Rico Penguin

  Alright the last exam for Dinosaurs is today so lets discuss the two final topics, swimming reptiles and (appropriately enough) Extinction.  I’ll use my original style for Dinosaur exams because frankly I’m pretty tired.

Short and long-necked plesiosaurs, ichthyosaurs, and mosasaurs. Their relative speeds and individual characteristics?

  Plesiosaurs were likely the slowest of the group, which frankly was not much of a hindrance given their size. Whales don’t exactly travel at mach 1 through the sea but they get the job done. In the world of plesiosaurs you have the long neck versions, Elasmosaurs, and the short necked version, Pliosaurs. The Elasmosaurs may have struck their pray like a snake, recoiling their long necks and lashing out from the fog of the sea. This would actually seem like a more reasonable origin for the snake striking system than just getting high one day and telling all your snake buddies you have a ‘great idea’.

Can you guess which one is the long neck and which one is the short neck?

  Mososaurs are probably the second group in terms of speed. These fellows were short necked, long, snake-ish (not so much snake moreso ish), reptiles with four fins (not unlike Plesiosaurs). Now while second they were second in speed, when taking their size into account, isn’t much of a silver medal. They were gold in the sense that their size would cause you to poo in fear and then their speed would gobble you up before you could escape.

  One thing I forgot to mention is their long paddle tails, this would of sucked because its in the study notes as “something you need to know” so that could have very well been a missed question .

  The final group to talk about is the Ichthyosaurs, these little dudes are adorable-ish and fast like dolphins. They had fish like fins that waggled left to right and everything else really was so fish like that I might as well use the slide image instead of trying to describe a fish.

  They gave live birth like sea mammals, tail first even, scientists know this because they found a fossil that died during birth and it has a smaller fossil (a baby) sticking out its rump tail first. What a way to go out.

How did plesiosaurs swim?

  Obviously we can’t ask them but there are many visual cues when you look at an animals bone structure as to how it likely moved. They had four sets of flippers that they probably used like oars, which is pretty neato and quite a cool visual. There is no modern day animal in the sea that does this (to my knowledge) which makes it all the more interesting.

What are fish-eating teeth like?

  Long, Pointed, and Spaced. Essentially they are like those pronged spears people use to not only possible spear a fish but to at the very least entrap it between the prongs.

What are the adaptations for speed in Ichthyosaurs?

  I already gave this one away, they were built like dolphins and swam with a tail that was side to side and not up and down or anything else.

How did they give birth?

  Ah…gave this one away too. Just like sea mammals they birthed live and backwardly facing so that the animal could breath the longest (since the umbilical cord wouldn’t have snapped yet).

How did Eurhinosaurus live?

  An Ichthyosaur with a very long upper jaw or bill that looked a lot like a sawfish. They likely swam through fields of fish and swung their heads around to chop up pray then came back through and gobbled that stuff up. Regardless they weren’t winning any beauty competitions.

What were Mosasaurs related to and how did they swim and eat.

  Lizards, especially Komodo Dragons and Snakes. These are the large snakelike fellas I told you about earlier that were pretty fast and pretty huge. They had a ratcheting snake like jaw just like a snake that probably…well..ratcheted food down their gullet.

Om nom nom.

Mass vs background extinctions?

  Background extinctions happen all the time, something like 99+% of all things that have ever lived on the planet are dead and gone. Given time all species go extinct, unfortunately even we are extremely vulnerable.

  Mass Extinctions involve basically everything on the Earth dying off geologically instantly.

What were the two biggest mass extinctions?

  The P-TR (Permian-Triassic) and the K-T extinctions, had you been alive for either you wouldn’t be alive (which goes without saying ;D).

What is the probable cause of the K-T extinction?

  An asteroid dropping hits junk into the Gulf of Mexico region of the world.

What were the consequences of an asteroid impact?

  Temperatures rise dramatically for a short period of time (hundreds of degrees dramatically), matter is rocketed into the atmosphere and blankets the entire planet in darkness for a while, most vegetation and anything else that can burn on the surface of the earth does. Also you have animals dying and anything that eats them dying and anything that eats them dying. See where I’m going with this?

What evidence do we have to support this hypothesis?

  There are large quantities of Iridium about the point where the KT boundary is which is not an element you’d commonly see on the surface of Earth, however from an extraterrestrial source its not all that unheard of. They also have found a crater that fits the estimated 10 km asteroid. Yeah I know big dude. Essentially in a flash 10 billion Hiroshima sized bombs were exploded and the world was changed forever (organically speaking).

  Amazing stuff. Looking forward to the exam, all credit here should be directed to my Professor. The images, the questions, and indeed the knowledge I gained to answer them are thanks to him.

  Today we’ll be discussing some interesting aspects about Dinosaurs and the Extinctions that ended their reign on the planet. Interesting stuff. Also knocks out one more class this quarter to have documentation for.

  The first dinosaur we will talk about today is Pachycephalosaurus (which I assume means hard headed or thick skulled lizard). For those that have seen JP movies the following image will remind you of what it looked like with skin and CG .

  These little…well relatively little, they weren’t exactly things you could step on as a human, are pretty interesting when you take a look at their builds.

