Hi all,
We have decided to stick with Thursdays at 5 pm for our weekly meetings. I will be choosing the first paper for discussion. Please email me if you would like to present a paper (dfraser1@connect.carleton.ca). I will be making a Google calendar so people can schedule themselves and also see who else is scheduled. I'll get to it eventually! I promise!
See you next week. Look for my annoyingly frequent emails.
Thursday, September 29, 2011
Wednesday, September 28, 2011
Pterosaurs were capable of powered flight
Palmer and Dyke (2011) analyze the flight dynamics of pterosaurs (http://rspb.royalsocietypublishing.org/content/early/2011/09/22/rspb.2011.1529.abstract).
According to Palmer and Dyke, pterosaurs would not have been capable of powered flight if previous reconstructions are accurate. The author's suggest new configurations of the wing membrane that would have enabled powered flight in giant pterosaurs such as Quetzalcoatlus.
According to Palmer and Dyke, pterosaurs would not have been capable of powered flight if previous reconstructions are accurate. The author's suggest new configurations of the wing membrane that would have enabled powered flight in giant pterosaurs such as Quetzalcoatlus.
Tuesday, September 27, 2011
Saturday, September 24, 2011
Mammalian Evolution
I found an interesting paper that is in early online edition with Science. The paper is titled "Impacts of the Cretaceous terrestrial revolution and KPg extinction on mammalian diversification" by Meredith et al. (2011). Unfortunately, I was unable to access the PDF yesterday at school (database failure I suppose) so I will have to base my discussion on the abstract.
The authors constructed a "molecular supermatrix" and used it to build a large mammalian phylogeny using multiple fossil calibrations. Importantly, they find support for the "long fuse" model of mammalian diversification, which predicts that the mammalian orders we know today diversified after the KPg boundary. These results seem to agree with Bininda-Emonds et al. (2007) The delayed rise of present day mammals in that both studies show long evolutionary fuses. However, they appear to disagree on one important point, the impact of the KPg boundary on mammalian diversification. Meredith et al. (2011) state that their phylogeny suggests that the KPg extinctions and subsequent opening of niches was very important in the diversification of modern mammals. In contrast, Bininda-Emonds (2007) do not find a significant effect of the KPg mass extinction.
Meredith et al. (2011) suggest that their methods are superior and the reason for this difference in interpretation. For those of you who do not know, Bininda-Emonds (2007) used supertree analyses. Essentially, many trees from the literature are glued together (I assure it is more complex than this). Meredith et al. (2011) use a "molecular supermatrix." I am not presently aware of what a molecular supermatrix is besides that it is a large matrix based on molecular data. As a result, I have no basis for judging which method would be "most accurate." My "gut feeling" is to agree with Meredith et al. because I can envision the component trees of a supertree coming from very divergent sources, some more reliable than others. I will return to this issue once I have accessed the full Meredith et al. (2011) article, however.
The authors constructed a "molecular supermatrix" and used it to build a large mammalian phylogeny using multiple fossil calibrations. Importantly, they find support for the "long fuse" model of mammalian diversification, which predicts that the mammalian orders we know today diversified after the KPg boundary. These results seem to agree with Bininda-Emonds et al. (2007) The delayed rise of present day mammals in that both studies show long evolutionary fuses. However, they appear to disagree on one important point, the impact of the KPg boundary on mammalian diversification. Meredith et al. (2011) state that their phylogeny suggests that the KPg extinctions and subsequent opening of niches was very important in the diversification of modern mammals. In contrast, Bininda-Emonds (2007) do not find a significant effect of the KPg mass extinction.
