paleontology
voltagegate | July 12, 2007So how is it that spiders are more closely related to horseshoe crabs - marine arthropods that haven't changed much in the past 250 million years - than to a more obvious choice, the insects?
The answer to that question is more complex than you might think.
Up until the middle of the 20th century, before evolutionary theory was completely accepted by mainstream biology and supported by genetic analysis, taxonomists (scientists who place organisms in groups) classified organisms according to their modern anatomy. If organisms shared common physical structures (like chelicerae or mandibles)…
clock | July 10, 2007I am sometimes not aware that my blogospheric friends know each other well. So, for instance, I had no idea that Sean Carroll of Cosmic Variance blog and the crew at Project Exploration (see the brown square on my left side-bar) are friends. But apparently they are. So, Sean went dinosaur digging and dug out a bunch of bones of a new genus (and took pictures of the process).
mikethemadbiologist | July 5, 2007I've always thought if the evolutionary biologists who invented the term macroevolution--any evolutionary change at or above the level of species--knew the mischief that the creationists would do with it, they would have 'uninvented' the term right then and there.
I've been meaning to write about this for some time, but this post by ScienceBlogling Mike Dunford where he discusses a creationist who misuses macroevolution finally gave me the much needed kick in the assreason to do so. Creationists--some anyway--have built a cottage industry out of claiming that while they might accept '…
clock | June 26, 2007As more and more people are slowly coming out of the woodwork and revealing they are going to Science Foo Camp, I am getting more and more excited about it! Yes, I have registered and reserved my hotel room already.
Sure, people like Neal Stephenson and Carl Djerassi are going to be there (as well as all those bloggers I linked to before - see the link above), but I am so excited to be able, for the first time, to meet in person Gabrielle Lyons, the power behind Project Exploration (the link to their site has been on my sidebar - scroll down - for about a year now). I wrote about it in more…
voltagegate | June 25, 2007This post was from last July, when I suppose I felt like siphoning some science history into a blog post after reading a great post from Carel. Early 20th century paleontology was exciting stuff.
Tangled Bank # 59 is just itchin' to be read at Science and Reason.
My highly subjective pick of the bunch: A look at the Cambrian explosion from Rigor Vitae:
Everyone's talking about the Cambrian Explosion, it seems. While evolutionary biologists discuss the actual rate of adaptive radiation, a handful of creationists have hailed it as proof of...something...I forget exactly what. The Cambrian…
voltagegate | June 19, 2007From ScienceDaily/Press TV:
The ancestor of today's giant panda really was a pygmy giant panda, says Russell Ciochon, UI professor of anthropology. Ciochon is a co-author of an article published in the June 18-22 online edition of the journal Proceedings of the National Academy of Sciences (PNAS). Previous discoveries of teeth and other remains made between 1985 and 2002 had failed to establish the animal's size.
Ciochon says that the ancient panda (formally known as Ailuropoda microta, or "pygmy giant panda") was probably about three feet in length, compared to the modern giant panda, which…
grrlscientist | June 13, 2007tags: researchblogging.org, dinosaur, bird, fossil, Gigantoraptor erlianensis, China
An artist's painting of the newly discovered Gigantoraptor dinosaur, depicted with other smaller dinosaurs. Fossilized bones uncovered in the Erlian Basin of northern China's Inner Mongolia region show the Gigantoraptor erlianensis was about 26 feet in length and weighed 3,000 pounds. The discovery of the giant, birdlike dinosaur indicates a more complicated evolutionary process for birds than originally thought.
Image: Institute of Vertebrate Paleontology & Paleoanthropology (Beijing, China) [larger]…
clock | June 13, 2007China finds new species of big, bird-like dinosaur:
Eight meters (26 ft) long and standing at twice the height of a man at the shoulder, the fossil of the feathered but flightless Gigantoraptor erlianensis was found in the Erlian basin in Inner Mongolia, researchers wrote in the latest issue of Nature.
The researchers said the dinosaur, discovered in April 2005, weighed about 1.4 tonnes and lived some 85 million years ago.
According to lines of arrested growth detected on its bones, it died as a young adult in its 11th year of life.
What was particularly surprising was its sheer size and…
clock | June 9, 2007OK, it's been about 20 years since I was last in vet school and I have fogotten most of the stuff I learned there. But I remember a few things.
I clearly remember the Pathology class (and especially the lab!) and the Five Signs (or stages) of Death: pallor mortis (paleness), algor mortis (cooling), rigor mortis (stiffening), livor mortis (blood settling/red patches) and decomposition (rotting). The linked Wikipedia articles are pitifully anthropocentric, though, and there is much more cool stuff to learn when comparing various animals.