  The top vertebrae in their spinal column locks in to the skull into what is called the “occiput”, this connection means that with their head down they (as the image above shows) have a perfect spinal alignment. Likewise their spine even has interlocking mechanisms so that if there is an impact they don’t slip out of place. They have pretty thugged out hips that are fused to that part of their spine which suggests that it transfers kinetic energy from their spine down through their legs and out to the Earth. From the evidence provided the appear to basically be bipedal versions of what class? That’s right:

  While I imagine the Pachycephalosaurus is far more well kempt (they were picky about their looks…ok that’s probably not true), this is likely our modern analogy for the little buggers. However as stated in class (the real one I’m in not this fake study one I’m teaching), their heads don’t seem like they’d be suited for two dude dino’s to be headbanging to get some…well…banging done later. The rounded nature of their head means that they’d have to hit spot on to each other to not risk doing serious damage (which doesn’t seem to be the goal in most mating fights unless you are a pissed off hippo).

Mommy says we are special! RAWR!

  However that sort of pointed skull would be perfect for directing the full weight of the dinosaurs energy into say…the ribs or even a leg bone of a dinosaur. It would more than likely break it which is really all they need to do to stop an attacker from trying to gobble them or their family up.

  Their skulls are even built in such a way that kinetic energy should travel around their brain instead of into it, so while you might think these guys would bash themselves retarded in fights they actually could have held up quite well with whatever cognitive level dinosaurs had.

  In the same clade but a little further up we have the Ceratopsia, if that sounds to you like Triceratops then you are in luck because that’s essentially what I’m about to talk about.

    Firstly we are transitioning from mouthy looking mouths to beaky looking mouths. They had wide cheeks, and dental batteries inside their beaky mouths. If you have seen an elephants tooth you’ll know what a dental battery is (it is what it sounds like I suppose). Interestingly the frill on the neck is not something they all had.

      We’ll start with the Psittacosaurus which sounds like something out of Pokemon, and frankly looks like something out of pokemon. This is likely the earliest of the group, with bipedal motion but large front arms suggesting they could have easily been used for walking as well (a transitionary animal). Cute little buggers. Beat, cheeks, and the gambit except no frill.

    Next you have the Protoceratops which gets us closer to the stereotype for the species. These buggers were something like the size of a hog, which means they still could have killed you if they wanted to. The males apparently had a bump on their nose (perhaps a future horn) that made them sexually dimorphic from their lady friends, I suppose this is handy for poking some lady Protoceratops that just won’t pay attention to you. In their front legs their long narrow scapulas may have functioned as another joint which is kinda neat.

    Above is a skeletal layout of a member of the Ceratopsidae. Again we are looking at sexual dimorphism in the skulls of these animals, specifically the frills and horns, interestingly also it looks like not only predators were trying to pwn the frills but so were other Ceratopsidae. The frills were highly vascularized which means they probably had a covering over them. They tend to be lightly built with holes in their structure (skeletally). Their frills likely had multiple uses from mating rituals, to defense, to heat discharge. Truly a functional flap.

    One final note on these fellas is that the bones in the back of their skull were not only fused for support but also ended in a ball joint which helped it swivel nicely. Cool stuff.

    So lets move on to the idea of Endothermic and Ectothermic organisms. For those of us who went through public school you have hot blooded and cold blooded. Basically you have Endothermic creatures which generate their heat internally, they tend to also be called Homeothermic which means they are basically the same temperature all the time. Humans for instances are Endothermic and Homeothermic, so are basically all mammals.

    Your other set of animals are Ectothermic, their heat is generated externally and they are considered Poikilothermic, which means their temperatures vary. Basically when it comes to dinosaurs we are not sure if they were Endothermic or Ectothermic, however the ones we are finding with feathers are almost certainly Endothermic as they use the feathers to insulate. On the flip side you have massive dinosaurs who might have cooked if they didn’t have optimized systems. Albeit really there isn’t much to say that a giant ectotherm would do much better.

    Also certain dinosaurs have been found dead covering their nests, which suggest warm blooded (keeping the eggs warm).

  And with that we’ll stop this part of studying for today because I have to go read a silly book for an exam I have tomorrow.

Characteristics of Ornithischia

    There are some important things to know about Ornithischia when you are confronted by them. Well firstly I’d check your BAC but after that remember that all of them are Herbivores. Keep in mind that generally speaking you are more likely to be killed by Herbivores than Carnivores (they are aggressive enough to dwarf the hunger of many Carnivores). The had something called Ossified tendons up and down their spines. Now I don’t quite understand what this is yet. I’d look online but frankly I’m hoping to have it unraveled to me in the course. An image from future slides is as follows.

  It is even nice enough to point out the tendons, you’ll notice the cross hatching of them. Fascinating stuff. They possessed a horny bill on the front of their lower jaw. Think Triceratops if you want a quick (and relatively universal) visual.

  Finally they had their backwards pointing pubis bones. Which was more birdlike, which if memory serves, is where the orni comes in.

  Now I’m going to have to actually put the rest of these on hold. I’ve been stepping beyond my knowledge level in these latest questions and there is no reason to misinform myself and others. But this will most certainly be re-touched on.

  So unlike the dinosaurs this shouldn’t end up extinct, just delayed. Who knows what tomorrow holds.