Meredith et al. (2011) suggest that their methods are superior and the reason for this difference in interpretation. For those of you who do not know, Bininda-Emonds (2007) used supertree analyses. Essentially, many trees from the literature are glued together (I assure it is more complex than this). Meredith et al. (2011) use a "molecular supermatrix." I am not presently aware of what a molecular supermatrix is besides that it is a large matrix based on molecular data. As a result, I have no basis for judging which method would be "most accurate." My "gut feeling" is to agree with Meredith et al. because I can envision the component trees of a supertree coming from very divergent sources, some more reliable than others. I will return to this issue once I have accessed the full Meredith et al. (2011) article, however.
Thursday, September 22, 2011
Stolen Post - Body Size Evolution
I was reading Jerry Coyne's blog (http://whyevolutionistrue.wordpress.com/2011/09/22/want-evolutionary-change-wait-a-million-years/) this morning and realized I had downloaded this (http://www.pnas.org/content/108/38/15908.abstract) paper when it was in the early edition and completely forgotten about it. I will spare you a detailed commentary on the paper as Jerry Coyne does a much better job than I would. In short, the paper looks at body size evolution for several vertebrate groups (mammals, squamates, and birds) using both fossil and modern datasets. They found that body size is bounded over time intervals shorter than 1 Ma. On time scales longer than 1 Ma, they found bursts of body size evolution.
This is evidence for punctuated equilibrium but the authors do not use this terminology in the paper. They also do not cite Eldredge and Gould. Am I wrong to expect them to? They do, however, cite Gould's book on The Structure of Evolutionary Theory. I suppose that will suffice.
This is evidence for punctuated equilibrium but the authors do not use this terminology in the paper. They also do not cite Eldredge and Gould. Am I wrong to expect them to? They do, however, cite Gould's book on The Structure of Evolutionary Theory. I suppose that will suffice.
Sunday, September 18, 2011
Organizational Meeting September 29th 5 pm
The doodle poll has spoken. Unfortunately it was very close but I am sticking to "majority rules." We will meet Thursday September 29 5 pm at Mike's Place. We will discuss what day and time to meet weekly. I suspect the doodle poll will help with this. For those of you who can't meet until 5:30 we can change the meeting time to then but I will mention that it usually takes everyone a half hour to procure a beer and get situated. Being a bit late is no "biggy."
I will reserve a table because Mike's Place tends to be busy on Thursdays. This might be one point of discussion for scheduling the rest of the meetings! Oliver's tends to be less busy so if we find that Mike's is too crazy, we can migrate.
See you September 29 at 5 pm
Thursday, September 15, 2011
Additional Paleo News
To supplement the papers that Dani discussed below, here is a paper that made the rounds in the popular media today:
http://www.sciencemag.org/content/333/6049/1619.abstract
http://www.cbc.ca/news/technology/story/2011/09/15/science-dinosaur-feathers.html
To make a short story shorter, the paper reports evidence of non-avian dinosaur feathers preserved in amber from Alberta.
T
Big Papers
The September 9 issue of Science is dominated by the discovery of Australopithecus sediba.Here is the link to the main paper on the subject (http://www.sciencemag.org/content/333/6048/1421.short). The specimens pre-date the first occurrences of Homo (our genus) in the fossil record. According to the authors, this means that A. sediba is a potential candidate as the direct ancestor to Homo. The authors use careful wording saying that A. sediba "cannot be precluded as an ancestor to Homo," which is true. At least they recognize how difficult it is to identify direct ancestors in the fossil record (in fact, I think you would need some OUTSTANDING evidence to make that argument). Either way, the specimens seem interesting and there are several other papers in the same issue on A. sediba.
The fall issue of Paleobiology also contains an interesting paper on the evolution of diet and tooth wear in fossil whales (http://www.bioone.org/doi/abs/10.1666/10038.1). The authors investigated wear facet patterns and stable isotopes in several artiodactyl (even-toed hoofed mammals) groups and sister groups to modern whales. They found that whale tooth wear was much different from their closest relatives (the artiodactyls) and conclude that fossil whales changed their diet before the evolution of morphological changes to the jaw and tooth crowns. This is an interesting result that should keep us palaeoecologists on our toes!
