Friday, December 5, 2014

Night Changes: Why Color Blind People Aren't So Strange (But Really Are at the Same Time)

"Why does your Tyrannosaurus skull have rings on its eyes?"  "Why are reptiles and amphibians, animals often brushed aside as "less superior" to mammals, frequently very colorful?"  "By contrast, why are so many mammals so drab?"  "Does it ever drive you crazy just how fast the night changes?"  All of these questions and more are ones that I've either received or asked over the last few months, and surprisingly, they are all (sort of) tied together.
A selection of the stars of this post.  In the top row from left to right, we have a Prestosuchus skull, Micronesian kingfisher, Opthalmosaurus skull, African elephant, and a white-necked raven.  Second row, we have a male peafowl, Microraptor specimen, myself pulling a "District 9" with a T-rex arm and Stan the T-rex next to me at the Morrison Natural History Museum (now you finally know what I look like [irresistible], you can cross that off your bucket list), a Mandarin Goby, and the hand of Zach Evens descending upon a brightly colored newt.  Finally, in the bottom row, we see a pair of tiger salamanders, a coyote that ran amok on the University of Colorado campus last winter, and several bees swarming a hummingbird feeder at the MNHM.  Did I forget anything?  Oh, right, the album cover of One Direction's new album "Four."  A further bonus for all you "Natural Worlders" out there: can you find the names of twenty-one One Direction songs scattered throughout the blog post?  Try not to stay up all night searching for them, one way or another I have no doubt you can figure it out.  Just shoot me and email, and I can get back for to you about where they are.  Just one of those little things that makes reading my blog so worthwhile.
When people first walk into the Morrison Natural History Museum near Denver, Colorado, you might see a rock hammer-toting, cowboy-hat wearing, beard-wielding paleontologist talking about lizard pseudo-placentas, the anatomy of the dinos in Jurassic park, or whether said dinosaurs would taste like chicken.*  You might notice the bathroom first, which is more or less right across the room from the front entrance.  Or, like most people, you might notice our cast of Stan, one of the most complete specimens of Tyrannosaurus rex known to mankind.  We tend to get a lot of questions about this bad boy (T-rex consistently being the favorite dinosaur of pretty much everybody), and one question that we get a lot pertains to his eyes.  You might have missed it if you were looking at the fantastic picture above, but take a look at the pictures below and you should see it: it looks like we've put little rings where the eyes should be.  The question is: Why does our Tyrannosaurus skull have rings on its eyes?
Believe it or not, this was not a once in a lifetime phenomena, and it is not a trick (excuse me, an illusion) we created to make the placement of the oculars more apparent for the casual observer.  It's real, and it's called the sclerotic ring.  Without getting too technical, the sclerotic ring is a ring of several bones that actually is inside of the eye of the animal, and is usually thought to help support the eye.  What I find really interesting about the ring is that the default condition in vertebrate animals is possession of this bony ring.  Even though you might not see it in a lot of museum specimens due to display difficulties or preservation issues, a sclerotic ring is present in most/all fish, lizards, birds, and dinosaurs.**  You won't see it in modern crocodilians, though, and it seems like at least some snakes don't have them either.  What's another group that doesn't have the ring?  You guessed it: mammals.
One with the ring, one without.  My bro Masaki Kleinkopf poses next to the mounted skeleton of the pterosaur Pteranodon at the Rocky Mountain Dinosaur Resource Center (RMDRC) in Woodland Park, Colorado.  Check out dat ring doe.
A mounted skeleton of the emperor penguin (Aptenodytes forsteri) at the American Museum of Natural History (AMNH) in New York.  If you liked it, you should have put a ring on it.
Skull of the therizinosaur dinosaur Falcarius on display at the Wyoming Dinosaur Center in Wyoming.  One ring to rule them all.
At this point you might be expecting some profound, fascinating statement that explains why some animals have the ring and some animals don't.  Believe me, very few things would please me more than to be able to explain this to you.  Unfortunately, I don't know.  Even more unfortunately, nobody really knows!  Although various explanations have been put forth over the years, I can't really find a fool('s gold fire)proof, satisfactory interpretation that broadly explains this phenomenon, and in this post I don't really wish to wade any further into this debate than we have already.  We have a few more questions to answer tonight.
The small feathered dinosaur Microraptor on display at the Wyoming Dinosaur Center in Wyoming.  You can see both the impressions of feathers off the wings and legs (making this Velociraptor-cousin comparable to the Sopwith Camel British biplane active during World War I), as well as the sclerotic ring nestled within the orbital.  My preciousssss.....
The name of this ichthyosaur, Opthalmosaurus, actually means "eye lizard," the name of which refers to the big @$$ eyes and sclerotic rings of this particular genus.  Better not put it on your finger, Dumbledore, it might be a Horcrux.
The pseudosuchian Prestosuchus, on display at the AMNH in New York.  This ring just exudes fellowship, don't you think?
Why is Nagini usually more brightly colored than Crookshanks or Scabbers?  Why are Polly's pigments predominantly prettier than Pongo's or Perdita's?  Although undeniably more handsome after true love's first kiss, there's no denying than many frogs and toads out there are much more exciting to look at than Prince Charming.  There's got to be a reason why the characters in "Finding Nemo" were so much brighter (sorry Dory, but I mean in terms of color) than Remy from "Ratatouille," or why Kevin is much more conspicuous than Dug in "Up." But what is the reason?  The answer seems to be fairly simple: with few exceptions, most mammals are colorblind. Primates are one of these exceptions, which is why we humans are able to differentiate between cherry and grape Jolly Ranchers and an elephant might fail, and why the Green lantern comic books and Bionicles absolutely tanked in the feline and canine demographics.  Mammals are good at a lot of things, but one thing that they're not very good at is seeing in color.  A picture is better than words in many cases, so check out some pics below of animals that can most definitely see in color.
Here we have a white-necked raven (Corvus albicollis) correctly putting four different colored game pieces into the correct slots at a special Teen Career Day event at the Denver Zoo that I attended with my sister.  He did all eight tiles in the correct category, and it didn't take him very long, either!  Some of my friends wouldn't be able to do it with such speed and accuracy....
Male peafowl (Pavo cristatus), often referred to as peacocks, are just one of many species of bird that use brightly colored feather to attract their mate.  Maybe that's why Sauron was so angry: he knew that, no matter what he did, the giant eagles would always be able to naturally two-up him.