What are the distinctions between the Sauropod groups Brachiosauridae, and Diplodocidae?

  This one is probably going to be short but it’ll be fun. You likely saw some images last time so I won’t repost them however the skulls are different.

  From the first group of Camarasaurs you have the Camarasauridae (which we aren’t learning about) and the Brachiosauridae which we are. Of these the special characteristics consist of demarcated snouts (check a dictionary I actually don’t know haha), chisel-like teeth in the entire mouth, they have longer front limbs than back ones, and finally they are heavier than the Diplodocidae (and Titanosaurs in general).

    Now unintuitively so the Titanosaurs are as stated before lighter than the Camarasaurs, of which the Titanosaurs comprise two different sub groups. You have the Titanosauridae which we aren’t interested in (because its not part of the Exam) and the Diplodocidae. With the Diplodocidae you have special traits of long broad noses, nostrils on the top of their head as opposed to front, pencil-like teeth instead of chisel like (big difference trust me), teeth at the front of the jaw (looks pretty weird to me brown skull on last post set is of this), long and slender fellows, and they have a V-shaped neural spine on the neck that is pretty neat. If it doesn’t come up later, that neural spine is likely for the attachment of that ligament from the previous post. When thinking of cranes you get a general idea of how handy a series of wires like that would be.

    I believe that is it for now. I hope you enjoyed this little foray into information about dinosaurs. Oh and so you get SOME sort of visual fun out of this lemme grab an image from our slides for you.

  Good stuff.

  Now I’m not sure if this will actually last 7 days but we DO have 7 study guide questions for the next exam so I will cover one question per day to get myself prepared far earlier than the day before this time around. I received a 95% on the first exam if you were curious.

Sauropodomorpha:

Prosauropoda and Sauropoda: Life habits of, including use of tails, speed, evidence for aquatic or terrestrial habit, feeding methods as suggested by teeth, ability to move necks, herding as suggested by tracks, purpose of v-shaped dorsal spines on neck.

  Well lets flesh this question out to be a few questions and work from there.

What are the life habits of Prosauropoda and Sauropoda?

      First it is important to say that these dinosaurs were a bit unusual. That had big hind legs and somewhat shorter arms. This made it quite apparent that they were bipedal, however for a portion of them this is hard to grasp because their sheer size would mean that being bipedal given their proportions would be very difficult. They are considered the transitional phase of a creature going from bipedal to Quadra pedal, they are just in that really irritating limbo stage. Now that I look back this describes the PROsauropods, the sauropods (which came later) were fully Quadra pedal as far as I can tell.

    My personal opinion is that when they weren’t in a hurry to get somewhere or when they were going long distances they went bipedally, however when they wanted to do something quickly or travel short distances they’d (somewhat awkwardly) move quadrapedally.

Prosauropods, more than likely did not stand like this. But it is for you to see their arms.

Sauropods. You knot the big herbivores. Quadrapedal. This and the previous image are from the slides and not me. Full Credit to whoever originally made them (as well as the Professor for providing them).

Expanding upon the previous question what was the use of their tails?

  Their tails were likely used for balancing. They aren’t short or flexible enough to drag on the ground, why they would drag them is beyond me. It seems more a consequence of gravity for low level reptiles than an evolutionary perk.

The Speed at which they moved?

  As stated before I’m relatively convinced that they didn’t move very fast. Well the Prosaurapods actually might have been fast, they were much smaller. But the Saurapods were most certainly slow.

The evidence for aquatic or terrestrial habit?

  Both groups have body types that are very very similar to elephants. It is likely given the similar walking styles and their body shapes that the saurapods and Prosarapods were terrestrial, but may have enjoyed a swim just like Elephants.

The feeding methods as suggested by their teeth?

 
Again from course.

      Now while the teeth might look long you’ll notice they are all blunt. This is one of multiple skull related traits that lead us to believe they eat leaves. The next thing to notice is their lower jaw and the hinge for it. On a carnivore this would be above and lead down to the teeth however on an Herbivore it would be below. This is because they didn’t need to sheer flesh but instead would yank large quantities of food off of trees.

      This image from the slides shows you in the middle a carnivore and on the right an herbivore. You will notice that the herbivore has extra space on the sides of their teeth to store food to aid in grinding it. Carnivores have no sides and you can usually see their teeth on the sides of their mouth without much work. Whereas one party (the carnivores) don’t really care where the meat drops I’d be pissed if I spent a bunch of time yanking leaves off a tree just to drop a bunch.

What do we know about their neck mobility?

      This one is tricky. For the Prosauropods it was likely similar to all other small bipedal dinosaurs. The Sauropods however couldn’t (or rather it is very unlikely that they could) raise their heads higher than the highest level of their spine. This is probably because frankly when you are as big as they are you don’t really need to lift your head much higher. I mean…what would you lift it for? Peek on some other dinosaurs who are bathing or something. Jeeze not all dinosaurs were perverts. However for visual aid here is a nice picture from our slides to see the sheer size of these beasts.

How do tracks found of these animals suggest herding behavior?

    Considering that the tracks that have been found tend to not overlap (unless there are vast quantities of tracks) and move with one another it is highly likely that these animals herded.

