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Watch The Earliest Humans Clip - Mankind The Story of All of Us | HISTORY

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Watch The Earliest Humans Clip - Mankind The Story of All of Us | HISTORY

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This Face Changes the Human Story. But How?

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This Face Changes the Human Story. But How?

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Learn how your family history is connected to the human journey with National Geographic's Geno 2.0 DNA ancestry kit.

A trove of bones hidden deep within a South African cave represents a new species of human ancestor, scientists announced Thursday in the journal eLife. Homo naledi, as they call it, appears very primitive in some respects-it had a tiny brain, for instance, and apelike shoulders for climbing. But in other ways it looks remarkably like modern humans. When did it live? Where does it fit in the human family tree? And how did its bones get into the deepest hidden chamber of the cave-could such a primitive creature have been disposing of its dead intentionally?

This is the story of one of the greatest fossil discoveries of the past half century, and of what it might mean for our understanding of human evolution.

Chance Favors the Slender Caver

Two years ago, a pair of recreational cavers entered a cave called Rising Star, some 30 miles northwest of Johannesburg. Rising Star has been a popular draw for cavers since the 1960s, and its filigree of channels and caverns is well mapped. Steven Tucker and Rick Hunter were hoping to find some less trodden passage.

In the back of their minds was another mission. In the first half of the 20th century, this region of South Africa produced so many fossils of our early ancestors that it later became known as the Cradle of Humankind. Though the heyday of fossil hunting there was long past, the cavers knew that a scientist in Johannesburg was looking for bones. The odds of happening upon something were remote. But you never know.

Deep in the cave, Tucker and Hunter worked their way through a constriction called Superman's Crawl -because most people can fit through only by holding one arm tightly against the body and extending the other above the head, like the Man of Steel in flight. Crossing a large chamber, they climbed a jagged wall of rock called the Dragon's Back. At the top they found themselves in a pretty little cavity decorated with stalactites. Hunter got out his video camera, and to remove himself from the frame, Tucker eased himself into a fissure in the cave floor. His foot found a finger of rock, then another below it, then-empty space. Dropping down, he found himself in a narrow, vertical chute, in some places less than eight inches wide. He called to Hunter to follow him. Both men have hyper-slender frames, all bone and wiry muscle. Had their torsos been just a little bigger, they would not have fit in the chute, and what is arguably the most astonishing human fossil discovery in half a century-and undoubtedly the most perplexing-would not have occurred.

After Lucy, a Mystery

Lee Berger, the paleoanthropologist who had asked cavers to keep an eye out for fossils, is a big-boned American with a high forehead, a flushed face, and cheeks that flare out broadly when he smiles, which is a lot of the time. His unquenchable optimism has proved essential to his professional life. By the early 1990s, when Berger got a job at the University of the Witwatersrand ("Wits") and had begun to hunt for fossils, the spotlight in human evolution had long since shifted to the Great Rift Valley of East Africa.

Most researchers regarded South Africa as an interesting sidebar to the story of human evolution but not the main plot. Berger was determined to prove them wrong. But for almost 20 years, the relatively insignificant finds he made seemed only to underscore how little South Africa had left to offer.

The fossil record is frustratingly ambiguous. Slightly older than H. erectus is a species called Homo habilis, or "handy man"-so named by Louis Leakey and his colleagues in 1964 because they believed it responsible for the stone tools they were finding at Olduvai Gorge in Tanzania. In the 1970s teams led by Louis's son Richard found more H. habilis specimens in Kenya, and ever since, the species has provided a shaky base for the human family tree, keeping it rooted in East Africa. Before H. habilis the human story goes dark, with just a few fossil fragments of Homo too sketchy to warrant a species name. As one scientist put it, they would easily fit in a shoe box, and you'd still have room for the shoes.

Then, in 2008, he made a truly important discovery. While searching in a place later called Malapa, some ten miles from Rising Star, he and his nine-year-old son, Matthew, found some hominin fossils poking out of hunks of dolomite.

Over the next year Berger's team painstakingly chipped two nearly complete skeletons out of the rock. Dated to about two million years ago, they were the first major finds from South Africa published in decades. (An even more complete skeleton found earlier has yet to be described.) In most respects they were very primitive, but there were some oddly modern traits too.

