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Evolutionary Biology, Life Science, Science Education, Human Evolution, and Stuff.
Greg Laden
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- December 16, 2008
- 10:25 AM
- 1,780 views
Coffee as a source of biodiesel: A closer look
by Greg Laden in Greg Laden's Blog
Owing to popular demand among the readership of this blog, I've taken a closer look at the original article claiming that spent coffee grounds can be employed as a source of fuel. There are several important details that come though in the paper coming out in the next issue of the Journal of Agricultural and Food Chemistry that have not come through in the press reports. Read the rest of this post... | Read the comments on this post...... Read more »
Kondamudi, NarasimharaoMohapatra, Susanta, & Misra, Mano. (2008) Spent Coffee Grounds as a Versatile Source of Green Energy. Agicultural and Food Chemistry.
- November 28, 2008
- 09:01 PM
- 1,737 views
The Political Gender Gap
by Greg Laden in Greg Laden's Blog
A new study published by Chiao et al. in the journal PLoS ONE explores the gendered nature of American voting behavior. Subjects were asked to rank politicians -- based only on photographs of each politician's face -- along different quality scales, and also to choose among these photographs who should be President. The study concludes that male and female candidates are evaluated on distinctly different terms, and that male and female voters do this evaluation in somewhat (but not dramatically) different ways. The authors conclude that "...contrary to popular notions, people are not necessarily using deliberate and rational strategies in deciding who to vote for, especially when it comes to (voting for) women." Well, duh. I think we already knew that. But despite the obvious naivete of the researchers in this particular statement, their study is still interesting and well done, and I'd like to explore it a bit further. Read the rest of this post... | Read the comments on this post...... Read more »
Joan Y. Chiao, Nicholas E. Bowman, & Harleen Gill. (2008) The Political Gender Gap: Gender Bias in Facial Inferences that Predict Voting Behavior. PLoS ONE, 3(10). DOI: 10.1371/journal.pone.0003666
- November 12, 2008
- 07:54 AM
- 1,660 views
The Emergence of Treatment-Resistant Fungus
by Greg Laden in Greg Laden's Blog
It is hard to kill fungus. Well, not really. They can't handle being burned and chlorine does them in and lots of other chemicals are bad for hem. But when a fungus infects a person ... like with Aspergillos, an infection with Aspergillus in the lungs, fungi are tricky. To kill an infectious agent, one typically poisons it somehow, but to ingest, inject, inhale, or even topically apply a chemical may also affect the person. The reason it is relatively easy to kill an infecting bacterium than it is to kill an infecting fungus is, in part, because fungi are phylogenetically more closely related to human than are bacteria, and share more of their basic cellular process. Therefore a treatment that might kill the infecting cell by interfering with a basic process may also interfere with the health of the human in the case of a fungal infection. With bacteria, there is a wider range of possible poisons that will affect the bacterium but not the humans.
By the way, a common side effect of anti-bacterials is disruption of normal digestive process in humans. This is because some of our digestive process requires a healthy flora of bacteria. Some bacteria are an extension of our digestive organs, and they are negatively affected when we try to kill a bacterial infection elsewhere in our bodies.
This is an evolutionary explanation for this important biological pattern which, in turn, is an important context in which infectious disease is better understood. Evolution is important in understanding medical physiology although, astonishingly, many medical physiologists don't seem to get this (Indeed, the word "evolution" does not appear in this paper except in the bibliography). But I digress.
The point of this post is to highlight some resent research (Published in PLoS) indicating that resistant strains have merged of Aspergillus fumigatus, which is species of Aspergillus that causes one nasty form of lung infection.
