Human Evolution on EARTH Magazine

Hard-knock hominid skeletons tell harsh tales

Wed, 13 Feb 2019 16:15:25 -0500

The malformed skull of a 2- to 3-year-old Pleistocene hominid (top) found in France shows signs of hydrocephalus, a swelling of the braincase due to excess fluid in the skull. The hole in the top of the skull is thought to have been cut postmortem. Abnormally bowed femurs (bottom) in the fossil skeleton of a 10-year-old boy found at the Sunghir site in Russia may have been caused by chronic nutritional stress or an inherited disorder. Credit: both: Erik Trinkaus/PNAS.

The Pleistocene was a hard time for hominids. Homo fossils from this period, when humans evolved and expanded from Africa and across Eurasia, are riddled with an unusual number of skeletal abnormalities. Swollen braincases, bowed femurs, twisted long bones, pronounced dwarfism and malformed teeth are just a few of the unusual skeletal features found in many Pleistocene hominid fossils. A new statistical study has confirmed that these anomalies occur at higher-than-expected rates in the Pleistocene fossil record. But whether this elevated incidence was mainly caused by nutritional stress or inbreeding, or if it’s an artifact of preservational bias, is unknown.

"Cradle of Humankind" fossils can now be dated

Mon, 04 Feb 2019 10:50:12 -0500

A light-colored flowstone deposit lies atop lithified red sediments in a South African cave were hominin fossils were found. Researchers dated such flowstones to constrain the ages of fossils found in adjacent sedimentary layers. Credit: Robyn Pickering

Robyn Pickering was taught as an undergraduate about a collection of limestone caves in northern South Africa known collectively as the Cradle of Humankind for the trove of early hominin fossils discovered there. She learned that, unlike hominin fossils unearthed in East Africa, whose ages have been constrained by dating the surrounding layers of volcanic ash, the fossils in the Cradle — including well-preserved specimens of Australopithecus africanus and the recently discovered Homo naledi, among others — were impossible to date independently.

Climate cooling a driver of Neanderthals' extinction

Thu, 29 Nov 2018 16:46:00 -0500

Analyses of cave speleothems from Romania revealed periods of rapid climatic cooling in Eastern Europe about 44,000 and 40,000 years ago that, according to recent research, likely contributed to the decline of Neanderthals. Credit: shutterstock.com/Procy

Neanderthals disappeared from Europe roughly 40,000 years ago, and scientists are still trying to figure out why. Did disease, climate change or competition with modern humans — or maybe a combination of all three — do them in? In a recent study, researchers offer new evidence from Eastern Europe that climate change was a major player in the Neanderthals’ disappearance.

Speartips point at south-to-north Clovis dispersal

Tue, 03 Jul 2018 11:35:35 -0400

Several routes have been proposed for the first human migrations into North America, with the most widely accepted suggesting a north-to-south traverse through an ice-free corridor east of the Rocky Mountains. But a new analysis of hundreds of spearpoints found across the western U.S. is turning this model on its head. Credit: map: K. Cantner, AGI; photo: Heather Smith.

During the last ice age, long before people first entered North America, much of the Canadian and American Rockies were buried under massive ice sheets. As the ice age waned about 13,000 years ago, an ice-free corridor 1,500-kilometers long and several hundred kilometers wide opened east of the Rocky Mountains.

Trio of studies track stone tool technology in Kenya

Tue, 05 Jun 2018 17:02:59 -0400

About 300,000 years ago, East Africa was a hotbed of human evolution and innovation. Sweeping ecological changes contributed to the emergence of modern humans, and spurred the first long-distance trade routes and novel toolmaking technologies. Three new studies published in Science shine a spotlight on Kenya’s Olorgesailie Basin, where the clunkier Acheulean tool technology gave way to the smaller, sleeker Middle Stone Age tool technology famously associated with Homo sapiens.

Weedy seeds gathered in once-green Sahara

Tue, 05 Jun 2018 16:36:57 -0400

Today, the vast and arid Sahara Desert seems an unlikely place to find early signs of seed gathering and plant cultivation in Africa, but new evidence shows that, 10,000 years ago, people were collecting, sorting and saving seeds near a rock shelter known as Takarkori.

Oldest human remains outside Africa found in Israel

Tue, 01 May 2018 16:01:28 -0400

Close-up view of the human jawbone fossil found in Misliya Cave in northern Israel, showing details of the crown topography and dental features. Credit: both: Rolf Quam/Binghamton University.

The recent discovery of a jawbone belonging to Homo sapiens, and associated stone tools, in Israel may push back the timing of the earliest human migration out of Africa by as much as 50,000 years.

A new look at Cheddar Man

Tue, 01 May 2018 15:56:12 -0400

Cheddar Man's dark skin defies conventionally held ideas that Britons have long been light-skinned. Credit: ©Tom Barnes/Channel 4.

In 1903, a skeleton was found in a limestone cave in Cheddar Gorge, near Somerset, England. Radiocarbon dating in the 1970s revealed the remains to be more than 10,000 years old, making it the oldest near-complete human skeleton found in Britain. Now, as yet unpublished research suggests Cheddar Man’s genome reveals a surprisingly different appearance for the Mesolithic man from what’s long been thought, according to researchers who analyzed DNA from the skeleton.

Drought drove early humans from Africa

Fri, 23 Feb 2018 11:12:48 -0500

Homo sapiens, which first emerged in Africa between 150,000 and 200,000 years ago, migrated in waves to different parts of the world. Credit: K. Cantner, AGI.

Genetics studies have dated the largest migrations of early Homo sapiens out of Africa to between 70,000 and 55,000 years ago, although smaller groups may have left earlier. The most widely accepted exodus theory, known as the “green carpet” or “green Sahara” hypothesis, holds that people likely left during wetter periods in the Sahara and Arabia, which would have allowed easier passage into Eurasia via the Middle East. But new research supports the opposite idea: that drier conditions may have triggered at least some of the exodus.

