Stories tagged Diversity of Organisms

Apr
13
2014

Tiktaalik roseae: Field Museum of Natural History
Tiktaalik roseae: Field Museum of Natural HistoryCourtesy Eduard Solà via Wikipedia
If 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.

In the meantime, watch the first episode, and read about some of the reaction to Shubin's find here, here, and here.

LINKS
University of Chicago Tiktaalik roseae page

Mar
05
2014

Virus: Giant viruses are genetically more complex and about 25 percent larger.
Virus: Giant viruses are genetically more complex and about 25 percent larger.Courtesy jiparis
A husband-and-wife-led research team has announced finding an ancient virus laying dormant in Siberian permafrost for more than 30,000 years!

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.

SOURCES and LINKS
National Geographic story
Sydney Morning Herald
More about giant viruses

Mar
03
2014

Numbered days?: Zebra mussels totally cover a piece of underwater equipment from Lake Michigan.
Numbered days?: Zebra mussels totally cover a piece of underwater equipment from Lake Michigan.Courtesy M. McCormick
For 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!

Feb
14
2014

The Canadian Rockies: Source of a new treasure trove of amazing Cambrian fossils
The Canadian Rockies: Source of a new treasure trove of amazing Cambrian fossilsCourtesy Mark Ryan
Just over a century ago, paleontologist Charles Doolittle Walcott discovered a truly remarkable fossil quarry in British Columbia. The site, known as the Burgess Shale, was found on Mt. Field in Yoho National Park, and contained an abundant amount of fossilized remains of soft-bodied creatures - several new to science - from the Cambrian Period around 505 million years ago. In 1989, paleontologist Stephen Jay Gould detailed the spectacular find and its implications in a book titled, "Wonderful Life: The Burgess Shale and the Nature of History".

Burgess Shale trilobite: Science Museum of Minnesota collection.
Burgess Shale trilobite: Science Museum of Minnesota collection.Courtesy Mark Ryan
This week, a newly discovered fossil site, located in the same shale formation high in the Canadian Rockies but 26 miles southeast of Walcott's quarry, was announced in the journal Nature Communications. The new location, named Marble Canyon, is proving to be another Lagerstätte, a sedimentary deposit of extraordinary and exceptionally preserved fossils. The discoverers report that of the 3000 specimens found so far and representing 55 species, about half are invertebrates also found at the Walcott Quarry, and in some cases are more abundant and better preserved.

"[T]here is a high possibility that we'll eventually find more species here than at the original Yoho National Park site, and potentially more than from anywhere else in the world," said lead author Jean-Bernard Caron, an invertebrate paleontologist at Toronto's Royal Ontario Museum.

So far twenty-two percent of the species discovered at Marble Canyon are new to science. The formation is estimated to be about 100,000 years younger than the original site. China's Chengjiang fossil beds have produced some of the same kinds of animals found at Marble Canyon and is about 10 million years older.

Arthropods (e.g. trilobites) are the most common animals found in the Burgess Shale, and finely preserved fossils from the new site provide remarkable views of neural tissues, retinas, corneas, some internal organs.

Back in 2012, Gaines and his colleagues followed the Burgess shale exposures on foot, trekking across the mountainsides in hopes of finding new fossils sites. What they discovered at Marble Canyon is far more than they could have wished for.

"I think the most profound implication is that the Burgess Shale can't just be the only one that there is," Gaines said. "There's a lot more out there in the Canadian Rockies and other places."

Any fossil remains uncovered at Marble Canyon and at similar sites will only add to our understanding of evolution and how complex life developed during the Cambrian Explosion.

Gallery of new Burgess Shale fossils

SOURCES and LINKS
Nature Communications
ScienceDaily story
"Wonderful Life" by Stephen Jay Gould
LiveScience story
Previous Burgess Shale Buzz story
More about the Burgess Shale

Dec
28
2013

Restoration of Haplocanthosaurus: a Late Jurassic sauropod whose remains are found in Colorado, Utah, and Wyoming.
Restoration of Haplocanthosaurus: a Late Jurassic sauropod whose remains are found in Colorado, Utah, and Wyoming.Courtesy FunkMonk via Wikimedia Commons
The 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.

Mounted skeleton of Haplocanthosaurus delfsi: Cleveland Museum of Natural History
Mounted skeleton of Haplocanthosaurus delfsi: Cleveland Museum of Natural HistoryCourtesy ScottRobertAnselmo via Wikimedia Commons
Compared 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.

Haplocanthosaurus hindlimb: Science Museum of Minnesota
Haplocanthosaurus hindlimb: Science Museum of MinnesotaCourtesy Mark Ryan
The 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

Dec
09
2013

Charlie Darwin: The schoolbook victory in Texas obviously makes him feel like Charlie Sheen.
Charlie Darwin: The schoolbook victory in Texas obviously makes him feel like Charlie Sheen.Courtesy National Portrait Gallery
Last 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.”