Berger decided the skeletons were a new species of australopithecine, which he named Australopithecus sediba. But he also claimed they were "the Rosetta stone" to the origins of Homo. Though the doyens of paleoanthropology credited him with a "jaw-dropping" find, most dismissed his interpretation of it. A. sediba was too young, too weird, and not in the right place to be ancestral to Homo: It wasn't one of us. In another sense, neither was Berger. Since then, prominent researchers have published papers on early Homo that didn't even mention him or his find.

Berger shook off the rejection and got back to work-there were additional skeletons from Malapa to occupy him, still encased in limestone blocks in his lab. Then one night, Pedro Boshoff, a caver and geologist Berger had hired to look for fossils, knocked on his door. With him was Steven Tucker. Berger took one look at the pictures they showed him from Rising Star and realized that Malapa was going to have to take a backseat.

Skinny Individuals Wanted

After contorting themselves 40 feet down the narrow chute in the Rising Star cave, Tucker and Rick Hunter had dropped into another pretty chamber, with a cascade of white flowstones in one corner. A passageway led into a larger cavity, about 30 feet long and only a few feet wide, its walls and ceiling a bewilderment of calcite gnarls and jutting flowstone fingers. But it was what was on the floor that drew the two men's attention. There were bones everywhere. The cavers first thought they must be modern. They weren't stone heavy, like most fossils, nor were they encased in stone-they were just lying about on the surface, as if someone had tossed them in. They noticed a piece of a lower jaw, with teeth intact; it looked human.

Berger could see from the photos that the bones did not belong to a modern human being. Certain features, especially those of the jawbone and teeth, were far too primitive. The photos showed more bones waiting to be found; Berger could make out the outline of a partly buried cranium. It seemed likely that the remains represented much of a complete skeleton. He was dumbfounded. In the early hominin fossil record, the number of mostly complete skeletons, including his two from Malapa, could be counted on one hand. And now this. But what was this? How old was it? And how did it get into that cave?

Most pressing of all: how to get it out again, and quickly, before some other amateurs found their way into that chamber. (It was clear from the arrangement of the bones that someone had already been there, perhaps decades before.) Tucker and Hunter lacked the skills needed to excavate the fossils, and no scientist Berger knew-certainly not himself-had the physique to squeeze through that chute. So Berger put the word out on Facebook: Skinny individuals wanted, with scientific credentials and caving experience; must be "willing to work in cramped quarters." Within a week and a half he'd heard from nearly 60 applicants. He chose the six most qualified; all were young women. Berger called them his "underground astronauts."

With funding from National Geographic (Berger is also a National Geographic explorer-in-residence), he gathered some 60 scientists and set up an aboveground command center, a science tent, and a small village of sleeping and support tents. Local cavers helped thread two miles of communication and power cables down into the fossil chamber. Whatever was happening there could now be viewed with cameras by Berger and his team in the command center. Marina Elliott, then a graduate student at Simon Fraser University in British Columbia, was the first scientist down the chute.

"Looking down into it, I wasn't sure I'd be OK," Elliott recalled. "It was like looking into a shark's mouth. There were fingers and tongues and teeth of rock."

Elliott and two colleagues, Becca Peixotto and Hannah Morris, inched their way to the "landing zone" at the bottom, then crouched into the fossil chamber. Working in two-hour shifts with another three-woman crew, they plotted and bagged more than 400 fossils on the surface, then started carefully removing soil around the half-buried skull. There were other bones beneath and around it, densely packed. Over the next several days, while the women probed a square-yard patch around the skull, the other scientists huddled around the video feed in the command center above in a state of near-constant excitement. Berger, dressed in field khakis and a Rising Star Expedition cap, would occasionally repair to the science tent to puzzle over the accumulating bones -until a collective howl of astonishment from the command center brought him rushing back to witness another discovery. It was a glorious time.

The bones were superbly preserved, and from the duplication of body parts, it soon became clear that there was not one skeleton in the cave, but two, then three, then five ... then so many it was hard to keep a clear count. Berger had allotted three weeks for the excavation. By the end of that time, the excavators had removed some 1,200 bones, more than from any other human ancestor site in Africa-and they still hadn't exhausted the material in just the one square yard around the skull. It took another several days digging in March 2014 before its sediments ran dry, about six inches down.

