New research led by the University of Washington challenges the 140-year-old assumption that finding fossilized remains of prehistoric animals with such teeth meant the animals were living in grasslands and savannas. Instead it appears certain South American mammals evolved the teeth in response to the gritty dust and volcanic ash they encountered while feeding in an ancient tropical forest.
Our ancestors evolutionarily split from those of rhesus monkeys about 25 million years ago. Since then, brain areas have been added, have disappeared, or have changed in function. This raises the question: Has evolution given humans unique brain structures? Previous research has been inconclusive, but by combining different research methods, researchers in The Netherlands now say they have the first piece of evidence that could prove that humans have unique cortical brain networks.
"The sounds uttered by birds offer in several respects the nearest analogy to language," Charles Darwin wrote in "The Descent of Man" (1871), while contemplating how humans learned to speak. Language, he speculated, might have had its origins in singing, which "might have given rise to words expressive of various complex emotions." Now researchers from Massachusetts Institute of Technology, along with a scholar from the University of Tokyo, say that Darwin was on the right path.
RNA bases are thought to have been a part of life from the very beginning. However, RNA don’t form base pairs in water unless they are connected to a polymer backbone, a trait that has baffled scientists for decades. Researchers at the Georgia Institute of Technology have an alternate theory for the origin of RNA. They think the RNA bases may have evolved from a pair of molecules distinct from the bases we have today, and they have demonstrated their theory using self-assembly techniques.
Ancient languages hold a treasure trove of information about the culture, politics and commerce of millennia past. Yet, reconstructing them to reveal clues into human history can require decades of painstaking work. Now, scientists at the University of California, Berkeley, have created an automated “time machine,” of sorts, that will greatly accelerate and improve the process of reconstructing hundreds of ancestral languages.
What came first: the bipedal human ancestor or the grassland encroaching on the forest? A new analysis of the past 12 million years' of vegetation change in the cradle of humanity is challenging long-held beliefs about the world in which our ancestors took shape—and, by extension, the impact it had on them.
A series of rapid environmental changes in East Africa roughly 2 million years ago may be responsible for driving human evolution, according to researchers at Penn State University and Rutgers University.
A research team led by biogeochemists at the University of California, Riverside has tested a popular hypothesis in paleo-ocean chemistry, and proved it false. The team has ruled out zinc as a factor in the delayed diversification of single-celled and multicellular organisms.
Two groups—clades—of grasses that once had a common ancestry diverged. The PACMAD clade was predisposed to evolve a more efficient "C4" means of photosynthesis than grasses in the BEP clade. In a new study, a Brown University-led team pinpoints the anatomical differences between the clades that led to the PACMAD's tendency toward C4.
One of the great mysteries of life is how it began. For more than a century, scientists have struggled to reconstruct the key first steps on the road to life. Until recently, their focus has been trained on how the simple building blocks of life might have been synthesized on the early Earth, or perhaps in space. But because it happened so long ago, all chemical traces have long been obliterated, leaving plenty of scope for speculation and disagreement. Now, a novel approach to the question of life's origin attempts to redefine the problem.
Researchers have discovered why plants and animals had a hard time recovering from the largest mass extinction in Earth’s history 250 million years ago. The reason: global warming. Because of environmental consequences of rising temperatures, those species that survived the extinction didn’t fully recover for 5 million years.
Opsins, the light-sensitive proteins key to vision, may have evolved earlier and undergone fewer genetic changes than previously believed, according to a new study that used computer modelling to theorize the evolutionary developments of these structures. The analysis incorporated all available genomic information from all relevant animal lineages.
Bacteria have a bad rap as agents of disease, but scientists are increasingly discovering their many benefits, such as maintaining a healthy gut. A new study now suggests that bacteria may also have helped kick off one of the key events in evolution: the leap from one-celled organisms to many-celled organisms, a development that eventually led to all animals, including humans.
Microorganisms that crashed to Earth embedded in the fragments of distant planets might have been the sprouts of life on this one, according to new research. The research team reports that under certain conditions there is a high probability that life came to Earth during the solar system's infancy when Earth and its planetary neighbors orbiting other stars would have been close enough to each other to exchange lots of solid materials.
Emerging from the investigation of a mysterious nitrogen-fixing microbe that has a very small genome, an international team of investigators has found that certain type of photosynthetic bacteria not only provides nitrogen to its host single-cell algae, it appears now to be the most widespread nitrogen-fixing organism in the oceans.
Several years ago researchers at Michigan State University reported discovering a novel, evolutionary trait in a long-studied population of Escherichia coli . These same biologists have now analyzed this new trait's genetic origins and found that in multiple cases, the bacteria needed more than one mutational step. The finding documents this step-by-step process and highlights the importance of evolutionary changes that alter the physical arrangement of genes, leading to new patterns of gene regulation.
For nearly 260 years, researchers have classified species based on visual attributes like color, shape and size. But some species, such as Symbiodinum , a group of single-celled algae that live inside corals and are critical to their survival, could not have been found using the system that Carl Linnaeus pioneered. Instead, DNA analysis is providing the clue, and many new species are being found as a result.
A new study of giant viruses supports the idea that viruses are ancient living organisms and not inanimate molecular remnants run amok, as some scientists have argued. The study may reshape the universal family tree, adding a fourth major branch to the three that most scientists agree represent the fundamental domains of life.
Scientists have discovered well-preserved frozen woolly mammoth fragments deep in Siberia that may contain living cells, edging a tad closer to the "Jurassic Park" possibility of cloning a prehistoric animal. Russia's North-Eastern Federal University said an international team of researchers had discovered mammoth hair, soft tissues and bone marrow some 100 m underground during a summer expedition in the northeastern province of Yakutia.
Competition is a strong driving force of evolution for organisms of all sizes: Those individuals best equipped to obtain resources adapt and reproduce, while others may fall by the wayside. Many organisms also form cooperative social structures that allow resources to be defended and shared within a population. But surprisingly, even microbes, which are thought to thrive only when able to win the battle for resources against those nearest to them, have a somewhat sophisticated social structure that relies on cooperation, according to Massachusetts Institute of Technology scientists.
Charles Darwin hypothesized in 1880 that most species could not disperse across the Eastern Pacific Barrier, an uninterrupted 4,000-mile stretch of water with depths of up to 7 miles that separates the central from the eastern Pacific Ocean. Scientists have confirmed this hypothesis for many species, but recent research by Penn State University is the first to determine its effect on coral.
Squid’s colorful, changeable skin enables the animal—and their close relatives, cuttlefish and octopus—to display extraordinary camouflage. But how squid control their skin’s iridescence, or light-reflecting property, has been unknown until now. Researchers at the Marine Biological Laboratory report that nerves in squid skin control the spectrum and speed of color change, marking the first time neural control of iridescence in an invertebrate species has been demonstrated.
The start of the universe should be modeled not as a Big Bang, but more like water freezing into ice, according to a team of theoretical physicists at the University of Melbourne and RMIT University. The have suggested that by investigating the cracks and crevices common to all crystals our understanding of the nature of the universe could be revolutionized.
Our family tree may have sprouted some long-lost branches going back nearly 2 million years. A famous paleontology family has found fossils that they think confirm their theory that there are two additional pre-human species besides the one that eventually led to modern humans.
According to two scientific articles published this week, poisoned-tipped arrows and jewelry made of ostrich egg beads found in South Africa show modern culture may have emerged about 30,000 years earlier in the area than previously thought. The findings reinforce the theory that modern man emerged from southern Africa.