Monday, October 20, 2008
Life's Beginnings
In a quick break from SVP, just thought I'd mention an interesting article in Science that appeared on the 16th. Apparently, two fo Stanley Miller's students were going through his lab after his death and found a couple of samples fom his famous experiment on the creation of organic molecules in the primordial soup and decided to retest them. They found double the number of amino acids that Miller found 50 years ago. 22 amino acids were found, including all 20 of the ones used by living organisms today. They did note that the atmosphere back then did not have as much hydrogen as in Miller's experiment, but it did exist at those levels around volcanic outlets, prompting the idea that time and volcanoes may have helped spur the creation of life on Earth.
Sunday, October 19, 2008
Dinos at the SVP meeting
All of the abstracts for the talks and posters I will be mentioning can be found in the Journal of Vertebrate Paleontology, Volume 28, Supplement to Number 3.
I will start with the dinosaurs because 1) they are cool, 2) they are my favorite animal even though they aren't technically in my field of research any more than any other particular animal, and 3) everybody likes dinosaurs, right?
Schmitz gave an interesting talk during the Romer Prize session in which he looks at the orbits of dinosaurs and, after comparing them with modern animals, was able to determine that, even though most dinosaurs were indeed diurnal like commonly thought, many dinosaurs were most likely nocturnal or cathemeral (active all the time). All the pterosaurs he studied were diurnal, but Syntarsus was nocturnal, and Herrerosaurus and the larger (over 296 kg) herbivores were cathemeral.
Evans showed that hadrosaurine crests were unrelated to olfactory ability in that the olfactory region was not involved in the crest. He also showed that the sound estimated from the crest and the optimal hearing frequency based on inner ear casts matched quite nicely. Combine this with the finding that hadrosaurines had enlarged cerebral hemispheres, making them rather intelligent compared to most other dinosaurs, and the conclusion is that they had a complex social structure and their crests played a role in social signalling.
Tsuhiji discussed the first known complete skull of Avimimus, finding that it was a basal oviraptosaur with the horizontal canal of its semicircular canals being more avian than Archaeopteryx.
Hurlburt discussed dino brains, finding that while their forebrain percentages were in the low avian range, their cerebral EQs (cerebrumin proportion to body mass) placed them between reptiles and birds, but closer to reptiles.
Andy Farke did a decent job ruling out the shock absorber hypothesis for the frontal sinuses in ceratopsians and modern bovids, but couldn't say what if any function they might have had.
Longrich found that having feathers on the legs allowed Archaeopteryx to increase lift and reduces turning radius and drag thereby improving performance at low gliding speeds. He also found the original Berlin specimen had feathers preserved on its legs until overzealous preparators removed them. Interestingly he says this supports the arboreal origin of flight.
This puts him in direct opposition to Dececchi and Larsson, who looked at the anatomy of derived maniraptorans to see how well they compared to known claw or grip climbers and found their anatomy was all wrong to be arboreal, saying that, while they may have gotten into trees from time to time, they certainly weren't arboreal and were scansorial at best.
Zanno reprted a new phylogeny of therizinosaurs based on two new specimens, which broke up the presumed monophyly of therizinosaurs and oviraptors, putting therizinosaurs as basal maniraptora and ecologically convergent with oviraptors. Interestingly, this makes herbivory rather common in maniraptora, so they evolved from hypercarnivores into herbivores and omnivores with the derived manirpatora that were hypercarnivores secondarily derived it.
Barrett reviewed the hypothesis that dinosaurs coevolved with cycads and found no evidence that they either ate them or would have had problems even if they had and no association with large dinosaurs, so absolutely no evidence that dinosaurs in particular had anything to do with cycad evolution.
Carrano did another study of dino diversity in the late Maastricthian and found no evidence that dinos were on the decline in the Western US, but can't say globally as the data just isn't there.
Hayashi found that stegoasaur spikes had thick compact bone but ankylosaurs spikes and clubs had thin bone on their periphery so they clearly were doing something different with them.
Ok, it's getting late and there is much more to say, but for now, I will report on one last crazy thing. Witmer described the first detailed description of ankylosaur nasal passages and the best way to describe them is the crazy straw nose. I can honestly say I have never seen anything quite like it. The nasal passages, rather than having a series of paranasal sinuses, had a crazy twisted tortuous path through the head. Very odd.
I will start with the dinosaurs because 1) they are cool, 2) they are my favorite animal even though they aren't technically in my field of research any more than any other particular animal, and 3) everybody likes dinosaurs, right?
