Mountain barriers

Mountains are important engines of evolutionary change. A mountain range can present a formidable barrier to movements of animals and divide populations, preventing them from exchanging genes with one another. The division of a single population into two by the gradual introduction of some geographic barrier, like the uplift of a mountain chain, is known as a vicariant event. Vicariance is an important process in evolutionary change and is responsible for much of the biological diversity we see today.

Taiwan has, by all appearances, an excellent example of a vicariant event dividing a single ancestral population into two separate species. The bulbuls are widespread Old-World family of birds (Pycnonotidae). Taiwan has several members of this avian group including the Chinese Bulbul (Pycnonotus sinensis), a widespread bulbul in East Asia, found both on the island of Taiwan and in Mainland China (see photo left). The Chinese Bulbul's name in Mandarin Chinese is "Bai Tou Wang" which means "white headed old man" after the characteristic white patch on the back of the head. This bird is abundant at low elevations throughout Western and Northern Taiwan where it is considered a crop pest. Farmers often leave fine nets up around their fields that snare these birds in flight and they are left to die hanging tangled in the mesh of the net. A little cruel, yes, but this practice is tolerated largely due to the fact that prohibitions against netting wild birds can be difficult to enforce due to a variety of reasons. Also, the netting occurs in agricultural areas where most of the birds killed in these nets belong to very widespread and common species.

There is also another very similar bulbul is found on Taiwan. This is one of the 16 endemic avian species found on Taiwan, the Taiwan or Styan's Bulbul (Pycnonotus taivanus), found on the east side of the Taiwan Central Mountain Range. This bulbul is very similar to the Chinese Bulbul with a notable exception being the lack of white on the back of the head (see photo right). Because these two species occur on either side of the Taiwan Central Mountain Range they appear to be a classic example of speciation due to a vicariant event, in this case the uplift of Central Taiwan. Different species divided by mountain ranges, bodies of water or other geographic features is a common occurrence among birds and in Taiwan we can see this on a relatively small scale.

However, the two species do have a zone of contact in Southern Taiwan where their ranges overlap and they hybridize so their genetic isolation is incomplete. Taiwan and Chinese Bulbul seem to be a case of vicariance in action but recent work suggests that despite their differing appearance there are few genetic differences between these species. These birds are great subjects for future research and genetic comparisons of these species can potentially tell us much about how new species form.

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The Hilton it ain't...

Watching the Discovery Channel you may think of field biologists in far flung corners of the globe tracking down rare plants and animals in exotic locations. Not all field biology takes place in exotic, "wild" locales. Often the subjects of one's research are pretty ordinary suburban organisms like Grey Squirrels (Sciurus carolinensis) or House Sparrows (Passer domesticus), but, sometimes research does take you far afield into more adventurous settings.

But, what is often left out is just how dirty and difficult field work can be. This weekend's field expedition across Taiwan's south cross highway to the east side of the Taiwan Central Mountain Range was about as unglamorous as field work gets. We managed to find a tea plantation that allowed us to stay in the workers quarters on the cheap (see photo left). Normally during the height of the tea harvest there are 50 plus workers staying in this modest building. Luckily save for the farm manager and a couple workers we were the only people staying on the farm. The sleeping area consisted of a concrete floor and a raised platform where we all slept on moldy comforters. The kitchen doubled as a storage room/office and we ate instant noodles lunch and dinner with some pork or boiled cabbage on the side and bread for breakfast. I'll leave the bathroom undescribed to spare the reader the more graphic unpleasantries of fieldwork.

However, life aways has trade offs and spartan living conditions are balanced by seeing some great birds, getting some good data and enjoying some spectacular scenery (see me in photo right). Somehow the birds, the scenery and the camaraderie of one's colleagues stick in my mind a little more than the living conditions and this keeps me coming back to the beautiful mountains of Taiwan. Sleeping on hard surface or eating a steady diet of cabbage and instant noodles are sometimes worth it to see these fantastic views and incredible wildlife.