A Micronesian kingfisher (Todiramphus cinnamominus) sittin' purty at the Denver Zoo.  Return of the King(fisher), am I right?
A clown fish (subfamily: Amphiprioninae) taking refuge amongst the stinging tentacles of a sea anemone at the Denver Zoo. 
The Mandarin goby (Synchiropus splendidus), a particularly beautiful fish, and very brightly colored as well. 
One of my two betta fish (Betta splendens), Juan Priestly.  Bright bodies with frilly fins?  Glad I'm not a betta fish, this one would steal my girl right out from under me.
Just like the default condition for vertebrates is to possess a sclerotic ring, so too does it seem that the default condition for vision is color.  So if mammals are supposedly so superior, why do so many of us lack this colorful condition?  Many paleontologists have been looking back to the Mesozoic Era, the age of the dinosaurs, to try and solve this colorful conundrum.  Just as mammals have been the dominant terrestrial vertebrates for the last 65 million years, so too did the dinosaurs rule the land during the Mesozoic, suppressing all other forms of life and filling most of the major terrestrial niches.  One of those life forms that was consistently suppressed from the Triassic through the Cretaceous was mammals.  Mostly small, shrew-like animals, Mesozoic mammals are usually thought to have been small, nocturnal creatures, pittering and pattering around the bodies of the sleeping dinos, ready to run at a moments notice.  Key word in that last sentence: nocturnal.
Can you see the little mouse-looking animal hiding underneath the box in the middle of the photograph?  That's Hufflepuff (Huffle to his friends), a small meadow vole (Microtus pennsylvanicus) that tried to hide underneath my legs when a red fox (Vulpes vulpes) happily tried to make a meal out of him last year on CU campus!  Knowing he probably had had the vole equivalent of a heart attack and taking pity on him, I said "I'll save you tonight!" and let him recover for a few days in my room before letting him go to let him live while he was young (which isn't long, I don't think most voles live longer than a year or so, but I could be wrong).  A nocturnal critter, he would have very little use for color vision, and has relatively drab coloration.
More wildlife from CU campus!  This coyote (Canis latrans) caused a bit of a stir last winter when it decided to crash on Farrand Field for a few hours, right in the middle of CU campus.  Although not exclusively nocturnal, coyotes are often active at night, but are quite adaptable, as was evidenced by this particular coyote's behavior, alive and well in the middle of campus!  Note the relatively drab coloration.
I have a friend who is partially colorblind, about as colorblind as an elephant according to some recent studies.  If you see him outside, he's going to be wearing sunglasses (unless he's done something to piss off Poseidon).***  Is he doing it just to look cool?  Well, yes, I suppose that's at least partially the case.  But for him, and for many other people who suffer from color blindness, it seems like they make up for it with above average night vision.  Essentially, an imbalance of rods (a photoreceptor that is not sensitive to color but is sensitive to light and dark conditions and aids in night vision) and cones (a photoreceptor that is sensitive to color and less sensitive to light/dark conditions) leads to many who are color blind reporting better than average ability to see what's going on in low-lighting conditions.
An African elephant drinking some water at the Cheyenne Mountain Zoo in Colorado Springs.  Drab colors?  You betcha!
When all of these seemingly disparate ideas are regarded holistically, it seems to make sense.  By default, most vertebrates enjoy a wide range of color vision (sometimes even a wider range than humans!).  However, during the Mesozoic dinosaurian domination, some groups of vertebrates such as the mammals were forced to take up residence during the night.  For millions of years, these little creatures lived a nocturnal existence, and it seems like being able to see in color no longer proved to be a competitive advantage for them.  Following the extinction of the dinosaurs and the subsequent radiation of mammals, it appears that the possession of color vision was unnecessary for them to survive and thrive.  Many mammals are still largely nocturnal today (think of your kitty at home and all of her midnight memories), which might have something to do with this disparity between their rods and cones.  All in all, it would appear that changes of the night can have some pretty profound effects on your ability to see across the color spectrum.


*You will probably come across them doing some serious work as well, but dinosaur taste-testing can be pretty important.
**I thought that Dr. Bakker, who I talked to a lot about this, mentioned that most or all frogs had the sclerotic ring, but I have been unable to confirm or deny this with a quick search through the resources I have at my disposal.
***Twice.