Read the rest of this post... | Read the comments on this post...... Read more »
Eveline Snelders, Henrich A. L. van der Lee, Judith Kuijpers, Anthonius J. M. M. Rijs, János Varga, Robert A. Samson, Emilia Mellado, A. Rogier T. Donders, Willem J. G. Melchers, & Paul E. Verweij. (2008) Emergence of Azole Resistance in Aspergillus fumigatus and Spread of a Single Resistance Mechanism. PLoS Medicine, 5(11). DOI: 10.1371/journal.pmed.0050219
- March 10, 2009
- 11:18 AM
- 1,646 views
A most amazing set of spoor
by Greg Laden in Greg Laden's Blog
Dino spoor, that is. A recently reported finding in PLoS ONE clarifies a number of questions about how certain dinosaurs held their front limbs (zombie/Frankenstein-position palm-down vs. huggie-wuggie palms-facing-each-other). This research confirms ...
that early theropods, like later birds, held their palms facing medially, in contrast to ... prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.
Figure 7 from the paper. Restoration by Heather Kyoht Luterman of Early Jurassic environment preserved at the SGDS, with the theropod Dilophosaurus wetherilli in bird-like resting pose, demonstrating the manufacture of SGDS.18.T1 resting trace.
The find is from southwestern Utah. In particular, the tracks were found in the Whitmore Point Member of the Moenave Formation (WP), which in turn is one of about nine or so formations that are exposed in Zion and Kolob canyons in Zion National Park. The WP Member itself is about 100 meters thick. The Moenave Formation and together with the Kayenta formation (just above it) are considered to be Lower Jurassic in age. The base of the Moenave formation is a disconformity caused when the basin was uplifted, and thus eroded, for about ten million years. Subsequent to this shallow seas to the north of this region repeatdly expanded or shifted into this area, and the sediments of the Moenave formatoi represent lake, river, and flood plain (river-side and beyond) sediments that were part of this sea basin.
Because of the constant (in geological time) shifts between environments, the Moenave Formation possesses layers bearing fossils and traces of a wide range of sediments. Within the WP Member itself, there are plant fossils in some of the lower layers, and fish fossils throughout. Dinosaur bones have been found in the upper most layer. But in many layers, from the lowest to nearly the uppermost, there at tracks. The tracks discussed in this paper are from the lower part of the formation.
Figure 2 from the paper: Stratigraphic section of the Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm. Resting trace and trackway SGDS.18.T1 is in the "Top Surface" of the Main Track-Bearing Sandstone Bed (indicated by the blue arrow) in the Whitmore Point Member of the Moenave Formation.
The reason that I'm pointing all of this out is to give an (accurate) impression of the significance of this basin (see this discussion). There are many hundreds of meters of sediment at Zion and other nearby locations (including the Grand Canyon) that tell the story of major changes in the landscape, and that preserve long, well represented records of life. Immense geological time is represented here, as well as the occasional brief and fleeting moments, like when some dinosaur lays down to rest and leaves behind an impression of its body, which happens, against all odds, to be preserved as a trace fossil. It is a paleontologists dream:
Twenty-five track-bearing horizons contained within a small area (1 km2) in St. George, Utah, contain a diverse, theropod-dominated ichnofauna. The most fossiliferous and diverse surface ... is preserved within the St. George Dinosaur Discovery Site at Johnson Farm ... museum. Mudflat, shoreline, and periodically submerged surfaces coincide on the same bedding plane as evidenced by mud cracks, ripple marks (current, symmetrical, wind-driven, interference, and wave-formed), erosive mega-ripples, load and flute casts, rill and tool marks of various sizes, raindrop impressions, and invertebrate and vertebrate ichnites. [an "ichnite" is a fossilized foot print.] This suite of sedimentary features formed on a beach or shoal along the shores of an Early Jurassic freshwater body (Lake Dixie) that underwent seasonal regressive-transgressive fluctuations. The majority of theropod trackways on this surface trend north-south, paralleling the paleoshoreline. The 22.3 m long SGDS.18.T1 trackway ... includes the unique crouching traces....