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Another shrike!

This trip seems to be the year of the shrike. In addition to the common species found on Taiwan during this time of year, the Brown Shrike (Lanius cristatus) and the Long-tailed Shrike (Lanius schach), we found another member of the Lanius clan. The Bull-headed Shrike (Lanius bucephalus, see photo left) is a rare vagrant to the island of Taiwan. They are more commonly found wintering in mainland China after their breeding season in Manchuria, the Korean Peninsula and Japan. This was a lucky find. We ran across this lone male Bull-headed Shrike while surveying birds on the east side of the Taiwan Central Mountain Range on a tea plantation at about 4,900 feet elevation. These birding surveys are important as they document the movements and distribution of birds during different times of the year. Knowing about bird distributions and movements are critical in understanding different ecological and evolutionary processes in avian species and long term data can potentially tell us about the ecological effects of global climate change. Maybe Bull-headed Shrikes will be a more common sight in the future? Maybe not? We'll need lots of keen eyed birders to keep watch for these and other rare vagrants.

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Shrikes, killer songbirds

Most songbirds we encounter are mild-mannered little birds that eat seeds or small insects. Members of the shrike family (Laniidae) are exceptions to that rule. Shrikes prefer open habitat where they survey their surroundings from a high perch for passing prey items. Top of the menu are large insects, like grasshoppers, and often other vertebrates like lizards, mice or small birds. To kill vertebrate prey shrikes have a special adaptation, the tomial tooth, an extension of the upper mandible that shrikes use to dislocate the neck vertebrae of their prey. Falcons have evolved a very similar structure independently of shrikes and use it in much the same way to dispatch their prey. Shrikes are also famous for keeping larders of their prey for later. A shrike's larder consists of large insects and vertebrate prey impaled on thorny bushes and trees or in some areas on barbed wire fences.

We've seen many shrikes during this latest trip to Taiwan with two species making up all the sightings, the Brown Shrike (Lanius cristatus, see photo above taken at the Aogou wetlands on Dec 10) and the Long-tailed Shrike (Lanius schach, see photo right taken near Yuanshan on Dec 8). There are only two species of shrike in all the Americas and neither of American species are found on the island of Taiwan. Eurasia and Africa are the strongholds for shrike diversity with most of of the 28 species in the genus Lanius occurring on these continents. Brown Shrikes are winter migrants but Long-tailed Shrikes can be seen all year on Taiwan. Lanius shrikes are common but still great birds to see on any trip to Taiwan.

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The crane! The crane!

Cranes are popular birds in the far east with an important place in Chinese, Korean and Japanese art and culture as symbols of peace and harmony, so when they show up unexpectedly in places where they aren't normally seen it can be a big deal. On December 7 during this year's trip to Taiwan, with University of Minnesota student Bailey McKay, we had the good fortune of seeing four wintering Red-crowned Cranes (Grus japonensis) in the agricultural fields around Jingshan. The sighting was easily made from the roadside with binoculars and a spotting scope gave excellent looks at this beautiful bird. A single adult plumage individual was in a grassy field along a river filled with Black-crowned Night Herons (Nycticorax nycticorax) and other waders. A short drive around the corner from this bird revealed three more individuals (2 in adult plumage and 1 in juvenile plumage, see photo left. I know it isn't the greatest photo but the birds were very far away.). This was a big surprise as it was only the third record for Red-crowned Crane in Taiwan and the first such sighting in four years. Prior to the last sighting four years ago there were no records of this species for over 60 years! All previous sightings were of solitary individuals making this year's sighting the largest known wintering population of Red-crowned Cranes in Taiwan to date.