Nothing is clear about who left marks on ancient bones

Fri, 05 Jan 2018 17:58:46 -0500

Two crocodile teeth found at the collection site along with a horse leg bone with marks that Yonatan Sahle's team studied. Credit: Y Sahle et al./PNAS 2017.

An ongoing debate regarding the origin of scrape marks on ancient animal bones has taken a new turn. The marks were first thought to have been made by early hominid butchers, then by trampling, and now it’s looking like crocodiles might have been responsible, according to a recent study in Proceedings of the National Academy of Sciences (PNAS).

19th-century discovery now reveals modern human arrival in Sumatra

Thu, 14 Dec 2017 06:57:40 -0500

New research at Lida Ajer Cave in Sumatra, combined with data from human teeth found there in the 1880s, suggests humans were in Indonesia roughly 20,000 years earlier than previously thought. Credit: Julien Louys.

Modern humans began journeying out of Africa by at least 75,000 years ago, eventually expanding across the planet. Evidence of these early human travels, including fossils and artifacts, is typically spotty and difficult to find. But one such discovery more than a century ago has shed new light on the appearance of humans in Southeast Asia.

Mysterious Miocene bipedal footprints found in Crete

Mon, 11 Dec 2017 13:02:20 -0500

Photos, laser scans and interpretations of three footprints dated to the Late Miocene and preserved in sedimentary rock in western Crete. Numbers denote digits, and "ba" and "he" refer to interpretations of ball and heel imprints, respectively. Credit: Gierliński et al., Proceedings of the Geologists' Association, August 2017.

A curious set of 5.7-million-year-old bipedal footprints found in western Crete — far from the cradle of humanity in Africa and dating to the Late Miocene, long before hominins are thought to have walked upright — has paleoanthropologists scratching their heads.

Bipedalism left its mark on human skull: Kangaroos and upright rodents show same signs

Mon, 19 Jun 2017 13:20:41 -0400

The transition to bipedal walking in our ancestors changed the hominin skeleton in many ways. New research looking at how upright walking affected the structures at the base of the skull in both early humans and other bipedal mammals, like kangaroos, is shedding light on a once-controversial marker for bipedalism.

Lucy liked hanging out in trees

Thu, 06 Apr 2017 10:13:48 -0400

A new study focused on Lucy's upper arm bones, which held clues revealing an arboreal, climbing lifestyle for the hominin. Credit: John Kappelman/University of Texas, Austin.

Lucy, the 3.2-million-year-old human ancestor discovered in Ethiopia in 1974, is one of the most complete early hominin skeletons ever found. Still, despite the skeleton’s completeness, debate continues about how Lucy got around: Did she spend most of her time walking on the ground or climbing in trees? In a new study, scientists studying Lucy’s upper limb bones have found that she likely spent more time in trees — and was a more capable climber — than later hominin species like Homo erectus and Homo sapiens.

Geologic Column: Evolution of an ape-man

Thu, 06 Apr 2017 09:09:08 -0400

The title page to Charles Darwin's "On the Origin of the Species", published in 1859. Credit: Public Domain.

By the time I was 12, I had identified the greatest writer in the world. His name was Edgar Rice Burroughs and he wrote adventure stories about an ape-man named Tarzan. Burroughs described him as having a “straight and perfect figure muscled as the best of the ancient Roman gladiators must have been muscled, and yet with the soft and sinuous curves of a Greek god.” You could see at a glance his “wondrous combination of enormous strength with suppleness and speed.” Tarzan was human, but he’d been orphaned in Africa and raised by a she-ape in the jungle. That made him an ape-man for sure in any kid’s estimation. The first Tarzan story appeared in 1912, but the most significant date for ape-men was half a century earlier, in 1859, when Charles Darwin published “On the Origin of Species,” which encouraged the search for a real ape-man called the “missing link.”

Dental plaque reveals later start date for hominin cooking

Wed, 29 Mar 2017 14:00:30 -0400

The Sima del Elefante site is located near the famous Sima de los Huesos hominin site in Spain's Atapuerca Mountains. Credit: Hardy et al., The Science of Nature, December 2016.

Ancient teeth have long been a source of information about ancient diets, mainly through analyses of isotopic compositions and wear patterns. In a new study published in the Science of Nature, researchers studied microfossils of food particles extracted from the teeth of a 1.2-million-year-old unidentified hominin found at the Sima del Elefante site in northern Spain. The microfossils include traces of raw animal tissue, uncooked starch granules from grasses, pollen grains from a species of pine tree and insect fragments. The lack of charring of the recovered fibers and an absence of micro-charcoal suggest the bearer of the teeth neither cooked his or her food nor spent significant time around a fire source.

Early humans dealt with Ethiopian supervolcanoes

Wed, 08 Feb 2017 14:05:12 -0500

Modern geochronological techniques were used to calculate the age of volcanic deposits and build an eruptive history for the volcanoes of the Ethiopian Rift. Credit: William Hutchison.

About 200,000 years ago, modern humans evolved in East Africa, including in what’s now Ethiopia. They — like earlier hominins who had preceded them — likely encountered occasional explosive eruptions spewing ash and lava into the air and onto the landscape, according to a new study in Nature Communications.

Green corridors led humans out of Africa

Tue, 20 Dec 2016 22:02:31 -0500

Climate and vegetation changes over the past 120,000 years affected human dispersal out of Africa. Credit: K. Cantner, AGI, after Peter de Menocal and Chris Stringer, 2016

A trail of fossil, archaeological and genetic clues suggests that modern humans, who first evolved in East Africa about 200,000 years ago, may have made forays outside Africa via the eastern Mediterranean and the Arabian Peninsula as early as 120,000 years ago. But most fossil and archaeological evidence suggests they didn’t begin widely populating the rest of the world until about 60,000 years ago.

