All posts tagged: millionyearold

1.4 million-year-old footprints reveal an ancient group of human-sized hominins

1.4 million-year-old footprints reveal an ancient group of human-sized hominins

Published by Jenni Sidey

Eight large ancient human relatives crossed the same lakeshore about 1.43 million years ago. Their foot shape resembles Paranthropus boisei, but their large body size also fits Homo erectus. The tracks suggest that several adult males moved together, offering rare evidence of early group behavior. Eight ancient human relatives crossed a muddy lakeshore in northern Kenya about 1.43 million years ago. Their footprints survived together, preserving a rare moment of group movement that now challenges old ideas about their bodies and social lives. The 21 tracks were left by eight individuals at a site called GaJi10 near Lake Turkana. Their foot shapes resemble prints previously linked to Paranthropus boisei, a heavily built hominin known for its powerful jaws and large teeth. Yet the track-makers were unexpectedly large. Some may have stood close to 6 feet tall and weighed around 165 pounds, dimensions more often associated with Homo erectus. That tension makes the footprints difficult to assign with complete certainty. Their anatomy points toward Paranthropus, while their body size looks more like Homo. Kevin Hatala of …

World’s first right-hander could be this 550 million-year-old worm

World’s first right-hander could be this 550 million-year-old worm

Published by Jenni Sidey

Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. By signing up, you confirm you are 16+, will receive newsletters and promotional content and agree to our Terms of Use and acknowledge the data practices in our Privacy Policy. You may unsubscribe at any time. As anyone who’s grown up favoring their southpaw can attest, the world overwhelmingly caters to right-handers. The vast majority of humans (somewhere around 85-90 percent) are right-handed, a tendency influenced by a combination of genes and environment. But it turns out this long-known preference towards the right may go back much further than scientists once thought—hundreds of millions of years further back, in fact. This preference toward the right may have been shared by some of the oldest known multicellular organisms. That’s the core argument presented in a study published this week in the journal Scientific Reports. The international team of researchers examined over 100 well-preserved fossils of Spriggina floundersi, an ancient, inch-long worm-like animal that wriggled its way around southern Australia about …

574 million-year-old fossils reveal a lack of sex delayed evolution for millions of years

574 million-year-old fossils reveal a lack of sex delayed evolution for millions of years

Published by Jenni Sidey

Fern-like bodies once covered the seafloor, some stretching as tall as a person. Yet for millions of years, the animal world barely seemed to budge. That long pause has puzzled paleontologists for decades. The first large animals appeared during the Ediacaran Period. Early communities changed slowly, despite the arrival of multicellular life after billions of years dominated by microbes. However, a new analysis argues that part of the answer lies in how those early animals reproduced. It also points to how that reproductive strategy kept competition low. Researchers from the University of Cambridge say many of Earth’s earliest animals spread asexually, sending out connected clones by runner-like structures called stolons. In stable deep-water environments, that strategy worked well. But it also appears to have limited dispersal, softened competition, and slowed the pressures that usually drive evolution. “Life was pretty nice during the Ediacaran, so the need for sex was rather limited,” said lead author Dr Emily Mitchell from Cambridge’s Department of Zoology. “There was relatively little competition, so there was no real pressure to change …

Ancient teeth unlock million-year-old secrets of where early humans evolved

Ancient teeth unlock million-year-old secrets of where early humans evolved

Published by Jenni Sidey

Teeth are like tiny biological time capsules. They tell stories about ancient diets and environments long after their owners have died and landscapes have changed. After bones break down, tooth enamel stays hard and unchanged, even in fossilized teeth that have been buried under sediment and rock for millions of years and are now being uncovered by erosion or excavation. Tooth enamel forms when an animal is young, and it remains chemically stable for the rest of that animal’s life. The food an animal eats and the water it drinks during its youth leave chemical signals within the enamel. Because of that, hidden within the enamel of fossilized teeth, scientists can find traces of extinct forests, expanding savanna grasslands, shifting climates and evolving animal communities. A small group of oryx forage in the open savanna of Awash National Park in Ethiopia, with scattered acacia trees and dry grasses illustrating the park’s semi-arid environment. (CREDIT: Zelalem Bedaso) These clues from ancient meals are enabling scientists to reconstruct pictures of entire ecosystems, including forests, wetlands and grasslands that existed at the time. It’s …

1.9 million-year-old finding points to the earliest evidence of humans outside of Africa

1.9 million-year-old finding points to the earliest evidence of humans outside of Africa

Published by Jenni Sidey

When a stone sits on the Earth’s surface, cosmic rays quietly pepper it, leaving behind rare isotopes like tiny time stamps. Bury the stone deep enough, and that cosmic “printing press” shuts off. From there, those isotopes decay in a predictable way. In geology, that is as close as you get to a stopwatch. That stopwatch, along with two other independent clocks, has helped researchers build a sharper timeline for ‘Ubeidiya, an early prehistoric site in Israel’s Jordan Valley. The site has long mattered to anyone trying to map how early humans moved beyond Africa. A new study argues the site is at least 1.9 million years old, older than many past estimates and among the earliest known records of early humans outside Africa. The work was led by Prof. Ari Matmon of the Hebrew University of Jerusalem, Prof. Omry Barzilai of Haifa University, and Prof. Miriam Belmaker of the University of Tulsa. Their approach leaned on three dating methods that ask the same question in different ways: how old are the sediments and artifacts …

67 million-year-old fossil reveals the origin of freshwater fish hearing

67 million-year-old fossil reveals the origin of freshwater fish hearing

Published by Jenni Sidey

A tiny fossil fish from Alberta is forcing scientists to rethink a story that has sat quietly in textbooks for decades. It is a story about how freshwater fish rose to dominance, and how a few bones in the head may have helped them do it. In a paper, University of California, Berkeley paleontologist Juan Liu and colleagues describe a newly named fossil, Acronichthys maccagnoi. The fish lived about 67 million years ago. It measured only about 2 inches long. Yet it preserved something rare and powerful: a clear middle ear structure that lets many freshwater fish hear far better than most ocean fish. That structure is called the Weberian apparatus. It is a chain of tiny bones that links an air-filled bladder to the inner ear. In modern fish, that bony bridge expands hearing into higher pitches. It gives many freshwater species a sensory edge that still echoes today. Photograph, x-ray image, 3D segmentation, and locality map of †A. maccagnoi. (CREDIT: Science) A Freshwater Success Story Gets a New Beginning Roughly two-thirds of freshwater …