SCIENCE IN THE NEWS WEEKLY
Human Ancestors Weren't Knuckle-Walkers
Researchers have finally unveiled the fossilized remains of Ardipithecus ramidus, a human ancestor that lived 4.4 million years ago. First discovered in 1994, "Ardi" is the oldest fossil skeleton from the human lineage. Fifteen years of painstaking reconstruction and analysis, now published in the journal Science, suggest that Ardi was a forest-dwelling biped who still climbed trees using all fours.
Millions of years later, Ardi's descendants were throwing wild parties in Rome. Archaeologists have uncovered what they believe are the ruins of Nero's rotating banquet hall on Palatine hill. Although historians referenced the emperor's architectural novelty, concrete evidence was lacking until now. It appears that the floor, 50 feet in diameter, rotated on a mechanism of four water-powered spheres.
But 1.8 billion years earlier, things were much less festive: Earth was locked in its so-called "boring billion years," a phase during which oxygen levels remained low and life remained unicellular and simple. Now researchers think organisms with sulfur-based metabolisms caused the stagnation by producing large oceanic dead zones and outcompeting species that released oxygen.
In other news of the ancient past, scientists have happened upon a cache of hundreds of fossilized dinosaur eggs in the state of Tamil Nadu, India. The soccer-ball-sized eggs are all unhatched, are covered in a layer of volcanic ash and date to 65 million years ago—right around the time of the dinosaurs' extinction. Researchers hope the find will shed light on what caused the extinction.
Although the cause of mass extinction remains debatable, what killed individual dinos can be more obvious. A new analysis of Tyrannosaurus rex and other dinosaur skeletons reveals that the fearsome tyrant dinosaurs were laid low by trichomonosis—a parasitic disease that still infects modern birds. The infection caused lesions that ate through the dinos' jawbones, sometimes so severely that the animals may have starved.
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