Works Cited:

Sunday, September 21, 2014

Taima the Seattle Seahawk and the Genus Buteo

For those of you who watching the Broncos/Seahawks game right now, you might have noticed clips of a random bird of prey flying around which, if you're anything like me, that was the highlight of the entire game.  Named Taima, the bird is the mascot for the Seattle Seahawks football team, an augur hawk (Buteo rufofuscus).  Although sometimes referred to as the augur buzzard, I prefer the name augur hawk, as buzzard is sometimes a bit of a confusing name.*  According to the Seahawks website, Taima has been the "first one out of the tunnel" prior to every game.**  The augur hawk is one of the most common hawks in Africa, and inhabits an enormous portion of the eastern and central part of the continent.  Open plains, grasslands, and forests are the augur's preferred habitat, fairly similar to its close North American cousin, the red-tailed hawk (Buteo jaimaicensis).
Taime the Seattle Seahawk!  Photo Credit: www.seahawks.com
The broad-winged hawk (Buteo platypterus) is one of the smallest members of the genus, and a hawk that's involved in a very interesting new project, the aptly named "Broad-Winged Hawk Project."  Similar in many ways to the OCEARCH shark tracking project, the BWHP is using satellite telemetry technology to track broad-winged hawks on their migration from Pennsylvania, all the way down to Central and South America.  You can join in the tracking fun by clicking on the link HERE!  Several of the nestling broad-wings were from pretty close to where my friend Zach Evens's cabin in Pennsylvania was that we visited in August!
A broad-winged hawk.  Photo Credit: Julie Waters
There are a ton of other hawks in the genus Buteo besides the red-tail, augur, and broad-wing, several of which we've talked about here on the blog, such as the red-shouldered hawk (B. lineatus), rough-legged hawk (B. lagopus), and the Swainson's hawk (B. swainsoni).
A rough-legged hawk on the hand of Anne Price, the Curator of Raptors for the Raptor Education Foundation at one of the raptor shows at the Best Western Denver Southwest!
*In the Americas, a buzzard typically refers to a vulture, while in the Old World, buzzard is often attributed to members of the genus Buteo, of which the augur hawk is a member.  We Americans tend to refer to buteos simply as hawks, which is part of what can lead to this confusion.

**For those of you not in the know, the tunnel is not a metaphorical tunnel, and instead refers to a legit tunnel that leads from the locker room onto the stadium.

Works Cited:

Wednesday, September 10, 2014

Anoxic Conditions From Everest to Europa: Swamps, Fossils, Naked Mole Rats, and the Hunt for Extraterrestrial Life