Finally, the September 2 issue of Science contains an interesting paper on a new woolly rhino (http://www.sciencemag.org/content/333/6047/1285.short). The age of the fossil assemblage and the morphology of the rhino suggest that the woolly variety evolved in Tibet prior to the onset of the Pleistocene ice age. The authors conclude that the "woolliness" was a pre-adaptation that enabled the megaherbivores to survive the cold Pleistocene. I don't like the term pre-adaptation because it seems to suggest that the rhinos were psychic and grew hair because they knew the ice age was coming. Of course, this is not what they mean but I would prefer the use of different terminology (and throwing out the term pre-adaptation altogether in fact). What they really mean is that faunas adapted to the cold Himalayan environment probably gave rise to the woolly animals of the Pleistocene.
The fall issue of Paleobiology also contains an interesting paper on the evolution of diet and tooth wear in fossil whales (http://www.bioone.org/doi/abs/10.1666/10038.1). The authors investigated wear facet patterns and stable isotopes in several artiodactyl (even-toed hoofed mammals) groups and sister groups to modern whales. They found that whale tooth wear was much different from their closest relatives (the artiodactyls) and conclude that fossil whales changed their diet before the evolution of morphological changes to the jaw and tooth crowns. This is an interesting result that should keep us palaeoecologists on our toes!
Finally, the September 2 issue of Science contains an interesting paper on a new woolly rhino (http://www.sciencemag.org/content/333/6047/1285.short). The age of the fossil assemblage and the morphology of the rhino suggest that the woolly variety evolved in Tibet prior to the onset of the Pleistocene ice age. The authors conclude that the "woolliness" was a pre-adaptation that enabled the megaherbivores to survive the cold Pleistocene. I don't like the term pre-adaptation because it seems to suggest that the rhinos were psychic and grew hair because they knew the ice age was coming. Of course, this is not what they mean but I would prefer the use of different terminology (and throwing out the term pre-adaptation altogether in fact). What they really mean is that faunas adapted to the cold Himalayan environment probably gave rise to the woolly animals of the Pleistocene.
Monday, September 12, 2011
General Info and Organizational Meeting
First of all, welcome back or welcome for the first time. I am Dani and you will be hearing a lot more from me as the semester goes on. I am a PhD student in the biology department. You will also be hearing from Thomas, an MSc student in geology.
The mandate of this group is to discuss high quality research in the areas of evolution and palaeontology. We try to discuss topics that will interest all of us. This means we don't discuss descriptions or studies with a narrow focus. For newcomers, excellent papers for discussion are most often found in the journals Nature, Science, Proceedings of the National Academy of Sciences, and Proceedings of the Royal Society B. Our discussions are by no means restricted to these journals, however. If you wish to see some of the papers we discussed last year please see our older posts.
If you would like to contribute to the blog, please email me (dfraser1@connect.carleton.ca) and I can give you the appropriate privileges after you create a blogspot account. Blog posts should be on the topics of evolution and/or palaeontology. I encourage posting links to interesting papers. Please keep in mind that journal articles are copyrighted and should not be uploaded to the blog. If anyone does so their privileges will be revoked. Additionally, if any inappropriate comments or "author bashing" (making negative comments about authors we have discussed) is found on the blog, your privileges will also be revoked. The blog is public access and all of our professional reputations are "on the line."
Now that the nasty business is out of the way, I can get to my primary reason for writing this post. We need to have an organizational meeting so we can determine what day of the week to meet (last year it was Wednesdays at 5:30 pm) and we need to schedule the first few people to choose papers. In keeping with tradition, I will probably choose the first paper (time and date to be determined) because I would like to set the tone for the discussion group. This year we're going to be a little more technological. Please fill out the following doodle poll. I will be cruel and schedule the meeting using "majority rules."
Once we have the date chosen, I will send another email to inform everyone. I will then be creating a google calendar that we can use for scheduling presenters. You will all be given access (provided you have a google account).