SOURCES
Dallas Morning News story
Evolution is True article

Oct
23
2013

With the announcement of the Ultimate Dinosaurs: Giants of Gondwana exhibit comming to the Science Museum of Minnesota, I was thinking back to all the questions I have had regarding dinosaurs. Tyrannosaurus rex: the Tyrant Lizard King on display at the Royal Tyrrell Museum in Drumheller, Alberta.
Tyrannosaurus rex: the Tyrant Lizard King on display at the Royal Tyrrell Museum in Drumheller, Alberta.Courtesy Mark Ryan

Questions like: "Who gets to name Dinosaurs?" "What is this dinosaur named after?" and "What does this name mean?". I thought that I'd take some time here to answer these questions.

Oct
16
2013

Turkey vulture (Cathartes aura): an ugly yet somewhat majestic raptor species often seen soaring around Hawk Ridge in Duluth, Minnesota during the annual fall migration.
Turkey vulture (Cathartes aura): an ugly yet somewhat majestic raptor species often seen soaring around Hawk Ridge in Duluth, Minnesota during the annual fall migration.Courtesy Mark Ryan
Birds seem to be a big part of my recent experience, so I thought I'd put together a little post of events featuring our fine, feathered friends.

Here at the Science Museum of Minnesota, an antique model of Archaeopteryx originally created by modelmaker Gustaf Sundstrom in 1934 is on display once again as Object of the Month for October. Archaeopteryx model by Gustaf Sundstrom
Archaeopteryx model by Gustaf SundstromCourtesy Mark Ryan
Archaeopteryx has long been considered the earliest bird - it lived around 150 million years ago during the Late Jurassic - sharing the world with giant sauropods and vicious therapods such as Apatosaurus and Allosaurus, respectively. Even though Archaeopteryx has been recently re-categorized from being a "dinosaur-like bird" to being a "bird-like dinosaur" (I'm not sure what the difference is but I suspect it has do do with percentages) - anyway, it still ranks as one of the great transitional fossils. You can see the Object of the Month display in the Collections Gallery on the 4th floor of the Science Museum of Minnesota all this month.

Another bird-related story deals with naturalist and artist John James Audubon and his artistic masterpiece Birds of America, both which I've covered before here.

Audubon's Whooping Crane: plate no. 226 from the artist's masterpiece Birds of America.
Audubon's Whooping Crane: plate no. 226 from the artist's masterpiece Birds of America.Courtesy Mark Ryan
Back in the early 19th century Audubon, tramped around the American frontier seeking just about every kind of bird he could find, shoot, and paint for his masterpiece natural history tome, Birds of America. The original edition featured 435 exquisite plates of birds drawn in natural size, were etched in copperplates (along with some engraving and aquatint), then printed in black and white and printed on large double-elephant folio-sized (30 x 40) handmade paper. Each of the large black and white prints were hand-painted in watercolors by a team of skilled colorists and bound into two volumes. Long considered one of the greatest collections of natural history illustration, only some 200 sets were completed in the mid-19th century. Of those only about 100 remain in existence. The rest were either destroyed or disassembled and sold off as individual prints. Because they were hand-colored, these large first editions are considered "originals" and are quite valuable. Smaller, more inexpensive prints and editions were later created and sold.

Audubon exhibit: Preview Night at the Bell Museum
Audubon exhibit: Preview Night at the Bell MuseumCourtesy Mark Ryan
Lucky for us one of the original Double Elephant Folio sets is held by the Bell Museum of Natural History in Minneapolis. Even luckier for us, the Bell has just opened a brand new exhibit, called Audubon and the Art of Birds, which is centered around some of these beautiful originals of Audubon's wonderful illustrations. I attended the preview a couple weeks back and let me tell you, it is a chance in a lifetime to see these rare and beautiful natural history illustration masterpieces. The exhibition opened on October 5th and runs in two sections. Right now, 33 of Audubon's mammoth prints grace the walls of the exhibit (along with illustrations by other bird artists) then other restored mammoth prints of Audubon illustrations will be rotated in during a two week shutdown in January, and the exhibit's second half reopens on February 1st. Find more information about the exhibition here.

On the lookout for birds: Visitors to Hawk Ridge Bird Observatory scan the skies for migrating raptors above Duluth, Minnesota.
On the lookout for birds: Visitors to Hawk Ridge Bird Observatory scan the skies for migrating raptors above Duluth, Minnesota.Courtesy Mark Ryan
Last week, my wife and I took a day-trip to Duluth and stopped at Hawk Ridge Bird Observatory, located on Skyline Parkway overlooking the east end of the city. The site is a favorite autumn destination for bird-watchers of all kinds. Snared and tagged raptor: Hawk Ridge volunteer Jessica displays the wing of a sharp-shinned hawk.
Snared and tagged raptor: Hawk Ridge volunteer Jessica displays the wing of a sharp-shinned hawk.Courtesy Mark Ryan
Official bird-counters were still there tabulating hawks, eagles and other raptors migrating south for the winter. The count will continue through October. Set and release: a lucky Hawk Ridge visitor launches a banded sharp-shinned hawk back into the wild.
Set and release: a lucky Hawk Ridge visitor launches a banded sharp-shinned hawk back into the wild.Courtesy Mark Ryan
The birds don't like crossing the wide expanse of Lake Superior on their way south, so they funnel into Duluth to cross there. We only saw a couple birds in the air while we were there (some 680 had been counted earlier in the day), but a couple of hawks snared just down the road were brought up to the ridge overlook for banding and release. Volunteers tagged and recorded the hawks (a goshawk - Accipiter gentilis - and a sharp-shinned hawk - Accipiter striatus), then enlisted the help of a couple of lucky onlookers to release them back into the wild. It was a beautiful afternoon on the Ridge.