Figure 4 from the paper. Eubrontes trackway with resting trace (SGDS.18.T1) in the Whitmore Point Member of the Moenave Formation, St. George, Utah. A, Overhead, slightly oblique angle photograph of SGDS.18.T1 resting trace. Note normal Eubrontes track cranial to resting traces (top center) made by track maker during first step upon getting up. Scale bar equals 10 cm. B, Schematic of SGDS.18.T1 to scale with A: first resting traces (manus, pes, and ischial callosity) in red, second (shuffling, pes only) traces in gold, final resting traces (pes and ischial callosity) in green, and tail drag marks made as track maker moved off in blue. Note long metatarsal ("heel") impressions on pes prints. C, Direct overhead photograph and D, computerized photogrammetry with 5 mm contour lines of Eubrontes trace SGDS.18.T1. Color banding reflects topography (blue-green = lowest, purple-white = highest); a portion of the berm on which the track maker crouched is discernible. Abbreviations: ic = ischial callosity, lm = left manus, lp = left pes, rm = right manus, rp = right pes, td = tail drag marks.
Because early Jurassic dinosaurs of the type that left these tracks had relatively undifferentiated feet, it is impossible to assign these tracks to species. The tracks themselves, grouped together from different locations but looking similar, form what is called an "ichnotaxon" ... a species or set of species as represented by tracks of similar morphology. Indeed, when dealing with dinosaurs, perhaps we should say that a given ichnotaxon of this type may even represent a set of genera. The paper itself provides a lengthy discussion of this issue, if you want to delve into it.
The paper concludes that ...
... other ostensible theropod manus [manus = front foot] prints are either dubiously attributable to theropods, dubiously made by the manus of a pes-print [pes = back foot] maker, or uninformative with regard to the track maker's forelimb functional morphology. Because the crouching traces in the trackway [studies here] match the architecture of known theropods, we support the alternative interpretation that most, if not all, other prints showing manus impressions instead pertain to ornithischian or other non-theropodan dinosaurs or dinosauriforms with functionally tridactyl pedes. [This trackway] therefore includes the only unambiguous theropod manus impressions recognized to date and indicates that the avian orientation of the manus, with medially-facing palms, evolved very early within the Theropoda. Less parsimoniously, this posture evolved in immediate dinosaur ancestors; absence in other dinosaurs would thus constitute reversals.
The lack of marks in [this trackway] made by the distal thoracic and pelvic limbs and the ventral portion of the pelvis indicate that, while resting, even the earliest theropods adopted a modern ratite-like [bird-like] posture with the legs folded symmetrically beneath the body such that the weight of the body was distributed between each metatarsus and pes. ... The clear symmetry of [this trackway] demonstrates that even some of the oldest, basal-most theropods engaged in this additional avian-style behavior, which therefore also evolved very early in the theropod lineage or was retained in theropods from pre-dinosaurian archosaurs.
Background and references:
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Andrew R. C. Milner, Jerald D. Harris, Martin G. Lockley, James I. Kirkland, & Neffra A. Matthews. (2009) Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace. PLoS ONE, 4(3). DOI: 10.1371/journal.pone.0004591
- December 5, 2008
- 06:21 PM
- 1,644 views
Allen's Rule, Phenotypic Plasticity, and The Nature of Evolution
by Greg Laden in Greg Laden's Blog
Allen's Rule. One of those things you learn in graduate school along with Bergmann's Rule and Cope's Rule. It is all about body size. Cope's Rule ... which is a rule of thumb and not an absolute ... says that over time the species in a given lineage tend to be larger and larger. Bergmann's Rule says that mammals get larger in colder environments. Allen's Rule has mammals getting rounder in colder climates, by decreasing length of appendages such as limbs, tails and ears.
All three rules seem to be exemplified in human evolution. Modern humans tend to be larger and rounder in cooler environments than in tropical environments. Over time, the human lineage has gotten larger ... australopiths of the Miocene and Pliocene were smaller than Homo erectus and modern Homo sapiens. In comparing contemporary African modern humans and European Neanderthals, the latter are rounder and have shorter limbs, especially the distal parts of the limbs (forearms and the leg below the knees). In fact, this difference in body proportion is one of the key features that physical anthropologists use to distinguish between regular modern humans and Neanderthals when faced with that task.
