Stories tagged LOL

Oct
07
2013

Enrolled trilobite: The trilobite's strategy of rolling itself up into a ball for protection dates back to some of its earliest known ancestors in the fossil record. This fossil trilobite (Isotelus?) was found in Late Ordovician shale in St. Paul, Minnesota.
Enrolled trilobite: The trilobite's strategy of rolling itself up into a ball for protection dates back to some of its earliest known ancestors in the fossil record. This fossil trilobite (Isotelus?) was found in Late Ordovician shale in St. Paul, Minnesota.Courtesy Mark Ryan
A new study appearing in Biology Letters shows that trilobites - everyone's favorite prehistoric water bug - developed an effective survival strategy much earlier than previously thought.

Trilobite fossils from Early Cambrian rock formations in the Canadian Rockies and elsewhere lend evidence that some of the earliest trilobites used enrollment (i.e rolling themselves up into a ball like an armadillo) to protect themselves from predators or the environment. Trilobite fossils found here in Minnesota are several million years younger dating back to the Late Cambrian through Late Ordovician Periods (500 - 430 mya) and are often found enrolled. It was an effective survival strategy.

Trilobites were arthropods, which meant they possessed exoskeletons, segmented bodies and jointed appendages. Their closest extant relative is the horseshoe crab. Trilobite bodies - for the most part - were comprised of a head (cephalon) positioned on a body (thorax) that was divided into three lobes: essentially an axial dividing a left and right pleura, and a tail (pygidium). The mouth (hypostome) was located on the underside. It's thought that most early trilobites were predators and/or scavengers who spent their lives roaming the sea floors looking carcasses, detritus or living prey to feed upon. Most trilobites possessed complex eyes (although some were eyeless). Like other arthropods (e.g. today's lobsters), trilobites would outgrow their exoskeletons, discarding them (molting) as they grew in size or changed shape. Their newly exposed soft skin soon hardened into a new, tough, outer casing. Once hardened, their segmented exoskeletons (composed of calcium carbonate) were ventrally flexible, giving them the ability to roll up into a ball should they need sudden protection from whatever threatened them.

Some early trilobite forms from Middle Cambrian-aged fossils had been viewed as incapable of enrolling but the new research based on much older fossils found in mudstones in the Canadian Rockies in Jasper Park pushes back the origins of the strategy to some of the earliest trilobites to appear in the fossil record (Suborder Olenellus). These appeared 10-20 million years earlier at the very beginnings of the Cambrian Period and show evidence of having already developed the ability to enroll.

Trilobites in some form or another existed across a span of more than 270 million years, a very successful run by any measure. The enrollment strategy certainly contributed to their longevity. Although trilobites were already in decline, the last of their kind were wiped out in the great extinction event that marked the end of the Permian Period and the start of the Triassic. They weren't the only casualty of the extinction: nearly 90 percent of Earth's species were terminated along with them.

Even though trilobites are extinct (they died out in the Permian Mass Extinction along with around 90 percent of Earth's species) they were an extremely successful and adaptable life form. No wonder they remain today a favorite among fossil collectors.

SOURCE and LINKS
Paper at Biology Letters
Major Trilobite features
A Guide to the Orders of Trilobites

Oct
16
2012

Flu shot: A new study shows that flu shots are effective, at best, up to 59 percent of the time. Researchers are encouraging drug companies to develop new and better flu shots for the future.
Flu shot: A new study shows that flu shots are effective, at best, up to 59 percent of the time. Researchers are encouraging drug companies to develop new and better flu shots for the future.Courtesy r Joseph R Schmitt
Hey, I got my flu shot last week. It's been about 10 years now I've been able to get a free flu shot covered by my health insurance plan. And I'm happy to say I've never had the flu in all that time.

That, of course, is all anecdotal evidence. But some researchers at the University of Minnesota have been studying the issue of flu shots and have some new ideas on the matter. Based on their findings, they're encouraging new research to find a "game-changer" new vaccine to make flu shots more effective.

The Center for Infectious Disease Research and Policy at the U released its findings yesterday. And overall, they found that flu shots had, at best, a 59 percent effectiveness rate for adults ages 18 to 64. Effectiveness rates for flu shots for people younger and older than that age group were inconsistent. The nasal-spray vaccine was found to have an efficacy of 83 percent in children ages 6 months to 7 years.

Vaccine manufacturers haven't made any significant changes to flu vaccine formulas for many years, mostly based on the idea that the flu shots were highly effective. But the new report challenges that theory and encourages new research to find different approaches to flu vaccines, with those new approaches aiming to have a higher rate of prevention.

In the meantime, the researchers are still encouraging people to get a flu shot this season. Some protection is better than no protection, they point out. And they also said that their findings showed no reason to believe that flu shots cause any harm to people who receive them.

What do you think? Are you getting a flu shot this year? Share your thoughts here with other Science Buzz readers.