The new kid on the block

Wed, 17 Aug 2016 10:47:34 -0400

Location of Rising Star Cave in Guateng Province. Inset map: Location of Guateng Province in South Africa. Credit: Animalparty, CC BY-SA 4.0.

In 2013, cave explorers discovered a trove of human-like fossils in the Rising Star Cave in South Africa. Since then, more than 1,500 fossils belonging to at least 15 individuals have been excavated from the site. The fossils display a mishmash of primitive and more advanced features that seem to place it somewhere between Australopithecus and early Homo species, such as a small cranial capacity closer to Australopiths, but with finer facial features, more like Homo.

Hominid vs. hominin

Wed, 17 Aug 2016 10:37:49 -0400

Once genetics entered the picture, the definitions of hominids and hominins changed. Credit: K. Cantner, AGI.

Before genetics came along and revealed just how closely modern humans and chimpanzees are related, humans were classified in their own family, Hominidae, separate from old world monkeys, which were in the family Pongidae.

Redefining Homo: Does our family tree need more branches?

Tue, 16 Aug 2016 17:03:27 -0400

The hominin family tree is frequently revised, but researchers disagree about where many fossils should be placed on the tree. Credit: K. Cantner, AGI.

As the sole surviving species of the genus Homo, we Homo sapiens are one of the most taxonomically lonely species living on Earth today. But dig back a few thousand years or more and we find ourselves with plenty of company: Many now-extinct species shared the genus Homo, ranging from the robust Homo neanderthalensis, to the hobbit-like Homo floresiensis to the more primitive Homo habilis and Homo erectus. But do all these species, with their wide diversity of physical and cultural traits, actually belong in the same genus?

New dating of 'hobbit' sheds light on when it lived

Mon, 15 Aug 2016 13:18:41 -0400

A reconstruction of Homo floresiensis by Atelier Elisabeth Daynes. Credit: Kinez Riza.

Since 2004, when scientists first announced the discovery of fossil remains of a new species of hominin from Indonesia — dubbed Homo floresiensis and nicknamed “hobbits” due to the species’ meter-tall stature — researchers have been trying to pinpoint exactly when H. floresiensis lived and when it died off. Several recent studies shed light on the topic.

Teeth hold clues to human success, Neanderthal decline

Wed, 20 Jul 2016 13:30:44 -0400

During the Upper Paleolithic, modern humans and Neanderthals coexisted until about 40,000 years ago, when Neanderthals went extinct for unknown reasons. Wear patterns on teeth from both humans and Neanderthals are providing insight into how different dietary strategies may have led to Homo sapiens’ success and the Neanderthals’ decline.

Denisovan DNA found in modern Pacific Islanders, ancient Spaniards

Thu, 14 Jul 2016 10:21:16 -0400

Denisovans were first identified from a 41,000-year-old finger bone found in a cave in Siberia. In two new studies, traces of Denisovan DNA have been found in modern Melanesians and in 430,000-year-old remains at the Sima de los Huesos site in Spain. Credit: K. Cantner, AGI.

In the time that Homo sapiens and Neanderthals were coexisting — and interbreeding — there was at least one more human species on the landscape, the Denisovans. First identified from a 41,000-year-old finger bone found in a cave in Siberia, the Denisovans are now thought to have been widespread around Eurasia. In two new studies, scientists have shed additional light on the relationship of Denisovans to other humans, finding new traces of Denisovan DNA in ancient and modern genomes.

Could early Homo pass the sniff test?

Thu, 16 Jun 2016 12:41:27 -0400

A reconstruction of Homo habilis at the Museum of Archaeology in Herne, Germany. At some point in the diversification of early Homo, facial features that resembled those of humans began to replace the ape-like countenance of early hominins. Credit: Lillyundfreya, CC BY-SA 3.0.

Like modern humans, early hominins walked upright and had opposable thumbs, but their faces were more ape-like, with flattened noses and protruding foreheads. It wasn’t until the evolution of the genus Homo that hominin faces began to look more human — flatter overall but with protruding noses. Along with changes in external appearance came internal changes as well, though these are less well understood as soft-tissue structures preserved in the fossil record are hard to come by. In a new study, researchers comparing both modern human and nonhuman primate nasal cavities offer some clues as to how our respiratory system evolved on the inside to compensate for the changes on the outside.

Ancient Indonesian tools made by mysterious inhabitants

Thu, 19 May 2016 22:12:43 -0400

These stone artifacts were found scattered on the ground near Talepu Hill on the island of Sulawesi, and date to at least 118,000 years ago. Credit: Erick Setiabudi.

The island of Sulawesi is one link in a chain of islands between mainland Asia and Australia, and was likely an important stepping stone in human dispersal from Eurasia through Oceania to Australia. Previous research has placed modern humans on Sulawesi as early as 40,000 years ago, but scientists have now dated a set of stone tools to at least 118,000 years ago, suggesting humans occupied the island far earlier than thought.

Underwater archaeology reveals pre-Clovis people butchered mastodon in Florida

Fri, 13 May 2016 13:20:49 -0400

Team member Neil Puckett of Texas A&M University surfaces from the dive excavation in Florida with a 14,550-year-old limb bone from a juvenile mastodon. Credit: Brendan Fenerty.

Following the discovery of stone tool artifacts uncovered near Clovis, N.M., in 1932, archaeologists have thought that the people who made the tools — named the Clovis people — were the first to populate the Americas, about 13,500 years ago. But evidence has been mounting for cultures even older than the Clovis, with archaeological sites and artifacts older than 14,000 years found as far south as Chile and genetic evidence dating the first incursions into North America to about 15,000 years ago. Now, a new study reporting on an underwater archaeological excavation at a site in Florida that dates to 14,550 years ago is adding more evidence of pre-Clovis people, and shedding light on how they may have spread across the Americas.

