A Dinosaur on the Christmas Dinner Table

If you recall my post from back around Thanksgiving, the Wild Turkey -- like all birds -- is a modern day dinosaur.  What better opportunity to share this little fact with your friends and family than over the Christmas Turkey?

Below are some resources for turning the remains of your holiday feast into a biology lesson, but before we get into details I want to first answer a simple question: What exactly is a dinosaur anyway?

Dinosaur's are a group of (mostly extinct) reptiles that arose around the early Triassic period about 230 million years ago (mya).  They persisted until the mass extinction event that occurred 65mya at the end of the Cretaceous period, (also the end of the Mesozoic era and start of the Cenozoic era), when all of the dinosaur lineages save modern birds died out.

To put this talk of dinosaurs and birds into perspective, lets take a crash course in vertebrate taxonomy. Starting with the ancestor of all land vertebrates, we can follow evolution forward to the present, noting major points of divergence along the way.  We're of course skipping a lot, taking the fast track from the first vertebrate land animals to modern day birds.

The first amphibian-like terrestrial tetrapods appeared over 350mya (Late Devonian into the Carboniferous period), with the Synapsids (whose descendants became the modern mammals) splitting off 25+ million years later.  Another 25 million years or so later, ancestral turtles and other Testudines appeared, then the sphenodonts (the tuatara) and the squamates (lizards and snakes), then crocodilians, then dinosaurs and birds.

These relationships can be summarized as follows (here I've included proper group names as well as extant representatives):

•  Amniotes - Descendants of the first egg-laying terrestrial vertebrates (~ 340mya) split around ~325mya
• Synapsids - Mammalian ancestors
• ...
• Mammals ~ 200 mya
• Primates ~ 55+ mya
• Human-Chimp Split ~ 5-10 mya
• Saurapsids - Modern Reptilians
• Anapsids - Turtles
• Diapsids - Other modern reptiles (including birds), split ~ 300mya
• Lepidosauria -Tuatara, Lizards and Snakes
• Sphenodonts - Tuatara
• Squamates - Lizards, Snakes
• Archosauria - Crocodilians, Dinosaurs (including birds)
• Crocodilia
• Dinosauria - Two dinosaur groups diverged ~250 mya
• Ornithischia - "bird-hipped", beaked - but not birds!
• Saurischia - "lizard-hipped", toothed ancestors of birds.
• Sauropodomorpha - big herbivores like Diplodicus.
• Theropoda - bipedal carnivores like T. rex, Velociraptor and...
• Aves - modern birds, originating ~ 150mya

Whew!  So to sum up, birds have been around since their divergence from the other dinosaurs during the Cretaceous period (145-65mya), and are the only surviving Dinosaurs of the big Cretaceous extinction 65mya. Their closest living relatives are the Crocodilians (together with dinosaurs and other relatives, these are the Archosaurs), then the lizards and snakes (which all together form the Diapsid reptilians), then turtles (all together, the Saurapsids). After all the reptilians, the next closest relatives are the mammals (all together, these are all of the living Amniotes), then amphibians, fishes, etc.

So how do you bring all this information to the dinner table?  Well the easiest way to see the relationship between dinosaurs and birds is from the differences and similarities in their skeletal structure.

Source: The Origin and Early Evolution of Birds | Geology Rocks

Other ideas can be found here, and for a nice reference you can bring with you to the Christmas dinner table...

Source: Image from here, modified by Tom Holtz here.

Resources:

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1. Prothero, S. 2007. Evolution: What the Fossils Say and Why It Matters. Columbia Univ. Press.
2. The Dinosauria, from the University of California Museum of Paleontology website.
3. Wikipedia (links above).
4. Wedel, Matt. Your Holiday Dinosaur, University of California Museum of Paleontology website.
5. Holtz, Tom. Your Thanksgiving/Christmas Therapod from Dave Hone's Archosaur Musings.

Signs of Evolution in Primate Teeth

I've been busy with thesis work lately, but I'll try and get back to regular posts after the holidays! 

For now, here's a nice little clip on primate evolution, which I came across on the YouTube channel for the U.S. National Institute of Standards and Technology (yes, they have one!).

I'll let Dr. Constantino explain...

Please Recycle (Your Seal Carcasses...)

Check out this beautiful time-lapse video from the BBC of a seal carcass being recycled under an ice sheet somewhere in the antarctic's McMurdo Sound.  By "recycled" I of course mean it's remains are being cleaned up by a bunch of 3-meter nemertean worms, various echinoderms and assorted little arthropods.

[Hat tip to PZ Myers for the link.]

Conspiracy Revealed: Climate Change & Hacked Emails

Here's a great video on the apparently not-so-news-worthy details of those stolen emails that prove that climate change (or global warming, or whatever you prefer to call it) is really just a big international hoax (cough, cough). 

