Tuesday Tetrapod: Columbia liva

Posted by tigerhawkvok on August 11, 2009 18:04 in tuesday tetrapod

As of the time of this daft, another Trekcon Photoblog post is pending, but for now — time for another Tuesday Tetrapod, in the form of Columba livia, or the Columbian Rock Dove, more commonly known as the pigeon.

< !-- Image here --> Columbian Rock Dove, image from Wikipedia and naturespicsonline.com

C. liva. Photo from Wikipedia; original by Alan D. Wilson.

The most common bird in the world, the pigeon is found on all the continents except for Antarctica. Columbidae are part of "near passerine" birds, for which the terms "dove" and "pigeon" are generally used interchangeably. Like all passerines, the pigeon has a large reversed hallux that provides for automatic perching behavior with no need for conscious control, due to an interior "ratcheting" mechanism.. The family Columbidae encompasses all doves, which have a variety of color phenotypes but a more restricted degree of obvious physiological / morphological differences. At LHS, I've in fact worked with ring-necked doves, Streptopelia capicola, which are starkly similar in morphotype to the rock dove.

Pigeons are able to produce "crop milk", which is a fatty fluid produced by cells in their crop that serves a similar function to, but is quite different from, milk. It is also used to feed their young.

Star Trek - Saturday

Posted by tigerhawkvok on August 10, 2009 13:50 in General , sci-fi

Quick photoblog of the Las Vegas Star Trek Convention — to be updated as I upload the remainder of my photos still on my camera, an a real blog entry later. Sadly, the often long distance and often poor lighting means these aren't the best photos ever...

Currently, these photos are from Saturday only:


Linda Park / Ensign Hoshi Saato


Voyager Panel — Left to Right, Robert Picardo / the Doctor, Roxanne Dawson / Lieutenant B'Elanna Torres-Paris, Ethan Phillips / Neelix , Tim Russ / Lt. Cmdr. Tuvok.


Random Klingons and random cute girl dressed in 2009 movie EVA/Skydiving jumpsuit (pretty amazingly done!)


George Takei doing signatures (Sulu)


Some random nerds.

Yosemite Waterfalls

Posted by tigerhawkvok on August 04, 2009 21:17 in General

This past weekend I visited Yosemite National Park. Not too terribly much exciting — and only saw eight unique tetrapod species — but I want to go to Yosemite or Yellowstone sometime fairly soon again and try for more animals. However, I thought I'd share this photo of Vernal Fall, which I thought came out exceptionally well.


Vernal Falls, at 37.7274262N 119.5437725W


Tuesday Tetrapod: Heterodon nasicus

Posted by tigerhawkvok on August 04, 2009 00:03 in tuesday tetrapod

For today's Tuesday Tetrapod, I'll focus a bit on microcharacters as we look at Heterodon nasicus, or the Western Hog-Nose


Wally, H. nasicus




Sorry for the yellowish last two photos, I forgot to manually adjust my white balance. H. nasicus is well adapted for a subterranean lifestyle, and it has a whole suite of characters to that end. Note the ridges on the scales, which help prevent dirt from adhering to the animal, and the blunted rostrum with a keratinzed "hog nose" tip, used for digging.

Behaviorally, the snake tends to dig and is rarely on the surface of it's substrate. For a defense mechanism, it hisses and shakes it tail similar in manner to kingsnakes, though the substrate they usually occupy make this less effective. They tame well as pets, though may still hiss from time to time. < !-- behaviours -->

1970s 'Global Cooling' scare - except not

Posted by tigerhawkvok on July 29, 2009 20:27 in anti-science , public science

In a sideways way through Panda's Thumb, I ran across commentary about the purported "Global Cooling Scare" that went on in the 1970's. I'd always just chalked that one up to media alarmism that took scientific warnings to the extreme which discredits the current actual work on global climate, but I'd never done any research. Digging even just a little bit in, however, reveals this:

During the period we analyzed, climate science was very different from what you see today. There was far less integration among the various sub-disciplines that make up the enterprise. Remote sensing, integrated global data collection and modeling were all in their infancy. But our analysis nevertheless showed clear trends in the focus and conclusions the researchers were making. Between 1965 and 1979 we found (see table 1 for details):

  • 7 articles predicting cooling
  • 44 predicting warming
  • 20 that were neutral

Sources from realclimate.org and newscientist.com, with quotation from realclimate.