Humans evolved early to be more efficient sleepers

Tue, 19 Apr 2016 15:41:39 -0400

Chimpanzees sleep an average of 11.5 hours per day, usually in a tree nest, whereas humans snooze for just seven hours. Credit: Kathelijne Koops, University of Zurich, Switzerland.

We humans spend about a third of our lives asleep. While that might sound like a lot, we require less sleep than most mammals. In a new study, researchers have quantified how much less sleep we need than other primates, and the findings may offer clues to how and when human sleep patterns evolved.

China's Red Deer Cave people may have survived until the last ice age

Mon, 18 Apr 2016 17:41:16 -0400

Artist's reconstruction of a Red Deer Cave man. Credit: Peter Schouten.

In the 1980s, a collection of bones from very small hominids was excavated from a cave in southwestern China, alongside a number of bones from a species of large red deer. Nicknamed the “Red Deer Cave people,” but not yet declared a distinct species, researchers previously dated radiocarbon in the sediments where the bones were found to about 14,000 years ago. In a new comparative study, the same team has now found that the hominids from which the bones came appear to have been similar to — although far smaller than — Homo habilis and Homo erectus, suggesting it could indeed be a new species.

Rising Star cave hominid walked its own way

Fri, 08 Jan 2016 08:04:08 -0500

The hand and foot of the newly discovered hominin species, Homo naledi. Credit: Peter Schmid/Will Harcourt-Smith.

After dozens of human-like fossils were discovered in a cave in South Africa last summer, they were declared distinct enough to be classified as a new species: Homo naledi. Two recent studies looking in detail at the new hominid’s hands and feet are revealing how different they were from other early humans.

South African cave system reveals new early human ancestor

Wed, 23 Dec 2015 13:01:21 -0500

Homo naledi's head as reconstructed by paleoartist John Gurche, who spent about 700 hours recreating it from bone scans. Credit: Mark Thiessen/National Geographic, for the October 2015 issue of National Geographic magazine.

The Rising Star Cave system, near Johannesburg, South Africa, has never been extensively explored because of its complexity and extremely narrow passages. But in 2013, when a team of intrepid cavers from the Speleological Exploration Club of South Africa pushed through a narrow 12-meter-long chute with an average width of only 20 centimeters, they discovered a chamber filled with what looked like human bones.

Human hands not most advanced

Thu, 12 Nov 2015 09:08:44 -0500

With longer fingers, chimpanzees have lower thumb-to-finger-length ratios than humans. Credit: Almécija et al., Nature Communications, 2015, CC BY 4.0.

Compared to chimpanzees, our recent evolutionary cousins, humans have long thumbs relative to our fingers. This trait has endowed our ancestors and us with a particular talent for grasping and working with tools, which likely contributed to our evolutionary success over the last several million years since splitting off from the last common ancestor (LCA) shared by the two groups. But rather than humans having the more evolved hand — a prevailing hypothesis since the late 20th century — a new study suggests that chimps’ hands, with lower thumb-to-finger-length ratios, have changed considerably more.

Butchery or trampling? Controversy marks ancient animal bones

Mon, 02 Nov 2015 11:18:24 -0500

Marks on a fossilized rib bone, one of the two controversial bones. Credit: Zeresenay Alemseged.

At some point in early human evolution, our ancestors began regularly hunting, butchering and consuming meat from large game, a protein- and fat-rich change in diet that may have helped fuel the development of a larger and more complex brain. When exactly this change took place has long been a matter of debate. Stone tools from 2.6 million years ago have offered the most solid evidence to date. But the discovery several years ago of a pair of 3.4-million-year-old animal bones in Dikika, Ethiopia, that appear to show cut marks indicative of butchery could push the date back significantly. Some researchers think the bones were marked by incidental trampling, however, not by early humans.

Benchmarks: July 11, 1997: Neanderthal DNA unraveled

Tue, 27 Oct 2015 12:39:33 -0400

Artist's rendering of Neanderthals. Credit: art by Randii Oliver.

On July 11, 1997, six scientists announced they had sequenced DNA from a Neanderthal fossil. It was the first time anyone had analyzed the genetics of an extinct hominin, and the findings gave paleoanthropologists a new perspective on Neanderthals’ place in the human family tree.

Earliest stone tools pre-date Homo

Mon, 24 Aug 2015 10:26:18 -0400

Sonia Harmand examines a primitive stone tool found in Kenya. Credit: MPK-West Turkana Archaeological Project.

Tool making is thought to be one of the defining characteristics of the transition from apes to early man. Now, the discovery of a set of stone tools dating to 3.3 million years ago is pushing back this critical stage of early human development by more than half a million years, and, according to one researcher involved, disproving “the long-standing assumption that Homo habilis was the first tool maker.”

The new anthropology: From bones and stones to biology and behavior

Tue, 05 May 2015 09:25:52 -0400

Grasslands in Tanzania's Serengeti National Park in East Africa may be similar to some of the habitats in which early humans evolved. Credit: ©Noel Feans, CC BY-2.0.

Paleoanthropology has traditionally been a dusty science, with new discoveries usually involving bones, teeth and stone tools painstakingly picked from the dirt. But in recent years, the field has embraced a more integrated approach to understanding our ancestors, studying them not just in terms of their skeletons and artifacts, but also their biology and behavior as formerly living, breathing organisms.

Scientists sequence oldest modern human genome to date

Mon, 05 Jan 2015 16:34:49 -0500

The Ust'-Ishim femur belonged to a modern human man who lived in western Siberia roughly 45,000 years ago. Credit: Bence Viola, MPI EVA.

A chance fossil find along a Russian river has provided researchers with the oldest genomic data ever sequenced from a modern human. The fossil, a nearly complete left femur, was pulled from a bank along the Irtysh River near the Ust’-Ishim district in western Siberia in 2008 by a Russian artist before it made its way to scientists.

Ancient cave art discovered in Indonesia

Mon, 05 Jan 2015 16:06:52 -0500

Stencils of a splayed human hand in an Indonesian cave date to about 40,000 years ago. Credit: Kinez Riza.