There were some 1,550 specimens in all, representing at least 15 individuals. Skulls. Jaws. Ribs. Dozens of teeth. A nearly complete foot. A hand, virtually every bone intact, arranged as in life. Minuscule bones of the inner ear. Elderly adults. Juveniles. Infants, identified by their thimble-size vertebrae. Parts of the skeletons looked astonishingly modern. But others were just as astonishingly primitive-in some cases, even more apelike than the australopithecines. "We've found a most remarkable creature," Berger said. His grin went nearly to his ears.

But What Is It?

In any case there was only one way to get the analysis done quickly: Put a lot of eyes on the bones. Along with the 20-odd senior scientists who had helped him evaluate the Malapa skeletons, Berger invited more than 30 young scientists, some with the ink still wet on their Ph.D.'s, to Johannesburg from some 15 countries, for a blitzkrieg fossil fest lasting six weeks. To some older scientists who weren't involved, putting young people on the front line just to rush the papers into print seemed rash. But for the young people in question, it was "a paleofantasy come true," said Lucas Delezene, a newly appointed professor at the University of Arkansas. "In grad school you dream of a pile of fossils no one has seen before, and you get to figure it out."

The workshop took place in a newly constructed vault at Wits, a windowless room lined with glass-paneled shelves bearing fossils and casts. The analytical teams were divided by body part. The cranial specialists huddled in one corner around a large square table that was covered with skull and jaw fragments and the casts of other well-known fossil skulls. Smaller tables were devoted to hands, feet, long bones, and so on. The air was cool, the atmosphere hushed. Young scientists fiddled with bones and calipers. Berger and his close advisers circulated among them, conferring in low voices.

Delezene's own fossil pile contained 190 teeth-a critical part of any analysis, since teeth alone are often enough to identify a species. But these teeth weren't like anything the scientists in the "tooth booth" had ever seen. Some features were astonishingly humanlike-the molar crowns were small, for instance, with five cusps like ours. But the premolar roots were weirdly primitive. "We're not sure what to make of these," Delezene said. "It's crazy."

The same schizoid pattern was popping up at the other tables. A fully modern hand sported wackily curved fingers, fit for a creature climbing trees. The shoulders were apish too, and the widely flaring blades of the pelvis were as primitive as Lucy's-but the bottom of the same pelvis looked like a modern human's. The leg bones started out shaped like an australopithecine's but gathered modernity as they descended toward the ground. The feet were virtually indistinguishable from our own.

"You could almost draw a line through the hips-primitive above, modern below," said Steve Churchill, a paleontologist from Duke University. "If you'd found the foot by itself, you'd think some Bushman had died."

"Weird as hell," paleoanthropologist Fred Grine of the State University of New York at Stony Brook later said. "Tiny little brains stuck on these bodies that weren't tiny." The adult males were around five feet tall and a hundred pounds, the females a little shorter and lighter.

"The message we're getting is of an animal right on the cusp of the transition from Australopithecus to Homo," Berger said as the workshop began to wind down in early June. "Everything that is touching the world in a critical way is like us. The other parts retain bits of their primitive past."

In some ways the new hominin from Rising Star was even closer to modern humans than Homo erectus is. To Berger and his team, it clearly belonged in the Homo genus, but it was unlike any other member. They had no choice but to name a new species. They called it Homo naledi (pronounced na-LED-ee), tipping a hat to the cave where the bones had been found: In the local Sotho language, naledi means "star."

How Did It Get There?

Back in November, as Marina Elliott and her mates were uncovering that startling trove of bones, they were almost as surprised by what they weren't finding. "It was day three or four, and we still hadn't found any fauna," Elliott said. On the first day a few little bird bones had been found on the surface, but otherwise there was nothing but hominin bones.

"When you have eliminated the impossible," Sherlock Holmes once reminded his friend Watson, "whatever remains, however improbable, must be the truth."

Deliberate disposal of bodies would still have required the hominins to find their way to the top of the chute through pitch-black darkness and back again, which almost surely would have required light-torches, or fires lit at intervals. The notion of such a small-brained creature exhibiting such complex behavior seems so unlikely that many other researchers have simply refused to credit it. At some earlier time, they argue, there must have been an entrance to the cave that afforded more direct access to the fossil chamber-one that probably allowed the bones to wash in. "There has to be another entrance," Richard Leakey said after he'd paid a visit to Johannesburg to see the fossils. "Lee just hasn't found it yet."

But water would inevitably have washed rubble, plant material, and other debris into the fossil chamber along with the bones, and they simply aren't there. "There isn't a lot of subjectivity here," said Eric Roberts, a geologist from James Cook University in Australia, svelte enough to have examined the chamber himself. "The sediments don't lie."