Above elevations of 6500 meters (21,300 feet), most climbers tend to start using supplemental oxygen.  At altitudes higher than this, oxygen is spread so thin that humans can have a very tough time breathing.  Even people who come from sea level to my hometown of Boulder, Colorado at an elevation of 1,655 meters (5,430 feet) often get altitude sickness, and there's still a whole lot of altitude to go before you even get to Everest Base Camp.  Most birds don't fly as high as the summit of Mt. Everest, because most birds have no reason to fly that high.  However, for the bar-headed goose, the Himalayas form an unfortunate, but not impassable, barrier between their winter feeding grounds in India and their Tibetan nesting grounds.  These geese have been reported flying over some of the highest Himalayan peaks, and they're not the only ones that fly this high.  On November 29th, 1973, a Rüppell's griffon, a type of Old World vulture, collided with an airplane at an altitude of 11280 meters (37,000 feet).  By comparison, oxygen cylinders are recommended for sailplane pilots flying over 3660 meters (12,000 feet)!
Here we have a beautiful (and extraordinarily neat) size comparison and altitude chart of a number of things covered in the post, including the altitude of Denver, the summit of Mt. Everest, the upper extent of the range of the snow leopard, and the height at which the Rüppells griffon got sucked into the jet engine.  I've also thrown in some other helpful and fun things for comparison as well.
Part of what helps birds survive at altitudes that could kill a human is a series of air sacs that allow air to flow in one direction through the body of the bird.  In humans, the air we breath in and out travels back and forth along the same tubes.  In birds, as well as some of their close dinosaurian cousins, these air sacs would have have allowed the air to flow more efficiently through their bodies.  While this is simply one of many adaptations that can help birds fly at incredibly high altitudes, other animals have evolved other adaptations to assist in high altitude living.  Scientists have determined that changes in the genes EGLN1 and EPAS1 are linked with animals living in oxygen impoverished environments, such as the snow leopard, humans native to Tibet, and naked mole rats.  Naked mole rats live in underground colonies of 20-300 individuals, and are one of two species of mammal that can be classified as "eusocial," meaning that their colonies display a caste system (similar to the social structure seen in ant and termite colonies).  These underground colonies are poorly ventilated, which means that as the mole rats inhale oxygen and exhale carbon dioxide, CO2 concentrations can increase to levels that would be unsafe for humans.  Fortunately, naked mole rats are well adapted to breathing very little oxygen, and their brains seem incapable of registering pain upon contact with acids, which is thought to help them in these CO2 rich confines.  They also demonstrate similar changes in the aforementioned genes as snow leopards and the Tibetan people, indicating another adaptation to these low oxygen (or hypoxic) conditions.
A group of naked mole rats all huddled together at the Cheyenne Mountain Zoo in Colorado Springs, Colorado.  Look at all of that eusociality!
Although hypoxic conditions can bode ill for human climbers and gregarious colonial rodents, low oxygen conditions can be great for paleontologists.  When oxygen levels drop to nearly zero, anoxic conditions prevail, and bacterial decomposition of organic material is greatly reduced.  This can be a major factor when it comes to soft-tissue preservation, such as feathers and skin.  A FEW WEEKS AGO, we talked about several famous fossil sites called Lagerstätten (a German term meaning "mother lode"), that are set apart from other fossil deposits due to the quality and/or quantity of the fossils discovered there.  One of the most famous examples is the Cambrian-aged Burgess Shale in British Columbia, Canada.  Abrupt burial of the 500 million year old organisms, coupled with the anoxic conditions that prevailed at the bottom of this body of water, ensured that these soft-bodied organisms would be preserved in exquisite detail.
A drawing of Opabinia, one of the many creatures that inhabited the Cambrian aged Burgess Shale in British Columbia, Canada.  Photo Credit: Sam Lippincott
Why do swamps often have that rotten egg smell?  Believe it or not, the answer is closely related to what we've already been talking about!  Under hypoxic or anoxic conditions, bacteria that use oxygen (O2) sometimes have to make do with sulfur (S).  If you look at a periodic table, you can see that sulfur (element #16) is directly below oxygen (element #8).  In the periodic table, each group (or column) of elements has very similar chemical properties, which means each element will react in a similar fashion.*  For the bacteria that can't get enough oxygen, they will sometimes turn to its close cousin sulfur instead.  Below is the chemical formula for cellular respiration, which is what these bacteria do, as well as some of the cells in humans.  On the left, we have the inputs: glucose (C6H12O6), and oxygen (O2).  When we breath in air, we are bringing oxygen into our lungs, and we can get glucose from the foods we eat.  On the right of the arrow, we have the outputs: water (H20), carbon dioxide (CO2), and energy.  Remember how we talked about the CO2 concentrations in naked mole rat burrows?  CO2 is one of the products of respiration, and one that can be harmful in large doses.  Energy is another product of respiration, which is the fuel that cells need to do their job.  In places where there is less oxygen input (such as at the top of Mt. Everest or in a naked mole rat burrow), the cells don't get as much energy output, and they can't do their job as well.
Now, instead of having oxygen as one of the inputs of cellular respiration, let's try sticking oxygen's close cousin, sulfur, into the equation to see what will happen.  As you can see below, the glucose on the left of the equation remains unaffected, as does the carbon dioxide output on the right of the equation.  But instead of having water (H2O) as another one of the outputs, we now see a molecule with the formula H2S.  Instead of forming water (hydrogen oxide), we have now formed a closely related molecule, hydrogen sulfide.  In swamps, large amounts of organic material leads to lots of bacteria and bacterial decomposition, which in turn can lead to lots of the oxygen being used up in the water.  That's when these bacteria start using sulfur to make their energy, producing hydrogen sulfide, with that characteristic rotten egg smell.  Even with this sulfur replacement, sometimes the bacteria just can't keep up with the amount of vegetation that is deposited in the swamp, and the organic material builds up.  If the rate at which the vegetation accumulates exceeds the rate which the bacteria can decompose the vegetation, then you have coal formation potential sometime in the future.
Let's take this one step further.  In normal respiration, where oxygen is one of the inputs and water (H2O) is one of the outputs, carbon dioxide (CO2) is another one of the outputs.  If animals and bacteria keep using up oxygen and turning it into carbon dioxide, why haven't we run out of oxygen?  Will we run out one day?  Fortunately, for the time being, plants have got our back, by undergoing a process called photosynthesis.  Photosynthesis is almost the exact opposite of respiration: carbon dioxide and water are the inputs, and glucose and oxygen are the outputs.  However, unlike respiration, light is one of the inputs of photosynthesis.  In the 1700s, a man named Joseph Priestly did experiments in which he sealed a mouse in a jar, and waited to see what happened.  The mouse, as you could probably predict, suffocated and died.  It used up its oxygen to create energy (as well as carbon dioxide), and eventually ran out of oxygen.  (This is why it's important not to put animals into completely sealed jars with no airflow, as they will suffocate.)  However, if he put a plant into the same jar as the mouse, the mouse didn't suffocate.  We now know that is because, as the mouse used up the oxygen, creating carbon dioxide, the plant would use the carbon dioxide, ultimately creating more oxygen.
As you probably know, plants need light to survive, and as we mentioned before, that's because light is one of the inputs of photosynthesis.  No light, no photosynthesis.  No photosynthesis, your plant dies.  For many years, scientists assumed that all life on Earth was directly dependent on the Sun for its energy.  That is, until 1977, when scientists discovered entire communities of biological organisms living thousands of meters beneath the surface of the ocean, too far from any sunlight to undergo photosynthesis.  So what was going on?  How were these communities able to survive without access to the sunlight?
A picture of one of the hydrothermal vent communities.  Photo Credit: NOAA
Hydrothermal vents are essentially underwater hot springs that form along tectonic boundaries thousands of meters beneath the surface of the ocean.  These underwater vents spew different compounds containing sulfur into the surrounding water, just like aboveground geysers do, too.  (If you have ever been to Yellowstone National Park, then you might even remember the rotten egg smell.)  Some bacteria that surround these vents are actually able to use these sulfur-containing compounds to create the energy needed to undergo a process similar to photosynthesis, called chemosynthesis (consult the equation below).  Chemosynthesis is very similar to photosynthesis, with a few key differences, the biggest difference being the sulfur reactions vs. sunlight as one of the inputs.  You can also see that, instead of having water (H2O) as an input like in photosynthesis, chemosynthesis instead uses hydrogen sulfide (H2S) as an input.  Then, instead of producing oxygen, the chemosynthetic organisms produce water and sulfur.  You can compare it to the oxygen-poor respiration equation that we talked about with the swamps, and see that it is similar to that equation as well, simply flipped around.
But that's not all.  Scientists have taken this idea a step (or rather, one giant leap) further.  The search for life on other planets thus far has yielded nothing, but that doesn't mean it's not there.  It is now realized that some of the factors that were once thought to limit the development of life, such as sunlight, might not be as crucial as we once thought, and the hydrothermal vent communities have been crucial in the maturation of these ideas.  Some scientists suspect that life could exist on Mars by using chemosynthesis, but a new candidate has been receiving an increasing amount of attention: one of Jupiter's moons, Europa.  Icier than the planet Hoth, Europa is now thought to have an ocean of liquid water up to 160 km (100 miles) deep surrounding the solid, rocky mantle, following the discovery of a magnetic field surrounding the moon, similar to the magnetic field that surrounds the Earth.
A picture of Jupiter's moon Europa, taken by NASA.  Photo Credit: en.wikipedia.org
What keeps the liquid ocean of Europa from freezing solid?  Jupiter is pretty far from the Sun, and even Mars, which is much closer to both the Sun and the Earth than Jupiter is, has had its water frozen for millennia.  It's thought that the gravity exerted by the enormous mass of Jupiter continually pushes and pulls, or tidal stresses, on its moons, which keep the planets from becoming tectonically inactive, like Mars.  Io, another of Jupiter's moons slightly larger than our Moon, is the most geologically active body in our Solar System.  The tidal stresses from Jupiter exerted on Io apparently make Io's ground itself buckle up and down, similar to the tides we experience here on Earth, except that instead of water moving up and down 18 meters (60 feet), its solid ground moving up and down up to 100 meters (330 feet!)  It's these same tidal stresses that make Io so geologically and volcanically active that help keep Europa from freezing solid.  It has been hypothesized that the tidal flexing might also create hydrothermal vents on the bottom of Europa's oceans, and it shouldn't take too much thinking to realize what that might mean: the potential for extraterrestrial life!
Jupiter and its four Galilean Moons (from top to bottom: Io, Europa, Ganymede, and Callisto).  Photo Credit: NASA
*For example, we humans, as well as all known lifeforms, are carbon-based.  In science fiction, such as Star Trek and Transformers, you will often hear about "silicon-based lifeforms."  Why silicon, as opposed to any other element?  If you look at the periodic table, silicon is in the same group as carbon, and situated right beneath it, and therefore has very similar chemical properties as carbon.



