All articles tagged with #evolution
A CT-based study of two exceptionally preserved Neanderthal pelves shows childbirth-related pelvic features closely resemble modern humans, while walking-related traits differ, implying the pelvic evolution was driven more by birth and pelvic floor stability than a simple trade-off with locomotion and challenging the long-standing obstetrical dilemma hypothesis.
A large-scale comparison of more than 5,800 chromosome-scale genomes across 4,454 species reveals that animal genomes evolve along a limited set of irreversible 'evolutionary highways' shaped by fusion-with-mixing. This framework enables reconstructing ancestry, identifying lineages with distinctive genome architectures, and informing biodiversity conservation and future genome-evolution research.
A University of Vienna study shows sea anemones, despite lacking brains, use bilaterian-style bone morphogenetic protein (BMP) shuttling with Chordin to shape their bodies. This suggests the mechanism predates the cnidarian–bilaterian split about 600–700 million years ago, potentially rewriting how and when the human body plan evolved, although convergent evolution remains a possibility.
New fossil data and genetic analyses suggest the traditional three-genus classification of human relatives (Homo, Australopithecus, Paranthropus) doesn’t reflect true evolutionary branches, with evidence that Australopithecus and Paranthropus may not form real clades; some researchers propose folding them into an expanded Homo genus to better map our family tree, though this would erase familiar distinctions and require changes in language and interpretation of human evolution.
About 8% of the human genome comes from ancient retroviruses. A viral gene called syncytin was repurposed to form the placental barrier, and different mammal lineages independently co-opted viral genes to solve the same reproductive problem, showing how ancient infections helped shape our biology.
Scientists report the discovery of 55-million-year-old primate fossils in southwestern Wyoming, with unusual features that could reveal greater early primate diversity and offer fresh clues about primate evolution.
Dogs and cats diverged from early carnivoran ancestors about 42.5 million and 30 million years ago, respectively. The first true dog, Hesperocyon, appeared in North America, while the first true cat, Proailurus, arose in Eurasia. Both lineages trace back to miacids, early carnivorans, and all mammals share a Last Universal Common Ancestor (LUCA) from about 4 billion years ago. Genetically, humans are slightly closer to cats in chromosome arrangement than to dogs.
A new study of 81 archosaur fossils indicates crocodile ancestors were warm-blooded as recently as 66 million years ago before evolving back to cold-blooded, energy-saving metabolism that aided aquatic ambushes and helped them survive the dinosaur extinction.
New research argues that the scarcity of tiny non‑avian dinosaurs results from ecological competition with small mammals rather than physiology; energy-based models fail to predict the dinosaur size distribution, implying an ecological size floor. The study also notes that birds—dinosaurs that evolved flight—could become much smaller by exploiting new niches, suggesting a symmetrical dynamic: mammals kept dinosaurs from shrinking while flight unlocked tiny bird sizes.
New research suggests both crocodile and dinosaur–bird lineages began warm-blooded; modern crocodiles retain a warm-blooded‑like heart but low blood flow, implying their ancestors were warm-blooded. The crocodile lineage then reverted to cold-blooded metabolism around 66 million years ago to enable long breath-holds as aquatic ambush predators, while birds remained warm-blooded and flight-capable—rewriting the deep evolutionary story of archosaurs.
Researchers used CT scans to examine 43 crocodilian species (both living and extinct) and found that the brains and inner-ear structures have changed very little over about 100 million years, suggesting an exceptionally effective brain design that helped these reptiles endure climate shifts and mass extinctions.
New analysis places LUCA—the Last Universal Common Ancestor—on Earth about 4.2 billion years ago, roughly 400 million years after Earth's formation, based on genetic mutation rates and shared cellular machinery. The study suggests LUCA was a simple prokaryote with an immune system and likely lived in a recycling microbial ecosystem, meaning all modern life traces back to this ancient ancestor, while the exact path from LUCA to later life remains to be fully understood.
A study suggests that fecal pellets from early animals helped deliver nutrients to deep ocean waters, feeding the biological pump and enabling larger, more diverse Cambrian life; by tracing fossil coprolites and the evolution of digestive systems, researchers propose a positive feedback loop where bigger animals produced bigger poop that further spurred diversification.
Researchers compile a global database of coprolites to show a Cambrian fecal revolution: as guts evolved from simple to complex, feces grew in size and variety, forming nutrient-rich pellets and carpets that sank into deeper waters, reshaping ecosystems and likely accelerating the emergence and diversification of modern marine life.
ScienceAlert's This Week in Science rounds up: a FIU-led study finds some people attract more mosquitoes due to skin scents and microbes; the Sun’s surface is revealed in unprecedented detail with swirling vortices; researchers identify bacteria behind the 'farm effect' on immunity; humans are a predator even bears and mountain lions fear; GLP-1 drugs may lower the risk of age-related macular degeneration; and a review suggests ancient feces helped kickstart the evolution of complex life.