Ice stalagmite. My furnace drowned during the recent floods in Boulder, and I replaced it with a high-efficiency furnace. The furnace discharges into a plastic pipe, which the technicians ran up the old flue. We are nearing the end of the first cold snap of the year, with nighttime temperatures running below 0 °F, and the condensation from the pipe evidently caused the ice stalagmite on the roof.
Recently in Evolution Category
I am a little bit late reporting this, but Josh Rosenau reported on November 26,
It’s a joy to be able to report on a sweeping victory for science education in Texas, and to be able to give an eyewitness report of the fight over the textbooks that will be used in that massive textbook market for years to come. The 2009 battle over Texas science standards made it quite possible that the textbooks adopted last week would be riddled with creationist claims, or would give creationist board members a toehold to demand that publishers rewrite their books or be left off of the state’s approved list. In the end, the books available to students will be solid, accurate, and honest about evolution and climate change.
25 years ago, according to a recent article in Science magazine, Richard Lenski put samples of E. coli bacteria into a dozen flasks filled with a solution of glucose and other nutrients, incubated them, stirred them, and every day removed 1 % and repeated the process, day after day, for 25 years (except for a brief interruption when he moved from one university to another). The author of the article, Elizabeth Pennisi, notes that Lenski’s bacteria
Photograph by Ben Rossi.
Photography contest, Honorable Mention.
Megachile rotundata – alfalfa leafcutting bee. Mr. Rossi adds, “I studied the mating behavior of these solitary bees for my PhD. This is a female sitting inside of a styrofoam nesting block, which is a styrofoam cube with many long tunnels running through it. The back of the block was resting against the glass inside of a glass tank, so I pointed my camera at one of the nesting holes from the outside of the tank.”
A new paper was recently published, and widely reported in the media, about a hominid skull discovered at the Dmanisi site in Georgia in 2005 (Lordkipanidze et al, 2013, Gibbons 2013). The fossil, D4500, is believed to belong to the same individual as a lower jaw fossil, D2600, previously found at the site. The combined skull, designated by the authors as “Skull 5” (the 5th skull from Dmanisi) is almost completely and perfectly preserved, making it one of the most spectacular finds in the entire hominid fossil record. And Dmanisi is rapidly becoming one of the most important sites ever found in the study of human evolution.
Skull 5’s brain volume of 546 cm3 is very small. The other Dmanisi skulls are between 600 cm3 and 730 cm3. (Earlier papers gave the size of the largest one as 780 cm3, but that estimate appears to have been reduced. By comparison, the average modern human brain size is 1350 cm3.) However the fossil also has a large and robust jaw bone, and a large and projecting face. This combination of a very small brain and a large face differs from all other known Homo fossils. The fossil is of a mature adult, and because of the robustness of the skull it is thought to belong to a male.
Scientists are naturally delighted at the discovery of such a superb fossil, but the real impact of Skull 5 comes from the conclusions that the authors have drawn from it.
The Dmanisi fossils are different enough from each other that had they been found at different locations, they might have been classified into different species. Similar differences have been used to create species such as Homo habilis and Homo rudolfensis in the past. The authors believe that the Dmanisi fossils all belong to one species, both because they all come from the same time and place, and because the pattern and amount of variability found between the skulls is similar to that found in populations of modern humans, chimpanzees, and bonobos.
Following that line of reasoning, they conclude that since a similar pattern of variation exists for all early Homo fossils in Africa, and in the absence of any evidence that the supposed different species of Homo were adapted to different ecological niches, the default and most parsimonious assumption should be that all of these fossils belong to a single highly variable lineage (though they recognize that this claim remains to be tested, and alternative scenarios exist). This would mean that Homo habilis, Homo rudolfensis, Homo ergaster and some other more obscure names did not really exist as separate species. The name of that single species would, for reasons of priority, be Homo erectus. Specimens allocated to H. ergaster would then be called Homo erectus ergaster, as a time-limited subspecies. The Dmanisi scientists had previously named a new species, Homo georgicus, for the Dmanisi fossils, but now retract that name and suggest that because the Dmanisi fossils arose from an ergaster population, they should be called Homo erectus ergaster georgicus.
We are looking to expand our genomics faculty by hiring a comparative genomicist. I’ve been at ASU for a couple years and everything about it has impressed me. The facilities and faculty are world class. The administration is very supportive. The faculty are very collaborative. The teaching loads are reasonable. Finding amazing undergraduates is trivial. Etc. Anyway, if you are on the job market in genomics/bioinformatics/evolutionary medicine you should apply.