What is the purpose of their v-shaped dorsal spines on the neck?

    Well the massive size of these animals required any reinforcements it could possibly get. This would have helped to support a ligament known as the Nuchal. Essentially it was a really long reinforcement line to help keep everything from falling apart. Likewise I’m pretty sure ligaments like this mean the animal wouldn’t have to straight to keep its head up (it would be able to relax and still have its head not slouch). Which is pretty important I’d say.

What are signs of a fast animal and what indicates their primary food source (carnivore, herbivore, omnivore)?

  When looking at an animal there are initial obvious hints. The stockier and thicker the bone the slower overall the animal will be. Now relative to humans just about any big animal will still stomp a hole through your torso if you try to slap them on the butt and run. A good rule of thumb when looking at the legs of an animal, the more ‘hinge points’ it has the faster the animal will move. Each hinge region (like your knee) essentially becomes a spring that helps an animal move much faster than even their muscles alone would allow. In Martial arts, people are told to stay on their toes which adds a new hinge at the Ankle.

  When looking for hints on the primary food source of an animal you check their teeth. It is the first place food goes for processing (Well the mouth is) and thusly the best place to learn about the animals favorite snacks. Plant eaters will almost always have flat teeth, like a mouth full of molars. This is for grinding up plants and other soft organic material. Carnivores will have some gnarly fangs (canines) that are used for shearing, crushing, and otherwise maiming their prey. The larger the teeth generally the larger the prey. If the creature had raisin sized teeth you could expect they ate insects. Omnivores have clippers in the front usually and grinders in the back (like you or me).

Linnean classification and cladistic classification, The meaning of general and specific characters, How to construct and use a cladogram, and What are the closest living relatives of dinosaurs?

  Linnean classification is the one that everyone is familiar with, the whole kingdom phylum order genus species thing. I probably missed a few and ordered it wrong but you get the idea. I’m just proud of myself for remembering that many pieces. Cladistic classification is actually a bit weird and sort of the species equivelant of being racist. To me at least.

  When looking at Cladistic classification you have two groups of examination, the General Characteristics and the Specific Characteristics. The general being things that an animal has, like bipedal movement, something that helps describe the animal but doesn’t solidify its rankings in uniqueness and the Specific like the opposable thumb which is purely a human characteristic. It’s neat stuff but you have to be cautious to not use terms so broad (such as having a heart) that they are meanginless.

  Cladograms are basically line charts that take a group of similar animals, that is animals that share a ton of general characteristics, and organizing them through a system of Specific characteristics. For instance you might work from say a T-rex and slowly move towards its nearest modern relative. Along the way picking out the characteristic that it and all the animals before it have but none of the ones after it do. It would look something like this.

  While not very similar, the way this works is that you start with a backbone for fish, which is something all animals above it have but none before it, then you move to legs with Lizards and above have but Fish do not, then you move to hair which Dogs and above have but Lizards and below do not, then finally the Opposable thumb. Which where you start is somewhat arbitrary it helps to put like items together.

  One of the professors more detailed examples is below:

What is a tetrapod? What are the characteristics of a tetrapod that set it apart from a fish? How did tetrapods evolve from fish?

    A tetrapod, literally four legged creature, the major separation that I can think of that separates them from fish is that they have legs with fin like appendages (when dealing with water) whereas Fish literally have fins. Fish also have much thinner skeletal structures because most weight is supported by water. They also tend to have massive heads to body ratios. The evolution was likely the transition from fin to fin like appendage to appendage.

What are Behaviors of crocodiles that separate them from other reptiles?

  They tend to use pack behavior (pretty efficiently), they vocalize (albeit not exactly eloquently), and take care of their babies after they hatch. It’s pretty cute to watch…all things considered.

What is erect stance and what are its advantages? What tetrapod groups do and do not have erect stance?

  An erect stance is any creature that stands at or near verticle with two limbs that are the primary source of motion and a second set of limbs that is primarily used for grasping. Of the saurischian (lizard hipped dinos) prosaurupods and theropods were bipedal, of the Ornithischian (bird hipped dinos) the Ornithopods were bipedal. All other options were quadrapedal.

How do Saurischia and Ornithischia differ?

  As stated before, Saura were the lizard hipped and the Ornith were bird hipped. Has to do with the direction of the Pubis. With the bird hipped having it pointing it back, the others having it pointing down or forward.

What are the names of the Era, periods and dates of the periods when dinosaurs were alive?

  Now this part is a bit hard to remember. Basically working backwards keep adding 65 million years and you’ll get ‘close’ to the right years. 65 Million years ago was the end of the Cretaceous, which was the fall of the dinosaurs, 144 million years ago was the end of the Jurassic which was the time we built a park full of dinosaurs (wait a second), 208 million years ago was the end of the Triassic period, and 245 million years ago was the end of the Permian and more importantly the start of the dinos. If you are taking a multiple choice you should be able to get close to these dates by just remembering 65 MYA and keep adding 65 . Or maybe more accurately adding 50.

Coelurosauria vs Carnosaur

  Coelursauria is a group of Theropods that are identifiable by their (generally speaking) long necks, small heads, gangly arms, and small size. Carnosaurs are your T-Rex’s and Allosaurus’s. Big mofo’s that have lots of big stuff and tiny ass arms.