Europe has long been thought to have been the home of the oldest art in the world — including a stash of cave paintings in northern Spain that date to about 40,000 years ago — but a new dating technique may put Indonesia on the ancient art map as well.

Down to Earth With: Naomi Levin

Tue, 09 Dec 2014 13:29:16 -0500

Naomi Levin is a stable isotope geochemist. Credit: Will Kirk/Homewood Photography, Johns Hopkins University.

Stable isotope geochemist Naomi Levin, a native New Yorker, says she could easily imagine alternate career paths that would have been more in line with her urban roots. But the hands-on nature of both fieldwork and lab work lured her to geology and anthropology. And after working with a string of prominent geochemists — including Jay Quade, Thure Cerling and John Eiler — as a graduate student and post-doctoral researcher, Levin has quickly moved to the top of her field.

Dating the demise of the Neanderthals

Tue, 09 Dec 2014 11:10:37 -0500

Researchers Thomas Higham and Katerina Douka examine samples at a Neanderthal site in Abric Romani, Spain. Credit: Thomas Higham.

For a time, _Homo sapiens _and Neanderthals shared space in Europe, likely interacting and possibly interbreeding, but roughly 40,000 years ago the Neanderthals died out for unknown reasons. Pinpointing the extinction of the Neanderthals has proved difficult due to limitations in carbon-14 dating techniques, the accuracy of which declines in samples approaching and older than 50,000 years due to a decreasing amount of carbon-14 for testing. Now, using a new dating technique, scientists have confirmed that Neanderthals likely disappeared between 41,000 and 39,000 years ago.

Down to Earth With: Molecular biologist Sarah L. Anzick

Fri, 03 Oct 2014 14:18:33 -0400

Sarah L. Anzick was 2 years old when a Clovis burial site was found on her family's ranch in 1968. In 2014, she was part of the team that analyzed the infant's genome, which shows that modern Native Americans evolved in the Americas. Credit: Sarah L. Anzick.

In May 1968, when Sarah L. Anzick was 2 years old, the 12,600-year-old remains of a male toddler were discovered at the base of a bluff on her family’s ranch near Wilsall, Mont. The Anzick infant — one of just a handful of ancient skeletons to have been found in North America and the only known Clovis burial site — had been carefully buried with more than 100 stone and bone tools.

Out of Africa, time and again

Tue, 02 Sep 2014 13:36:35 -0400

A study of genetic data and the shapes of skull bones among indigenous populations from Asia, Australia and Melanesia suggests modern humans left Africa in multiple waves separated by tens of thousands of years. Credit: ©Gossipguy, CC BY-SA 3.0.

There is widespread agreement among scientists based on fossil and geochemical evidence that modern humans evolved in Africa between 200,000 and 100,000 years ago before spreading around the world. But the timing and route of this dispersal, and whether it occurred as a single exodus or in multiple pulses, remain contested. Now, a new study throws its weight behind a multiple-dispersal hypothesis, suggesting a first group of modern humans left Africa as early as 130,000 years ago, followed by a second about 80,000 years later.

Spanish cave reveals possible new Neanderthal ancestor

Thu, 19 Jun 2014 14:40:44 -0400

Skull 17 from the Sima de los Huesos site in Spain. Credit: ©Javier Trueba/Madrid Scientific Films.

A trove of thousands of hominin fossils unearthed from a prolific cave in northern Spain is proving a boon for paleoanthropologists studying human evolution and the early ancestors of Neanderthals. The fossils are proving difficult to categorize as a recognized species, however, raising the prospect of a new category of hominin for these Middle Pleistocene specimens.

Fieldwork revises ice-free corridor hypothesis of human migration

Tue, 08 Apr 2014 19:26:45 -0400

Researchers sample a boulder known as a glacial erratic to determine when it was deposited. Credit: Lionel Jackson.

The existence of an ice-free corridor through Canada during the climax of last glaciation, which allowed the first Americans to cross the Bering land bridge from Siberia and move south (about 13,000 years ago), has long been postulated in North American archaeology. Now, research based on the exposure ages of glacial rocks found in the corridor suggests a puzzling conclusion — that the open pathway closed several thousand years prior to 20,000 years ago and didn’t open again until between 13,000 and 12,000 years ago, well after the first Americans were in the Americas.

From boom to bust in Neolithic Europe

Thu, 20 Feb 2014 10:11:20 -0500

Even after the introduction of agriculture to Europe about 8,500 years ago, growing Neolithic communities still experienced large population swings. Copyright Mary Harrsch, Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic

As agricultural practices spread from the Fertile Crescent across Europe, gradually expanding west and north starting about 8,500 years ago, they brought increased and localized food production to a continent where nomadic hunter-gatherers had long made their living subject to the whims of climate and the environment. With agriculture, long-term settlements developed, fertility rates rose and, thus, populations grew steadily. Or at least that’s been the conventional wisdom.

Science denialism: The problem that just won't go away

Mon, 18 Nov 2013 14:39:37 -0500

Editor's Note: Traditionally, EARTH has published a "highlights" or "year in review" issue at the end of the year. This year, we decided to try a new approach: We asked our staff and some frequent contributors to write a short commentary on something that grabbed their attention in 2013. We gave everyone carte blanche. What follows is a collection of extremely varied, often very personal insights into how the planet impacted each individual. You can find some online this month, but for the full grouping, you'll have to buy the issue here or subscribe.