The most interesting of the five signs of death is…
clock | June 7, 2007A paper in press in Current Biology (press release here) looks at mitochondrial DNA of mammoths and advances a primarily environmental cause for the mammoth extinction. Razib explains why such a black-and-white dichotomy is unhealthy.
Looking at a different hypothesis, also environmental, for the mammoth extinction (comet impact), Archy places the black-and-white dichotomy in the historical context and tries to figure out why the environmental hypotheses are so popular nowadays, while extinction at the hands of human hunters is not a popular idea any more.
grrlscientist | June 7, 2007tags: researchblogging.org, archaeopteryx, dinosaurs, mammals, fossils
Archaeopteryx fossil showing the distinctive head-back death pose of many articulated fossilized birds, dinosaurs and early mammals. Archaeopteryx is an ancient feathered dinosaur. This specimen is at the Humboldt Museum, Berlin. The skull is approximately two inches long.
If you've looked at the articulated 150-million-year-old Archaeopteryx fossils, you probably have noticed that they all have a weirdly similar pose; their heads are thrown over their backs, mouths open and tail curved upwards. Scientists have been…
clock | June 2, 2007In response to my previous post on the subject, I received a following e-mail (personal information omitted) from Colorado:
I'm active in opposing this for many reasons including the forced removal of American citizens from their homes and lands by the U.S. Military, the reality that the expansion serves the purpose of a multinational miltary-industrial complex, the use of the military as a tool of economic development for Colorado Springs, and the destruction of thousands of pre-historic and historic sites including world-class dinosaur digs and track ways.
Here are a couple of things that…
voltagegate | May 30, 2007Until very recently, no direct ancestors of the red panda (Ailurus) were known. Most paleontologists link Ailurus with previous, raccoon-like (procyonoid) fossil animals - Cynarctis, Phlaocyon, Aletocyon - mainly by the similarities in their molars.
A closer relative was described in the 1970's, an animal 50% larger than Ailurus found in Europe and North America, appropriately named Parailurus anglicus. Researchers concluded from these fossils that the red panda's ancestry was based solely in North America:
Intermediate forms between Parailurus and Ailurus are not known. The smaller size…
clock | May 30, 2007These two articles in Colorado Springs Independent and Denver Post are just the latest in an ongoing saga about the move by the U.S.Army to expand its Fort Carson base to include an additional million acres of land full of historical and prehistorical monuments, from wall paintings to dinosaur fossils.
The Fort Carson base, as it is now, is partially a nature preserve (like many military facilities are), but expansion, apart from kicking out many local farmers by using eminent domain, will intrude into areas rich with historical artefacts, not to mention dinosaur bones and tracks, most still…
clock | May 19, 2007When Archy writes about mammoths that is automatically the Obligatory Reading of the Day - an amazing post!
voltagegate | May 15, 2007Welcome to the 5th edition of Oekologie, the 'sphere's only blog carnival focusing on ecology and environmental science. We are always looking for hosts (especially for October) and contributors, so please check out those tabs if you're interested in either.
Some of you may know that I have a tendency to mix in some history when hosting science carnivals. So, for the first themed edition of Oekologie, we will be using ancient and medieval Arabic nature writing to frame our moving monthly mag of biological interactions in the environment.
Zoology One of the most famous Arabic zoological…
clock | May 8, 2007An Ancient Bathtub Ring Of Mammoth Fossils:
Pacific Northwest National Laboratory geologists have put out a call for teeth tusks, femurs and any and all other parts of extinct mammoths left by massive Ice Age floods in southeastern Washington.
The fossils, in some cases whole skeletons of Mammathus columbi, the Columbian mammoth, were deposited in the hillsides of what are now the Yakima, Columbia and Walla Walla valleys in southeastern Washington, where the elephantine corpses came to rest as water receded from the temporary but repeatedly formed ancient Lake Lewis. PNNL geologists are…
grrlscientist | April 13, 2007tags: researchblogging.org, Tyrannosaurus rex, dinosaurs, birds, fossils
Repeated analysis of proteins from a fossilized Tyrannosaurus rex reveal new evidence of a link between dinosaurs and birds: Of the seven reconstructed protein sequences, three were closely related to chickens.
Image: NYTimes
It was once thought impossible to obtain actual soft tissue, such as proteins, from fossils, but the impossible has happened and now, two research teams who published reports in this week's Science describe their findings: the closest relative to the fearsome Tyrannosaurus rex is .. a chicken.…
voltagegate | March 23, 2007European researchers at several institutions have found evidence that supports another one of Darwin's speculations: A male roe deer's antlers are representative of the individual's attributes, and thus play a central role in sexual selection.
Jean-Michel Gaillard comments, "Our results provide evidence that antler size of male roe deer mainly reflects their age and body mass, and is more resilient to variation in environmental conditions such as climate, food resources, and density."
"Body mass and age are both reliable descriptors of individual quality in most vertebrates and have been…