"It's an animal that appears to have had the cognitive ability to recognize its separation from nature," he said.

How Old Is It?

Berger's Triumph

A few weeks later, in August of last year, he traveled to East Africa. To mark the occasion of Louis Leakey's description of H. habilis, Richard Leakey had summoned the leading thinkers on early human evolution to a symposium at the Turkana Basin Institute, the research center he (along with the State University of New York at Stony Brook) had established near the western shore of Lake Turkana in Kenya.

"There's no one on Earth finding fossils like Lee is now," Leakey said.

"More of interest perhaps to this debate is Rising Star," he offered. For the next 20 minutes he laid out all that had happened-the serendipitous discovery of the cave, the crash analysis in June, and the gist of its findings. While he talked, a couple of casts of Rising Star skulls were passed hand to hand.

Then came the questions. Have you done a cranio-dental analysis? Yes. The H. naledi skull and teeth place it in a group with Homo erectus, Neanderthals, and modern humans. Closer to H. erectus than H. habilis is? Yes. Are there any tooth marks on the bones from carnivores? No, these are the healthiest dead individuals you'll ever see. Have you made progress on the dating? Not yet. We'll get a date sometime. Don't worry.

Then, when the questions were over, the gathered doyens did something no one expected, least of all Berger. They applauded.

The Braided Stream

Berger himself thinks the right metaphor for human evolution, instead of a tree branching from a single root, is a braided stream: a river that divides into channels, only to merge again downstream. Similarly, the various hominin types that inhabited the landscapes of Africa must at some point have diverged from a common ancestor. But then farther down the river of time they may have coalesced again, so that we, at the river's mouth, carry in us today a bit of East Africa, a bit of South Africa, and a whole lot of history we have no notion of whatsoever. Because one thing is for sure: If we learned about a completely new form of hominin only because a couple of cavers were skinny enough to fit through a crack in a well-explored South African cave, we really don't have a clue what else might be out there.

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This Face Changes the Human Story. But How?

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Homo naledi, discovered in a cave near Johannesburg, is a human ancestor unlike any species previously known. The find is arguably one of the most important discoveries in human origins research in half a century. It's also the most perplexing.

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Early Human Evolution: Early Human Culture

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Early Human Evolution: Early Human Culture

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Early Human Evolution: Early Human Culture

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Tools & Food | The Smithsonian Institution's Human Origins Program

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Tools & Food | The Smithsonian Institution's Human Origins Program

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The Smithsonian Institution's Human Origins Program

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By 2.6 million years ago
Early humans in East Africa used hammerstones to strike stone cores and produce sharp flakes. For more than 2 million years, early humans used these tools to cut, pound, crush, and access new foods-including meat from large animals.

How Do We Know This Zebra Was Food?

Stone tool marks on this zebra bone look like those made during butchery experiments. Scientists have made experimental stone tools and used them to butcher modern animals. There is a strong similarity between the marks their tools made and the marks on fossil animal bones, indicating that early humans used stone tools to butcher animals by at least 2.6 million years ago.

Handaxes came in handy
Beginning 1.7 million years ago
Around this time, toolmakers began to strike huge flakes off stone cores. They shaped the large flakes into handaxes by striking smaller flakes all around the edges. These multipurpose tools dominated early human technology for more than a million years. Ancient handaxes have been found in Africa, Asia, and Europe. Learn more about them and other Early Stone Age tools.

Handaxe Makers Cope with Catastrophe

Since the handaxes and tektites were in the same layer, both are the same age. Early humans must have moved into the area right after the impact. They may have made the handaxes from rocks that were exposed when forests burned.

A huge meteor impact occurred in the atmosphere near China 803,000 years ago and the shock caused earth rocks to melt and explode, forming tektites. Widespread forest fires followed. Shortly after, humans moved into the barren landscape and scavenged for resources.

What's cooking?
By 790,000 years ago
Control of fire provided a new tool with several uses-including cooking, which led to a fundamental change in the early human diet. Cooking released nutrients in foods and made them easier to digest. It also rid some plants of poisons.

The earliest hearths are at least 790,000 years old. Some researchers think cooking may reach back more than 1.5 million years.

unting Large Animals

By at least 500,000 years ago, early humans were making wooden spears and using them to kill large animals.

