Courtesy Public domain via WikipediaDeath of individuals is a fact of life, and in the same way so is extinction of species. An animal species lasts, on average, about 4 million years. It's claimed that 99 percent (or more!) of all species that have ever lived on Earth are now extinct. (If you are wondering how that number was calculated, you can read a couple explanations here).
The statistic becomes more credible when you consider this interesting image compilation of every animal that's gone extinct in just the last 100 years. The death list includes not only all sorts of birds and fish, but rhinos, hippos, deer, bi-valves, bison, horses, geckos, frogs, bats, lions, tigers, and bears - oh, my! (Because of its vastness the insect world is not included in the list).
Most of the life-forms pictured have been confirmed as extinct by the International Union for the Conservation of Nature (IUCN) along with a few others from reliable sources. That's not to say some straggling thought-to-be-gone individuals won't be sighted in some obscure location in the future but until then they'll be considered extinct.
The compilation not only gives a good picture of the diversity of life on our planet but also a good idea of the fragility of the biosphere.
SOURCE and LINKS
Every animal that have gone extinct in the last century on Pixable.com.
Endangered Species International
Center for Biological Diversity
Courtesy Public domain via WikipediaBack in 1911, German paleontologist Ernst Stromer discovered and described the remains of a then new Cretaceous dinosaur he named Spinosaurus aegyptiacus. The strange beast sported a huge sail framed around a series of giant spines that ran down its back. Unfortunately, all Stromer's fossil evidence was destroyed during the hostilities of WW II, when the British Royal Air Force bombed the Munich museum where the fossils were stored. Only a few scientific drawings and a single photograph remain.
Ninety years later an international team of researchers led by paleontologist Nizar Ibrahim returned to Stromer's original dig site and discovered additional specimens of Spinosaurus aegyptiacus, and in studying their fossils have come to some startling new conclusions about the strange dinosaur.
Courtesy University of Chicago Fossil LabSpinosaurus was a big boy - nine feet longer than the largest known Tyrannosaurus rex. And despite a long-held notion that dinosaurs were strictly terrestrial - i.e. they only dwelled on land (although like us, they probably occasionally swam in water), S. aegyptiacus appears to have spent much of his life in water, feeding on fish, and when on land (e.g to lay eggs) probably walked on all-fours, unlike every other known predatory dinosaur.
Paul Sereno, vertebrate paleontologist at the University of Chicago and a member of the research team, explains some of the new knowledge gleaned from the newly discovered fossil bones.
Courtesy M. R. Smith / Smithsonian InstituteOne of the strangest and more mysterious critters that scurried across the Middle Cambrian seafloor has baffled paleontologist since it was first identified in the 1970s. Was it a worm? Which side was up? Did it have legs or spikes or both? Was its head actually its tail? Did it have any extant descendents or was it an evolutionary dead-end? The worm-like creature was so baffling and so bizarre, it was given the very apropos name of Hallucigenia.
The tubular, spiked-worm possessed seven or eight pairs of legs and ranged in length from 2/5th of an inch to one and 1/4 inches and looks like something out of a bad dream. Early interpretations of their fossils were all over the map. The stiff spikes on it back were first thought to be its legs, and its legs misidentified as tentacles. What was thought to be its tail ended up being its head.
Using modern imaging technology, researchers from the University of Cambridge have been closely studying fossils from the famous Burgess Shale quarry located high in the Canadian Rockies, and are uncovering Hallucigenia's secrets. By studying the claws at the end of its legs they have been able to link it to modern velvet worms (onychophorans). Scientists have long suspected the two were somehow related but until now have failed to find anything significant to prove it. By studying Hallucigenia's claws they've determined that they're constructed of nested cuticle layers, very similar to how the jaws of velvet worms are organized. The similarity is no surprise since jaws are known to have evolved from a modified set of front legs.
But besides giving Hallucigenia a place in the lineage of life on Earth, the Cambridge team during the course of their study also discovered something else: that arthropods - which include crustaceans, spiders, insects and trilobites - aren't in fact as closely related to velvet worms as previously thought.
“Most gene-based studies suggest that arthropods and velvet worms are closely related to each other," said co-author Dr Javier Ortega-Hernandez. "However, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures – leaving velvet worms as distant cousins.”