LINKS
Object of the Month
Audubon and the Art of Birds
Hawk Ridge Bird Observatory
View Birds of America prints via the University of Pittsburgh

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

Sep
16
2013

Fossil of Hallucigenia in Burgess Shale
Fossil of Hallucigenia in Burgess ShaleCourtesy ap2il via Flickr
One of the strangest creatures to emerge from the famed Burgess Shale in the mountains of British Columbia, is the rightly named Hallucigenia, a strange spiky, wormlike creature that once scuttled across the Cambrian sea bottom more than 500 million years ago. Originally considered a totally unique (and baffling) creature, Hallucigenia has now been linked to other similar-aged wormlike creatures found around the world.

Hallucigenia first came to light in 1909 after Charles Doolitle Walcott, an expert in trilobites and secretary of the Smithsonian Institute, discovered a Lagerstätte in the mountains of British Columbia that was unlike any other found before.

Location of Walcott Quarry as seen from Field, BC
Location of Walcott Quarry as seen from Field, BCCourtesy Mark Ryan
Located in Yoho National Park on a steep slope between Mount Field and Wapta peak above the railroad town of Field, B.C., Walcott's quarry produced some of the strangest creatures - many of them soft-bodied and rarely found in the fossil record. The rock section, previously known as the Stephens Formation became known as the Burgess Shale, after nearby Burgess Pass. In the years following the discovery, Walcott and other scientists studied the strange fossils in an effort to decipher them and the environment in which they had lived and died.

Because of the high degree of preservation, the creatures that made the fossils were most likely buried suddenly in some sort of giant underwater mudslide that quickly entombed an entire marine community in an anoxic environment where decomposition was stifled. A perfect environment for preserving the soft-bodied tissue.

Display model of Hallucigenia: Royal Tyrrell Museum in Drumheller, Alberta
Display model of Hallucigenia: Royal Tyrrell Museum in Drumheller, AlbertaCourtesy Mark Ryan
Some of the Burgess Shale denizens appeared to be of completely new and unknown phyla with bizarre and unfamiliar body plans and no known descendents in the modern age. Hallucigenia certainly led the pack in this department. The tiny strangely constructed worm was only about an inch in length and confounded Walcott and other scientists for more than a century. They couldn''t even say for sure which side was up or down. Early Hallucigenia fossils showed a row of seven tentacles along one side. The opposite side contained seven sets of stiff spikes that were interpreted to be legs. A truly bizarre, aptly named freak-show creature that would be right at home in your average nightmare.

New evidence can often turn an old idea on its ear - or in this case, on its back. Recent scrutiny of newer, better-defined Hallucigenia fossils has revealed another set of "tentacles", leading scientist to realize they had Hallucigenia all flipped around. What they once thought was its top side was actually its bottom. Its dorsal "tentacles" were actually its legs. And its spiky "legs" belonged on its back, probably to serve as protection against predators.

This information along with a new study published in Proceedings of the Royal Society B now places Hallucigenia within a group of other worm-like creatures whose fossils are found around the world, including China, Canada, Great Britain, and Australia. It also links it to a living group - Onychophora - the velvet worms that mostly inhabit the tropical forests of the Southern Hemisphere.

"They may not be exactly the same species, but they are all probably related to the same group of worm-like creature that we call lobopods," said Dr. Jean-Bernard Caron, curator of invertebrate paleontology at the Royal Ontario Museum and the study's lead researcher. Caron is an expert in Burgess Shale fossils and his study of Hallucigenia and other fossils from the formation continues to glean new knowledge about the strange creatures that existed in the so-called Cambrian Explosion. Check out Caron's Burgess Shale website. It's full of great information about the quarry and the incredible fossils found there.

Burgess Shale location: Walcott Quarry sets on steep slope in valley between Mt. Wapta and Mt. Field.
Burgess Shale location: Walcott Quarry sets on steep slope in valley between Mt. Wapta and Mt. Field.Courtesy Mark Ryan
Walcott's Burgess Shale quarry has been designated a World Heritage site. The only way to visit it (or the fossil fields on nearby Mt. Stephen) is through guided hikes led by either Parks Canada or The Burgess Shale Geoscience Foundation. The 10 hour round-trip hike (rated moderate to difficult) takes participants up 2500 feet in elevation to Mt. Fields and requires reservations and a deposit. Fossil collecting is prohibited but the views are said to be spectacular.
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SOURCE and LINKS
The Province story
The Burgess Shale at Smithsonian website
Dr. Caron's Burgess Shale website
Parks Canada Burgess Shale info