Attack methods of carnosaurs (a term which describes shape but has no cladistic/evolutionary significance)?

  I’m not sure what this question means. But we theorized in class that various carnivores of modern day may give us a good idea of how carnosaurs hunted. It is unlikely that they acted like fast animals given their size and more than likely were hunting relatively slow prey.

Compare and contrast Allosaurus and Tyrannosaurus

  Tyrannosaurus has a huge strong head whereas the Allosaurus has a smaller head that is not as good at surviving side torque of a moving prey. The Tyrannosaurus also has much larger teeth and is overall larger. The teeth on the T-rex look like big fat fangs whereas the smaller Allosaur teeth are more bladelike. Allosaurus has longer arms too, so he could possibly scratch his itchy knee . The T-rex probably took a more gator like approach to killing while the Allosaur may have acted more like a large raptor or something similar, using its arms and head.

Evidence for stance and pack behavior in carnosaurs.

  The size of the creatures suggests that they weren’t super fast, their bodies just wouldn’t do well to support the weight at high speeds. Likewise considering their similarities to crocs it would seem reasonable to assume that they too act in pack patterns. Also there have been Carnosaurs that have been found with healed broken tibias which really would only happen if there was a pack looking out for one another. As for stance, a T-Rex couldn’t stand upright, it would be putting most of its weight on the weakest part of its Hip and likewise it would have to snap its own tail (fracture it) just to bend it along the ground like they often show them in museums.

Know the conditions of Sue’s skeleton and the other individuals she was preserved with.

  Sue has multiple conditions in her bones that show she likely suffered disease. She had a broken and healed tail, broken and healed ribs, and broken or malformed tooth. She even had bite marks that looked like another t-rex had bit her neck (A little too kinky for my tastes).

What kind of dinosaur is T. rex most closely related to?

  T-Rex is more closely related to various coelurasaurs than it is to other carnosaurs. Even the cute little compy is more closely related to it than Allosaur. According to Cladograms at least.

What is the evidence for how carnosaurs held their backbone?

  As stated before it had to do with the strong and weak points in their hips and the flexibility of their tails. They most likely leaned forward using their tails to balance the wait of their front leaning body and head.

How did Oviraptor live?

  Oviraptors  Their unfortunate skull structure made people incorrectly label them as egg eaters, in actuality they probably used their beaks to crush shelled creatures. For those that think I might be exaggerating.

How did Ornithomimosaurs and Dromaeosaurs live?

    Ornithomimosaurs were the dinosaur equivelant to the Ostrich. They share very common body types and were likely very fast. They probably ate plants, insects, and other small things.  Dromaeosaurs are actually what were incorrectly labeled velociraptors in Jurassic Park! . Not only were they wrongly labeled but the ones in the move were even increased in size by a few feet to make them look more menacing. So imagine a small version of those dinosaurs and you have them.

  On a somewhat unrelated note imagine this chasing your butt:

Principles of size, volume and surface area relationships. Be able to estimate weight of an object based on increase in a linear dimension, e.g. I have a cube that is 2 inches on a side and weighs 1 lb. How much would a cube of the same material weigh if it was 4 inches on a side?

  The size of a 3 dimensional object grows disproportionately in respect to the volume vs surface area. The volume goes up to the power of 3 whereas the surface area goes up to the power of 2. So an object that is 2 inches on the side and weights 1 lb would result in a 1lb for every 8 cubic inches. With this in mind a 4 inch cubed object has a total of 64 total cubic inches, that is 8 times larger so 8 lbs.

Early evolution of feathers and their purpose

  Feathers initially were more than likely downy and used for keeping animals insulated. As time progressed some animals probably grew longer feathers in order to glide from trees to catch certain flying insects and animals…oh and to surprise and catch non flying animals . Eventually you’d have flight.

Birds, characteristics of, and origins.

  The first bird is the Archeopteryx, well bird-like dinosaurs. Beak like mouths, long asymmetrical feathers and an in between stage of the hand that is very similar to bird like hands.

What is the first “bird” and what dinosaur group is it most closely related to?

  I think that my previous answer still fits here. If not that’ll be something on the exam I get wrong . Most closely related to Coelurasaurs.

What are the characteristics of Archeopteryx that make it bird-like and what makes it dinosaur-like?

  Feathers, Backward Pubis, bird like feet (3 toes front 1 toe back), all make it bird like. Teeth, distinct fingers, and a Gastralia make it dino like .

  Now quite honestly I had forgotten this is Wednesday. I really wish that was not the case. However over the next two days I’ll be covering the 6 chapters of info that will be in the exam. Hopefully it’ll all come to a better end than the one Dinosaurs succumbed.

  With 6 chapters to look over we split it cleanly down the middle. Today we’ll be discussing the Skeleton (hardest part), Classification and Relationships of Vertebrates (Step down in Hardness), and the Origin of Dinosaurs.

  Tomorrow you will (as well as I) be dealing with Size and Volume (Not too bad), Theropods-Carnosaurs (T-Rex And Friends), and Theropods-Coelosaurs (Raptors and Friends). Any errors in these headings will be corrected tomorrow as I go over the topics.