Works Cited:

Thursday, August 21, 2014

'Donts and 'Apsids: Ancestral Dinos and Mammals of the Mid-Triassic

When it comes to dinosaurs and mammals, neither had quite yet evolved yet.  Most people consider animals like Herrerasaurus and Eoraptor to be among the oldest known dinosaurs, but others now consider Nyasasaurus to be the oldest, originating from 240 MY old rocks from Tanzania.  Many dinosaurs looked very similar to other, closely related archosaurs, and only extensive research and more specimens will be able to shed light on these ancient critters.
Herrerasaurus skeleton at the Field Museum in Chicago.  Photo Credit: Sharat Ganapti
Mammalian ancestors took the form of the now-extinct dicynodonts and the cynodonts, the latter of which include modern mammals, as well.  In modern mammals, you can see how the skull only has a single hole behind the eye (the space where the coronoid process sneaks in between the main part of the skull and the extruding zygomatic arch), making it a synapsid, or "one-holer."  In previous posts, we've talked about primitive, mammal-like animals such as Dimetrodon and Cotylorhynchus.  Both of these critters are synapsids.  Diapsids, or "two-holers" (remember from our recent Latin/Greek Roots post that the root "di" means "two" [click HERE to read that post]), is another large group, and includes everything from crocodiles to dinosaurs, lizards to snakes, and tuataras to birds.  It also includes the archosaurs, a subgrouping of diapsids that are characterized by an additional hole in the skull, bringing the total number of skull holes up to three.  So some diapsids are also archosaurs, such as birds, dinosaurs, and crocodiles.  There's also the anapsids, which are animals with no holes in the skull, such as amphibians and turtles.  Taxonomically, this can get a bit confusing (especially since sometimes an animals classification doesn't correspond to the number of holes that it has at that point in its evolutionary history), and maybe later we can go into greater detail about these different 'apsids, but below we have a nice picture that should help clear things up a little.
Holes in the skull.  On the top left, we have the prehistoric sea turtle Protostega, an anapsid, with no extra holes behind the eye socket.  Below Protostega, we have Prestosuchus, a type of archosaur.  Not only does Prestosuchus have the two holes in the skull behind the eye socket that characterize older diapsids, but it also has a third hole, in front of the eye socket, but behind the nose openings.  On the bottom right, we have Edaphosaurus, a primitive synapsid.  The largest hole in the skull, furthest on the right, is what will one day become the hole that the coronoid process sneaks through, between the zygomatic arch and the rest of the skull.  In the picture above Edaphosaurus, you can see what I'm talking about, with the extinct mammalian synapsid Hyaenodon.  Here, you can see the little nub of the coronoid process between the zygomatic arch and the skull.
As we talked about in that Latin/Greek post that I mentioned above, the name of the primitive, fin-backed synapsid Dimetrodon means "two measures of teeth," referring to the two different types of teeth this animal possesses.  This is a feature known as "heterodonty," a term that means "different teeth."  Most mammals are heterodonts, and most other animals like reptiles are not, but it doesn't always work that way.  Modern cetaceans such as the sperm whale, as well as orcas and dolphins, are homodonts, meaning that they only have one type of tooth in their mouth.  If you look at ancient ancestors of whales, such as Basilosaurus or Zygorhiza, you can see that they have different types of teeth in their mouth.  This condition can be traced all the way back to 50 MY old Pakicetus.
A trio of cetacean skulls.  On the top left, we have Pakicetus, a terrestrial ancestor of the cetaceans, that lived in Pakistan approximately 50 MYA.  Below Pakicetus, we have Zygorhiza, a more derived and fully aquatic cetacean.  In both Pakicetus and Zygorhiza, you can see how the front teeth and back teeth are different, with the front teeth more for gripping prey, and the back teeth perfect for slicing.  On the right, you can see the skull of the modern killer whale, or orca, which has only one type of tooth in their mouth, the conical, gripping teeth.
Then, of course, there are the heterodont reptiles and dinosaurs such as the Cretaceous crocodilian Malawisuchus, and the dinosaurs Heterodontosaurus (literally meaning "different-toothed lizard") and the oviraptorosaur Incisivosaurus.  We also talked about the primitive pterosaur Dimorphodon (two morphs of teeth) in the Latin/Greek post as well.  If you look at the skulls of any of these animals, you can clearly see the different types of teeth in their mouth.  Cynodonts were not merely an aberrant heterodont form amongst a vast sea of closely related homodonts, but instead were precursors to the default heterodont condition seen in mammals.
The skull of Heterodontosaurus, on display at the American Museum of Natural History in New York.  You can see the two different types of teeth in the skull, especially in the lower jaw.
Works Cited:

Sunday, July 27, 2014

Osteoarthritis and Your Pets by Kathy Gagliardi, Guest Blogger

Many of us have pets, and nearly all of them, at least at one point in their lives, will be affected by something that only a trained veterinarian can help with.  But vets can't do it all themselves: they need you and I, the servants caretakers of the pets to be able to recognize something is wrong in the first place.  I asked Dr. Kathy Gagliardi whether she would be interested in sending me an article that I could post on here, and she was kind enough to oblige!  Here's a little bit about Dr. Gagliardi:

Dr Kathy Gagliardi is a veterinarian that works in Louisville, Colorado at VCA Centennial Valley Animal Hospital with small animals and exotic pets such as snakes, lizards, bunnies, ferrets, rats, birds, etc.., She loves the variety of animals she gets to work with and the variety of people. Her favorite part of her job is the human animal bond and getting to help keep that strong. She graduated from CSU Vet School in 2010 and has traveled a lot since graduating. She has done a variety of work in rural areas like southeastern Colorado and remote places in Africa.

Today, Dr. Gagliardi is going to be telling us a little bit about osteoarthritis, and what you can do to help out your beloved master pet!  
Osteoarthritis is a painful disease that affects many people and affects many of our beloved animals. Knowing what to do and how to recognize this disease is very important because it is the most common cause of chronic pain in dogs and cats. In the United States it is estimated that one out of five adult dogs suffer from arthritis. The definition of osteoarthritis is: progressive disease of inflammation and deterioration of the soft tissue, cartilage and bone in one or more joints. It is a chronic disease (develops over months to years) leading to pain and decreased mobility. The disease worsens as cartilage in the animal’s joint breaks down and friction between the bones causes pain. Inflammation in the joint also can cause abnormal bony growths on the joints and thickening of the surrounding soft tissue.

WHAT YOU CAN DO:

The first step in helping your pet is to recognize the signs of arthritis and tell your veterinarian. Ask yourself if you have noticed any of the following signs (be aware, the signs may not be present at all times): reluctance to climb stairs, difficulty jumping, stiffness after exercise, limping, difficulty rising, difficulty with positioning to eliminate, loss of appetite, and changes in behavior. Some animals are at greater risk for arthritis due to the following factors: being overweight, breed (a large or giant breed), previous joint injuries, and previously diagnosed elbow, knee, or hip dysplasia.

If you suspect your dog has arthritis, your veterinarian can do a physical exam on your pet to help determine the location. Also radiographs (X-rays) of the joints are often needed to confirm the diagnosis. Once a diagnosis has been reached, there are many different treatment options that can be offered. Treatment options include: pain medications, diet, exercise, joint supplements, physical therapy sessions, and acupuncture. Medications that are commonly used to treat osteoarthritis include: non-steroidal anti-inflammatory drugs (NSAIDs), joint supplements (like chondroitin and glucosamine), and pain medication like Tramadol. The chondro-protective joint medications like chondroitin and glucosamine are similar to those used in people however often have different doses or formulas so it is important to discuss the best one for your pet with your veterinarian. Alternative medicine is another great option for pets with osteoarthritis the benefits of physical therapy and acupuncture have proven to be an effective treatment in animals as well as people. Also being overweight and not exercising can make osteoarthritis worse so many pets treatment plan will also include diet and strict/set exercise routine.