Copy of Job Ad: http://cartwrig.ht/asu-sols-genomics-2013.pdf
Assistant Professor (JOB# 10593)
Arizona State University
School of Life Sciences
The School of Life Sciences and The Biodesign Institute at Arizona State University invite applications for a tenure-track faculty position at the level of Assistant Professor whose research focuses on comparison of biological systems at the genome scale. Anticipated start date is August 16, 2014. Preferred research methods may include but are not limited to theoretical, computational, populational, and empirical approaches to comparative and functional genomics. The successful candidate will be expected to develop an innovative, extramurally-funded, research program, teach at the undergraduate and graduate levels, and have a commitment to outreach and service. The successful candidate will be expected to mentor undergraduate and graduate students as well as postdoctoral fellows. A competitive start-up package and teaching load compatible with high research productivity will be provided.
Arizona State University has made a commitment to accelerating the translation of basic discoveries into practical benefits for society through the construction of state-of-the-art research facilities and the recruitment of world-class faculty members. The successful candidate will participate in university-wide health and/or sustainability initiatives supported by core facilities for functional genomics and next generation sequencing, functional proteomics, high throughput cellular screening, bioinformatics, high performance computing, and imaging. More information on genomic research opportunities at the Biodesign Institute and the School of Life Sciences at ASU can be found at http://genomics.asu.edu/.
Candidates must have a Ph.D. (or equivalent) in an appropriate field. Demonstrated teaching and research excellence is preferred.
Photograph by Louis Shackleton.
I saw a tweet wondering about what makes an animal a mammal:
So, I thought I’d go through a few of the common ideas about shared physical features of mammals.
What makes a mammal?
Is it giving live birth? Or having hair/fur? What about feeding their babies milk?
Well, kind of (I’ll tell you at the end what really does). First, let’s go through these three:
Photograph by Paul Blake.
Photography contest, Honorable Mention.
Xanthorrhoea australis – grass tree, Mount Michel (looking toward Mount Cordeaux), Great Dividing Range, southwest of Brisbane, Queensland, Australia.
by Carl Drews
What will happen to the Earth’s oceans as the level of dissolved CO 2 in the oceans increases? This post explores the likely consequences of this increase for plants and animals living in the oceans. We will not cover questions about the reality of climate change itself, nor the suggested causes of global warming (human-caused or natural).
The complexity of the earth system is such that nobody can be an expert on all aspects of the atmosphere, hydrosphere, and biosphere. Climate change involves many interrelated scientific disciplines. One of the great things about Panda’s Thumb is that it covers a wide range of scientific topics, and anyone can contribute their own expertise when their particular field comes up. I am sure that PT readers will correct me if I get something wrong here (and even if I don’t!).
Scientists meet up periodically to share their findings, usually at one or more annual meetings. We share results usually in oral presentations or in the form of a poster that we put up and stand near, in case anyone wants to engage in discussion.
I went to the annual meeting of the Society for Molecular Biology and Evolution (SMBE) this past summer. While at SMBE 2013 I saw several oral presentations, and perused through the posters, when I wasn’t presenting my own. I had a conversation with a PI who said something to the effect of, “I won’t attend a conference unless I am giving a talk.”
Okay, well, I suppose once one has obtained the level of status where talk invitations are constantly rolling in the door, I can understand being choosy about the presentation style for a conference. But, presumably, this PI will still have students and postdocs who will want to attend the conference, share their science, and get feedback on current projects. And most of those people will likely not have the prestige of giving a talk. So, how else to scientists share their results?
Photograph by Jeremy Lyon.
Photography Contest, Honorable Mention.
Cyclura lewisi – Grand Cayman blue iguana, Queen Elizabeth Botanic Park, Grand Cayman, Cayman Islands. Mr. Lyon writes, “Warning signs posted in the parking area inform visitors to check under their cars and behind their wheels before starting their vehicle. Unfortunately, road kills have played as large a role as any other in threatening the native population.
“A very recently declared species, the blue iguana is an example of a radiation event from the Cuban iguana, which has deposited subspecies on the other Cayman islands as well. Once critically endangered with wild individuals numbering little more than a dozen or so, this species has been brought back from the brink of extinction due to intensive conservation over the past few decades. The blue iguana is fighting threats from loss of habitat, invasions from imported common green iguanas, and predation from feral dogs and cats. Fortunately, the efforts of the wildlife conservationists have allowed the wild population to bound back to many hundred wild individuals in recent years.”