Local birders were already on the scene when we arrived at this site. In Taiwan birding is a major pass time and a half a dozen birders with 2,000 dollar spotting scopes and a 600 mm lenses on a 10 mega pixel digital camera is not an unusual occurrence, particularly in the winter when there are many different vagrant and transient migratory birds. Typically the first person to spot a rare bird are on their cell phones and within the hour birders from around the island are packing their gear and on the way. Our presence at the crane site attracted a lot of attention even by non-birders and soon after our arrival a line of locals had formed waiting to catch a glimpse of the cranes through Bailey's spotting scope (see right photo). One never knows what will turn up in the winter in Taiwan! Taiwan is a great place for these rare vagrant migrants and a great place to meet many enthusiastic, friendly birders.

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Who ruled the Paleozoic seas? The Eurypterid did!

This is a 380 million year old sea scorpion or eurypterid (Eurypterus sp.) from New York state (left). It one of the thousands of specimens in the invertebrate paleontology collection at the Cincinnati Museum Center. Eurypterids were aquatic predators with paddle-like appendages and spiked claws used for catching prey. Their closest living relatives are the arachnids (spiders, harvestmen, mites and scorpions). Eurypterid fossils are found in Ohio and Kentucky and in many other locations in the Eastern United States and around the globe. Eurypterids are the state fossil of New York state and many fine specimens, like this one in the Cincinnati Museum Center collection, have been unearthed in that region.

Now, being only about 15-20 cm in length, this species may not be that imposing but other eurypterids grew to much larger size. Shown here is another eurypterid specimen in the Cincinnati Museum Center collection, Megalograptus ohioensis, collected in Ohio (right). This fossil dates to about 445 million years ago and consists only of the distal portion of the one of the claws or chelicerae, a little like a lobster claw or that of a modern terrestrial scorpion. This portion of the claw alone is about 2 cm wide and nearly 4 cm long. The spines on the claw likely used for grasping slippery prey items are clearly visible. This fragment obviously came form a much larger animal than the New York Eurypterus specimen, however, size variation in eurypterids doesn't stop here.

In a new paper by Simon Braddy, Markus Poschmann and Erik Tetlle available online in the journal Biology Letters the authors describe a new specimen of the eurypterid, Jaekelopterus rhenaniae. The fossil remains described in the Braddy et al. paper are from an animal nearly 2.5 m long, that's just over 8 feet in length. Not only is this is the largest eurypterid described to date it is the largest arthropod ever. The claws of J. rhenaniae alone were over 40 cm long and lined with long spines. The authors speculate that higher oxygen levels in the paleozoic seas may have contributed to the gigantic size of many arthropods during this time but a lack of large vertebrate predators like marine reptiles may have also been a factor as well because large eurypterids like these went extinct about the time we begin to see large marine reptiles in the fossil record.

Read more about this on NPR and listen to an interview with the authors of the study. Thanks to Brenda Hanke of Cincinnati Museum Center for help on this post.

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Note the URL has changed!

I changed the URL to www.cincyevolution.blogspot.com. Hope everyone thinks it makes more sense than an old user name from a defunct email account!

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Time for a new blog name...

OK, when I made this thing I used a user name from an email account at an old job. Hardly a creative way to make a blog name. I'm taking suggestions for a new name for this blog. If I'm going to change the name I should do it now before too many people start reading it, if that indeed even ends up happening!

I'm thinking the URL name should be www.cincyevolution.blogspot.com. Let me know what you think! As for the blog name I'm open to changing that as well. Maybe the name and the URL should be the same? Don't know. Comments welcome!

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Stakeout vagrant birds beware...

There are few things that birders love more than a rare vagrant bird that turns up at someone's backyard feeder. A rare hummingbird at the backyard feeder of a birder instantly is posted on local birding sites and a steady stream of birders usually follows. Wisconsin recently had a doozy of a vagrant when a Green-breasted Mango (Anthracothorax prevostii) showed up at a backyard in Beloit. The northern limits of the Green-breasted Mango's range is in Mexico and there are only a handful of sightings in the US. After the bird failed to leave in the face of the approaching Wisconsin winter the Humane Society of Wisconsin made a controversial decision and took the bird into it's Milwaukee facility and later transfered the bird to the Brookfield Zoo in Chicago. Should vagrant birds be taken into captivity? After all evolution proceeds by those rare individuals in a population who can move into new environments. With global warming more tropical species will likely show up in temperate regions where they were previously never, or seldom, recorded. Is it up to local zoos and humane societies to take in these vagrants? I'm not sure they should. I guess the lesson is next time you hear about that great, state-record bird hanging out in someone's yard get there quick before the local humane society does!

see more on this story at NPR and the Chicago Tribune.

