Tag Archives: evolution

New Understanding of Earth’s Mantle Beneath The Pacific Ocean

By Guest PostMarch 24, 2012Scienceasthenosphere, boundary, carnegie, crust, earth, evolution, factors, gutenberg discontinuity, lab, lithosphere, lithosphere asthenosphere boundary, mineral, molten rock, nick schmerr, pacific ocean basin, planet, plate tectonics

Washington, D.C. — Scientists have long speculated about why there is a large change in the strength of rocks that lie at the boundary between two layers immediately under Earth’s crust: the lithosphere and underlying asthenosphere. Understanding this boundary is central to our knowledge of plate tectonics and thus the formation and evolution of our planet as we know it today. A new technique for observing this transition, particularly in the portion of Earth’s mantle that lies beneath the Pacific Ocean basin, has led Carnegie and NASA Goddard scientist Nick Schmerr to new insight on the origins of the lithosphere and asthenosphere. His work is published March 23 in Science.

The lithosphere-asthenosphere boundary, or LAB, represents the transition from hot, convecting mantle asthenosphere to overlying cold and rigid lithosphere. The oceanic lithosphere thickens as it cools over time, and eventually sinks back into the mantle at Earth’s so-called subduction zones. (more…)

What Makes Ticks Tick?

By Guest PostMarch 11, 2012Healthanaplasmosis, antibiotic therapy, apple, arthritis, babesiosis, bacterium, climate change, dengue fever, disease, durland fish, european ancestry, evolution, infectious diseases, iPhone, lyme disease, maine, malaria, michigan, minnesota, neurological problems, North America, Pennsylvania, placebo, ticks, united states, virginia, west nile virus, wisconsin

Durland Fish has researched ticks and their associated diseases for decades. A professor in the Division of Epidemiology of Microbial Diseases at the Yale School of Public Health, he has, among other things, contributed to the discovery that the bacterium that causes Lyme disease has European ancestry and that the disease, once nearly eradicated in North America, roared back with reforestation. More recently he helped develop a Lyme disease “app” for the iPhone and other Apple devices that provides users with detailed information about tick populations in any given area in the United States and even comes with a video on how to safely remove a tick. He has also worked on mosquito-borne West Nile virus and dengue fever. Students selected Fish as the school’s mentor of the year in 2010. (more…)

Evolution of Earliest Horses Driven by Climate Change

By Guest PostFebruary 24, 2012Environment, Nature, Scienceaaron wood, atmosphere, bighorn basin, body size, cabin fork area, carbon, carbon dioxide, cause and effect, climate model, clydesdale, concentration, doug boyer, dwarfing phenomenon, earliest horse, evolution, florida museum of natural history, fossil, geochemical analysis, global temperature, h richard lane, horse teeth, industrial revolution, jonathan bloch, mammal, national science foundation, natural selection, North America, nsf, ocean, ornithologist, oxygen levels, paleocene-eocene thermal maximum, petm, prediction, ross secord, sifrhippus sandae, stephen chester, temperature, university of florida, university of nebraska lincoln, worland, yale

*The hotter it gets, the smaller the animal?*

When Sifrhippus sandae, the earliest known horse, first appeared in the forests of North America more than 50 million years ago, it would not have been mistaken for a Clydesdale.

It weighed in at around 12 pounds–and it was destined to get much smaller over the ensuing millennia.

Sifrhippus lived during the Paleocene-Eocene Thermal Maximum (PETM), a 175,000-year interval of time some 56 million years ago in which average global temperatures rose by about 10 degrees Fahrenheit. (more…)

Studying The Evolution of Life’s Building Blocks

By Guest PostFebruary 20, 2012Sciencealbert szent gyorgyi, ancient life, bacterium, basic module, beginning of life, beginning of time, british columbia, building block, chemical building block, chemical reactions, evolution, evolution of life, geneticists, michigan state university, molecular complementarity, molecular paleontology, origin of life, paleontologists, physiologist, robert root bernstein, species, vancouver, vitamin c

VANCOUVER, British Columbia — Studying the origin of life at its building blocks offers a unique perspective on evolution, says a researcher at Michigan State University.

