Hailed as a find for the ages, a rare skull of a 1.8-million-year-old human relative could provide answers to longstanding questions about the lineage of our species. It also fuels debate over what differentiates one hominin species from another, and could mean that Homo habilis, Homo rudolfensis and other early bipedal hominins may all be members of Homo erectus, rather than distinct species.
What is it, exactly, that distinguishes us from other species? The definition of humankind has perplexed scientists, philosophers and theorists for centuries. DNA composition differentiates species in a technical sense, but that definition is hardly satisfying. Certainly there must be something more ethereal that separates us from “lower” forms of creatures. Over the centuries, several definitions have emerged — from using tools to speaking — but have then been proven insufficient in some heuristic way. So I propose another option: manipulating energy.
The debate over when our ancestors first used stone tools is not over just yet. In August, researchers had reported finding scratch marks on two 3.4-million-year-old animal bones that they said were made by Australopithecus afarensis — the ancestor made famous by Lucy — scraping meat off the bones with sharp-edged stones. If true, that would push tool use back to 800,000 years earlier than previously thought.
Last October, scientists formally introduced the world to Ardi the Ardipithecus, the well-preserved skeleton of a 4.4-million-year-old hominin found in Ethiopia. Eight months later, scientists have had time to digest the data from all 11 papers that were published in Science last fall regarding Ardi’s biology and ecology, and there is some dissent.
Did “Clan of the Cave Bear” get it right after all?
Probably not, but at least one aspect of the ice age saga is true: Modern humans interbred with Neanderthals. In fact, for many of us, as much as 4 percent of our DNA may be Neanderthal DNA. That’s the conclusion of a group of 56 scientists who have just announced today in Science that they’ve completed a draft sequence of the Neanderthal genome.
Last month, the Smithsonian’s National Museum of Natural History in Washington, D.C., unveiled its new (permanent) human evolution exhibit: the David H. Koch Hall of Human Origins. The exhibit seeks to answer the millennia-old question, What does it mean to be human?
Modern humans and Neanderthals lived side by side on the Eurasian landscape for tens of thousands of years — but it turns out they weren’t alone, much to researchers’ surprise. A team of researchers has found a hominin bone in a Siberian cave containing DNA that doesn’t match up with either known hominin species at that time, the researchers reported in Nature today, indicating that these humans shared the continent with a third, unknown hominin.
Ardipithecus ramidus was a hominid that lived in Ethiopia’s Afar region 4.4 million years ago. After spending more than a decade studying the species, scientists can now provide a sketch of what the hominid looked like:
Brain:Ardipithecus had a brain size similar to that of a female chimpanzee, about 300 to 350 cubic centimeters.
Stature: Standing 120 centimeters tall and weighing 50 kilograms, Ardipithecus was about the size of a chimpanzee.
Though counterintuitive, scientists have turned their attention away from the feet and to the wrist and forearm to better understand how humans evolved upright walking, or bipedalism. African apes are humans’ closest living relatives, and because these apes knuckle-walk, some paleoanthropologists have suggested that African apes and humans share a knuckle-walking ancestor. A new study, however, reveals that lumping the locomotion of all African apes together is a mistake: Knuckle-walking may have evolved more than once in the ape lineage.
Lucy, the 3.2-million-year-old Australopithecus afarensis fossil, has long been the poster child for early human evolution. But now she’ll have to share the spotlight with an even older hominid. After spending the last 15 years studying an ancient hominid species about the size of a chimpanzee, scientists revealed details about the 4.4-million-year-old Ardipithecus ramidus in a press conference today.