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Cdesign propentsists...

Not even bill size in Geospiza finches evolves as fast as creationist tactics.

The PBS series NOVA presented an excellent documentary titled 'Judgement Day: Intelligent Design on Trial' outlining the latest in a long list of judicial successes for the teaching of evolution in the United States. The case was the 2005 Kitzmiller v. Dover School District in the US District Court of the Middle District of Pennsylvania presided over by President Bush appointee John E. Jones III. The Dover, PA school board required teachers to present intelligent design (ID) as an alternative to evolution and steered students to the pro-ID text 'Of Pandas and People' of which copies were conveniently donated to the school by an anonymous benefactor.

This case was a triumph for science education. Judge Jones' decision concluded not only that the defendants in the case clearly had a religious agenda in violation to the first amendment establishment clause but also that they concealed this agenda to give the appearance of a secular purpose. Former school board members William Buckingham and Alan Bonsell were found to have lied in their original depositions as to the source of the 'Of Pandas and People' texts. Money for the text was raised in Buckingham's church and essentially laundered through Alan Bosnell's father. Judge Jones' decision however went beyond these particulars and declared that there was no evidence presented during the course of the trial to convince him that ID was a valid scientific pursuit, much less a well supported scientific theory.

Central in this case was the 'Of Pandas and People' text. There are many heroes in this case but perhaps the most damning evidence against the constitutionality of the Dover policy came from Southeastern Louisiana University philosophy professor Barbara Forrest. To demonstrate that the ID approach of 'Of Pandas and People' was truly creationism in disguise and thus in violation of the establishment clause as a public school text the plaintiffs subpoenaed the publishers of 'Pandas' to provide early drafts of the text. Forrest combed over thousands of pages and found that the language of the drafts changed to mesh the religious message with the latest judicial rulings.

For example, in 1987 the US Supreme Court case of Edwards versus Aguillard ruled that a Louisiana statute requiring equal time for "creation science" and evolution was in violation of the establishment clause. Drafts of 'Pandas' prior to the Edwards v. Aquillard ruling used the term "Creator" while post Edwards v. Aquillard "creator" was replaced with more vague and less overtly religious terminology like "intelligent agent". The NOVA documentary highlighted one of the more blatant examples of this "evolution" of creationism in response to the "selection" imposed on the movement by the courts and the US Constitution. In their haste to change the text to less obvious religious terminology to get around legal restrictions the publishers of 'Pandas' left behind some obvious editorial clues to their real goals. Places in the text that previously read "creationists" suddenly in later drafts appeared as "cdesign propentsists" and later as "design proponents". A clear editorial transitional form. Congrats to Dr. Forrest. One could not expect more from even the best paleontologists!

Kitzmiller v. Dover represents a stunning defeat for ID. The strategy of ID as a wedge to move the US from a secular society to one dominated by the particular religious views of a segment of the population is exposed in this ruling. It is also made clear that the acceptance of the science of evolution is not tied to any particular theistic or atheistic belief or political ideology. There could not be a better judge for this ruling. A political conservative appointed by a conservative president.

'Judgement Day: Intelligent Design on Trial' did an excellent job presenting the issues at stake in the Dover case. Ironically one of the quotes that stuck with me from the program was from one of the defendant's attorneys Patrick Gillen of the Thomas More Law Center.