Robert Root-Bernstein, MSU physiology professor, will answer the question of why a physiologist studies the origin of life at the annual meeting of the American Association for the Advancement of Science Feb. 16-20 in Vancouver, British Columbia. (more…)

A Bug’s (Sex) Life: Diving Beetles Offer Clues About Sexual Selection

By Guest PostFebruary 6, 2012Nature, Sciencearizona desert, co evolution, dawn higginson, diving beetles, dytiscidae, epifluorescence image, Europe, evolution, evolutionary relationship, female, fertilization, great diving beetle, hygrotus sayi, invertebrate, kari segraves, kelly miller, larva, male, mammal, mollusk, reproductive organ, scott pitnick, sexual evolution, sexual selection, sexual trait, speciation, sperm evolution, sperm storage, spermatheca, syracuse university, thermonectus marmoratus, university of arizona

*Studies of diving beetles suggest sperm evolution may be driven by changes in female reproductive organs, challenging the paradigm of post-mating sexual selection being driven mostly by competition among sperm.*

Studying female reproductive tracts and sperm in diving beetles (Dytiscidae), researchers from the University of Arizona and Syracuse University have obtained a glimpse into a bizarre and amazing world of sperm that can take on a variety of forms – including joining together into conglomerates that navigate the twisted mazes of the female reproductive tract.

Analyses of the evolutionary relationships among diving beetles reveal that sperm form appears to follow function dictated by female reproductive organs. (more…)

Ancient Dinosaur Nursery Oldest Nesting Site Yet Found

By Guest PostJanuary 27, 2012Scienceadam yates, cretaceous periods, david evans, dinosaur eggs, dinosaur footprint, dinosaur nesting site, dinosaur record, dinosaur reproduction, early dinosaur, early jurassic period, eric roberts, evolution, evolutionary history, excavation, fossil record, hans-dieter sues, hatchling, jurassic, massospondylus, oldest known embryo, prosauropod dinosaur, reproductive behaviour, robert reisz, royal ontario museum, sauropods, sedimentary rocks, smithsonian institute, South Africa

*UTM professor unearths fossils in South Africa*

An excavation at a site in South Africa has unearthed the 190-million-year-old dinosaur nesting site of the prosauropod dinosaur Massospondylus-revealing significant clues about the evolution of complex reproductive behaviour in early dinosaurs. The newly unearthed dinosaur nesting ground predates previously known nesting sites by 100 million years, according to study authors.

A new study led by University of Toronto Mississauga paleontologist Robert Reisz, with co-author, Professor David Evans of ecology and evolutionary biology and the Royal Ontario Museum, along with a group of international researchers, describes clutches of eggs, many with embryos, as well as tiny dinosaur footprints, providing the oldest known evidence that the hatchlings remained at the nesting site long enough to at least double in size. (more…)

Babies Are Born With “Intuitive Physics” Knowledge, Says MU Researcher

By Guest PostJanuary 26, 2012Scienceevolution, glass of milk, hidden objects, infants, intuitive physics, knowledge, kristy vanmarle, natural interaction, northwestern university, predict the future, skill, susan hespos, university of missouri, unsupported objects

*Numerous infant studies indicate environmental knowledge is present soon after birth*

COLUMBIA, Mo. – While it may appear that infants are helpless creatures that only blink, eat, cry and sleep, one University of Missouri researcher says that studies indicate infant brains come equipped with knowledge of “intuitive physics.”

“In the MU Developmental Cognition Lab, we study infant knowledge of the world by measuring a child’s gaze when presented with different scenarios,” said Kristy vanMarle, an assistant professor in the Department of Psychological Sciences in the College of Arts and Science. “We believe that infants are born with expectations about the objects around them, even though that knowledge is a skill that’s never been taught. As the child develops, this knowledge is refined and eventually leads to the abilities we use as adults.” (more…)

English Literature Influenced Prize-Winning Paleontologist

By Guest PostJanuary 14, 2012Science21st century, age of reptiles, ancient plant structure, carbon cycle, carboniferous period, cocktail party, dinosaurs, earth, ecology, evolution, excalibur movie, fieldwork, fossil record, giant fungus, harvard university, history of life, ice age, jung eun lee, kevin boyce, knowledge, la brea tar pits, lloyd degrane, los angeles, macroevolution, mammal fossils, michael foote, million years ago, mural, pair of calipers, paleontology, plant fossils, prehistoric life, scanning electron microscope, school, soil moisture, terrestrial ecosystems, vascular plants

For a short time in grade school, Kevin Boyce lived within two blocks of the La Brea tar pits in Los Angeles, a place where ice age mammal fossils had been discovered. Above his bed hung a poster of the Yale Peabody Museum’s famous Age of Reptiles mural. But it wasn’t a boyhood fascination with prehistoric life that influenced his interest in paleontology, but rather the medieval literary world of Chaucer that Boyce discovered in college.

“I didn’t think twice about fossils between the ages of 7 and 20,” said Boyce, associate professor in geophysical sciences. Even during his undergraduate studies in literature and biology at the California Institute of Technology in the early 1990s, the deep history of life on Earth was far from his mind. (more…)