Hydrological models locate ancient human migration routes

Wed, 30 Oct 2013 17:34:49 -0400

Google Earth image of North Africa encompassing Algeria, Tunisia, Libya and Egypt, with the three main rivers predicted by the researchers' simulations shown flowing toward the Mediterranean as they would have 100,000 years ago. The green dots correspond to archaeological finds from that period. Courtesy of Google Earth and Jorge Ramirez

Archaeologists and geologists have long hypothesized that major river systems flowed north through the Sahara Desert about 100,000 years ago. These rivers would have provided a sort of network of “green corridors” across the Sahara that early humans could have traversed as they migrated out of Africa. Ancient lake records, fossil river systems, and radioisotope data have offered evidence for the existence of flowing water in the region. Now, a team of researchers has developed a novel paleohydrogeological and hydraulic modeling approach to help confirm the existence and location of these ancient rivers. Their research complements existing evidence that all three of these rivers could have provided the necessary water and food sources for migrating humans.

Hominin skull discovery fuels debate about early human evolution

Thu, 17 Oct 2013 14:32:28 -0400

The face of Dmanisi Skull 5. Courtesy of Guram Bumbiashvili, Georgian National Museum

The Dmanisi Skull 5 early _Homo _cranium and herbivore fossil remains in situ at the discovery site. Courtesy of Georgian National Museum

Artist's reconstruction of the original _Homo erectus _owner of Dmanisi Skull' 5. Courtesy of J.H. Matternes

The Dmanisi site (in the upper right of the photograph), lies beneath a small medieval town about 85 kilometers from Georgia's capital Tbilisi. The site sits on top of a lava flow and covers some 50,000 square meters. Courtesy of Fernando Javier Urquijo

Five different hominid skulls have been found at Dmanisi so far, all exhibiting slightly different traits. The newest one, Skull 5 on the far right, is believed to be _Homo erectus_. The question is whether all five are _Homo erectus_ or are different species. Courtesy of M. Ponce de León and Ch. Zollikofer, University of Zurich, Switzerland

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.

Modern humans arrived in South Asia 25,000 years later than previously thought?

Wed, 12 Jun 2013 12:59:14 -0400

Stone tools and artifacts dated to 40,000 to 50,000 years ago from South Asia (shown) resemble slightly older finds in South and East Africa. Illustrations by Dora Kemp, McDonald Institute for Archaeological Research, Cambridge University

Figuring out when modern humans left Africa and migrated throughout the world is a complicated task. For example, some evidence suggests modern humans may have migrated out of Africa and into Asia as early as 120,000 years ago. Further evidence puts modern humans in India and other parts of South Asia prior to the super-eruption of Mount Toba in Sumatra, which took place 74,000 years ago. However, new research suggests that modern humans may not have reached South Asia until well after the Toba eruption.

Oceanic records paint a more complex picture of human evolution

Tue, 28 May 2013 17:17:06 -0400

It has long been hypothesized that human ancestors evolved the ability to walk upright — a feature that appeared about 6 million years ago — in response to African landscapes changing from forests to grasslands. Now, a group of scientists has assembled the most continuous timeline of landscape evolution and grassland development over the last 12 million years near the African Rift Valley in northeastern Africa — and the timeline contradicts conventional hypotheses.

New dates place Spanish cave art as oldest in Europe

Thu, 14 Jun 2012 12:31:02 -0400

Scientists have redated art in El Castillo Cave in Spain. The new dates place a hand stencil at earlier than 37,300 years ago and a red disk at earlier than 40,600 years ago — the oldest cave paintings in Europe. Image courtesy of Pedro Saura

The Panel of Hands in El Castillo Cave. Scientists have found a new date for a hand stencil: It is at least 37,300 years old. Image courtesy of Pedro Saura

Researchers removing calcite samples for dating from Tito Bustillo Cave, Spain. New dates put the art at between 29,000 and 36,000 years old. Image courtesy of Rodrigo De Balbín Behrmann

But were the artists modern humans or Neanderthals?

Scientists have studied Paleolithic cave art for more than a century, but new research suggests paintings and carvings in some Spanish caves are thousands of years older than previously thought, which would make them the oldest cave art in Europe. The new evidence has left researchers wondering if the artists were modern humans or Neanderthals.

Voices: Defending science: The link between creationism and climate change

Wed, 25 Apr 2012 17:24:04 -0400

What do creationists and climate change deniers have in common? Over the past few years, this riddle has been on our minds a lot at the National Center for Science Education, a nonprofit that has fought for more than a quarter-century to defend the teaching of evolution in the public schools. Now, we’re expanding to defend the teaching of climate change — and with it, science in general.

Running into the brick wall of Creationism again

Fri, 20 Jan 2012 03:51:09 -0500

I had recently moved to a new community and begun a new job. One night I was dining with some potential new friends. Upon learning that I am both a Christian and a passionate student of geology, one of my dinner mates proclaimed, “So, I suppose you believe in evolution, right? Well, I need to let you know that I HATE evolution.” I somehow managed to keep my cool. “And exactly why do you hate evolution?” I queried. “My minister has taught us that it is false Christian teaching,” she retorted. By that time, I could not hold myself back. I initiated some strong discussion aimed at educating.

Voices: An old Earth for all Muslims but how does evolution fit in?

Fri, 20 Jan 2012 03:51:09 -0500

It’s no secret that many of the protests and rebellions in North Africa and the Middle East this year have been dominated by globally connected, young, educated Muslims. One of the stated goals of many of these young people is improving the science and technology programs in their countries. They understand that to compete in the global marketplace, strong science and technology programs are necessary. That bodes well for these countries’ futures. But there are still threats to the scientific futures of these nations — including the quiet but growing population of people who reject the principles of evolution.

Voices: Redefining humanity through energy use

Fri, 20 Jan 2012 03:51:09 -0500

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.

"Missing link" or major hype?

Thu, 05 Jan 2012 06:41:58 -0500

Jørn Hurum, one of the scientists that announced the fossil find on Tuesday. 2009 AETN.

A squirrel-sized primate that lived 47 million years ago in the rainforests of Europe may be the common ancestor of monkeys, apes and humans, according to scientists who announced the discovery of the “missing link” fossil yesterday at a press conference. The well-preserved fossil has been at the center of a whirlwind PR blitz, including a History Channel documentary airing next week and an upcoming book — yet some scientists say the bones don’t live up to the hype.