SOURCE and LINKS
Courtesy Public domainThe Internet has been all a-buzz lately about the largest dinosaur - EVER - being discovered in Argentina. The beast is massive - equal to 14 elephants and as long as two tractor trailers! The story's accompanying photo (several, in fact) often shows an adult man laid out next to a gigantic titanosaur femur. Pretty impressive, at least at first. But the problem I had was finding out some idea of how long the bone was or how tall the man was. It's all relative, of course. It reminds of one of my favorite W. C. Fields scenes is in the movie YOU CAN'T CHEAT AN HONEST MAN where he plays a carnival barker at a sideshow touting the World's Largest Midget and the World's Smallest Giant, and featuring two guys of average height.
Courtesy Public domainThis kind of hyperbole has been around ever since dinosaurs were first discovered. If the bone pictured in the 1898 New York Advertiser article is as large as the caption claims, then the man standing next to it, William Harlow Reed, is eight feet tall as well(!) - an equally if not more impressive story that the newspaper obviously overlooked.
It should be noted that the sensational discovery was the catalyst for steel magnate Andrew Carnegie to spend lots of money to get himself his own dinosaur (Diplodocus carnegiei) in 1899. It wasn't quite as large as the one that inspired his quest but casts of Carnegie's dinosaur were given to various foreign heads of states, helping spread dinosaur fever to the world.
Courtesy Mark RyanOver in China, out of one of the richest hunting grounds for new and unusual dinosaur-era fossils, the earliest known member in the family of flying reptiles known as pterosaurs has been described in a paper published in Current Biology.
The flying reptile's name essentially means "first-born hidden serpent", the genus name Kryptodrakon referring to the popular martial arts film, "Crouching Tiger, Hidden Dragon" which was filmed near the location where the fossil was discovered in the Chinese autonomous region known as Xinjiang.
Sporting a wingspan of some 4.5 feet, Kryptodrakon lived in a floodplain environment during the Middle-Upper Jurassic period, about 163 million years ago. Descendents of the newly-discovered pterodactyloid would evolve into much larger flying reptiles such as the giant, Cessna-sized Quetzacoatlus found in Late Cretaceous sediments in Texas. Pterosaurs were not dinosaurs but share a common ancestor with them.
The research increases our knowledge of pterosaur development and was led by Brian Andres from the University of South Florida (USF), James Clark of George Washington Columbia College of Arts and Sciences, and Xu Xing of the Chinese Academy of Sciences.
Courtesy Eduard Solà via WikipediaIf you missed last week's PBS broadcast of Your Inner Fish, the documentary based on paleontologist-anatomist Neil Shubin's book by the same name, you have another chance to catch up on the first of three segments on the web. It's an excellent opening segment of the 3-part series, but is only available (for free!) right here through April 23, 2014.
The series deals with Shubin's search for the connections we all have with our fishy and reptilian ancestors. His discovery of the remarkable transitional fossil named Tiktaalik roseae on Ellesmere Island in the Canadian Arctic has added great evidence of our ties with our distant piscean relatives. The flat-headed, 375 million year-old Tiktaalik possessed the exact features - such as both lungs and gills, a wrist and neck - that you'd hope to find in a transitional form between swimming fish and land-walking tetrapods.
The next episode, titled Your Inner Reptile airs Wednesday, April 16th on your local PBS station. It's on here in the Twin Cities at 9pm but check your local listing for times in your area.
Jean-Michel Claverie and Chantal Abergel of Aix-Marseille University in France and their colleagues cut up pieces of permafrost samples - supplied by scientists from the Russian Academy of Science - and added them to petri dishes of amoebae only to see the one-celled animals ripped apart by unknown viruses. They isolated the attacking, larger-than-usual virus and named it Pithovirus sibericum, because of its resemblance to an earthenware jar. The permafrost samples had been collected from a frozen riverbank in Siberia in 2000.
The discovery brings the total number of known "giant viruses" to three. The extra-large viruses are about 25 percent larger than normal, genetically more complex, and composed of hardier stock.
"Among known viruses, the giant viruses tend to be very tough, almost impossible to break open," said Claverie and Abergel. "Special environments such as deep ocean sediments and permafrost are very good preservers of microbes because they are cold, anoxic and in the dark."
Two other giant viruses Mimivirus and Pandoravirus were also discovered by Claverle and Abergel in the last decade. The latter, in my opinion, is a disturbingly great name for this type of thing. But so far only the pithovirus has been observed in the laboratory infecting contemporary life forms. Luckily, none of them pose a threat to humans, but that's not to say future giant viruses thawed out of frozen environments or released by retreating ice caps won't be.
"I don't see why they wouldn't be able to survive under the same conditions," said Claverie.
Results of the research appear in the Proceedings of the National Academy of Sciences.