The wide range of treatment options can often make it overwhelming for a pet’s guardian to decide what is best for there pet. Therefore it is best to discuss the options in detail with your veterinarian to develop a treatment plan that is right for your pet. Your veterinarian will let you know which treatment modalities would best suit your pet.

VCA Centennial Valley Animal Hospital is a full service veterinary hospital in Louisville, Colorado. We are accredited by the American Animal Hospital Association (AAHA). We provide care for dogs, cats, birds, ferrets, rabbits, reptiles and exotics. Our Services include Preventive Care, Laser Surgery, Digital X-Ray, In House Pharmacy, Full Dental Care, In House Laboratory, Hospitalization, Acupuncture/Herbs, and Pain management.  Our Doctors and staff are compassionate, certified and friendly. www.cvah.com

I would like to thank Dr. Gagliardi for helping us out and letting us know all about osteoarthritis.  In the future, keep an eye out for a few more posts from Dr. Gagliardi!  Thanks again, and we look forward to hearing from you again soon!

Saturday, July 12, 2014

Barely Skating By: You Better (Os)Prey That I Stop Trying to Force This Pun (Day 3, SC 2014)

On our third day in South Carolina, we played some games in the morning, but by about noon everyone else was exhausted and had to take a nap. I was not tired, so with a small-footed, friendly companion in my ear, I set out on a quest to find some more excitement! Compared to the events of the day before, I didn’t find much (which is good considering that the day before I had walked into a banana spider web, and almost been bitten by a lone star tick). I did find several creatures, though, including this small green anole (Anolis carolinensis), pictured below.
I also got my first good look at the Mississippi kite (Ictinia mississippiensis).  We don’t have many kites in Colorado, with the Mississippi kite only occasionally in the state, and the swallow-tailed kite (Elanoides forficatus) a vagrant, so I don’t know as much about them as I do about some other raptor groups.  Apparently, the Mississippi kite is primarily an insectivore, and only sometimes will kill prey such as frogs and snakes.
Now this next identification I am not terribly certain about. Here in North America, we actually have two types of crow. Most people are familiar with the American crow (Corvus brachyrhynchos), which lives all over the United States. However, we have a second type of crow, the fishing crow (Corvus ossifragus), native to the eastern United States. The fishing crow looks very similar to the American crow, and the best way to tell the two crows apart is to listen to their respective calls. The American crow has the well know “caw, caw” sound, while the fishing crow has a much more nasally cry. Some websites do list other, physical characteristics to distinguish between the two, but for the most part, it seems like auditory verification is the best way to go. I also seem to remember thinking to myself that this crow, as well as five or six others nearby, were making noises that I didn’t think sounded like a normal crow.
After my fun-filled walk, I arrived back at the Beckley’s house, where people were starting to wake up. Jim asked if we wanted to go out gator hunting (I’d like to point out that when I talk about gator hunting I mean trying to find them to take pictures of them and get really excited and embarrass myself in front of the locals by making it abundantly obvious that I am, indeed, a tourist), and so my parents, sister, Chris, Jim and I all prepared to head out. While we were waiting in the driveway for everyone to get ready, I noticed one of those eastern gray squirrels (Sciurus carolinensis) running around. They really shouldn’t be this exciting for me, but for some reason even they seem exotic. Just like our fox squirrels (Sciurus niger), the gray squirrel has very flexible ankles so that they can climb down trees headfirst, like you can see here.
We also saw a male northern cardinal (Cardinalis cardinalis) flitting around in the trees. This bird is sexually dimorphic, with the females mostly pale brown, with tinges of red.
As is always the case, we were never far from a banana spider web. What was interesting about this particular web was Chris wasn’t really paying attention, and was spinning his iPod earbuds, and accidentally smacked one of the support lines of the spider web that was attached to a nearby clump of saw palmettos (Serenoa repens). Amazingly, it didn’t break: in fact, it barely even budged! It’s incredible how strong the tensile strength of this particular type of spider’s web is.  We've talked about similar-looking spiders that inhabit the South Pacific who also have incredibly strong webs, sometimes used by fisherman to catch fish!
At last, everyone was assembled, and we headed out. As we drove, I noticed an osprey (Pandion haliaetus) sitting in a nest very close to the road. I made a note of it, and decided to check it out the next day. Below is a picture from the next day. This is a story for another day. Maybe the next day. Who even knows.
We arrived at the first potential gator pond, one where Jim, Chris, my dad and I had fished for a few minutes on our last visit two years ago.  On that trip, I had spotted a gator track on the bank, so we know that they were sometimes in there.  But despite this, and despite a warning sign that graces the bank of nearly every pond close to human habitation in South Carolina, we saw no sign of a gator. Turtles, yes. This interesting looking fire ant (Solenopsis sp.) hill, now abandoned? Interesting, yes, as were these orange mushrooms and little burrows dug out by some sort of crab. But no gators.
On our way to a second pond, we stopped at a small crab dock that people use for fishing, crabbing, and shrimping. We likely wouldn’t see any gators here, since it was a salty, brackish area. The alligators here prefer fresh water over brackish or salty water, although I suppose anything is possible. It was pretty quiet and peaceful. Looking out over the water, we could see a laughing gull (Leucophaeus atricilla) flying nearby, and a brown pelican (Pelecanus occidentalis) taking off from the water across the Wando River.
Looking down between our feet, we could see why it was called a crabbing dock. Marsh crabs (Sesarma reticulatum)  are all over the area, and we could see many of them hanging out on the wooden poles supporting the dock. Just beneath the surface of the water, we could also see a blue crab (Callinectes sapidus) hanging onto one of the supporting pillars.
Jim pulled up a few of the traps hanging off the side of the dock to show us what was going on inside.  The first trap was a minnow trap, and inside were several mudminnows and finger mullets.  The central mudminnow (Umbra limi) is a member of the mudminnow family, family Umbridae.  Despite their name, mudminnows are not actually minnows, and are instead more closely related to the pikes in the family Escoidae.  The two families together make up the order Escoiformes.  Meanwhile, finger mullets seems to be a colloquial term that applies to any small member of the mullet family, family Mugilidae, although I'm not entirely sure how precise I am about this definition.
The other traps were for blue crabs, whose scientific name apparently translates to "savory beautiful swimmer."  Blue crabs are omnivorous, and can find themselves prey to herons, sea turtles, and large fish.  Inside one of the crab traps was a large portion of a bottomfeeding critter, like a ray or a skate.  It was a little tough to identify, but I think that it might have been part of a clearnose skate (Raja eglanteria), a relative of stingrays and, more distantly, sharks.