Schmitz gave an interesting talk during the Romer Prize session in which he looks at the orbits of dinosaurs and, after comparing them with modern animals, was able to determine that, even though most dinosaurs were indeed diurnal like commonly thought, many dinosaurs were most likely nocturnal or cathemeral (active all the time). All the pterosaurs he studied were diurnal, but Syntarsus was nocturnal, and Herrerosaurus and the larger (over 296 kg) herbivores were cathemeral.
Evans showed that hadrosaurine crests were unrelated to olfactory ability in that the olfactory region was not involved in the crest. He also showed that the sound estimated from the crest and the optimal hearing frequency based on inner ear casts matched quite nicely. Combine this with the finding that hadrosaurines had enlarged cerebral hemispheres, making them rather intelligent compared to most other dinosaurs, and the conclusion is that they had a complex social structure and their crests played a role in social signalling.
Tsuhiji discussed the first known complete skull of Avimimus, finding that it was a basal oviraptosaur with the horizontal canal of its semicircular canals being more avian than Archaeopteryx.
Hurlburt discussed dino brains, finding that while their forebrain percentages were in the low avian range, their cerebral EQs (cerebrumin proportion to body mass) placed them between reptiles and birds, but closer to reptiles.
Andy Farke did a decent job ruling out the shock absorber hypothesis for the frontal sinuses in ceratopsians and modern bovids, but couldn't say what if any function they might have had.
Longrich found that having feathers on the legs allowed Archaeopteryx to increase lift and reduces turning radius and drag thereby improving performance at low gliding speeds. He also found the original Berlin specimen had feathers preserved on its legs until overzealous preparators removed them. Interestingly he says this supports the arboreal origin of flight.
This puts him in direct opposition to Dececchi and Larsson, who looked at the anatomy of derived maniraptorans to see how well they compared to known claw or grip climbers and found their anatomy was all wrong to be arboreal, saying that, while they may have gotten into trees from time to time, they certainly weren't arboreal and were scansorial at best.
Zanno reprted a new phylogeny of therizinosaurs based on two new specimens, which broke up the presumed monophyly of therizinosaurs and oviraptors, putting therizinosaurs as basal maniraptora and ecologically convergent with oviraptors. Interestingly, this makes herbivory rather common in maniraptora, so they evolved from hypercarnivores into herbivores and omnivores with the derived manirpatora that were hypercarnivores secondarily derived it.
Barrett reviewed the hypothesis that dinosaurs coevolved with cycads and found no evidence that they either ate them or would have had problems even if they had and no association with large dinosaurs, so absolutely no evidence that dinosaurs in particular had anything to do with cycad evolution.
Carrano did another study of dino diversity in the late Maastricthian and found no evidence that dinos were on the decline in the Western US, but can't say globally as the data just isn't there.
Hayashi found that stegoasaur spikes had thick compact bone but ankylosaurs spikes and clubs had thin bone on their periphery so they clearly were doing something different with them.
Ok, it's getting late and there is much more to say, but for now, I will report on one last crazy thing. Witmer described the first detailed description of ankylosaur nasal passages and the best way to describe them is the crazy straw nose. I can honestly say I have never seen anything quite like it. The nasal passages, rather than having a series of paranasal sinuses, had a crazy twisted tortuous path through the head. Very odd.
News from the SVP meeting
Just got back from the annual meeting of the Society of Vertebrate Paleontology in Cleveland, where I reported on my work, but since I already know about mine, I won't report on it here other than to say it is devilishly difficult to reconstruct soft tissue from sediment traces, but there are things you can lean before prepping out a fossil. While I was gone, I missed the announcement of the first known vertebrate neck in tiktaalik, as reported in Nature (Downs, Jason P. et al. 2008. The cranial endoskeleton of Tiktaalik roseae. Nature vol. 455 (October 16), 925 -929). This is rather important as it provided a great advantage to the animal allowing it to turn its head without completely realigning its whole body. Downs gave a talk about this at the meeting, explaining that the head had several features making it more tetrapod-like, including the lack of an operculum and reduced hyomandibular bone that helped free up the neck and a more complex joints between skull bones reducing their mobility.
In the next several posts, I will relate several of the items I found interesting at the meeting, some of which you may hear about in other arenas, some you most likely won't.
In the next several posts, I will relate several of the items I found interesting at the meeting, some of which you may hear about in other arenas, some you most likely won't.
Friday, October 10, 2008
Civic Science Literacy in the United States
Yesterday I got the latest issue of Science News, in which the editorial discussed science in politics. Coincidentally, I also went to a talk by Jon Miller, from Michigan State University titled, “Scientific Literacy and Citizenship in the 21st Century.” His main thesis was that many of our most pressing social and political issues are at their core scientific and that this will only increase as time passes. Unfortunately, most people do not have even a basic understanding of science and as such, can not even understand enough of the issue to intelligently discuss them let alone make policy decisions about them.
