Tag Archives: mass extinction

Asteroid that Killed the Dinosaurs also Wiped out the ‘Obamadon’

By Guest PostDecember 11, 2012Nature, Scienceage of dinosaurs, alberta, asteroid collision, asteroid strike, bhart anjan bhullar, boundary, canada, carnivorous lizards, cerberophis, cretaceous, dinosaur species, dinosaurs, diversification, ecosystem, edmontosaurus, evolution, extinct lizard, flood, fossils, gracilis, harvard, jacques a gauthier, kill, lizard, mammals, mass extinction, montana, new mexico, nicholas r longrich, North America, obamadon, obamadon gracilis, odon, palaeosaniwa, paleogene, political significance, polyglyphanodontia, slender, snake, species, survivor, swamps, t rex, taxonomy, tooth, triceratops, united states, us president, yale, yucatan peninsula

The asteroid collision widely thought to have killed the dinosaurs also led to extreme devastation among snake and lizard species, according to new research — including the extinction of a newly identified lizard Yale and Harvard scientists have named Obamadon gracilis.

“The asteroid event is typically thought of as affecting the dinosaurs primarily,” said Nicholas R. Longrich, a postdoctoral associate with Yale’s Department of Geology and Geophysics and lead author of the study. “But it basically cut this broad swath across the entire ecosystem, taking out everything. Snakes and lizards were hit extremely hard.” (more…)

Dinosaur Die Out Might Have Been Second of Two Closely Timed Extinctions

By Guest PostSeptember 6, 2012Scienceaerosols, ammonite, antarctic peninsula, antarctic sediment, Argentina, asteroid, asteroid impact, carbon dioxide, deccan plateau, dinosaurs, earth, eduardo olivero, environmental effect, eric steig, fossil, free swimming, greenhouse gas, hell creek formation, history, India, isaac hilburn, james ross island, joseph kirschvink, magnetic field, magnetostratigraphy, mass extinction, matthew diamond, Mexico, montana, ocean floor, particles, peter ward, planet, ross mitchell, second event, sediment deposit, seymour island, species, thomas tobin, timothy raub, university, volcanic eruption, Washington, yale university, yucatan peninsula

The most-studied mass extinction in Earth history happened 65 million years ago and is widely thought to have wiped out the dinosaurs. New University of Washington research indicates that a separate extinction came shortly before that, triggered by volcanic eruptions that warmed the planet and killed life on the ocean floor.

The well-known second event is believed to have been triggered by an asteroid at least 6 miles in diameter slamming into Mexico’s Yucatán Peninsula. But new evidence shows that by the time of the asteroid impact, life on the seafloor – mostly species of clams and snails – was already perishing because of the effects of huge volcanic eruptions on the Deccan Plateau in what is now India. (more…)

Mass Extinctions Reset the Long-Term Pace of Evolution

By Guest PostJuly 3, 2012Scienceandrew z krug, animal kingdom, birth rate, bivalve, chicago esque, david jablonski, evolution, evolutionary rate, fossil, fossil mollusk, jurassic period, maryland outcrop, mass extinction, oysters, pace of evolution, paleontologist, pleistocene epoch, richard bambach, scallops, species diversification, time boundaries, university of chicago

A new study indicates that mass extinctions affect the pace of evolution, not just in the immediate aftermath of catastrophe, but for millions of years to follow. The study’s authors, University of Chicago’s Andrew Z. Krug and David Jablonski, will publish their findings in the August issue of the journal Geology.

Scientists expected to see an evolutionary explosion immediately following a mass extinction, but Krug and Jablonski’s findings go far beyond that.

“There’s some general sense that the event happens, there’s some aftermath and then things return to normal,” said Krug, a research scientist in geophysical sciences at UChicago. But in reality, Krug said, “Things don’t return to what they were before. They operate at a different pace, sometimes more rapidly, other times more slowly. Evolutionary rates shift, and that shift is permanent until the next mass extinction.” (more…)

Explosive Evolution Need Not Follow Mass Extinctions

By Guest PostFebruary 14, 2012Scienceadaptive radiation idea, canisius college, charles e mitchell, charlotte hsu, climate change, david w bapst, deforestation, diplograptines, ecological release hypothesis, ecosystem, evolutionary lag, explosive evolution, fossil record, graptoloid evolution, graptoloid history, graptoloids, h david sheets, life on earth, marine organisms, mass extinction, michael j melchin, neograptines, ordovician mass extinction, peter c bullock, physical traits, plankton, university at buffalo, university of chicago, zooplankton

In the wake of a mass extinction like the one that occurred 445 million years ago, a common assumption is that surviving species tend to proliferate quickly into new forms, having outlived many of their competitors.