Bunnies demonstrating Allen's rule.
The usual assumption is that these changes in body form are selected for as a result of various environmental pressures, and that these features of body size and shape become adaptive features seen in particular populations. The body shape story is part of the Darwinian story of adaptation as well as, in some cases, the story of racial differentiation among humans or other organisms.
And of course, it is all wrong, as usual.
Read the rest of this post... | Read the comments on this post...... Read more »
M. A. Serrat, D. King, & C. O. Lovejoy. (2008) Temperature regulates limb length in homeotherms by directly modulating cartilage growth. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0803319105
- February 4, 2009
- 10:01 AM
- 1,629 views
Did Triceratops fight with their faces?
by Greg Laden in Greg Laden's Blog
Or, more accurately, did these dinosaurs either engage in intraspecific combat (such as territorial or mating contests among males) or fight predators such as Tyrannosaurs, like in the movies?
Well, one thing we know for sure: If any folklore, belief, or 'fact' related to a fossil species sits around long enough, eventually someone will come along and study it. This usually involves reformulating the idea as one or more testable hypotheses, then attacking the hypotheses ... much like Tyrannosaurus might or might not have attacked Triceratops, to see if it can be killed, or alternatively, has the metal to survive for a while longer.
And thus, science progresses.
So now we have a paper entitled "Evidence of Combat in Triceratops" by Farke et al, just out in PLoS ONE. Read the rest of this post... | Read the comments on this post...... Read more »
Andrew A. Farke, Ewan D. S. Wolff, & Darren H. Tanke. (2009) Evidence of Combat in Triceratops. PLoS ONE, 4(1). DOI: 10.1371/journal.pone.0004252
- January 23, 2008
- 02:04 PM
- 1,602 views
After the End Permian Mass Extinction
by Greg Laden in Greg Laden's Blog
The end-Permian mass extinction event was the big daddy of all the known mass extinction events. Life on the planet Earth was almost entirely wiped out. A new paper explores the post-extinction recovery of ecological systems. Read the rest of this post... | Read the comments on this post...... Read more »
Sarda Sahney, & Michael Benton. (2008) Recovery from the most profound mass extinction of all time. Proceedings of the Royal Society B: Biological Sciences, -1(1), -1--1. DOI: 10.1098/rspb.2007.1370
- February 2, 2008
- 06:01 PM
- 1,580 views
The Great Potato Origins Debate May be Settled
by Greg Laden in Greg Laden's Blog
Solanum tuberosum, is an American cultivar related to the tomato and the eggplant (Remarkably, they are all in the same genus, but rarely to all three appear in the same dish). Potatoes, the lovely underground storage organ (USO) without which we would not have French Fries, or dipping chips to eat during the Super Bowl, twice baked potatoes, or Mr. Potato Head and his family, were domesticated by Native Americans in two local centers, one in the high Andes in eastern Venezuela and northern Argentina, and in the lowlands of south-central Chile. During the last half of the 16th century, th... Read more »
Mercedes Ames, & David Spooner. (2008) DNA from herbarium specimens settles a controversy about origins of the European potato. American Journal of Botony, 252-257. http://www.amjbot.org.floyd.lib.umn.edu/cgi/content/full/95/2/252
- March 12, 2009
- 11:41 PM
- 1,560 views
Palaeowomaen: Barbara Isaac, Women in The Field, and The Throwing Hypothesis
by Greg Laden in Greg Laden's Blog
The question of diversity in science, and more specifically, success for women, is often discussed in relation to bench or lab oriented fields. If you read the blogs that cover this sort of topic, they are very often written by bench scientists, for bench scientists, and about bench scientists. Which makes sense because most scientists probably are bench scientists.
Here I want to talk about a successful female social scientist with a strong connection to fieldwork, as well as theoretical and administrative contributions. This person is also someone who straddles the boundary between classic mid- to late-Twentieth Century patterns of professional activity (in these field sciences) and more recent patterns. I'm speaking here of Barbara Isaac. Read the rest of this post... | Read the comments on this post...... Read more »
Isaac, Barbara. (1987) Throwing and Human Evolution. The African Archaeological Review, 3-17.