So, it's just a popular misconception, actually. The fact of the matter is there was no cooling scare — even in the 1970s, it was, charitably, neutral; in reality, the consensus was still overall warming (not to be confused with global monotonic warming).

There you have it. A little research goes a long way.

Rube Goldberg

Posted by tigerhawkvok on July 29, 2009 19:59 in lhs , teaching

So for the past month or so I've been teaching summer camps again at the Lawrence Hall of Science, and I thought I'd put up last week's group's final Rube Goldberg project with the Lego Mindstorms kit:

They got really close, and if they had 30 more minutes I think they could have pulled it off, but getting that far in about 5 hours total is pretty impressive.

On an aside, for anyone that wants to embed YouTube code that doesn't use that pesky, invalid "<embed>" tag:

<object width="500" height="405" data='EMBED_URL' type="application/x-shockwave-flash">
<param name="movie" value="EMBED_URL_AGAIN"></param>
<param name="allowFullScreen" value="true"></param>
<param name="allowscriptaccess" value="always"></param>

Remember to escape ampersands (&) in the URL with "&amp;". This method is verified to work on Safari, Firefox, Chrome, IE6+, and Opera.

Are hybrid-electric cars really the solution?

Posted by tigerhawkvok on July 29, 2009 14:17 in public science , energy

For those of you who haven't heard the "Long Tailpipe" argument against electric / hybrid cars, I thought I'd mirror a post that Kit put up on it:

It really bothers me when people opposed to electric cars use the "long tailpipe" argument, which calls attention to the fact that switching to electric vehicles won't solve the energy requirement problem, since our power plants (most of which run on fossil fuels) will have to generate the excess energy for cars as well. In effect, this just shifts the source of pollution from the streets to the power plants; the amount would be roughly the same.

There are two problems with this assessment. Number one, shifting the source is the whole point. If there were some miracle new power supply that did not run on fossil fuel, or if we could make nuclear engines for every car, then of course they would run on electric motors utilizing this new energy anyway. As it is, most of our energy DOES come from fossil fuels, so that if our main concern is carbon production and other atmospheric problems (waste heat, particulate matter, etc), why not have the problem occur in a centralized, easier to maintain environment? It boils down to: which is worse, a million cars spewing a ton of CO2 into the air from a million tailpipes all over the place, or one big smokestack spewing a million tons from one location? Clearly, it is easier to put expensive filters, catalytic converters, etc on one exhaust pipe than a million, it is easier to clean the air/water/soil near one source of pollution than a million, utility companies can afford to be safer/more environmentally conscious/cleaner than a poor single person with a car, and the government can better regulate them. In all, I'd rather have to clean a quart of shit in my toilet than a quart thinly spread all over my house.

The second problem is that the amount of emissions is actually lower with a localized source. There are many ancillary carbon expenditures to maintain a fossil-fueled fleet of cars, such as the cost of fuel transportation to hundreds of gas stations instead of one power plant, and the fact that the land occupied by gas stations could be used for parks or homes or whatever else. It is arguably safer, too. Consider a coastal power plant (as many are): if it's near a refinery, the fuel can just be immediately pumped into the plants storage tanks. Even if not, an oil tanker could distribute it from a refinery to a pumping station and achieve the same goal. No tanker trucks, gas cans/tanks, or rail tanks needed.

So, even if it isn't THE solution to the problem, it makes it more manageable, and I think it's worth it. Crank out those electric vehicles!

For some reason, I just find the the mental imagery with "quart of shit spread thinly over the house" grossly amusing.

There might be an argument to make about the energy / carbon / etc costs associated with making the batteries with hybrid and electric cars, but those fall through so long as the marginal returns on energy production / localized CO2 emissions / etc can do better than break even over the lifetime of the battery per car. I'd be interested to see the costs associated with producing the batteries and the marginal returns — I'm curious how short the timeframe is.

Tuesday Tetrapod (2 of 2): Ophisaurus apodus

Posted by tigerhawkvok on July 29, 2009 01:23 in tuesday tetrapod

I was out much later than I thought tonight, so today's part two for the Tuesday Tetrapod won't have that much of an attached explanation. Without further adieu, Ophisaurus apodus, also known as Pseudopus apodus, or more commonly the scheltopusik.