Many people have the idea that knowing the science is not required because common sense will allow figuring out enough to adequately make decisions. While that was true a hundred years ago, that is far from reality today. The issues are simply too broad scale and complex for standard common sense to work. Quite simply, if you can’t even understand the arguments, you can’t decide what to believe using rational thought.
His talk had good news and bad news. The good news is that the United States was second only to Sweden in the number of its citizenry that could pass a basic science test. The bad news is that we only rate 25% (for comparison, Sweden was just over 35% and the EU averaged only 15%. We have also improved in the last twenty years as we only rated 10% in 1988. However, with the issues facing us now, having only 1 in 4 of the population able to even begin to understand them is a serious danger to democracy.
So what brought our score down below Sweden? The rank of the US in understanding evolution is 33 out of 34 countries with only 40% accepting evolution, ahead of only Turkey. Iceland was number one with over 80% of their populace conversant in basic evolutionary concepts. The factor most strongly correlated with the rejection of evolution was religious fundamentalism, which actually strongly negatively correlated with science literacy of any kind.
The causes for these scores were seen to lie in two factors: our high schools and our universities. Our high schools rate virtually last in the world. He hypothesized that this was due to the fact that we are the only country to fund our schools using property taxes, which woefully underfunds our public schools. However, this is counterbalanced by our universities, which rate among the best. We are also the only country that requires virtually all college students to take a year of a core set of general education courses which include introductory science courses in addition to the three years required for their major. Apparently, in other countries, students only take the courses relating to their major. Thus, those not in the sciences never need take a science class. Unfortunately, only 28% have a college degree, which is behind many other countries.
He and his colleagues correlated several factors that affected science literacy. Despite what many people seem to think, gender was not a factor and he rightfully disparages the prevalent attitude that girls can’t do math and science. In fact, considering that women now outnumber men in colleges by over 6% and are increasing their dominance in colleges, young women are more likely than men to be scientifically literate.
The single biggest factor (with a correlation of .78) was having had the basic science courses in college. Because of this large effect, he advocated gearing these courses to increasing their effectiveness in enhancing adult continuing education. Other often discussed effects were also evaluated, including internet use with a positive correlation of .39. Religious fundamentalism had the worst affect, with a negative correlation of .2. Interestingly, TV had no effect either positive or negative.
As a case study, he specifically studied attitudes toward climate change. They were only able to account for 30% of the variance, but of that 30%, the overriding factor was political party. Republicans were likely to dismiss it, Democrats were more likely to think it was a serious concern. Of those that were concerned, they were able to account for most of the variance about who tried to do something about it, such as contacting their congressmen to talk about political issues. Being scientifically literate had a correlation of .41, but a bigger influence was seen by having children, with a correlation of .55. Climate change is an inherently long term issue. Apparently, having children causes people to give more consideration to things that affect their kids. Again, religious fundamentalism negatively correlated with concern about climate change. Of course, the majority of religious fundamentalists were Republican.
I’ll just finish this summary of his talk with two thoughts of his. “Civic scientific literacy provides a set of conceptual and practical tools…to make full use of the Internet and related information centers.” One good thing that Bush has done for the country is that “Political scientists no longer argue that is makes no difference who wins the elections.”
Many people have the idea that knowing the science is not required because common sense will allow figuring out enough to adequately make decisions. While that was true a hundred years ago, that is far from reality today. The issues are simply too broad scale and complex for standard common sense to work. Quite simply, if you can’t even understand the arguments, you can’t decide what to believe using rational thought.
His talk had good news and bad news. The good news is that the United States was second only to Sweden in the number of its citizenry that could pass a basic science test. The bad news is that we only rate 25% (for comparison, Sweden was just over 35% and the EU averaged only 15%. We have also improved in the last twenty years as we only rated 10% in 1988. However, with the issues facing us now, having only 1 in 4 of the population able to even begin to understand them is a serious danger to democracy.
So what brought our score down below Sweden? The rank of the US in understanding evolution is 33 out of 34 countries with only 40% accepting evolution, ahead of only Turkey. Iceland was number one with over 80% of their populace conversant in basic evolutionary concepts. The factor most strongly correlated with the rejection of evolution was religious fundamentalism, which actually strongly negatively correlated with science literacy of any kind.