Can't wait to see everyone and to meet the newbies!
Sunday, September 11, 2011
Stephen Jay Gould
Yesterday was Stephen Jay Gould's birthday (1941 to 2002). I admit to not being familiar with all of his work. I have, however, read a large section of his book "The Structure of Evolutionary Theory" as well as several of his papers including his 1972 paper with Eldredge on Punctuated Equilibrium (Punctuated Equilibria: an alternative to phyletic gradualism) and his 1979 paper with Lewontin on spandrels (The spandrels of San Marco and the Panglossian Paradigm). I'll spare you a summary of these papers. Needless to say, Stephen Jay Gould has been an enormous influence for all palaeontologists and evolutionary biologists regardless of their agreement or disagreement with his hypotheses and ideas.
When I started graduate school in 2008 (my MSc), the first class I took was a group examination of Gould's final book. We did a lot of whining about how long and wordy the book is. Three years after taking that course, one year into my PhD, I realize that reading his book was an unparalleled experience. Having read it so early in my graduate career, it has really shaped the way I think about evolution (whether this is good or bad is in the eye of the beholder).
So thank you Gould and happy belated birthday!
If you would like to read more about Stephen Jay click the link below and download his papers (you might actually have to go to the library to read about PE). You won't regret it.
http://stephenjaygould.org/
When I started graduate school in 2008 (my MSc), the first class I took was a group examination of Gould's final book. We did a lot of whining about how long and wordy the book is. Three years after taking that course, one year into my PhD, I realize that reading his book was an unparalleled experience. Having read it so early in my graduate career, it has really shaped the way I think about evolution (whether this is good or bad is in the eye of the beholder).
So thank you Gould and happy belated birthday!
If you would like to read more about Stephen Jay click the link below and download his papers (you might actually have to go to the library to read about PE). You won't regret it.
http://stephenjaygould.org/
Saturday, September 10, 2011
Evolution is most definitely true
I suppose we should start this year off with a bit about why evolution is true. I doubt I need to convince anyone who is reading this blog of that fact but I think we will all enjoy a lecture by Jerry Coyne (Author of the book "Why Evolution is True").
Enjoy!
http://www.youtube.com/watch?v=w1m4mATYoig&feature=player_embedded
The rest of the videos can be found at:
http://commonsenseatheism.com/?p=4383
The rest of the videos can be found at:
http://commonsenseatheism.com/?p=4383
Friday, September 9, 2011
Thursday, September 8, 2011
Science!
Brad sent me this abstract. Definitely goes up there as one of the 'best' abstracts I have ever read. Lets just say I'm looking forward to the paper...
http://gsa.confex.com/gsa/2011AM/finalprogram/abstract_197227.htm
Also, as Dani mentioned in the previous post, the new semester is upon us and it's almost time to get the discussion meetings running again. If you are interested in contributing and/or attending meetings, please contact Dani (dfraser1@connect.carleton.ca) or myself (tcullen@connect.carleton.ca).
- T
Wednesday, September 7, 2011
New Semester!
Hi all,
The new semester is upon us and that means I will begin updating the blog once again. If you're interested in receiving weekly emails from the discussion group please email me at dfraser1@connect.carleton.ca.
Every week I will post a link to the focal paper and will post a summary of our discussion. I also tend to post interesting evolution and paleontology papers as I come across them.
I will be sending around an email relatively shortly about an organizational meeting (an excuse to drink beer at Mike's Place!).
The new semester is upon us and that means I will begin updating the blog once again. If you're interested in receiving weekly emails from the discussion group please email me at dfraser1@connect.carleton.ca.
Every week I will post a link to the focal paper and will post a summary of our discussion. I also tend to post interesting evolution and paleontology papers as I come across them.
I will be sending around an email relatively shortly about an organizational meeting (an excuse to drink beer at Mike's Place!).
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