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Scientists have discovered that the extinct megalodon shark was warm-blooded, as indicated by the isotopes in its tooth enamel. Their research suggests that the megalodon could maintain a body temperature about 13 degrees Fahrenheit warmer than the surrounding water, a significant difference compared to other contemporary sharks. A killer, yes. But analysis of tooth minerals reveals how the warm-blooded predator maintained its body temperature. Researchers have determined that the extinct megalodon shark was warm-blooded, able to maintain its body temperature higher than the surrounding water. However, the energy needed for this temperature regulation might have contributed to the megalodon’s extinction...

Species of the horse genus Equus first appeared on the North American continent during the Pliocene era and spread to and across Eurasia beginning around 2.5 million years ago. They disappeared from the Western Hemisphere during the megafauna extinction event at the end of the Pleistocene and the last glacial period. The return of equids to the Americas through the introduction of the domestic horse (Equus caballus) is documented in the historical literature but is not explored fully either archaeologically or genetically. Historical documents suggest that the first domestic horses were brought from the Iberian Peninsula to the Caribbean in...

It can be shown for the first time after a near complete skull of Australopithecus anamensis was found in Ethiopia. The ape-like adult male was about 5ft and weighed about 100lbs. Females were about 3ft 5in and around 62lbs. An upper jaw was found first. Dr Yohannes Haile-Selassie, of Cleveland Museum of Natural History, told journal Nature: “I couldn’t believe my eyes when I spotted the rest. "It was a dream come true.” "This is a game changer in our understanding of human evolution during the Pliocene." Professor Fred Spoor, an expert in anatomy at London's Natural History Museum, said...

About 2.6 million years ago, an oddly bright light arrived in the prehistoric sky and lingered there for weeks or months. It was a supernova some 150 light years away from Earth. Within a few hundred years, long after the strange light in the sky had dwindled, a tsunami of cosmic energy from that same shattering star explosion could have reached our planet and pummeled the atmosphere, touching off climate change and triggering mass extinctions of large ocean animals, including a shark species that was the size of a school bus. The effects of such a supernova—and possibly more than...

Over the course of the past 200 million years, our planet has experienced four major geological periods (the Triassic, Jurassic and Cretaceous and Cenozoic) and one major ice age (the Pliocene-Quaternary glaciation), all of which had a drastic impact on plant and animal life, as well as effecting the course of species evolution. For decades, geologists have also understood that these changes are due in part to gradual shifts in the Earth’s orbit, which are caused by Venus and Jupiter, and repeat regularly every 405,000 years. But it was not until recently that a team of geologists and Earth scientists...

Researchers then scoured the globe for thin layers of radioactive isotopes in rock strata and in 1999 struck figurative gold: Samples from beneath the ocean revealed some hard metallic layers, known as ferromanganese crusts that form slowly over millions of years, containing iron-60, an isotope with a half-life of 2.6 million years -- so short that the material must be much younger than Earth. The iron-60 was in a stratum laid down 2.2 million years ago. Similar layers of iron-60 have since been found elsewhere in the oceans. Astronomers have also been scouring the skies for groups of stars that...

Millions of years ago, a series of nearby supernovae sent radiation and debris raining down to Earth. The events left traces of radioactive iron-60 embedded in the sea floor and even on the Moon, and now, researchers are saying they may have had life-altering effects on the early inhabitants of our planet. At just hundreds of light-years away, two major stellar explosions may have spurred changes to the environment, and even increased the rates of cancer and mutation.

An international team of scientists has found evidence of a series of massive supernova explosions near our solar system, which showered Earth with radioactive debris. The scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans. The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms, said research leader Dr Anton Wallner from The Australian National University (ANU). "We were very surprised that there was debris clearly spread across 1.5 million years," said Dr Wallner, a nuclear physicist in the ANU Research...

The researchers trace the fossil record, which illustrates a timeline placing multiple species overlapping in time and geographic space. Their insights spur further questions about how these early human ancestors were related and shared resources... The 1974 discovery of Australopithecus afarensis, which lived from 3.8 to 2.9 million years ago, was a major milestone in paleoanthropology that pushed the record of hominins earlier than 3 million years ago and demonstrated the antiquity of human-like walking. Scientists have long argued that there was only one pre-human species at any given time before 3 million years ago that gave rise to another...

400 PPM: What’s Next for a Warming Planet Concentrations of greenhouse gases in the atmosphere have reached this level for the first time in millions of years. What does this portend? » On May 2, after nightfall shut down photosynthesis for the day in Hawaii, carbon dioxide levels in the atmosphere touched 400 parts-per-million there for the first time in at least 800,000 years. Near the summit of volcanic Mauna Loa—where a member of the Keeling family has kept watch since 1958—sensors measured this record through sunrise the following day. Levels have continued to dance near that benchmark in recent...

Global warming five million years ago may have caused parts of Antarctica's large ice sheets to melt and sea levels to rise by approximately 20 metres, scientists report today in the journal Nature Geoscience. The researchers, from Imperial College London, and their academic partners studied mud samples to learn about ancient melting of the East Antarctic ice sheet. They discovered that melting took place repeatedly between five and three million years ago, during a geological period called Pliocene Epoch, which may have caused sea levels to rise approximately ten metres.