The causes for these scores were seen to lie in two factors: our high schools and our universities. Our high schools rate virtually last in the world. He hypothesized that this was due to the fact that we are the only country to fund our schools using property taxes, which woefully underfunds our public schools. However, this is counterbalanced by our universities, which rate among the best. We are also the only country that requires virtually all college students to take a year of a core set of general education courses which include introductory science courses in addition to the three years required for their major. Apparently, in other countries, students only take the courses relating to their major. Thus, those not in the sciences never need take a science class. Unfortunately, only 28% have a college degree, which is behind many other countries.
He and his colleagues correlated several factors that affected science literacy. Despite what many people seem to think, gender was not a factor and he rightfully disparages the prevalent attitude that girls can’t do math and science. In fact, considering that women now outnumber men in colleges by over 6% and are increasing their dominance in colleges, young women are more likely than men to be scientifically literate.
The single biggest factor (with a correlation of .78) was having had the basic science courses in college. Because of this large effect, he advocated gearing these courses to increasing their effectiveness in enhancing adult continuing education. Other often discussed effects were also evaluated, including internet use with a positive correlation of .39. Religious fundamentalism had the worst affect, with a negative correlation of .2. Interestingly, TV had no effect either positive or negative.
As a case study, he specifically studied attitudes toward climate change. They were only able to account for 30% of the variance, but of that 30%, the overriding factor was political party. Republicans were likely to dismiss it, Democrats were more likely to think it was a serious concern. Of those that were concerned, they were able to account for most of the variance about who tried to do something about it, such as contacting their congressmen to talk about political issues. Being scientifically literate had a correlation of .41, but a bigger influence was seen by having children, with a correlation of .55. Climate change is an inherently long term issue. Apparently, having children causes people to give more consideration to things that affect their kids. Again, religious fundamentalism negatively correlated with concern about climate change. Of course, the majority of religious fundamentalists were Republican.
I’ll just finish this summary of his talk with two thoughts of his. “Civic scientific literacy provides a set of conceptual and practical tools…to make full use of the Internet and related information centers.” One good thing that Bush has done for the country is that “Political scientists no longer argue that is makes no difference who wins the elections.”
Monday, October 6, 2008
Dinosaur/Bird connection even stronger
Vargas AO, Kohlsdorf T, Fallon JF, VandenBrooks J, Wagner GP (2008) The Evolution of HoxD-11 Expression in the Bird Wing: Insights from Alligator mississippiensis. PLoS ONE 3(10): e3325. doi:10.1371/journal.pone.0003325.
This paper, published Oct.3rd, puts another nail in the coffin of the arguments against the dinosaurian origins of birds. One of the biggest arguments used to "disprove" the dino/bird relationship was that, using embryological evidence, birds have digits 2, 3, and 4 on their hands and lost digits 1 and5, but dinosaurs have digits 1, 2, and 3 and lost digits 4 and 5. Morphologically, bird fingers look like digits 1, 2, and 3, just like dinosaur digits. Vargas and crew looked at the activity of the HoxD-11 in crocodiles, birds and mammals. Mammals express HoxD-11 in digits 2-5, but not in 1, crocs express HoxD-11 in digits 2-5, but not in 1. Guess what? Birds express HoxD-11 in digits 2 and 3, but not in digit 1. So birds do not in fact have digits 2, 3, and 4 like the people who disagree with the dino-bird theory. So their biggest argument has now been quite convincingly obliterated. Think we can end this debate now?
This paper, published Oct.3rd, puts another nail in the coffin of the arguments against the dinosaurian origins of birds. One of the biggest arguments used to "disprove" the dino/bird relationship was that, using embryological evidence, birds have digits 2, 3, and 4 on their hands and lost digits 1 and5, but dinosaurs have digits 1, 2, and 3 and lost digits 4 and 5. Morphologically, bird fingers look like digits 1, 2, and 3, just like dinosaur digits. Vargas and crew looked at the activity of the HoxD-11 in crocodiles, birds and mammals. Mammals express HoxD-11 in digits 2-5, but not in 1, crocs express HoxD-11 in digits 2-5, but not in 1. Guess what? Birds express HoxD-11 in digits 2 and 3, but not in digit 1. So birds do not in fact have digits 2, 3, and 4 like the people who disagree with the dino-bird theory. So their biggest argument has now been quite convincingly obliterated. Think we can end this debate now?
Acid makes the oceans louder
In a study in the most recent Geophysical Research Letters, Keith Hestor and crew calculated that the predicted drop in oceanc pH of 0.3 points over the next 40 years will cause a 70% increase in the distance sound will travel in the oceans. It's not really understood why this happens but it is known that acidity increases the sound conductance of seawater. What was surprising was how much the rather modest decrease in pH would affect the conductance.