- January 24, 2008
- 10:04 AM
- 1,549 views
New Study of Antarctic Ice Loss
by Greg Laden in Greg Laden's Blog
The amount of ice lost to the sea from Antarctica has increased by 75 percent in the last 10 years. This is the result of an increase in glacial flow. It had previously been thought, and perhas was the case, that Greenland ice loss outpaced the Antarctica. This is no longer the case. Read the rest of this post... | Read the comments on this post...... Read more »
Eric Rignot, Jonathan Bamber, Michiel van den Broeke, Curt Davis, Yonghong Li, Willem van de Berg, & Erik van Meijgaard. (2008) Recent Antarctic ice mass loss from radar interferometry and regional climate modelling. Nature Geoscience. DOI: 10.1038/ngeo102
- March 12, 2009
- 08:03 AM
- 1,545 views
When Kissing Cousins get to Third Base
by Greg Laden in Greg Laden's Blog
It has long been known that incest is not as bad as you think. Anti-cousin marriage laws are like prohibition laws and blue laws. They arise from a Christian conservative movement that swept Western Civilization from the late 18th century through the 19th century, up to about the time of the repeal of Prohibition.
Sure, marrying, or just plain having sex with, your sibling is disgusting. I mean, think about it. No, wait, don't even think about it. But cousin marriage? That depends. Your cousin may be kinda cute, you never know.
(a repost)
But seriously, anthropologists have long known of ... and have had two distinctly different explanations for ... patterns of marriage that involve linking up various kinds of cousins. At this point, let's just say that cousin marriage tends to benefit ... in terms of coalition formation, power management, and with respect to inclusive fitness .... the ascending (older, in charge) generation, even if it is no necessarily ideal for the marrying generation. This may well explain the pattern that we see: Prescribed cousin marriage is common in many scieties, but the degree to which it happens is at least somewhat correlated, it would seem, with he level of patriarchy. The more control older typically male power brokers have over things, the more people stick with cousin marriage. The less such power, the more rule breaking we see.
Forbidding laws are foreboding things. If you make a law that says that some behavior should never, ever happen, then people may become more fearful of the outcome of such actions. Cousin marriage laws instituted mainly during the last half of the 19th century have led to the general understanding that if cousin have a baby, it will have two heads. But in fact, and this has been known scientifically for decades, the increased rate of revelation of hidden recessive mutations in marrying cousins is small. It is about the same as a woman over 35 or so having a child.
A paper just out in PLoS Biology reviews the history of cousin marriage, its prohibition and the related controersy, in the West.
The conclusion is the following interesting conundrum:
...we note that laws barring cousin marriage use coercive means to achieve a public purpose and thus would seem to qualify as eugenics even by the most restrictive of definitions. That they were a form of eugenics would once have been taken for granted. Thus J.B.S. Haldane argued that discouraging or prohibiting cousin marriage would appreciably reduce the incidence of a number of serious recessive conditions, and he explicitly characterized measures to do so as acceptable forms of eugenics .... But Haldane wrote before eugenics itself became stigmatized. Today, the term is generally reserved for practices we intend to disparage. That laws against cousin marriage are generally approved when they are thought about at all helps explain why they are seemingly exempt from that derogatory label.
It is obviously illogical to condemn eugenics and at the same time favor laws that prevent cousins from marrying. ...
Interesting, that link between religious belief and eugenics.
As a paper published in an Open Access journal, you can review it yourself. Do read this paper, it is well done and quite accessible.