Early humans butchered large animals as long as 2.6 million years ago. But they may have scavenged the kills from lions and other predators. The early humans who made this spear were hunting large animals, probably on a regular basis.

Reducing the risk

Hunting large animals was a risky business. Long spears like this one were thrust into an animal, enabling our ancestors to hunt from a somewhat safer distance than was possible with earlier weapons. Three wooden spears like the 400,000-year-old one illustrated here were found at Schöningen, Germany, along with stone tools and the butchered remains of more than 10 horses.

Oldest evidence of hunting

Explosion of technology
By 100,000 years ago
Eventually new kinds of tools replaced stone handaxes. Some were small or made of several parts. Some were made of bone, ivory, or antler. Over the past 100,000 years, as modern humans spread around the world, the pace of technological change accelerated-leading to today's extraordinary diversity of specialized tools.

Making clothing

Awls and perforators were probably invented in Africa and carried to colder climates, where they were used to pierce holes in clothing. Later, humans used bone and ivory needles to sew warm, closely fitted garments.

Carving and shaping

Burins are specialized stone flakes with sharp, chisel-like tips. Humans used them to work bone, antler, ivory, and wood and to carve designs and images on the surfaces of these materials.

More than 70,000 years ago, humans in Central Africa used some of the earliest barbed points to spear huge prehistoric catfish weighing as much as 68 kg (150 lbs.), enough to feed 80 people for two days. Later, humans used harpoons to hunt large, fast marine mammals.

Hunting fast and dangerous prey

Spear-throwers provided leverage for hurling spears and darts greater distances with more speed and accuracy and with less chance of injury from prey. Stone or bone points, attached to spears or darts, enabled humans to exploit fast-moving prey like birds and large, dangerous prey like mammoths.

Storing things

Early humans may have made bags from skin long ago. By around 26,000 years ago, they were weaving plant fibers to make cords and perhaps baskets. About 20,000 years ago, in China, they began making pottery.

Chimps Make Tools, Too

Chimpanzees in Guinea used this stone anvil and hammerstone to crack open oil palm nuts, an energy-rich food. Nut cracking is one of the most sophisticated examples of chimpanzee tool use.(Specimen courtesy of Professor Tetsuro Matsuzawa, Kyoto University Primate Research Institute, Kyoto, Japan)

Chimpanzees in Guinea use specially prepared sticks like this to "fish" for ants, a high-protein food. They make holes in the side of a nest, insert the stick, and pull it out-covered with ants. (Specimen courtesy of Dr. Kathelijne Koops and Dr. William McGrew, Cambridge University, England)

Benefits and Costs of Eating Meat

- Meat is a concentrated source of calories, protein, fat, and nutrients.

- Unlike many plants, most meat does not naturally contain toxic chemicals; so it was a relatively safe food for early humans.

- Meat is more quickly digested than plants and does not require large guts, saving energy for the brain and other organs.

- Hunting and scavenging large animals is risky and less predictable than gathering plants.

- Dangerous animals competed with early humans to obtain meat.

- Meat spoils quickly and can contain tapeworms and other parasites.

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By 2.6 million years ago Early humans in East Africa used hammerstones to strike stone cores and produce sharp flakes. For more than 2 million years, early humans used these tools to cut, pound, crush, and access new foods-including meat from large animals. How Do We Know This Zebra Was Food?

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Bill Nye Talks Dogs and Explores the Lessons of Canine Evolution - YouTube

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Bill Nye Talks Dogs and Explores the Lessons of Canine Evolution - YouTube

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Bill Nye Talks Dogs and Explores the Lessons of Canine Evolution

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Bill Nye the Science Guy returns to Big Think to discuss evolution, this time from a canine point of view. Nye explains how dogs evolved out of an early human-wolf interaction which today benefits both species. He also draws a comparison between dog breeds and the social construct of race, claiming that both are man-made myths not steeped in science.

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Public Release Item Scoring ~ CLG ~ School Improvement in Maryland

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Public Release Item Scoring ~ CLG ~ School Improvement in Maryland

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Public Release Item Scoring ~ CLG ~ School Improvement in Maryland

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A student washes her hands with antibacterial soap and water. Then she touches the agar in a petri dish with her thumb. The agar contains nutrients that support the growth of bacteria. Other students repeat the procedure after washing their hands with three different kinds of antibacterial soap.