Legless lizard

O. apodus. Photo by Flickr user Joachim S Mueller.

What's snazzy about this guy is that he's not a snake, he's in fact a legless lizard. As an anguid, it's a member of autarchoglossa whereas snake phylogenetic placement is uncertain. It is possible that snakes are within that node (which would make a degree of sense), but serpentes are not especially closely related to anguids in any case. They have a vaguely segmented appearance with a long lateral groove to permit breathing and give flexibility while still providing maximum protection. Additionally, they have eyelids (snakes have a clear scale over their eyes), visible ear holes, and sometimes vestigial hind limbs.

Tuesday Tetrapod (1 of 2): Fishapod?

Posted by tigerhawkvok on July 28, 2009 17:27 in paleontology , tuesday tetrapod

For today's first Tuesday Tetrapod, I present ... an unidentified "fishapod" fossil.


Basal tetrapod (?) fossil find.

Fossil anterior portion

Anterior portion of the fossil. Penny for scale.

Fossil posterior portion

Posterior portion of the fossil.

Whole fossil, rotated

This find was located by Sara's aunt and uncle (though I won't disclose the location — things are in process to get it into the proper hands for museum care). Since this is unidentified, it'll be a walk through the features we can currently see in the rock — though it is actually not wholly clear if it is actually a tetrapod yet (via discussions with UCMP contacts)!

So, here are some nifty features I think that lend toward identification as a basal tetrapod, or what is sometimes jokingly called a "fishapod":

Ribs on fossil tail

Note the ribs on the fossil tail. These are commonly found on animals with fleshy tails used for swimming.

  • Looking at the anterior portion of the fossil, there are obvious ribs along the caudal vertebrae. While these are apparently in the transverse direction, they could easily just be distortion from the process of fossilization.
  • There are structures adjacent to a large mass on the posterior half of the animal. While not quite clear in the photographs, it seems to be fairly robust and narrow element, and possibly two other connected elements near the midline. I postulate that these could be the pelvic girdle, femur, and a fibia/tibula
  • The pelvic structure appears mirrored across the vertebral column, though perhaps not strongly joined, indicated a basal state.
Fossil pelvic girdle

Region around the presumed pelvic girdle of the fossil. Light outline is one hypothesized articulation for the detached bone.

Finally, the anterior portion of the fossil has a well developed jaw that appears not exceptionally "fish-like" and more like early tetrapods. In addition, the cervical vertebrae have well-developed bones by them (processes?) that could be hyoid bones / remnants of gill arches, and well-developed hyoids are also seen in modern amphibians for feeding — though this part of my analysis is admittedly more sketchy, as I am not up on my fish anatomy.

So perhaps this entry is a week late -- but hopefully it was worth the wait!

Please note that all photos in this blog post were taken by Sara Weinstein, and copyright (or copyleft or any other form of release) belongs wholly to her. Please visit her blog and drop her a line there if you'd like to use the photos!

Compiled Phylogenies

Posted by tigerhawkvok on July 27, 2009 19:23 in biology , paleontology

I've finally ported over my work on phylogenetics that I did for the UCMP to its own dedicated site: http://phylogeny.revealedsingularity.net. I've tried to compile this with sources from multiple papers and college levels textbooks, which gives even it's current status a unique place on what I've found on the internet. As a tetrapod phylogeny, it is complete (excepting avilae and rodentia), but my goal is to eventually have all extant organisms down to family, and include important extinct outgroups.

This is a very very tall order, and a planned multi-year project, but I encourage anyone running across it to contribute or to comment.

While there are other places on the internet with phylogenies, this is different than most of those. It is more complete in certain respects than the Tree of Life, but lacks accounts at the various levels. On the other hand, it is all contained on a single page which allows comparisons not possible on other pages, and the citations provide the ability to double-check the phylogeny posted.

Finally, I've published the source code, so people can contribute more to the phylogeny, and improve functionality in a crowdsourcing effort. My goal? Reach a tentative family level completion in five years. Lets see if we can do it. Share, help out, and encourage others to help!

Inside Nature's Giants

Posted by tigerhawkvok on July 27, 2009 19:06 in General , biology , misc science

A quicky today — prompted by Darren's post over at TetZoo, I went on a hunt for US-visible versions of the UK series "Inside Nature's Giants". Here's a snippet from YouTube on the second episode on whales:

You can watch the entire playlist here, or the same user's upload of the Elephant, which I'm just now about to watch.

A Press Conference We Need

Posted by tigerhawkvok on July 25, 2009 21:03 in General , astronomy

I was thinking about the 40th anniversary of the moon landing, and I found myself wishing we were doing more to reach for the stars. So, here is a speech that I wish we would hear from President Obama — though I doubt very much we will.

