A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago – nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion.
The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago.
"This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way," said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. "Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals. This paper lets us put aside some of those interpretations."
In an effort to determine how, why, and when multicellularity arose from single-celled ancestors, Xiao and his collaborators looked at phosphorite rocks from the Doushantuo Formation in central Guizhou Province of South China, recovering three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death—qualities of complex multicellular eukaryotes such as animals and plants.
The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form. The complex multicellularity evident in the fossils is inconsistent with the simpler forms such as bacteria and single-celled life typically expected 600 million years ago.
Known as a 'Star of David' molecule, scientists have been trying to create one for over a quarter of a century and the team's findings are published in the 21 September 2014 issue of Nature Chemistry.
Consisting of two molecular triangles, entwined about each other three times into a hexagram, the structure's interlocked molecules are tiny – each triangle is 114 atoms in length around the perimeter. The molecular triangles are threaded around each other at the same time that the triangles are formed, by a process called 'self-assembly', similar to how the DNA double helix is formed in biology.
The molecule was created at The University of Manchester by PhD student Alex Stephens. Professor David Leigh, in Manchester's School of Chemistry, said: "It was a great day when Alex finally got it in the lab. In nature, biology already uses molecular chainmail to make the tough, light shells of certain viruses and now we are on the path towards being able to reproduce its remarkable properties.
"It's the next step on the road to man-made molecular chainmail, which could lead to the development of new materials which are light, flexible and very strong. Just as chainmail was a breakthrough over heavy suits of armour in medieval times, this could be a big step towards materials created using nanotechnology. I hope this will lead to many exciting developments in the future."
This new finding, led by Ilsedore Cleeves from the University of Michigan in the US, suggests that our water is significantly older than we’d ever imagined, and that water should be plentiful in other planetary systems too.
The discovery was made through the use of new computer simulations, developed by Cleeves and her team, of the early Solar System.
“While we can't go back in time to see the the Sun and Solar System at its formation, the wonderful thing about the vastness of the galaxy is that we can observe many other young Sun-like stars that are currently forming or have recently formed,” Cleeves told Becky Ferreira at Motherboard. "By studying these astrophysical objects using high power telescopes and numerical techniques, we can use this information to model the protoplanetary disk environment in great detail.”
The protoplanetary disk environment is where planets form. Containing large amounts of dust and gas particles that resulted from the collapse of an interstellar star-founding cloud, the protoplanetary disk and the new star next to it will rotate together, and the debris surrounding the disk will form new planets.
Publishing their results in the journal Science today, Cleeves and her team modelled the ‘heavy water’ in ice that was floating in the protoplanetary disk that formed our Solar System. Heavy water contains an isotope of hydrogen called deuterium, and it’s found in all water in the Solar System, including that on planets, icy moons, and inside comets and meteorites.
Hackers have begun exploiting the newly identified "Shellshock" computer bug, using fast-moving worm viruses to scan for vulnerable systems and then infect them, researchers warned on Thursday.
"Shellshock" is the first major Internet threat to emerge since the discovery in April of "Heartbleed," which affected OpenSSL encryption software that is used in about two-thirds of all web servers, along with hundreds of technology products for consumers and businesses.
"Shellshock" has the potential to wreak more havoc than "Heartbleed" because it enables hackers to gain complete control of an infected machine, which could allow hackers to destroy data, shut down networks or launch attacks on websites, experts said.
The "Heartbleed" bug only allowed them to steal data.
For general home users, keep an eye on manufacturer websites for updates - particularly for hardware such as broadband routers as many are based on Linux, which is the target of the new bug.
A new simulation illustrates the explosiveness of the volcano that lurks beneath Yellowstone National Park in Wyoming.
Around 640,000 years ago, the volcano blew its top and coated North America with roughly 1,000 cubic kilometers of ash, enough to fill Lake Erie twice over. A simulation of the eruption described August 27, 2014 in Geochemistry, Geophysics, Geosystems reveals that a similar outburst today would bury Billings, Mont., in more than a meter (about 40 inches) of volcanic glass shards and pulverized rock. Even New York and Atlanta would receive dustings several millimeters thick as winds whisked ash through the darkened atmosphere for days.
Researchers used simulation software called Ash3d that forecasts ash fall by applying global wind patterns to data from historical eruptions. Ash3d churns out results several times faster than previous simulators and is the first program to incorporate the physics of how ash particles clump within a cloud.
While geologists say Yellowstone will likely never erupt again, scientists around the world use Ash3d daily to predict the potential fallout from restless volcanoes — including Bárðarbunga, the Icelandic volcano that began erupting in late August.