  The questions are from the study guide and I’ll be trying to answer them to the best of my abilities with the notes.

  What are the various Modes of fossilization? What are the best conditions for preservation?

  While I’d like to be creative and start from the least efficient and work up to the best we’ll do a downward spiral instead. The first method of fossilization is the best, known as unaltered, it is called such because as best as one can hope the organism has come from the past to the present with the absolute least amount of damage (mostly genetic). Insects that are trapped in Amber (or other small animals) is a great example of unaltered fossilization. The next of these unaltered situations is freezing, which also retains much of an organisms parts (not so much and not so long as the amber would), and finally bog mummies. What all these things have in common is that they are extremely low oxygen environments (perhaps extreme is a strong word), in the case of the bog people the environment is also acidic, and in the case of bog and ice it is a cool environment. All these things reduce the speed of degradation, bacteria is not very happy in any of these environments.

  A fun, if not disturbing, bit of info is that in an oxygen free environment a condition known as saponification happens, essentially the fatty tissues of a body turn into a soap like matter. So perhaps the name eludes to the end result . Likewise desocate refers to mummification which is another efficient way to preserve bodies (as Egyptians have shown).

  Moving onto a replacement like preservation (the one more people are actually familiar with). When organic material like leaves are buried, they’ll eventually be pressed and degrade until all that is left is a carbon film, it ends up looking like a photograph.

  Per mineralization is a similar (to me) system where the pores in organic matter is filled with minerals, usually silicon, when you think about dinosaurs that are well preserved this is likely the cause. If it isn’t you have a case of molds and casts, the bones and other matter just completely decay (as they should, bone is very organic) leaving a hole in the ground that tends to be filled with a different concentration of minerals. As far as I know, there is no actual dinosaur bone found anymore, just very well preserved casts. That may indeed be wrong but its what I’ve taken away thus far from the class.

  Another fun note is that skin, feathers, eggs, nests and turds can still be recovered from very very old animals in the right environment.

What are the Characteristics of bones, tendons, and ligaments? What are the names of all the major bones in a Dinosaurs body (and consequently most animals)?

  When thinking about bones in the general sense you tend to have a very thick and good-for-clubbing outer layer that surrounds a spongy inner layer (that any lion will tell you is delicious). There are variances in both of these factors when talking about birds (which are much lighter all around), or elephants (which are much thicker in general). When I see a cross sectioned bird bone it reminds me of those cupcakes that were a little ‘too airy’ that you bit into and find nothing but an empty chasm inside. Which in terms of cupcakes is tragic.

  Tendons are the wonderful little ties that connect muscles to bones, these are one of the reasons you have bones in the first place. If your muscles could retain shape without the framework of bones you’d have no need for tendons either…which may sound a bit stupid in retrospect but its just a bit of info out of the ole brain here. Next you have Ligaments which connects bones to bones, which together with tendons and bones helps fulfill all the basic requirements for building an organism (structurally speaking…not functionally).

  The part I was dreading comes next. There are 30 major bones in a dinosaurs body. Lets see if I can find an easy way to name them all.

  We’ll separate it into 5 parts, you have the head region, the torso, arms+hands, legs+feet, and tail. Vertebrae is actually split into 4 pieces. With this in mind it would go as follows.

Head:
  Maxilla is the top half of a skull more specifically the upper jaw.
  Mandible is the bottom half (otherwise known as the lower Jaw).
  Cranium is the…well it is the Cranium, what we commonly call our skulls.

Torso:
  Cervical Vertebrae is the first of 4 sections of the spine+tail, it consists of the spine between the base of the cranium and the shoulder region.
  Dorsal (Trunk) Vertabrae is the second of 4 sections of the spine+tail, it consists of the space between the shoulders and the top of the hips (well right up util that point).
  Ribs are the ribs and if you are curious what they look like check out a snake skeleton, those guys are made of basically nothing but ribs.

Arms+Hands:
  Scapula is the first part of what is the arm, I believe the slang term for it is “shoulder blade” but I may be wrong there.
  Coracoid is the bone that connects your shoulder blade to the arm. I think, that’s a complete guess honestly, I look on wikipedia and I’m still kind of lost. It’s there though (as you’ll see in a picture later).
  Humerus AKA the Funny Bone, is the top bone in your arm.
  Radius, one of two bones in the lower half of your arm, to identify it remember radius to Pinky.
  Ulna, the other of the two bones, to identify it remember Ulna to thumb.
  Carpals, those first bones in the hand.
  Metacarpals, the second set of bones in your hand.
  Phalanges (In the Hand), the tips of your fingers, perhaps even your whole finger. (I think it actually is the entire finger).

  Legs+Hands:
    Sacral (Sacrum) Vertebrae is the third part of the spine that consists of the hip region.
    Ilium working clockwise it is the top of the 3 pieces of the pelvic region.
    Pubis the next bone working clockwise in the pelvic region.
    Ischium the final bone in the clockwise scan of the pelvic region.
    Femur, the largest single bone in the Human body, great for clubbing.
    Tibia, the front bone in the lower portion of your leg. Break this and you are in for some serious recovery.
    Fibula, the back bone in the lower portion of your leg. Breaking it isn’t quite as bad but still sucks.
    Tarsals, the top bones in your footsies.
    Metatarsals, the bottom bones in your footies.
    Phalanges (In the Foot), the little piggies from that horrible horrible children’s song.