Life in the Cretaceous polar seas
Karen Chin and several coauthors published an interesting (to me at least) paper in the Proc. R. Soc. B online journal August 19 called "Life in a temperate Polar sea: a unique taphonomic window on the structure of a Late Cretaceous Arctic marine ecosystem " (DOI
10.1098/rspb.2008.0801). Through study of the sediments and fossils within the late Cretaceous rocks on Devon Island, Canada, they were able to deduce that a thriving ecosystem lived in temperate waters in the polar seas. Whereas the modern ecosystem is supported by nutrient upwelling, the paleo ecosystem appears to have been supported by terrestrial forests that contributed abundant nutrients to the marine waters. So, while it may not have been exactly warm, at least there wasn't constant ice. Whatever lived there still had to deal with long cold nights though, but at least there was plenty of food.
10.1098/rspb.2008.0801). Through study of the sediments and fossils within the late Cretaceous rocks on Devon Island, Canada, they were able to deduce that a thriving ecosystem lived in temperate waters in the polar seas. Whereas the modern ecosystem is supported by nutrient upwelling, the paleo ecosystem appears to have been supported by terrestrial forests that contributed abundant nutrients to the marine waters. So, while it may not have been exactly warm, at least there wasn't constant ice. Whatever lived there still had to deal with long cold nights though, but at least there was plenty of food.
Sunday, October 5, 2008
World's Oldest Footprints
Man I wish I could have gone to the Geological Society of America meeting going on right now. A huge meeting with lots of great stuff, such as this talk reported by LiveScience.com given today reporting on the oldest known footprints. Soo-Yeun Ahn, a graduate student at Ohio State University presented a poster about a 570 million year old track site discovered in Nevada by his advisor, Dr. Loren Babcock in 2000. the track is apparently a centipede-like creature. Oh well, I am sure that the Society of Vertebrate aleontology will have tons of cool stuff (actually, I know it will, but I am not allowed to say anything about it until it is presented at the meeting because of the news embargo to allow the presenters to be the first to present their cool stuff to the world).
Wednesday, October 1, 2008
Dinosaur had avian air sacs redux
Sereno has come out with a new paper (Sereno PC, Martinez RN, Wilson JA, Varricchio DJ, Alcober OA, et al. (2008) Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina. PLoS ONE 3(9): e3303). In this paper he introduces a new dinosaur by the name of Aerosteon riocoloradensis, which falls out as a basal tetanuran, down with the allosauroids. But the main part of the paper lays out Sereno's view of the evolution of avian air sacs within the dinosaurs. Seeing as Pat O'Connor has published on this topic previously and his office is right down the hall from mine, I was a bit miffed at how dismissively Sereno treated Pat's work. While I have some issues with the paper, not least of which is that he seems to be saying basically the same thing as Pat while dissing him at the same time, I do think he does bring some additional points to the table and advances the discussion. It remains to be seen whether or not his claims hold up, but that's ok, it spurs debate and research, which is a good thing. The paper is worth a read.
Sympatric speciation through sensory isolation
Many people have claimed that new species have to be created by geographic isolation, that is, they do not believe that sympatric speciation (new species arising from a population in the same area) can happen. I personally think that is hogwash and it can certainly happen. A nice case in point is an article in the October 2 Nature by Seerhausen et al. called "Speciation through sensory drive in cichlid fish." Cichlids are amazingly diverse and many species occur alongside other species of cichlids. Seerhausen et al. studied several species that occur sympatrically when considering just two-dimensional geography, but occur at different depths. The species are different colors and their visual sensitivity matches the change in light absorption at the corresponding depth, meaning their eyes are optimized for lack of a better word for the depth at which they live and their coloration shows corresponding adaptation. it is fairly clear that these species all originated from the same ancestor that lived at all depths but then speciated by adapting to specific depths. The case could be argued that this depth separation counts as allopatric, or geographic separation, but I think that would be stretching the definition a bit thin as nothing prevents the fish from swimming throughout all depths other than their preferences.
International Dinosaur Month
Ah, the wonderful days leading up to meetings, when one realizes they have monthsof work to do in a few short weeks. Ok, so I've been bad and there has been lots of cool stuff that has come out, including a new group of whales to go along with a new fossil whale as published in the latest journal of Vertebrate Paleontology, but for right now let me just say that today is the start of International Dinosaur Month. Go hug your local paleontologist and enjoy your local dinosaurian fauna, either by doing some birdwatching or by eating some fried chicken I hope I don't have to tell you that birds evolved from dinosaurs and are thus technically dinosaurs themselves, right?).
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