Courtesy M. McCormickFor more than 20 years, zebra mussels have gone unchecked in midwest waters. Introduced to North America as stow-away passengers on the bottoms of Great Lakes shipping vessels that came from Europe, the invasive species have exploded to fresh waters in 34 states at an alarming rate.
But their days may be numbered. A New York-based researcher has discovered a bacterium that can kill zebra mussels (and also the related invasive species quagga mussels) without disrupting the rest of the food web.
After rounds of lab testing, the Environmental Protection Agency has okayed the commercial production of Pseudomonas fluorescens strain CL145A, which can then be applied to waters and kill the menacing mussels. In lab tests, the bacterium killed over 90 percent of the the invasive mussels in came in contact with.
Along with pushing out other species in the waters, the invasive mussels have also become a nuisance by clogging up intake pipes at water plants and attaching themselves to docks, piers and other submerged water equipment. Plans are still being developed on how to apply this new bacterium to the waters. All wise zebra mussels might want to start packing their bages and heading back to Europe before they find out what this new bacterium has in store for them!
Courtesy FunkMonk via Wikimedia CommonsThe partial remains of a somewhat rare sauropod dinosaur have been discovered in Old Snowmass, near Aspen, Colorado. Paleontologist John Foster of the Museum of Western Colorado in Grand Junction said that fossils of a Haplocanthosaurus were found by college student Mike Gordon in 2005 on land owned by his mom and stepfather. If you remember, Snowmass was the site near Aspen where a large collection of mammoths, mastodons, and other Ice Age mammals were uncovered back in 2010. This latest discovery is about six miles from the other site but in a much, much older rock layer. Foster said the Lower Morrison Formation, from where Haplocanthosaurus remains were collected dates back to the Late Jurassic, about 155-152 million years ago.
It's a very exciting find because few specimens of Haplocanthosaurus exist. The first were also found in Colorado, in Garden Park near Canon City, by Carnegie Museum of Natural History paleontologists William H. Utterback and John Bell Hatcher in 1901. The type specimens (H. priscus and H. utterbacki) were described by Hatcher in 1903. The fossils were prepared under the direction of chief preparator, Arthur S. Coggeshall.
Courtesy ScottRobertAnselmo via Wikimedia CommonsCompared to its larger and heavier long-necked, small-headed cousins such as Apatosaurus and Diplodocus, the Haplocanthosaurus was a relatively small-sized sauropod dinosaur with a length of 35 to 40 feet and weighing maybe 14 tons. While most sauropods have hollow spaces in their backbones, a distinguishing characteristic of Haplocanthosaurus is the solidness of its vertebrae which Foster confirmed by doing a scan of the fossil bones at a local hospital in Grand Junction.
Courtesy Mark RyanThe only mounted specimen of Haplocanthosaurus is the referred species (H. delphsi) on exhibit at the Cleveland Museum of Natural History in Ohio. No skull of the sauropod has ever been found so the head is just a fabricated guess. Other post-cranial remains exist, including some here at the Science Museum of Minnesota that were collected in Wyoming, but in general fossils of the dinosaur are rare. Material from only 10 individuals are known.
So far the Old Snowmass site has provided some vertebrae, ribs and a pelvis. but the landowners have been very accommodating in allowing the museum access to the dig site, and Foster hopes to find more Haplocanthosaurus bones - maybe even some skull material - in the coming summer season.
SOURCES and LINKS
Aspen Times story
More Haplocanthosaurus info
Osteology of Haplocanthosaurus by John Bell Hatcher
Jurrassic West: The Dinosaurs of the Morrison Formation and Their World by John Foster
Courtesy National Portrait GalleryLast month, on November 22nd, while many people in the country were observing the 50th anniversary of president John F. Kennedy's assassination by shots fired from the Texas School Book Depository, there was another significant event happening that day involving Texas schoolbooks. That same Friday, despite objections and obstructionist tactics by creationists, the Texas Board of Education approved several public school science textbooks that included full coverage of evolution and climate change. The vote came late in the day and although the creationist faction did manage to make the adoption of two biology books contingent on a committee ruling regarding some alleged "flaws" in the text, the Texas Freedom Network (TFN), a watchdog group instrumental in countering the irrational creationist attacks, expects the passage to stand.
“It’s hard to overstate the importance of today’s vote, which is a huge win for science education and public school students in Texas,” said Kathy Miller, TFN's president. “Four years ago this board passed controversial curriculum standards some members hoped would force textbooks to water down instruction on evolution and climate change. But that strategy has failed because publishers refused to lie to students and parents demanded that their children get a 21st-century education based on established, mainstream science.”