"Does science education have to be so narrow, so technical, so deferential to the existing paradigm that we can't even introduce students to what may be the next great theory" Patrick Gillen - Thomas More Law Center

The answer to Gillen's question is yes. Science is narrow. It is limited to those ideas that are testable against the empirical evidence. The range of scientific theories that should be taught in the public schools is also narrow, restricted to those theories that enjoy the support of the available evidence. As an explanation for the origins of biological diversity evolution has enjoyed the support of the empirical evidence for 150 years. ID has no scientific support and worse yet it is not testable as science. There may very well be a "great next theory" out there but until that theory accumulates some actual support then it has no place in the science classroom.

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Closest living relative of the primates...
Above is a photo of a unique member of the mammal clan, the flying lemur or colugo (Cynocephalus volans) from the collection at the Cincinnati Museum Center. This specimen was collected by former CMC zoology curator Robert Kennedy in 1987 on the Philippine island province of Biliran, the first record of this species for that location. This is the skin of the specimen. The skull and most of the skeleton are in the collection of the Smithsonian Institution. The fur is amazingly soft, a little like rabbit fur, and the digits have big recurved claws that look like those of a cat.

Flying lemurs aren't lemurs at all rather they belong to their own unique mammalian order; the dermoptera. There are only two species of flying lemur in the world and both are found in the tropical forests of South-East Asia. One species, the Sunda Flying Lemur (Galeopterus variegatus), is found on the Indo-Malay Peninsula, Singapore, Sumatra, Java and Borneo while the only other living flying lemur, the Philippine flying lemur (Cynocephalus volans) is confined to the islands of the Philippines. If the lemur misnomer wasn't confusing enough, flying lemurs don't fly either, at least not powered flight like a bird, butterfly or bat. These arboreal mammals can glide from tree to tree much in the same way a flying squirrel does. The limbs are connected by loose folds of skin and when the limbs are outstretched the skin creates a large surface area that provides lift in the same way the stretched out fabric of a kite keeps it aloft. Flying lemurs are mostly active at night and they are herbivorous with their diet consisting mainly of leaves, fruits and flowers.

For a long time the place flying lemurs occupy on the mammal family tree has been a mystery. Most scientists placed them somewhere in between insectivorous mammals, like shrews and moles, and the bats. However, a recent study published in the journal Science by Jan Janecka (Department of Veterinary Integrative Biosciences, Texas A&M University) and his colleagues uses modern comparative genomics to shed light on the evolutionary relationships of flying lemurs. As it turns out, according to Janecka and colleagues, the common name flying lemur is not as far off as once thought. The two extant species of flying lemur are the sister group to all the primates, that is to say that primates as a group and flying lemurs are each others closest relatives. This conclusion was drawn on the basis of DNA sequencing of nearly 14,000 letters in the genetic code from flying lemurs, primates, treeshrews and other mammals. Analysis of these DNA sequences reveal that there are shared genetic mutations in flying lemurs and primates that are not found in other mammalian groups. For example, for a particular gene called TEX2 flying lemurs and all the primates sequenced in this study share a deletion of three amino acids not found in other mammals. Together the combined results from these genetic data suggest that the evolutionary split between primates and flying lemurs occurred approximately 63 million years ago, shortly after the extinction of the dinosaurs.

Does this mean that gliding flight was a trait in the ancestors of the primates? Probably not. It is important to remember that flying lemurs have undergone as much evolution as primates since both split from a common ancestor about 63 million years ago. The specialized characters found in modern flying lemurs evolved over time. Because the closest living mammalian group to the grouping of flying lemurs and primates are the treeshrews, a group who (like primates) do not exhibit the gliding behavior found in flying lemurs, one may conclude that the specialized gliding lifestyle of flying lemurs evolved after their split from the mammalian lineage leading to modern primates.

The Janecka study, and many others like it, emphasizes the power of modern molecular genetics in untangling evolutionary puzzles. Because of their close relationship to the primates flying lemurs have the potential to tell us much about the early evolution of primate genomes, including the human genome.

For additional reading see the news article in PennState Live and the original article in Science.