But new research shows that tiny marine organisms called graptoloids did not begin to rapidly develop new physical traits until about 2 million years after competing species became extinct. (more…)

Global Extinction: Gradual Doom as Bad as Abrupt

By Guest PostFebruary 8, 2012Environment, Sciencebrooks ellwood, canadian arctic, carbon dioxide, charles henderson, coal deposit, dead zone, earth, ellesmere island, extinction, factor, fossil, geologic history, geology, global extinction, greenhouse, greenhouse gas, h richard lane, harry rowe, indian ocean, katherine freeman, marine life, mass extinction, national science foundation, ocean, permian period, permian triassic boundary, sedimentary rock, siberian traps, siberian volcanic activity, south china, steven bates, tethys, the great dying, thomas algeo, timothy lyons, united states, university of calgary, university of cincinnati, volcanic deposit, volcanic rock, volcanism in siberia, warming, west blind fiord

*In “The Great Dying” 250 million years ago, the end came slowly*

The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life–and it killed in stages–according to a newly published report.

It shows that mass extinctions need not be sudden events.

Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. (more…)

First Plants Caused Ice Ages

By Guest PostFebruary 1, 2012Environment, Natureatmospheric carbon, atmospheric carbon level, calcium, carbon cycle, carbonate rocks, chemical weathering, climate, earth surface, first land plants, global cooling, granite, ice ages, iron, liam dolan, magnesium, marine life, mass extinction, mineral, modern moss, ocean, ordovician period, oxford university, phosphorus, physcomitrella patens, reduction, rocks, silicate rocks, tim lenton, university of exeter

*New research reveals how the arrival of the first plants 470 million years ago triggered a series of ice ages. Led by the Universities of Exeter and Oxford, the study is published in Nature Geoscience.*

The team set out to identify the effects that the first land plants had on the climate during the Ordovician Period, which ended 444 million years ago. During this period the climate gradually cooled, leading to a series of ‘ice ages’. This global cooling was caused by a dramatic reduction in atmospheric carbon, which this research now suggests was triggered by the arrival of plants.

Among the first plants to grow on land were the ancestors of mosses that grow today. This study shows that they extracted minerals such as calcium, magnesium, phosphorus and iron from rocks in order to grow. In so doing, they caused chemical weathering of the Earth’s surface. This had a dramatic impact on the global carbon cycle and subsequently on the climate. It could also have led to a mass extinction of marine life. (more…)

Mass Extinction Victim Survives! Snail Long Thought Extinct, isn’t?

By Guest PostJune 9, 2011Environment, Naturealabama aquatic biodiversity center, coosa river in alabama's, diarmaid o foighil, dropping dead, ecology and evolutionary biology, envision dinosaurs, exotic tropical creatures, freshwater limpet, global hotspot of temperate freshwater biodiversity, kentucky state nature preserves commission, mass extinction, rhodacmea filosa's, species of mollusk, u-m museum of zoology, university of michigan

ANN ARBOR, Mich.—Think “mass extinction” and you probably envision dinosaurs dropping dead in the long-ago past or exotic tropical creatures being wiped out when their rainforest habitats are decimated. But a major mass extinction took place right here in North America in the first half of the 20th century, when 47 species of mollusk disappeared after the watershed in which they lived was dammed.

Now, a population of one of those species—a freshwater limpet last seen more than 60 years ago and presumed extinct—has been found in a tributary of the heavily dammed Coosa River in Alabama’s Mobile River Basin. Researchers from the University of Michigan, the Alabama Aquatic Biodiversity Center and the Kentucky State Nature Preserves Commission reported the rediscovery May 31 in the online, open-access journal PLoS One. (more…)

The Winners of Mass Extinction: With Predators Gone, Prey Thrives

By Guest PostMay 11, 2011Scienceage of fishes, age of the crinoids, crinoid fossils, devonian era, devonian period, ecology, ecosystem, Environment, fish, fossil record, fossils, hangenberg event, lauren sallan, lotka volterra cycles, marine vertebrate, mass extinction, modern biodiversity, natural experiment, ocean life, ohio state university, paleontologist, population of prey species, predator prey dynamics, predator prey relationships, residual defenses, robert nicholls, thomas kammer, university of chicago, william ausich

*Extinction of fishes 360 million years ago created natural ecology experiment*

In present-day ecology, the removal or addition of a predator in an ecosystem can produce dramatic changes in the population of prey species. For the first time, scientists have observed the same dynamics in the fossil record, thanks to a mass extinction that decimated ocean life 360 million years ago.

What was bad for fish was good for the fish’s food, according to a paper published online in Proceedings of the National Academy of Sciences. Researchers from the University of Chicago, West Virginia University and The Ohio State University found that the mass extinction known as the Hangenberg event produced a “natural experiment” in the fossil record, with results that mirror modern observations about predator-prey relationships. (more…)