One of the big "Gotcha!" emails seems to be this one, which was widely quoted for these two gems of easily misinterpreted science lingo:

I've just completed Mike's Nature trick of adding in the real temps to each series for the last 20 years (ie, from 1981 onwards) and from 1961 for Keith's to hide the decline.

and

We can't account for the lack of warming at the moment and it is a travesty that we can't.

So what's it all boil down to??

Real world Coyote vs. Roadrunner!

More photos over at Bill Schmoker's Nature & Birding Blog, BRDPICS - Check it out!!

Mid-week Reptilian: Happy Turkey Day!

What more appropriate reptilian to showcase this holiday than the one on the dinner table? How about it's wild counterpart - the Wild Turkey (Meleagris gallopavo).

The Wild Turkey is the largest of the 2 extant turkey species (the other being the Oscillated Turkey of S. America).  There are around six recognized subspecies (nominate South Mexico M. g. gallopavo, Gould's M. g. mexicana, Eastern M. g. silvestris, Florida M. g. osceola, Merriam's M. g. merriami,  and Rio Grande M. g. intermedia) and a variety of domestic breeds including the somewhat pitiful breed most Americans will be carving up this Thanksgiving.  Turkeys are classified in the order Galliformes, which includes the other chicken-, grouse- and pheasant-like birds. In the past turkeys belonged to their own family (Meleagrididae), but recently they've been deemed more closely related to the grouse and pheasants lumping the three previously distinct family groups into the family Phasianidae. 

Figure 1: Two male Eastern Wild Turkeys doing a courtship display.

Figure 2: The completely unrelated Turkey Vulture, here regally poised atop

a decaying deer carcass (for your post-Thanksgiving-dinner pleasure).

Turkey's received their common name from their early arrival to Europe, when they were imported to Turkey from the new world.  They became know as "Turkey Fowl" on the market, and as Europeans moved to the Americas, the name stuck.  In spanish many call turkey pavo, likely from early European confusion with Peafowl (genus pavo), and in parts of Central American and Mexico turkey are known commonly by their Nahuatl name of guajolote.

Turkey are conspicuous birds, and not surprisingly hold a place in U.S. history.  Aside from the Thanksgiving tradition, there is also Benjamin Franklin's rather famed criticism of the Bald Eagle as our national emblem.  In a 1784 letter to his daughter Sarah, he compares a few other birds with that "bird of bad moral character", the eagle - including the Wild Turkey.

For in truth, the turkey is in comparison a much more respectable bird, and withal a true original native of America. Eagles have been found in all countries, but the turkey was peculiar to ours; the first of the species seen in Europe, being brought to France by the Jesuits from Canada, and served up at the wedding table of Charles the Ninth. He is, besides, (though a little vain and silly, it is true, but not the worse emblem for that,) a bird of courage, and would not hesitate to attack a grenadier of the British guards, who should presume to invade his farmyard with a red coat on.

Kids Explain Evolution: The Charlie's Playhouse Compilation

A while ago, some of you may have seen requests for parents to share some video of their kids answering the question "What's Evolution?" The result is the video version of the Ask the Kids! project at Charlie's Playhouse which is now available on the web (including right down below...)

On the Origin of Species turns 150

I'm sitting here in an airport Starbuck's somewhere in the midwest, and thought I'd try and crank out a quick blog post while I was killing time. So given today is the 150th anniversary of Darwin's first edition of On the Origin of Species, here are a few odds and ends that caught my eye:

• A cool graphical representation of the book's evolution from the first to the final (sixth) edition.
  
• Video from the recent UCLA visit by Ray "Banana Man" Comfort & Kirk "Master Debator" Cameron
• Panda's Thumb says Happy Birthday to the Origin 
• There's a lot of media coverage about how the book is still controversial (which says a lot more about people than the book), and unfortunately
  
• Some media outlets are picking up creationist crap (though read the comments).
  
• http://www.Darwin150.com is also on facebook.
• Other happenings from around the world.
  

NSF launches Evolution of Evolution website

The National Science Foundation has launched a new website called the Evolution of Evolution: 150 Years of Darwin's On the Origin of Species. A cursory look at the site revealed a nice (though a bit overpackaged) presentation at how the theory of Evolution has pulled together a broad array of scientific disciplines, and expounds upon a few cool, important or otherwise noteworthy examples of the recent scientific accomplishments as well as significant historical work.  Also a bit of history surrounding Darwin and his legacy - no doubt in celebration of his 200th birthday this year, and the 150th anniversary of On the Origin of Species this Tuesday, the 24th of November.

If you get a chance to work through any of the site in detail, feel free to leave your impression in the comments below.

The appropriate response to an awesome new animal...

"Wow! Whoa! Wow!"