A new study could help resolve a longstanding debate about the origins of the first people to inhabit the Americas, researchers report in Science. The study relies on genetic information extracted from the tooth of an adolescent girl who fell into a sinkhole in the Yucatan 12,000 to 13,000 years ago.
Don't let their cute names fool you: The Mearns' pouch mouse and the delicate mouse can be dangerous. These and other rodents commonly harbor pathogens that can be deadly to humans. According to new research by Stanford Univ. scientists, populations of pathogen-carrying rodents can explode when larger animals die off in an ecosystem, leading to a doubling in the risk of potentially fatal diseases spreading to humans.
In a lifetime of fishing for winter steelhead, Oregon's Stan Steele has seen it get harder and harder to hook into hatchery-bred fish. A growing body of evidence is showing that his experience is not a fish story, but the result of natural selection. Wild fish retain the aggression that lands them on the end of a hook better than hatchery fish. Prodded by fishermen, scientists will now try to breed the bite back into hatchery steelhead.
The smallest, most abundant marine microbe, Prochlorococcus, is a photosynthetic bacteria species essential to the marine ecosystem. An estimated billion upon billion of the single-cell creatures live in the oceans, forming the base of the marine food chain and occupying a range of ecological niches based on temperature, light and chemical preferences, and interactions with other species.
Few Americans question that smoking causes cancer. But they express bigger doubts as concepts that scientists consider to be truths get further from our own experiences and the present time, an Associated Press-GfK poll found. Americans have more skepticism than confidence in global warming, the age of the Earth and evolution and have the most trouble believing a Big Bang created the universe 13.8 billion years ago.
Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists exploring large fields of impact glass in Argentina suggest that what happened on Earth might well have happened on Mars millions of years ago. Martian impact glass could hold traces of organic compounds.
From far away, the top of a leaf looks like one seamless surface; however, up close, that smooth exterior is actually made up of a patchwork of cells in a variety of shapes and sizes. Interested in how these cells individually take on their own unique forms, a team sought to pinpoint the shape-controlling factors in pavement cells, which are puzzle-piece-shaped epithelial cells found on the leaves of flowering plants.
As one of the most widely consumed and commercially important beverages on the planet, one would expect the experts to know everything there is to know about lager beer. But it was just a few years ago that scientists identified the South American yeast that somehow hitched a ride to Bavaria and combined with the domesticated Old World yeast used for millennia to make ale and bread to form the hybrid that makes lager or cold stored beer.
Why zebras have black and white stripes is a question that has intrigued scientists and spectators for centuries. A research team in California has examined this riddle systematically and have found that biting flies, including horseflies and tsetse flies, are the evolutionary driver for zebra stripes.
Fossil remains show that sometime around 252 million years ago, about 90% of all species on Earth were suddenly wiped out in what was the largest of this planet’s five known mass extinctions. But pinpointing the culprit has been difficult, and controversial. Now, a team of Massachusetts Institute of Technology researchers may have found enough evidence to convict the guilty parties, but you’ll need a microscope to see the killers.
Paleontologists studying fossilized feathers have proposed that the shapes of certain microscopic structures inside the feathers can tell us the color of ancient birds. But new research from North Carolina State Univ. demonstrates that it is not yet possible to tell if these structures, thought to be melanosomes, are what they seem, or if they are merely the remnants of ancient bacteria.
For four decades, polychlorinated biphenyls (PCBs) and heavy metals from nearby manufacturing plants flowed into New Bedford Harbor, creating one of the EPA’s largest Superfund cleanup sites. It’s also the site of an evolutionary puzzle: small Atlantic killifish are not only tolerating the toxic conditions in the harbor, they seem to be thriving there. In a new paper, researchers may have an explanation for their genetic resistance to PCBs.
The largest mass extinction in the history of animal life occurred some 252 million years ago, wiping out more than 96% of marine species and 70% of life on land. Multiple theories have aimed to explain the cause of what’s now known as the end-Permian extinction. But pinpointing the cause of the extinction requires better measurements of how long the extinction period lasted.
When people see a skunk, the reaction usually is “Eww,” but when they see a group of meerkats peering around, they often think “Aww.” Why some animals use noxious scents while others live in social groups to defend themselves against predators is the question that biologists in California have sought to answer through a comprehensive analysis of predator-prey interactions among carnivorous mammals and birds of prey.
A substantial fraction of the Neanderthal genome persists in modern human populations. A new approach applied to analyzing whole-genome sequencing data from 665 people from Europe and East Asia shows that more than 20% of the Neanderthal genome survives in the DNA of this contemporary group, whose genetic information is part of the 1,000 Genomes Project.
Insects may thrive in the warmer average temperatures predicted by climate models but are threatened by greater temperature variation also anticipated in many areas around the globe, a Yale Univ.-led study predicts. Scientists have tested the impact of temperature on 38 species of insects. The team coupled that data with historic climate data and climate projections for 2050 to 2059 in order to assess effects of temperature variability.
An international team of scientists have examined the earliest communities of large multicellular organisms in the fossil record to help answer this question of why life forms began to get larger about 580 million years ago. The research reveals that an increase in size provided access to nutrient-carrying ocean flow, giving an advantage to multicellular eukaryotes that existed prior to the Cambrian explosion of animal life.
"Where do new genes come from?" is a long-standing question in genetics and evolutionary biology. A new study from researchers at the Univ. of California, Davis, published in Science Express, shows that new genes are created from non-coding DNA more rapidly than expected.
A closer look at microbes reveals there is big business going on in their very small world, and sometimes we are part of the transaction. In a published report, an international team of researchers argue that microbes, like many animals, can evolve into savvy traders, selling high and buying low.
One of the most hotly debated issues in current human origins research focuses on how the 4.4-million-year-old African species Ardipithecus ramidus is related to the human lineage. “Ardi” was an unusual primate. Though it possessed a tiny brain and a grasping big toe used for clambering in the trees, it had small, humanlike canine teeth and an upper pelvis modified for bipedal walking on the ground.
An international research team has produced a high-quality genome sequence of a Neanderthal woman from a toe bone found in 2010 by Russian archaeologists. The genome will allow detailed insights into the relationships and population history of the Neanderthals and other extinct hominin groups.
Interplay between genes and the environment has been pondered at least since the mid-1800s. But until the arrival of modern genomic sequencing tools, it was hard to measure the extent that the environment had on a species’ genetic makeup. Now, researchers studying fruit flies that live on opposite slopes of a unique natural environment known as “Evolution Canyon” show the driving force in the gene pool is largely the environment.
Rain as acidic as undiluted lemon juice may have played a part in killing off plants and organisms around the world during the most severe mass extinction in Earth’s history. About 252 million years ago, the end of the Permian period brought about a worldwide collapse known as the Great Dying, during which a vast majority of species went extinct. The cause of such a massive extinction is a matter of scientific debate.
Scripps Institution of Oceanography researchers are unraveling the mechanisms behind a little-known marine worm that produces a dazzling bioluminescent display in the form of puffs of blue light released into seawater. This effect, produced by mucus, hasn’t been studied in more than 50 years. But two recent studies have helped reignite the quest to decode the inner workings of the worm’s bioluminescence.
Earth’s oldest sedimentary rocks are not only rare, but also almost always altered by hydrothermal and tectonic activity. The Pilbara district in Australia is a rare exception. A new study has revealed the well-preserved remnants of a complex ecosystem in a nearly 3.5 billion-year-old sedimentary rock sequence.