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Taxonomy | Science | Classroom Resources | PBS LearningMedia

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Taxonomy | Science | Classroom Resources | PBS LearningMedia

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For centuries, taxonomists have been organizing the diversity of life. Aristotle was the first to attempt to do this. Then, in the 1700s, Carolus Linnaeus introduced the idea of genus and species. Later, Charles Darwin revolutionized science with the idea that species can change over time and that all animals may have a common ancestor.

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Basic Genetics [Internet]. Salt Lake City (UT): Genetic Science Learning Center; 2016 [cited 2018 May 23] Available from http://learn.genetics.utah.edu/content/basics/

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Pin by Rachael Guillen on Teaching Ideas | Pinterest

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Pin by Rachael Guillen on Teaching Ideas | Pinterest

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History of the World in Seven Minutes - YouTube

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History of the World in Seven Minutes - YouTube

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Read how others have recognized the Understanding Evolution website.

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The list below includes scientists and thinkers who have contributed to our understanding of life on Earth, especially evolution. The list is given chronologically, and is divided into sections according to themes in the history of evolutionary thought.

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Barenaked Ladies - History of Everything (Official The Big Bang Theory Video) - YouTube

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Barenaked Ladies - History of Everything (Official The Big Bang Theory Video) - YouTube

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Barenaked Ladies - History of Everything (Official The Big Bang Theory Video)

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Group: Barenaked Ladies Song: History of Everything Opening song of "The Big Bang Thoery" (Drawing Video)

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The list below includes scientists and thinkers who have contributed to our understanding of life on Earth, especially evolution. The list is given chronologically, and is divided into sections according to themes in the history of evolutionary thought.

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Read how others have recognized the Understanding Evolution website.

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Population pyramids: Powerful predictors of the future - Kim Preshoff | TED-Ed

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Population pyramids: Powerful predictors of the future - Kim Preshoff | TED-Ed

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Population pyramids: Powerful predictors of the future - Kim Preshoff

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Population statistics are like crystal balls -- when examined closely, they can help predict a country's future (and give important clues about the past). Kim Preshoff explains how using a visual tool called a population pyramid helps policymakers and social scientists make sense of the statistics, using three different countries' pyramids as examples.

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Shrinking Dinosaurs Evolved into Flying Birds

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Shrinking Dinosaurs Evolved into Flying Birds

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Today's birds evolved from dinosaurs that shrank continuously for 50 million years, researchers say.

Dinosaurs first emerged about 245 million years ago, and they came to dominate the planet. They included the largest animals ever to walk across the surface of Earth. Their reign came to an end with a bang - a cosmic impact from an asteroid or comet maybe 6 miles (10 kilometers) wide. However, not all of the dinosaurs were killed by this impact - they became the birds that are now found on every continent on Earth.

"Birds are the only dinosaurs that are still alive today," said lead study author Michael Lee, an evolutionary biologist at the South Australian Museum and the University of Adelaide in Australia.

Birds evolved from carnivorous dinosaurs known as theropods, which included giant predators such as Tyrannosaurus rex and talon-footed raptors such as Deinonychus. Recent studies of theropods keep finding more and more birdlike traits, such as feathers, wishbones, hollow skeletons and three-fingered hands, Lee said. [ Avian Ancestors: Dinosaurs That Learned to Fly (Gallery)]

To learn more about how small, graceful fliers such as hummingbirds evolved from massive ground-dwelling theropods, scientists developed a detailed family tree of birds and their dinosaur ancestors, mapping out this evolutionary transformation. They analyzed more than 1,500 anatomical traits from 120 species of early birds and all branches of the theropod family tree, and estimated when the two diverged from each other and how quickly each lineage changed.

A flock of early birds (Longirostravis) preen a large dinosaurian relative (Yutyrannus) some 120 million years ago in what is now northern China.

Credit: Brian Choo

The researchers discovered that the branch of theropods that gave rise to modern birds consisted of the only theropods that kept shrinking. In the lineage that led directly to birds, body size decreased during the course of at least 12 different stages over 50 million years or so, from stiff-tailed carnivores known as tetanurans that lived about 198 million years ago and weighed about 359 lbs. (163 kilograms) to Archaeopteryx, long considered the first known bird, which lived about 150 million years ago and averaged about 1.7 lbs. (0.8 kg).

"No other dinosaur group underwent such an extended period of shrinkage," Lee told Live Science.

In addition to this miniaturization, the scientists discovered that bird precursors evolved new skeletal adaptations - such as wings, enlarged brains, smaller teeth and large eyes - four times faster than other dinosaurs.

