All articles tagged with #fossil record
New fossil evidence from Denmark suggests that ammonites survived up to 200,000 years after the asteroid impact that killed the dinosaurs, challenging the long-held belief that they went extinct simultaneously with the dinosaurs. The findings imply a delayed extinction possibly caused by long-term ecosystem disruptions, highlighting how fossil record interpretations can be revised with new discoveries.
A new theory suggests that the molecular clock, which estimates the timing of evolutionary events, may have sped up during major evolutionary transitions, potentially explaining the 30-million-year gap between the predicted age of the common ancestor of complex animals and their first fossil appearance, thus aligning Darwin's theory with fossil evidence.
Recent research questions Lucy's status as the direct ancestor of humans, suggesting other species like A. deyiremeda or A. africanus might be closer to our lineage, sparking debate among scientists about human evolutionary origins.
A study reveals that anacondas have maintained an average length of 13-16 feet for the past 12 million years, indicating their size has remained remarkably constant since the Miocene epoch, despite environmental changes and other species going extinct.
Researchers have discovered that many dinosaurs, including Protoceratops, likely laid soft-shelled eggs, which are less likely to fossilize, explaining their rarity in the fossil record. This finding, supported by chemical analysis, suggests soft eggshells were common even late in the dinosaur era and may have been used by marine predators like mosasaurs, indicating diverse reproductive strategies among prehistoric creatures.
New research suggests that sponges are the earliest animals on Earth, based on chemical evidence from over 541 million years ago, supporting the idea that they resemble our original animal ancestors.
A study of a 56-million-year-old fossil bird reveals that the ancestors of ostriches and emus were once capable of long-distance flight, challenging previous theories that their distribution was due to continental drift. Instead, these birds independently evolved flightlessness after arriving on different continents, with their ancestors being capable of extensive travel.
Scientists have successfully sequenced DNA up to 2.4 million years old from Greenland sediments, but the preservation of ancient DNA is limited by environmental factors, with ideal conditions being cold, dark, and dry. Theoretically, DNA could survive for about 6.8 million years under perfect conditions, but practically, the oldest meaningful DNA comes from much more recent specimens, such as Neanderthals and ancient human relatives. The potential for discovering older DNA remains, especially in cold environments like Antarctica, continues to excite researchers.
Scientists discovered that the ratfish, a primitive fish, has a unique appendage called a tenaculum with true teeth outside its head, challenging traditional views on tooth placement and suggesting more flexible dental systems in vertebrates.
Scientists have developed new genetic techniques to identify Denisovan fossils in the fossil record, successfully matching two ancient skulls from China to the Denisovan profile and suggesting the potential to discover more extinct human relatives through genetic phenotyping.
A paleontologist discovered the first known Silurian horseshoe crab, Ciurcalimulus discobolus, from Indiana, dating back around 424 million years, filling an 80-million-year gap in the fossil record and suggesting that horseshoe crabs persisted beyond the end Ordovician mass extinction.
Rising deep-ocean oxygen levels, driven by the spread of woody plants, around 390 million years ago facilitated the migration and diversification of marine animals into deeper habitats, significantly influencing evolutionary patterns among early vertebrates, with implications for understanding both ancient and modern oceanic oxygen dynamics.
Recent evidence suggests that life on Earth emerged much faster than previously thought, possibly within a few million years of the planet's formation, challenging the long-held view of a hellish, uninhabitable early Earth and emphasizing the need for open-minded research into the origins of life.
New fossils from Ethiopia reveal that early Homo and a previously unknown Australopithecus species co-existed around 2.6-2.8 million years ago, challenging the linear view of human evolution and suggesting a more complex, branching process during a critical period of environmental change.
Scientists have uncovered detailed fossils from southern Africa that reveal the rich ecosystems just before Earth's largest mass extinction at the end of the Permian period, providing new insights into which species thrived and which vanished, and offering a broader understanding of global extinction patterns.