolaz Tushabramishvili of the Georgian State Museum and their colleagues at the University of Haifa, Hebrew University, and Harvard University, analyzed animal remains in a rock shelter in the Republic of Georgia that was used by Neanderthals and later by modern humans. Apparently, Neanderthals and modern humans hunted the same prey in the same way. Their favored quarry was a large, fleet mountain goat called the Caucasian tur. "We saw again and again that Neanderthals were hunting the prime-age adults — the fastest, the most nutritious, but also the hardest ones to capture," says Adler. Hunting such difficult prey requires a high degree of cooperation and communication and a detailed understanding of the goats' seasonal routines, he notes. "Our study indicates very clearly that Neanderthals were not only good hunters, they were the top predators in whatever environment they occupied; they were the most dangerous thing in town."
Still, Adler notes that "while modern humans didn't have an edge in hunting, they did seem to form larger social networks. We tested this by looking at the stone tools and what kind of stone the artifacts were made of. All the Neanderthal artifacts were made of stone they could find locally, within three miles. Modern humans, on the other hand, had artifacts made of material that you could only find at least 60 miles away, so they would have had to negotiate relationships with other modern humans. In times of trouble a modern human group would have some other group to turn to for help, whereas a Neanderthal group didn't. So if modern humans suddenly appeared in your territory, and you didn't know the other Neanderthal groups around you, you would have nowhere to turn. You'd be in big trouble."
Then again, modern humans may have formed more widespread alliances merely because their population density was higher. If the Neanderthals didn't lose out because of their inferior social skills, maybe they interbred with modern humans and simply disappeared into the larger population. In that case, some Neanderthal DNA should still be afloat in the modern gene pool. Svante Pääbo, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, may soon be able to address both issues.
In 2006 Pääbo managed to extract DNA from a 38,000-year-old Neanderthal skeleton in Croatia. "Our goal for the next two years is to create a rough draft of the Neanderthal genome," he says. He is particularly keen to study a gene called FOXP2, believed to be involved in muscle control of the larynx. If the Neanderthal gene resembles the one in modern humans, that would suggest that Neanderthals had linguistic abilities equal to our own. The genome map will also refine our family tree. Our ancestors may have gotten up to 25 percent of their DNA from Neanderthals — including genes for red hair and pale skin and possibly a gene linked to brain size. "The only way to clarify this is to study a Neanderthal and get the hard data," says Pääbo. We won't really know what it means to be human until we understand what it meant to be a Neanderthal.
9. Ancient Fish Fills Missing Link
Excavations carried out over six years in the treeless, grassless, soil-less Ellesmere Island in the Canadian territory of Nunavut, 750 miles from the North Pole, have yielded a remarkable treasure: a 375-million-year-old, scaly, fin-legged, flat-headed, swivel-necked creature called Tiktaalik roseae. Named after the Inuit word for "large shallow-water fish," Tiktaalik fills in one of the most significant gaps in evolutionary history — the transition between swimming fish and the first animals to walk onto land.
Paleontologist Neil Shubin, of the University of Chicago and the Field Museum of Natural History, and his colleague Ted Daeschler, of the Academy of Natural Sciences in Philadelphia, planned their Arctic search with great care. Three hundred 75 million years ago, the Canadian Arctic was near the equator, with a subtropical climate — a plausible place for an aquatic creature to venture from surf to turf.
"Looking at the evolutionary tree, and knowing something about evolution and Earth history, we predicted there would be a The 4- to 9-foot-long creature had fins, which held limblike bones forming a shoulder, elbow, and wrist that could do a push-up; broad ribs and scales; and a neck that allowed the animal to swivel its head. "That the skull was disconnected from the shoulder is something we would not have expected in an animal that was still a fish," Daeschler says. "Our hypothesis is that it was an adaptation to shallow water and gave the animal more ability to hunt."
"What is really exceptional about Tiktaalik is that it is not some esoteric branch of evolution," Shubin says. "We are not looking at an evolutionary dead end. When we look at the origin of the neck in Tiktaalik, the origin of the wrist inTiktaalik, we are talking about human history. We can trace our own history back to things like this. The transition we are seeing in these Devonian fish is a piece of our distant past."
Kathy A. Svitil
40. New Dinosaur King Rears Its Head
Tyrannosaurus rex slipped further in the ranks of terribleness with the enthronement of a bigger, badder king of the dinosaurs: Spinosaurus aegyptiacus, a gigantic predator that stalked Africa around 100 million years ago and whose head alone was almost six feet long.
After examining skull fragments of Spinosaurus, paleontologist Cristiano Dal Sasso of the Civic Natural History Museum in Milan, Italy, and his colleagues estimated that the whole animal would have measured between 52 and 59 feet from tip to tail, as much as a dozen feet longer than the largest known T. rex and bigger than the previous record holder among carnivorous dinosaurs, Giganotosaurus; a full-grown adult might have stood 20 feet tall and weighed as much as nine tons. In addition to its astonishing bulk, Spinosaurus had a fearsome ridge, or sail, down its back, a croc-like jaw, and strong, taloned arms to catch its prey. "We were astonished when we calculated its overall size," says Dal Sasso. "We realized that we were studying the largest predator of all times."