"Birds arose from the most 'evolvable' dinosaurs," Lee told Live Science.

All in all, "being smaller and lighter in the land of giants, with rapidly evolving anatomical adaptations, provided these bird ancestors with new ecological opportunities, such as the ability to climb trees, glide and fly," Lee said in a statement. "This evolutionary flexibility helped birds survive the deadly meteorite impact, which killed off all their dinosaurian cousins."

Ultimately, "birds out-shrank and out-evolved their dinosaurian ancestors, surviving where their larger, less-evolvable relatives could not," Lee said in a statement.

In the future, the researchers would like "to see these methods applied to help understand rates and patterns of evolution in other groups," Lee said. "For instance, how fast did mammals evolve after the dinosaur extinctions? We know they evolved rapidly, but we don't have exact rates yet."

The scientists detail their findings in the Aug. 1 issue of the journal Science.

Follow us @livescience, Facebook & Google+. Original article on Live Science.

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Shrinking Dinosaurs Evolved into Flying Birds

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Today's birds evolved from dinosaurs that shrank continuously for 50 million years, researchers say. Dinosaurs first emerged about 245 million years ago, and they came to dominate the planet. They included the largest animals ever to walk across the surface of Earth.

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Dinosaurs’ 'Shrinkage' Into Birds Explained | Video

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Dinosaurs’ 'Shrinkage' Into Birds Explained | Video

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science life space animal sex politics scientific

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LiveScience is where the curious come to find answers. We illuminate our fascinating world, and make your everyday more interesting. We share the latest discoveries in science, explore new innovations in tech, and dissect the weird, wacky and phenomenal occurrences that impact our society and culture.

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Humans are unique creatures on the planet, though it wasn't always this way. Long ago, some bizarre human relatives, such as Nutcracker Man and a Homo species whose miniature bodies resembled the hobbits on Lord of the Rings, roamed Earth. Scientists are even finding evidence that modern humans crossed paths with some of our relatives, with fossils suggesting Homo sapiens may have had sex with Neanderthals and even a newly discovered species called the Denisovans. In news and features, we will cover human evolution and origins, revealing the mysteries of humanity, details on human ancestors and the evolutionary steps that led to modern humans.

Related Topics: DNA and Genes, Evolution, Fossils

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Humans are unique creatures on the planet, though it wasn't always this way. Long ago, some bizarre human relatives, such as Nutcracker Man and a Homo species whose miniature bodies resembled the hobbits on Lord of the Rings, roamed Earth.

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What is evolution and how does it work? Evolution 101 provides the nuts-and-bolts on the patterns and mechanisms of evolution. You can explore the following sections:

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Fossil Hominids: the evidence for human evolution

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Fossil Hominids: the evidence for human evolution

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Fossil Hominids: the evidence for human evolution

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An overview of human evolution, summarizing current thinking and describing the fossil evidence for Australopithecus and Homo. Also refutes many creationist arguments about human evolution.

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national center for biotechnology information

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The NCBI Taxonomy database is a curated set of names and classifications for all of the organisms that are represented in GenBank.

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Evolution: Library: Phylogeny: Why Classify?

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Evolution: Library: Phylogeny: Why Classify?

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Evolution: Library: Phylogeny: Why Classify?

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Lungfish and perch both live in water and look like fish, so pheneticists group them together (a), although the lineage leading to lungfish split from the other fish hundreds of millions of years ago, and the resemblance between them is due to convergent evolution.

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Test your skills at judging who's who on the tree of life.

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Evolution: Survival: Coral Reef Connections

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Evolution: Survival: Coral Reef Connections

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Evolution: Survival: Coral Reef Connections

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Dive in and learn why how this beautiful world is so fragileinterconnected.

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Help our contestants find the perfect date.

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A demonstration of how a new species can evolve.

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Evolution: Darwin: In the Name of Darwin

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Evolution: Darwin: In the Name of Darwin

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Evolution: Darwin: In the Name of Darwin

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Racism and bigotry are linked, unjustly, to Darwin. Learn why.

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Human Evolution by The Smithsonian Institution's Human Origins Program

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Human Evolution by The Smithsonian Institution's Human Origins Program

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The Smithsonian’s Human Origins Program | The Smithsonian Institution’s Human Origins Program

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Explore the revolution and the controversies around it.