Diane B. Paul, Hamish G. Spencer (2008). "It's Ok, We're Not Cousins by Blood": The Cousin Marriage Controversy in Historical Perspective PLoS Biology, 6 (12) DOI: 10.1371/journal.pbio.0060320 Read the comments on this post...... Read more »
Diane B. Paul, & Hamish G. Spencer. (2008) “It's Ok, We're Not Cousins by Blood”: The Cousin Marriage Controversy in Historical Perspective. PLoS Biology, 6(12). DOI: 10.1371/journal.pbio.0060320
- February 1, 2008
- 01:02 PM
- 1,536 views
Friday Peer Reviewed Cat Blogging
by Greg Laden in Greg Laden's Blog
A paper just out in Genomics presents a very thorough study of cat genetics. Cat as is in kitty cat. The findings are expected, yet surprising in a few areas. The conclusion the authors draw about cat origins is very weak, in my view, but the information this study provides about cat breed genetics is excellent and will be of value cats around the world.
Read the rest of this post... | Read the comments on this post...... Read more »
M LIPINSKI, L FROENICKE, K BAYSAC, N BILLINGS, C LEUTENEGGER, A LEVY, M LONGERI, T NIINI, H OZPINAR, & M SLATER. (2008) The ascent of cat breeds: Genetic evaluations of breeds and worldwide random-bred populations. Genomics, 91(1), 12-21. DOI: 10.1016/j.ygeno.2007.10.009
- May 23, 2009
- 10:08 PM
- 1,534 views
New Global Warming Predictions: Bad news and really bad news.
by Greg Laden in Greg Laden's Blog
One item is just published in the Journal of Climate. Simply put, the use of some very sophisticated and probably quite trustworthy models suggests that extratropical cyclones (so this means winter storms and such, mainly) will have a good deal more precipitation in them.
In the model ...
... There is a small reduction in the number of cyclones but no significant changes in the extremes of wind and vorticity in both hemispheres. ... The largest changes are in the total precipitation, where a significant increase is seen. Cumulative precipitation along the tracks of the cyclones increases by some 11% per track ... while the extreme precipitation is close to ... (some 27%).
In another study not available to me but coming out in the same journal in a few days, the overall effects of climate change are predicted to be much worse than previously thought.
This is based on MIT's Integrated Global Systems Model, which is a computer simulation of both global economic activity and climatic systems. This mega-simulation was run 400 times using slight variations in input parameters. According to a press release:
The new projections... indicate a median probability of surface warming of 5.2 degrees Celsius by 2100, with a 90% probability range of 3.5 to 7.4 degrees. This can be compared to a median projected increase in the [previous major study, conducted in] 2003 ... of just 2.4 degrees. The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated. Read the rest of this post... | Read the comments on this post...... Read more »
Bengtsson, L., Hodges, K., & Keenlyside, N. (2009) Will Extratropical Storms Intensify in a Warmer Climate?. Journal of Climate, 22(9), 2276. DOI: 10.1175/2008JCLI2678.1
- December 18, 2008
- 10:56 AM
- 1,524 views
How to make an elephant turn invisible
by Greg Laden in Greg Laden's Blog
Dear reader, I know I promised you snakes in this particular post, but but before I get to the snakes, I have to make a digression to mention the elephants. The elephants in the Upper Semliki River Valley in the Eastern Congo at the time our expedition (late 1980s) are especially interesting because at the time it was believed that no elephants lived there. Yet, as part of my research, I discovered that this was inaccurate. A herd of invisible elephants roamed the park. I told almost no one at the time for fear that they would be poached. In fact, this is the first time I've mentioned it in a public forum.
