Journal

Dinosaurs and Their Environment – Exam #1


  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.
     
 

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  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?

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