Before Lucy: Older hominid Ardi challenges thinking about human evolution

Thu, 05 Jan 2012 06:41:58 -0500

An artist's reconstruction of _Ardipithecus ramidus_. Illustration 2009, J.H. Matternes

Reconstruction of the 'Ardi' skeleton. Illustration 2009, H.J. Matternes

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. Despite the similarity in size, Ardipithecus didn’t look or act like a chimpanzee, which the researchers say suggests that the last common ancestor of chimpanzees and humans was not chimpanzee-like either. As a result, they said, scientists may need to rethink some long-standing ideas about the origins of the human family tree.

Benchmarks: February 12, 1809: Charles Robert Darwin is born - and so began modern biology

Thu, 05 Jan 2012 06:41:58 -0500

During his five weeks in the Galapagos Islands, Darwin collected many samples, some of which are shown in the traveling Darwin exhibit. Denis Finnin, American Museum of Natural History

As celebrations in honor of Charles Darwin’s 200th birthday are in full swing this month, a revolution is rumbling through evolutionary biology. In the 150 years since Darwin published his landmark book “On the Origin of Species,” scientists have elucidated much of the molecular underpinnings of how evolution — natural selection, punctuated equilibrium and the like — works. One of the pillars of evolutionary theory has long been the notion that the DNA sequence is the only molecular information that is passed on from one generation to the next. But over the last decade or so, an avalanche of studies has shown that epigenetic settings — specific markings on the genome that can turn a gene on or off — can be heritable as well. Moreover, some of these epigenetic changes are triggered by environmental influences, such as stress or diet, suggesting that there is much more to evolution than just random variation followed by selection of the fittest.

Benchmarks: November 22, 1859: "On the Origin of Species" published

Thu, 05 Jan 2012 06:41:58 -0500

Ben Tillman, University of Sydney Library

Asa Gray was one of Charles Darwin's most vocal proponents in the United States in the late 19th century. Library of the Gray Herbarium, Harvard University

About a decade ago, I was fortunate enough to hold in my hands a first edition of Charles Darwin’s “On the Origin of Species.” The green cover was cracked and frayed. The cardboard backing protruded through the torn corners. I put the book down and stared at it in awe. The owner of this book was Asa Gray, one of America’s greatest botanists, an important early American supporter of natural selection, and a friend of Darwin’s.

Creationism creeps into mainstream geology

Thu, 05 Jan 2012 06:41:58 -0500

Field trip 409 at Red Rock Canyon Open Space near Colorado Springs, Colo. Steven Newton

Steve Austin, chair of the geology department at the Institute for Creation Research, was one of the field trip leaders. Steven Newton

It was easy to miss the part where the field trip leader said the outcrop formed during Noah’s Flood. After all, “During these catastrophic flood flows, turbulent, hyperconcentrated suspensions were observed to transform laminar mudflows” sounds like a reasonable description of alluvial fan processes. And “massive marine transgression” sounds scientific enough. But when creationist geologists use those phrases, they take on a very different meaning.

Earliest fossil evidence of humans in Southeast Asia?

Thu, 05 Jan 2012 06:41:58 -0500

Archaeologists excavating Callao Cave in the Philippines. Armand Salvador Mijares

This 67,000-year-old foot bone may be evidence of the oldest-known humans in the Philippines. Armand Salvador Mijares

Modern humans reached the islands of Southeast Asia by approximately 50,000 years ago, but our ancestors’ journey was not easy. Even during times of low sea level, a voyage to some of these islands would have required crossing open water, leaving many scientists to wonder how humans arrived on the most isolated islands. Now the story is growing more complicated: A group of archaeologists has discovered a 67,000-year-old foot bone that they say represents the earliest-known presence of humans in the northern Philippines and may be among the oldest-known traces of modern humans in all of Southeast Asia — that is, if the bone truly belongs to Homo sapiens. The bone’s small size and unusual features make it difficult to determine exactly which species of Homo it was — Homo sapiens, Homo floresiensis or something else?

Games: In Spore, cells divide and conquer

Thu, 05 Jan 2012 06:41:58 -0500

A Spore creation explores the primordial soup of the Cell phase.

In the Creature phase, players are constantly tweaking their creations, adding or removing wings, eyes or limbs.

Spore's Tribal phase involves defending your species' hut, fire and food.

Spore Electronic Arts

I’m no evolutionary biologist, but I’m pretty sure that you can’t just add a horn or an extra ear to your own body whenever you feel like you need a leg up on the competition, so to speak.

Highlights of 2010: What does it mean to be human?

Thu, 05 Jan 2012 06:41:58 -0500

The sequencing of the Neanderthal genome in 2010 helps scientists answer the age-old question

Calling someone a “Neanderthal” in the heat of an argument may not be such an insult after all. Last May, scientists announced they had completed a draft sequence of the Neanderthal genome, and found evidence that Neanderthals and modern humans interbred, likely sometime 80,000 to 50,000 years ago when modern humans left Africa and ventured into Eurasia — Neanderthal territory. Those encounters left a mark in the modern gene pool: As much as 4 percent of the DNA in people with European or Asian ancestry may be Neanderthal DNA, the researchers reported in Science.

Homo erectus footprints show modern way of walking

Thu, 05 Jan 2012 06:41:58 -0500

Fossil footprint, likely left by _Homo erectus_, found in Kenya. Image courtesy of Professor Matthew Bennett, Bournemouth University

An optical laser scan shows three footprints from the _Homo erectus_ footprint trail mixed with a range of other animal prints. Image courtesy of Professor Matthew Bennett, Bournemouth University

Bennett with the trail of fossil _Homo erectus_ footprints in northern Kenya. Image courtesy of Professor Matthew Bennett, Bournemouth University

In the Great Rift Valley in northern Kenya, researchers have discovered a cluster of footprints that look almost exactly like those you or I might leave on a sandy beach. These prints, however, were left by early hominins more than 1.5 million years ago, making them the oldest known evidence of fully modern bipedalism.