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That pesky penguin...

With Bailey's help (see yesterday's post) we finally finished that pesky, greasy, old penguin. This is a little penguin (Eudyptula minor) found along the coasts of New Zealand. This species is also called the fairy penguin or little blue penguin for the beautiful iridescent blue plumage on it's back. In the little penguin's native New Zealand it is known for nesting under the porches of homes along the coast. This male specimen died at the Cincinnati Zoo and Botanical Garden where it was part of a long-term captive flock. Preparing a study skin from a penguin carcass was a real challenge and I was lucky to have Bailey's help. Compared to the small songbirds, large aquatic birds like waterfowl and penguins have an enormous layer of fat beneath their skin. Of course this is a great adaptation for the bird as it provides insulation and buoyancy but it is a real pain to deal with when preparing the skin. Fat left in a study skin will gradually seep through making the feathers oily and leaving a greasy stain on any substrate the specimen is left lying on. Hopefully we managed to get enough of the fat from the skin to make it an OK study skin, we'll see. I'm thinking Bailey and I will have to nickname our first penguin study skin "Ol' Greasy"!

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Bird skinning at Cincinnati Museum Center

Bailey McKay (right) Mason Milam (left)

Bailey McKay from the University of Minnesota visited Cincinnati this weekend to help us with some bird skinning work. Today we had a very successful skinning seminar attended by Cincinnati Museum Center (CMC) staff and volunteers and graduate students from the University of Kentucky. We prepared seven specimens today and another five specimens over the weekend, everything from blue-gray gnatcatchers to blue grosbeaks to northern parulas, we even prepared a little penguin generously donated to the museum from the Cincinnati Zoo and Botanical Garden. Skinning seminars will be a regular occurrence at the CMC Geier Center from now on and hopefully Bailey will be back to give us more tips and tricks on turning birds into museum quality specimens. More on the experience with that pesky penguin in the next post...

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The things themselves

I haven't blogged in ages but I'll try to add stuff on a more regular basis. The move from college professor to museum curator has been time consuming. In efforts to make the switch to museum curator I've been brushing up on my taxonomy and systematics. I ran across this quote in the book Describing Species: Practical Taxonomic Procedure for Biologists by Judith E. Winston. It's from the father of modern systematics, the Swedish botanist and taxonomist Carolus Linnaeus, and it sums up the essence of a natural history museum, and well, any museum.

"The first step in wisdom is to know the things themselves" - Linnaeus (1735)

The alter-ego to the Cincinnati Museum Center across the Ohio in northern Kentucky, the Creation Museum, has been called a theme park rather than a museum precisely because it has no collections. Any institutions calling themselves "museums" who have no actual collections or any museums whose exhibits show no actual objects should consider Linnaeus' words.

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I know, I know, the last post is linking to a video from well over a year ago but it is a great episode of the Charlie Rose Show. I encourage all students in my evolution course to watch it.

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Charlie Rose - E.O. Wilson & James Watson on Charles Darwin

An hour on the life and work of Charles Darwin with James Watson, chancellor, Cold Spring Harbor Laboratory, and E.O. Wilson, professor emeritus, Harvard University.

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Ronald Numbers has written the definitive history of creationism recently published in a new expanded version, The Creationists, 2006, Harvard University Press. He arguably has one of the most even-handed, insightful and informed perspectives on the evolution-creation debate. Numbers cites a very vocal secular atheist minority as contributing to the erosion of science education rather than offering solutions. In a recent interview for Salon.com Numbers says,

"I don't know what the figures are right now, but I bet half of the scientists in America believe in some type of God. So I think Dawkins and Dennett are in a minority of evolutionists in saying that evolution is atheistic. I also think it does a terrible disservice to public policy in the United States." - R. Numbers, January 2, 2007

Understanding of the motivations and beliefs of those who reject evolution is critical in improving science education. As long as the public perceives science as an enterprise hostile towards religous convictions the evolution-creation debate will continue indefinitely.

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