clip-image002.jpg General

Dinosaurs and Their Environment – Exam #1 (Part 1.5-2)

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 :P. 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! :D. 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 :P. 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 :).

  • Amanda Freeman

    How did the T-Rex scratch his butt? I am asking seriously. My six year old has asked and I want to provide him with the correct answer. For now I have told him that he drug its butt on the ground like a dog does.


    • Rico Penguin

      Well there is no way to know for sure. Unfortunately all the evidence we have to go by is relative guesswork. By examining the skeletal structures and environmental settings of modern animals and their analogous prehistoric ancestors we (probably) are making pretty accurate guesses.

      That being said your guess about dragging the butt on the ground isn’t that far off from the general system of guesswork.

      I’m not sure exactly how they’d have scratched an itchy butt, the only problem I’d see with dragging their behind is that the sheer weight of their body might not be the most comfortable on their hips and would make dragging pretty difficult.

      If the itch was really bad I wouldn’t be surprised to see them rubbing it against a tree or a rock. Something a little higher than the ground so that they aren’t potentially putting themselves in a dangerous position just to get rid of an itch.

      Although if you check out modern reptiles, which likely had similar skin as most larger dinosaurs, they don’t tend to look very itchy. If they are itchy they surely don’t seem to care very much.

      So if I was to guess I’d have to go with the tree or rock situation, however as I said before the dragging on the ground isn’t exactly a bad guess considering the general system used by Paleontologists.

      much appreciated the question (even if it had been a joke).

      Have a wonderful day.