59. Fossilized Frog Marrow Found
In August researchers examining fossils in the National Museum of Natural Sciences in Madrid reported the first example of fossilized bone marrow, found in 10-million-year-old remains of frogs and salamanders. Because of the way the slabs containing the bones were fractured during preparation, they revealed a clean cross section of bone, in which the red of the bone marrow and the yellow of the fatty marrow were clearly visible.
Paleobiologist Maria McNamara of University College Dublin theorizes that the bones provided a protective environment for the marrow, preventing microbes from infiltrating and destroying the soft tissue. Why has no one noticed this material — which may contain DNA and proteins — before? "We think one reason is that when well-preserved fossils with traces of other soft tissue, such as muscle, are studied, people focus on those and sample those," McNamara says. "But when I was doing the museum work in Spain, I was using a binocular microscope to study each specimen. If I'd been skimming through them, I don't think I would have found the marrow."
66. Hobbit Wars Heat Up
When small, humanlike bones were discovered in a cave on the Indonesian island of Flores in 2003, anthropologists knew they had found something exceedingly odd. But what? A new species of dwarf people? A colony of pygmy freaks? Half-joking, some researchers simply referred to the remains as "hobbits." The evidence from 2006 has sharpened the speculation. In September Penn State evolutionary biologist Robert Eckhardt published a paper attacking the idea that Flores Man was a separate species of hominin, related to Homo erectus, that lived in isolation as recently as 13,000 years ago. That idea is championed by Peter Brown of the University of New England in Armidale, Australia, a codiscoverer of Flores Man. Eckhardt argues that the bones share many features, such as rotated teeth and a receding chin, with the Rampasasa pygmies living today near the cave where the remains were found. He notes that the average Rampasasa is just a foot taller than Flores Man. "They may have been going through a temporary food shortage that made them small even for pygmies," he says. In addition, his team found that the most complete specimen of Flores Man was so misshapen that the individual likely suffered from some sort of developmental abnormality, which might explain why the brain was so small.
But when anatomists at Stony Brook University in New York examined the Flores specimens at the request of Brown's team, they supported that group's very different interpretation. They found that Flores Man's shoulders were hunched slightly more forward than in modern humans, and the extraordinarily short legs ended in long feet. Such features seem to tag the Flores people as a separate species, not pygmy versions of modern humans. In addition, some of the oldest Flores remains date back before modern humans were thought to be in the area, which suggests that Flores Man was a distinct species. These little remains could rewrite the story of modern human evolution, so don't expect the debate, or the tempers, to cool down anytime soon.
85. Dodo's Lost World Resurrected
While a few dodo bones and one skeleton remain in museums, they aren't enough to tell biologists exactly why or how the birds went extinct more than 300 years ago. So Dutch geologist Kenneth Rijsdijk was thrilled when he unearthed a cache of 3,000-year-old dodo bones on the island of Mauritius last December. By July he had more good news: The seven-acre site holds a near-complete fossilized ecosystem, including plants, bacteria, reptiles, mammals, and other birds. "There's a lot of potential to reconstruct their world," Rijsdijk says. "What did it look like, and what was the effect of man?"
37. Little Lucy Found
When paleoanthropologist Zeresenay Alemseged of the Max Planck Institute in Germany first saw what appeared to be tiny hominid remains encased in 3.3-million-year-old sandstone in northern Ethiopia — just miles from where the famous Lucy skeleton was found 32 years earlier—he knew he had found something special. After five years of painstakingly extricating bones from sandstone, he was rewarded with the near-complete skeleton of a 3-year-old female — Australopithecus afarensis — the oldest remains of a child hominid ever found.
Such fossils are exceedingly rare, partly because a child's remains are smaller and more likely to have been scattered by predators. Also, at that age the skeleton consists mostly of cartilage, which is more vulnerable to decay than bone. The ancient toddler shows key anatomical features of A. afarensis, including a shoulder blade midway in shape between that of a human and a gorilla, along with features rarely seen, like a full set of both baby and adult teeth. "To me, the most exciting part is the face," says Alemseged. "We no longer have to extrapolate from adults what a child looked like, because we can finally look at her."
94. Tough Times for Tyrannosaur Teens
Life was rough for teen tyrannosaurs, according to Florida State University paleontologist Gregory Erickson. Analysis of a trove of North American dinosaur fossils shows a highly elevated death rate among tyrannosaurs who had recently reached sexual maturity, which occurred between the ages of 14 and 18. "Love may have been a dangerous game for these animals," Erickson says. Competition for mates and nesting sites probably took a toll: Only 2 percent of T. rex's relatives survived all the way to reach their maximum life span of about age 30.