An elephant I photographed in 1999 in Pilanesberg, South Africa. Some of early Pilanesberg elephants -- young males brought here from Kruger National Park -- took to killing rhinos who had come down to the watering hole to drink. Better behaved older adult elephants from Kruger were then introduced to 'teach' these young elephants how to act properly. This apparently worked, and the rhino slaying stopped. Subsequently, the elephant population in Pilanesberg has gotten out of control. On my last trip there a few years ago, I watched as a herd of some 20 elephants tore down about 15 trees in less than a half hour, eating only a few leaves off of each tree. Subsequently, several elephants died in a wildfire in Pilanesberg, and the rangers have started to cull them by shooting. This problem is the subject of research recently published in PLoS ONE, and referenced at the end of this post. Read the rest of this post... | Read the comments on this post...... Read more »
Tarryne Burke, Bruce Page, Gus Van Dyk, Josh Millspaugh, & Rob Slotow. (2008) Risk and Ethical Concerns of Hunting Male Elephant: Behavioural and Physiological Assays of the Remaining Elephants. PLoS ONE, 3(6). DOI: 10.1371/journal.pone.0002417
Stephen Blake, Sharon L. Deem, Samantha Strindberg, Fiona Maisels, Ludovic Momont, Inogwabini-Bila Isia, Iain Douglas-Hamilton, William B. Karesh, & Michael D. Kock. (2008) Roadless Wilderness Area Determines Forest Elephant Movements in the Congo Basin. PLoS ONE, 3(10). DOI: 10.1371/journal.pone.0003546
Bindi Thomas, John D. Holland, & Edward O. Minot. (2008) Elephant (Loxodonta africana) Home Ranges in Sabi Sand Reserve and Kruger National Park: A Five-Year Satellite Tracking Study. PLoS ONE, 3(12). DOI: 10.1371/journal.pone.0003902
Leigh-Ann Woolley, Joshua J. Millspaugh, Rami J. Woods, Samantha Janse van Rensburg, Robin L. Mackey, Bruce Page, & Rob Slotow. (2008) Population and Individual Elephant Response to a Catastrophic Fire in Pilanesberg National Park. PLoS ONE, 3(9). DOI: 10.1371/journal.pone.0003233
- July 29, 2008
- 07:01 PM
- 1,522 views
Re-examining the cause of speciation and species diversity in the tropics
by Greg Laden in Greg Laden's Blog
Did Past Climate Changes Promote Speciation in the Amazon?
Any time you've got a whopping big river like the Amazon (or a mountain chain like the Andes, or an ocean, or whatever), you've gotta figure that it will be a biogeographical barrier. Depending on the kind of organisms, big rivers, high mountains, oceans, forests, deserts, and so on can provide a habitat or a barrier, and when there is a barrier, populations may end up splitting across that barrier and diverging to become novel species.
The role of the big tropical rivers such as the Amazon and the C... Read more »
Scott Solomon, Mauricio Bacci, Joaquim Martins, Giovanna Gonçalves Vinha, Ulrich G Mueller, & Peter M Bennett. (2008) Paleodistributions and Comparative Molecular Phylogeography of Leafcutter Ants (Atta spp.) Provide New Insight into the Origins of Amazonian Diversity. PLoS ONE, 3(7). DOI: 10.1371/journal.pone.0002738
- June 30, 2009
- 10:46 AM
- 1,518 views
The Science of Lion Prides
by Greg Laden in Greg Laden's Blog
Although the paper addresses Tanzanian lions, this is a photograph of a Namibian lion Starting some years ago, we began to hear about revisions of the standard models of lion behavioral biology coming out of Craig Packer's research in the Serengeti. One of the most startling findings, first shown (if memory serves) as part of a dynamic optimization model and subsequently backed up with a lot of additional information, is the idea that lions do not benefit by living in a group with respect to hunting. They live in groups despite the fact that this sociality decreases hunting effectiveness. This is a classic case of "but wait, I can see it with my own eyes!" vs. data.