Just as we finished investigating the traps, one of us spotted something: a dorsal fin, slicing in and out of the water! It was a bottlenose dolphin (Tursiops truncatus), the first sighting of the trip! We watched for several minutes as it cruised by a few times. It looked like there was at least one other dolphin out there, which comes as no surprise considering their gregarious nature.  Jim was telling us how he had seen a bottlenose dolphin actually send a wave of water and fish up onto a sand bank, and intentionally strand itself on the bank to snap up some fish, before sliding back into the water.  This behavior has actually been filmed on the fantastic BBC program "Planet Earth!"
After the excitement of the dock, it wasn’t even disappointing to not see anything at the third pond. Besides, we had many more days of gator-hunting filled vacation ahead of us! When we got back, we spotted a good-sized skink, I believe a five-lined skink (Plestiodon fasciatus) hanging out on the wall above their garage.
That night, we decided to go to dinner at the Morgan Creek Grill.  This is a double-decker restaurant, with a fancier side below, and a less fancy level on top, where we have eaten at the last two times we visited. With a very nice view overlooking the Intracoastal Waterway, we’ve seen dolphins there in the past. As we waited outside for our table, I was able to get some nice pictures of some very exciting seabirds, including this juvenile gull. Lots of brown pelicans and laughing gulls were flying by as well, and several times we were able to watch as several gulls swooped and dove at each other, fighting over scraps of food. We also got to watch a group of laughing gulls diving at the water to catch fish, which was cool as well!
As we ate, a cute dog sailed by, manning the helm of the boat.
I don’t know if this was intentional or not, but this ship’s anchor looked a lot like a shark tooth!
So here we have the new and improved, updated faunal list after Day Three:

Amphibians:

American Toad (Anaxyurus americanus)
Green Tree Frog (Hyla cinerea)
Southern Leopard Frog (Lithobates sphenocephalus)

Birds:

American Crow (Corvus brachyrhynchos)
Anhinga (Anhinga anhinga)
Black Vulture (Coragyps atratus)
Brown Pelican (Pelecanus occidentalis)
Carolina Wren (Thryothorus ludovicianus)
Fishing Crow (Corvus ossifragus)
Great Blue Heron (Ardea herodias)
Great Egret (Ardea alba)
House Sparrow (Passer domesticus)
Laughing Gull (Leucophaeus atricilla)
Mississippi Kite (Ictinia mississippiensis)
Northern Cardinal (Cardinalis cardinalis)
Osprey (Pandion haliaetus)
Red-Winged Blackbird (Agelaius phoeniceus)
Reddish Egret (Egretta rufescens)
Turkey Vulture (Cathartes aura)

Fish:

Central Mudminnow (Umbra limi)
Clearnose Skate (Raja eglanteria)
Mullet (Family: Mugilidae)

Invertebrates:

American Cockroach (Periplaneta americana)
Atlantic Horseshoe Crab (Limulus polyphemus)
Banana Spider (Nephila sp.)
Blue Crab (Callinectes sapidus)
Fire Ant (Solenopsis sp.)
Lone Star Tick (Amblyomma americanum)
Marsh Crab (Sesarma reticulatum)
Mosquito (Family: Culicidae)
Squareback Marsh Crab (Armases cinereum)
Wolf Spider (Family: Lycosidae)

Mammals:

Bottlenose Dolphin (Tursiops truncatus)
Eastern Gray Squirrel (Sciurus carolinensis)
Raccoon (Procyon lotor)
White Tailed Deer (Odocoileus virginianus)

Plants:

Saw Palmetto (Serenoa repens)
Trumpet Creeper (Campsis radicans)

Reptiles:

American Alligator (Alligator mississippiensis)
Five-Lined Skink (Plestiodon fasciatus)
Green Anole (Anolis carolinensis)



Works Cited:

Related Posts Plugin for WordPress, Blogger...
Related Posts Plugin for WordPress, Blogger...