  Tail:
    Caudal (Tail) Vertabrae is essentially the tail. In raptors it is fused at about halfway down to the tip making it like a rod.
    Haemal Arches are what I believe to be the ‘ribs’ of the tail. For keeping it nice and sturdy.
    
    Below is an image to help clear up my terrible descriptions.
     
 

  Because of time constraints the following will be on tomorrows lecture as well. Good thing I’m starting very early.

What are signs of a fast animal and what indicates their primary food source (carnivore, herbivore, omnivore)? Linnean classification and cladistic classification, The meaning of general and specific characters, How to construct and use a cladogram, and What are the closest living relatives of dinosaurs? What is a tetrapod? What are the characteristics of a tetrapod that set it apart from a fish? How did tetrapods evolve from fish?What are Behaviors of crocodiles that separate them from other reptiles? What is erect stance and what are its advantages? What tetrapod groups do and do not have erect stance? How do Saurischia and Ornithischia differ? What are the names of the Era, periods and dates of the periods when dinosaurs were alive?

[ Index ]
Part 1 – The Introduction
Part 2 – From Universe to Solar System
Part 3 – From Solar System to Earth

  So when last we met (if memory serves) we were discussing the first life on Earth. Tiny tiny little organisms that one cannot see with their naked eye (unless you squint really really hard…ok you still can’t). Slowly the organisms become more complex, initially it was a matter of symbiosis for at least some. Small organisms began fusing to one another (see mitochondria) to create more complex and indeed more efficient systems. With the noticeably copious amounts of space in the sea and the development of an Atmosphere there was not much to worry about but taking in energy, via eating or sunlight, and reproducing like you had nothing left to do.

  Some organisms split like a particularly tasty banana in your ice cream, others mated. As time passed and the bigger is better mentality started to pick up we begin to see visible formations in the sea. Eventually plants will dominate the sea and spread out onto land. With the introduction of a nice firm atmosphere (firm my way of saying effective) to protect their cells from the ultraviolet sunlight there was little reason to stay bound to the sea. The first’ ‘animals’ would be completely secluded to the sea and would spread quite well. Considering the absolutely massive nature of the ocean and its ability to reduce gravity’s effect on organisms it makes surviving and growing much easier than on land (at least initially, these days you get eaten by many crazy animals in the sea).

  Once the surface land is absolutely covered in plants (maybe sooner) there is a revelation, as always, a copious amount of food leads to the introduction of something that’ll eat it. Indeed someday there will be a bacteria that absolutely engorges itself on our plastic waste, it is just a matter of waiting. As the first animals move to land they bring a second source of food to the land, that being them. Carnivores would soon fill that gap as well. I often wonder if the copious levels of land carnivores are what lead some animals to return to the sea. Indeed all sea mammals are incidents of animals that were initially land mammals and moved to the sea. The motion of a dolphin is hauntingly similar to the motion of a gazelle, and in some cases you can find the remains of what once were legs in whale corpses and other sea mammals as they move ever closer to lose all evidence of their previous adventures on land.

   Somewhere in here you have dinosaurs rise. They have a pretty long and successful run (I believe there was a mass extinction or two) until the drop of a meteor that I’ve read was large enough to fill the rose bowl (or some football stadium). It impacted somewhere in the gulf of Mexico and utterly dominated the planet. Basically all life on Earth died. Before this point there were tiny little mice like animals, which might not be accurate, so just imagine a cute little mammal of your choice. Essentially before Dinosaurs were extinguished this was the pinnacle of our particular class in the animal kingdom. After dinosaurs mammals popped out and started to show their talents. It would be some many millions of years but eventually a particularly successful class of apes came to be the most dominant of all animal species (relative to land mass covered…and I suppose not counting insects).

  People often wonder why Humans made that jump mentally. As I’ve stated before I think it was a case of substantial amounts of food. Evolutionarily there is no real advantage to being exceedingly smarter than your prey, it doesn’t take much to catch a Gazelle, strength and big teeth will do it more often than not. However with a single mutation of the brain taking it just far enough above the average level of ape intelligence it would become, much like the original organisms spreading across the planet, a snowball effect. With every evolutionary generation the human brain would grow larger, at one time even there was more than one type of human. However, for reasons I don’t know personally, one particular answer I’ve heard was the mistake by the now extinct humanoids to let their opponents spread into Europe and across to Asia, this essentially locked them into a small area and they died off. But again take that with a grain of salt.

  So slowly but surely, this ever increasing effect, like the pull of a black hole growing with each uncontrollable growth we move on to modern day. Which is where we will stop for now. Tomorrow may indeed be the final episode of this little collection. It’ll be about what is to come (in the most general of senses) and the ‘end’…as well as a bit of philosophy that I hope someday to get clarified.

  I’ve often wondered just how people know how a certain animal would walk when all they have is bones. Well low and behold my Dinosaur course (I for the life of me will never remember its technical name) has explained it quite well. I’m not sure if this will be a long update but it should be informative.