Some of the most recent work done by Packer's team has just been highlighted in a pretty nice write up by Mattt Walker in the BBC, representing a paper just coming out. The most interesting finding: Male lions kill (or attempt to kill) females from neighboring prides in order that their own pride obtains numerical superiority in pursuit of territorial competition. Read the rest of this post... | Read the comments on this post...... Read more »
Mosser, A., & Packer, C. (2009) Group territoriality and the benefits of sociality in the African lion, Panthera leo. Animal Behaviour. DOI: 10.1016/j.anbehav.2009.04.024
- May 12, 2009
- 09:53 AM
- 1,512 views
More emotional intelligence = more orgasms
by Greg Laden in Greg Laden's Blog
According to a study just coming out in the Journal of Sexual Medicine, "variations in emotional intelligence--the ability to identify and manage emotions of one's self and others--are associated with orgasmic frequency during intercourse and masturbation." Read the rest of this post... | Read the comments on this post...... Read more »
Burri, A., Cherkas, L., & Spector, T. (2009) Emotional Intelligence and Its Association with Orgasmic Frequency in Women. Journal of Sexual Medicine. DOI: 10.1111/j.1743-6109.2009.01297.x
- January 6, 2009
- 01:48 PM
- 1,510 views
Pink Iguanas and Disappearing Islands
by Greg Laden in Greg Laden's Blog
It turns out that a recently discovered population of land iguanas on the Galapagos is probably a new species that represents the basal (original) form of Galapagos land iguana. Moreover, this iguana is found in an unexpected place, according to a paper just coming out in the Proceedings of the National Academy of Sciences (PNAS).
And it's pink. Read the rest of this post... | Read the comments on this post...... Read more »
G. Gentile, A. Fabiani, C. Marquez, H. L. Snell, H. M. Snell, W. Tapia, & V. Sbordoni. (2009) An overlooked pink species of land iguana in the Galapagos. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.0806339106
Snell, H.L., Snell, H.M., & Tracy, C.R. (1984) Variation among populations of Galapagos land iguanas (Conolophus): contrasts of phylogeny and ecology. Biological Journal of the Linnean Sociey, 185-207.
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- March 10, 2009
- 09:00 PM
- 1,507 views
The Identification of the Two "Missing" Romanov Children Using DNA Analysis
by Greg Laden in Greg Laden's Blog
I first became acquainted with the Romanovs (as historical figures, not the actual Romanovs) reading in middle school about Russian History. Later, someone turned me on to Massie's Nicholas and Alexandra, which is quite a well known popular historical account of the last Czar of Russia and his family. Everyone knows the story of the end. The core of Czar's family -- the Czar Nicholas, his wife Alexandra, and his children -- had been arrested and all of them were transported to a remote location in the Urals. A complex series of events had begun involving Czarist and Revolutionary forces. At one point, it occurred to the local revolutionary officials who were responsible for the incarceration of the Czar and his family that their execution would be a good idea, to avoid their recapture by Czarists forces in the area, and to break the loyalty of Czarist supporters still resisting the Revolution. So, on July 17th, 1918, the Czar and his family, their doctor and a nurse were escorted to an empty room in the compound in which they were being held and shot. The details are rather ghastly, as summarized by an eye witness to the event. Read the rest of this post... | Read the comments on this post...... Read more »
Coble MD, Loreille OM, Wadhams MJ, Edson SM, Maynard K, & et al. (2009) Mystery Solved: The Identification of the Two Missing Romanov Children Using DNA Analysis. PLoS ONE, 4(3). DOI: http://dx.plos.org/10.1371/journal.pone.0004838
- July 9, 2009
- 11:00 AM
- 1,504 views
Wildlife in Protected Areas Compared to Non-Protected Areas of Kenya
by Greg Laden in Greg Laden's Blog
It has become virtually axiomatic that as climate shifts or other potential insults to the ecology of a given area occur, plants and animals enclosed in parks bounded by "impermeable" landscapes are at great risk. Instead of the extreme ranges of a plant or animal moving north or south, or across a gradient of rainfall, or up or down in elevation, organisms that are protected in parks are also stuck in the parks and risk local extinction when change happens or disease becomes endemic, or poaching uncontrolled or fire more common or .... well, we can go on and on.
In a new study on "The Status of Wildlife in Protected Areas Compared to Non-Protected Areas of Kenya,", the famous Kenyan wildlife ecologist David Western has demonstrated the severity of this problem in that East African nation.
From the abstract: Read the rest of this post... | Read the comments on this post...... Read more »
Western, D., Russell, S., & Cuthill, I. (2009) The Status of Wildlife in Protected Areas Compared to Non-Protected Areas of Kenya. PLoS ONE, 4(7). DOI: 10.1371/journal.pone.0006140
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