My fellow Americans:

It has been forty years since humanity first set foot on another celestial body. It has been forty years since we left the fragile confines of our blue marble and looked down upon it from another world.

Those forty years have seen remarkable advances. Our pocket calculators, phones, and PDAs have more than the entire sum of processing power used to launch, land, and coordinate the Apollo missions. We escaped the Cold War, we built giant particle accelerators that attempt to glimpse the first moments of this universe.

And yet, for more than 35 years, we've all humbly retired to this planet of ours and been content to live our our lives here, not reaching out.

We've done great science on other planets. Kepler searches for Earths around other stars; Spirit and Opportunity and countless other missions to Mars map it out in increasing detail. New Horizons is pointed toward the rock we call Pluto, so far out our Sun is barely distinguishable from the rest of the stars in the sky. The great Jovian planets, and their moons, are photographed with wonderful instruments we send their way. But a human has not ventured out to another celestial body since the end of Apollo.

I cannot say it better than John F. Kennedy, so I won't try. The importance of reaching out beyond our globe is not for science, but for the human spirit. Its a deep motivation, and to give another generation the wonder of space, showing that another world is accessible to them. That they or their children might step foot on another world. It is time that humanity begins its process of slowly moving out of our fragile nest, and move in to new worlds.

To that end, I give our country, our species, a challenge. We shall land on the Moon once more by 2019, Mars by 2024 and have a permanent station on either by 2035. It will not be easy. It will not be cheap. And great advances will have to be made along the way. But I know we can do this. Each grand step into unknown territory has brought our species more knowledge, more technology, and further insights into our world, and even if we do not see it now, I have no doubt that we can do so again. Let it be said in 2109 that 2009 was the year that humanity truly looked up into the sky and decided that they had grown old enough, and wise enough, to become a species not of one world but of many.

Thank you, and goodnight.


Posted by tigerhawkvok on July 24, 2009 22:27 in General

It's official ...

I am going to the Star Trek convention in Nevada this coming August.

Later this week, an Office 2010 review, and next week, a double Tuesday Tetrapod to make up for this week.

Tuesday Tetrapod: Mus musculus

Posted by tigerhawkvok on July 14, 2009 11:55 in tuesday tetrapod

Today's (late) Tuesday Tetrapod is Mus musculus, or the house mouse.


Feeder mice

Mice, as a member of the clade Glires, are one of the closest relatives to the primate clade Euarchonta, and the closest living non-primate relatives to humans.

That's it for today -- I'll try to get up another post some time this week, though!

Tuesday Tetrapod: Gymnopis multiplicata

Posted by tigerhawkvok on July 07, 2009 22:48 in tuesday tetrapod

Today's Tuesday Tetrapod is to be a bit enlightening — as I introduce a tetrapod that is a bit lacking in the "pod", and in addition, is very little known. I introduce Gymnopis multiplicata, a caecilian.

G. multiplicata

G. multiplicata. The "smile" is where its mouth is. Photo from Flickr user teague_o, taken in Costa Rica.

Often described as looking like large worms, caecilians are tetrapods — they have the whole tetrapod complement of parts, with a vertebra, occasionally with limb remnants, noses, jaws, teeth, and so on. However, they are also very unique in their morphology in many ways. Among their odder features include eyes covered by skin and two (very small) chemosensitive tentacles. Furthermore, their jaw musculature is unique in having two sets of jaw muscles for closing their jaws, unique among vertebrates in a condition known as streptostyly.

It's worth taking a look at their skull morphologies over on Digimorph: Typhlonectes, Scolecomorphus, Icthyophis, and Dermophis. Their skulls are strongly akinetic and completely roofed except for sensory openings, known as stegokrotaphy (with minor exceptions). Other interesting morphological traits include highly reduced or absent tails (their cloaca is at the terminus of their body), and the annular rings around their body, thought to be homologous to salamander costal grooves.

As lissamphibia, they are dependant on water in their environment for reproduction and to prevent dessication. You can see their relevant phylogeny here. Caecilians are known from the lower Jurassic.

Watch some fascinating behaviours from caecilians as they effectively nurse their young with their skin. They strip the flesh off their mother, which exudes a white, milky substance, and the skin grows back rapidly, often within 24 hours. I couldn't find a good general feeding video, though.

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