  For those curious most of these images are snagged from the PowerPoint presentation which probably were initially snagged from Google images. Unfortunately I can’t cite them specifically better than that.

  Dinosaurs were erect walkers, that is to say while reptiles such as the Comodo Dragon below actually have legs that first go to the left or right (away from the body) and then at the elbow or knee bend to go earth ward, Dinosaurs instead stood straight up and down on their four legs (think Elephant). Anyone who has seen this bone configuration will note that it requires large exaggerated body movements for the animal to move forward. There are various videos online of these animals moving and I highly suggest checking one out.

   (Imaged from: elalmanaque)

  But as I was saying earlier how do we know this? Well interestingly enough (and somewhat intuitive once you think about it) bones do not very greatly between organisms. There are a series of bone formations depending on a few strict walking options. You have the 45% comodo like stance, the literal 90% exactly comodo stance, the straight stance of an elephant or Gazelle like animal (or bipeds even) or perhaps 1 or 2 other variations that I’m not thinking about .

  When you look at the leg bones of an animal that are in good condition you can discern which of these stances they would have used and it just becomes a matter of thinking like an architect.

  On the left you have an alligator femur. It may be hard to tell from the image but essentially the top part of the femur that goes into the Alligators hip is essentially just one big ball. This is because nearly all alligators (and crocodiles) walk in the exaggerated arcing motion (again think Comodo if necessary). The reason for this is that no other shape would effectively work in these large circular motions but a sphere, at least no other shape that is easy to make …evolution is a lazy lazy mistress (more on that tomorrow maybe). However on the right you have the bone of an erect walker, in fact doubly so because it is also a bipedal walker, that is-you guessed it-a human femur. Alright…I don’t know if you DID guess it but I have always wanted to put that in a post.

  The human femur join basically plugs in like a socket, because it is only moving in one plane (if you are lucky haha). Likewise the knee joint is very specialized with a channel down its center because all dragging happens forward and back and the channel probably provides a region for adequate cushioning. For a better visual let me grab the image that actually inspired this post.

  This is an amazing shot that seems to perfectly portray my point. The knee joint on a human or any upright walker is made quite specialized. It REALLY does not want to go to the left or right and anyone who has ever had their leg do that can tell you it is a terribly painful experience.

  This is why we know how dinosaurs walk, and indeed we most likely even know how they swam. All animals in any particular walking style swim almost (if not exactly) the same! It’s really fascinating, you can take a snake that has is not native to lakes or ponds and chuck it in. You’ll find it swimming along like absolutely any other snake. You take any reptile or lizard with the same arm and leg setup of crocs or Comodo’s and they will swim exactly the same. These little bits of info are courtesy of the professor of course, I just felt they were important enough to get out to you folks.

  In a closing note since this should pretty much inform people is something else extremely fascinating to me and frankly something that should be brought up in every evolutionary discussion. Has anyone ever wondered why all sea mammals swim in a different manner than any other type of sea creature? A dolphin swims in the same manner as a Gazelle runs! It’s really fascinating to watch a dolphin swim straight along a path and then watch a gazelle run down a straight path. You will see the exact same body motions between the two organisms. At some point long ago a land mammal, for whatever reason, returned to the sea and structurally it changed enough to streamline to the water however, and this is what I find so intriguing, it didn’t change the way that it moves. Essentially if a dolphin had legs instead of a tail fin I’m sure it would swim even more hauntingly like its land based siblings.

  Indeed who needs to imagine?: http://www.ebaumsworld.com/video/watch/481248/ . The kid in this video actually exists, this is his record breaking performance. You’ll notice how he is armless and motions through the water almost exactly like a dolphin. Fascinating stuff.

  You ever had a bombshell drop in a class and had nobody but you seem truly interested. I would appear that inside the bone of a Tyrannosaurus Rex they found actual fleshy bits!

http://www.smm.org/buzz/blog/tyrannosaurus_rex_flesh_pictures
http://www.msnbc.msn.com/id/7285683/

  However as with all things it would appear that UW is trying to crush this wonderful bit of news for me (Darn you UW). So I’m not entirely sure whether or not I’m reading about the same bone or if one bone has flesh and another is sludge or if indeed that one both is just sludge (even though those scans that look like bird flesh are pretty convincing). But it gives some hope, I don’t feel that any dinosaur could function properly with our current environment compared to theirs. Perhaps we could work to make pygmy versions of them. However considering that you can’t even have cats without people letting them into the wild (or pythons for that matter) I suppose this would certainly end poorly.

  There are constant reminders that the most unlikely of events can indeed happen. Offhand I don’t know the principle but there is the idea that anything that can happen will happen (or has). I like this for one reason, if we are to assume that any value greater than 0 is possible (that is anything that can happen can happen…pretty novel concept) then it would seem pretty silly to assume anything that has a 1 in a trillion chance is never going to happen.

  Yet you will find people constantly treat it like that. “There is a one in a gajillion chance you’d have written the exact thing as that other person on your own.” Yet the fact remains the original person wrote it on their own. Likewise if there is any chance then it may have indeed happened. Just seems silly to have fractions over a hundredth if we aren’t going to treat them as possible.

  Ah…at any rate it is good to see some possible truth from Jurassic park .