It's all in the wrist: Humans lack a knuckle-walking ancestor

Thu, 05 Jan 2012 06:41:58 -0500

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. Therefore, the researchers say, humans probably did not evolve from a knuckle-walker but instead from a more general tree-dweller.

Move over Homo habilis: Early human evolution remapped

Thu, 05 Jan 2012 06:41:58 -0500

The cranium of the juvenile_ Australopithecus sedib_a. Brett Eloff, picture courtesy of Lee Berger and the University of the Witwatersrand

Lee Berger of the University of the Witwatersrand with the _Australopithecus sediba_ skull. Picture courtesy of Lee Berger and the University of the Witwatersrand

_Australopithecus sediba_ skull reconstruction. ESRF, picture courtesy of Lee Berger and the University of the Witwatersrand

Reconstructed pelvises of the juvenile male (left) and adult female (right) _Australopithecus sediba_ specimens. Peter Schmid, courtesy of Lee Berger and the University of the Witwatersrand

Right hand of the adult female _Australopithecus sediba_ against a modern human hand. Peter Schmid, courtesy of Lee Berger and the University of the Witwatersrand

Mapping out how one species of early hominin branches to another has always been complicated by the rarity of complete specimens and lack of precise dating methods for fossils more than 50,000 years old. Now researchers studying the braincase, pelvis, hands and feet of a primitive hominin — which lived about the same time early Homo species were evolving — are taking full advantage of a rare, nearly complete assemblage of fossils and a new highly accurate dating method to once again redraw humankind’s ancient lineage.

New cousin joins primate family tree - but it's also no missing link

Thu, 05 Jan 2012 06:41:58 -0500

Teeth and jaw remains of _Afradapis_. Erik Seiffert et al., Nature 2009

Blogging on EARTH

Darwinius — the purported primate “missing link” that made headlines last spring — is back, sort of. Scientists have now found a close cousin of the primate — and they say the new fossil is no more a missing link than Darwinius was.

Not the oldest hominid

Thu, 05 Jan 2012 06:41:58 -0500

At 4.4 million years old, Ardipithecus ramidus is not the oldest known hominid. In 2002, scientists announced they had discovered a hominid skull from the Sahel region of Chad. Named Sahelanthropus tchadensis, the species dates to about 7 million years ago. And a few years earlier, scientists had announced the discovery of several hominid fossils, including a thigh bone, in Kenya that dated to about 6 million years ago. They named the species Orrorin tugenensis.

Paleo Patrol: A hominin family reunion at the Smithsonian

Thu, 05 Jan 2012 06:41:58 -0500

Erin Wayman (pictured in Cardiff, Wales) writes Paleo Patrol for EARTH. Spencer Wayman

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?

Paleo Patrol: Neanderthal genome offers clues on what makes us human

Thu, 05 Jan 2012 06:41:58 -0500

Erin Wayman (pictured in Cardiff, Wales) writes Paleo Patrol for EARTH. Spencer Wayman

Did “Clan of the Cave Bear” get it right after all?

Paleo Patrol: Primates of the Caribbean

Thu, 05 Jan 2012 06:41:58 -0500

Erin Wayman (pictured in Cardiff, Wales) writes Paleo Patrol for EARTH. Spencer Wayman

The only monkeys you’ll find on the islands of the Caribbean today were brought there (intentionally or not) by people. But just a few thousand years ago, thriving populations of primates existed across the Caribbean. The discovery of exceptionally well-preserved monkey bones in the Dominican Republic is helping researchers better understand the evolutionary history of these now-extinct primates.

Paleo Patrol: Was mankind's first leap in a forest or savanna?

Thu, 05 Jan 2012 06:41:58 -0500

Erin Wayman (pictured in Cardiff, Wales) writes Paleo Patrol for EARTH. Spencer Wayman

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.

Questions arise over earliest evidence of human tool use

Thu, 05 Jan 2012 06:41:58 -0500

Possibly stone tool-modified bones from Dikika, Ethiopia. Dikika Research Project

Two parallel cut marks possibly made by stone tools cutting into tissues on the rib of a cow-sized or larger ungulate. Dikika Research Project

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. However, a new study challenges this interpretation and says that the marks were not made by early humans, but came instead from sediments grinding against the surface of the bones.

Texas Board of Education votes to strike amendment questioning evolution

Thu, 05 Jan 2012 06:41:58 -0500

Blogging on EARTH

Evolution will still be taught in Texas. After months of proposed amendments, statements by special interest groups and lengthy debate, the Texas Board of Education voted 8-7 today to strike language from its curriculum that required students to “analyze and evaluate the sufficiency or insufficiency” of common ancestry, a major tenant of the theory of evolution.

The Coconino's starring role in the creationist-geologist battle

Thu, 05 Jan 2012 06:41:58 -0500

Contact of the Toroweap Formation (top) and the Coconino Sandstone (bottom) in the Grand Canyon. Steven Newton

Arizona’s Coconino Sandstone — a deposit seen in the Grand Canyon and elsewhere — plays a central role in the creationist argument that the upper rocks of the Grand Canyon were deposited during Noah’s Flood. In fact, the posters presented by students and faculty of Cedarville University at the 2010 annual meeting of the Geological Society of America (GSA) in Denver, Colo., pushed a consistent narrative: The Coconino did not form in an eolian (wind-blown) environment. Why is this so important? If the Coconino is eolian, it means the Flood did not happen.

The vital statistics

Thu, 05 Jan 2012 06:41:58 -0500

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:

Third hominin coexisted with modern humans and Neanderthals

Thu, 05 Jan 2012 06:41:58 -0500

Outside of Denisova Cave, where 'X-woman' was discovered. Bence Viola

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.