Lesson 1: Appearances and Anatomy

Question 1

What is Paleontology?

Answer 1

The study of all prehistoric life.

Question 2

What is a fossil?

Answer 2

Any preserved evidence left behind by a prehistoric organism. The word fossil literally means “dug up”.

Question 3

What are types of fossils?

Answer 3

Footprints, eggshells, coprolites (poop), skin and feather impressions, but mostly bones.

Question 4

What are the smallest dinosaurs that we know of?

Answer 4

Birds. However, small dinosaurs like Microraptor and Fruitadens were probably less than a metre long and weighed less than a Kg.

Question 5

What are adaptations?

Answer 5

They are traits that have evolved to serve specific functions.

Question 6

List the 4 major adaptations of bones that help animals to survive.

Answer 6

1. Bones passively resist gravity and maintain an animal’s form.
2. Bones provide a ridged framework for muscle attachment.
3. Bones provide protection and can also be major components of horns and other robust weapons.
4. Bones store mineral reserves.

Question 7

What are vertebrates?

Answer 7

They are animals that have two special kinds of skeletal adaptations: skulls and vertebrae.

Question 8

What are vertebrae?

Answer 8

They are structures made primarily of bone and/or cartilage that surround a portion of the spinal nerve cord.

Question 9

What are some examples of vertebrates?

Answer 9

Fish, amphibians, turtles, snakes, birds, and mammals. The first vertebrates were aquatic animals that evolved over 500 mil. years ago.

Question 10

What are some examples of invertebrates?

Answer 10

Insects, spiders, snails, squids, clams, jellyfish, and worms.

Question 11

What is the brain case?

Answer 11

It is a hollow chamber formed by multiple skull bones that houses the brain.

Question 12

Dinosaur skulls also have multiple pairs of large openings. Name the 5.

Answer 12

1. The nares (singular: naris) are the pair of openings for the nostrils.
2. The orbits are the pair of openings for the eyes.
3. Lateral sides of the skull are called the laterotemporal fenestrae.
4. Fenestrae on the top of the skull are called the supratemporal fenestrae.
5. Antorbital fenestrae. The function of the antorbital fenestra is unclear. They may have simply been adaptations that made dinosaurs skulls lighter, or they may have also housed large sinus cavities that helped warm the air that dinosaurs breathed.

Question 13

What is a centrum?

Answer 13

Spool or disk-shaped body of a vertebra.

Question 14

What is the neural arch?

Answer 14

It is located above the centrum in a vertebra and covers the neural canal.

Question 15

What is the neural canal?

Answer 15

It is the opening in each vertebra, through which the spinal nerves run.

Question 16

What are vertebral processes?

Answer 16

They provide attachment surfaces for muscles and sometimes provide articulation surfaces for ribs.

Question 17

What are two common types of vertebral processes?

Answer 17

1. Transverse processes, which extend from the lateral sides of the vertebrae.
2. Spinous processes, which extend upwards from the neural arch.

Question 18

What are cervical vertebrae?

Answer 18

Vertebrae (singular: vertebra) in the neck. Cervical vertebrae often have extra-large openings for blood and nerve channels and are adapted to support the weight of an animal’s head.

Question 19

What are dorsal vertebrae?

Answer 19

Vertebrae in the back. Dorsal vertebrae often have tall spinous processes and large rib articulation surfaces.

Question 20

What are sacral vertebrae?

Answer 20

Vertebrae in the hips. Because the pelvic bones serve as solid anchors for powerful leg muscles, the pelvic bones are fused to the sacral vertebrae.

Question 21

What is the sacrum?

Answer 21

To further increase the strength of the hips, the sacral vertebrae are also fused with one another and form a single solid bone structure.

Question 22

What are caudal vertebrae?

Answer 22

Vertebrae in the tail.

Question 23

What are chevrons?

Answer 23

Underneath caudal vertebrae are bones called chevrons. Chevrons protect a large blood and nerve channel and provide support for tail muscles.

Question 24

Discuss the difference between the ribs in animals and dinosaurs.

Answer 24

In dinosaurs, all dorsal vertebrae connect with ribs; however, in mammals, the dorsal vertebrae close to the hips do not. Also unlike mammals, some dinosaurs had gastralia, or “belly ribs”.

Question 25

What are gastralia?

Answer 25

They are small ribs positioned across a dinosaur’s underbelly, underneath the ribcage.

Question 26

What are tetrapods?

Answer 26

Animals that evolved from an ancient ancestor with four feet and four limbs. Most tetropods still have four feet and limbs, although some, like humans, have hands instead of front feet and some, like snakes, have lost their limbs altogether.

Question 27

What are some examples of tetrapods?

Answer 27

Dinosaurs, mammals, reptiles and amphibians.

Question 28

What are limb girdles?

Answer 28

They connect the limbs of a tetrapod to the rest of the skeleton.

Question 29

The forelimbs of a tetrapod connect to what?

Answer 29

The pectoral girdle.

Question 30

What is the scapula?

Answer 30

It is the largest bone in each side of the pectoral girdle.

Question 31

The hind limbs of a tetrapod connect to what?

Answer 31

The pelvic girdle, or hip bones.

Question 32

The upper hipbone is called the what?

Answer 32

Ilium. It is the ilium that the sacral vertebrae are fused to.

Question 33

What are below the ilium?

Answer 33

The pubis and ischium. The pubis is positioned in front of the ischium, nearer the belly, and the ischium is positioned behind the pubis, nearer the tail.

Question 34

What is the acetabulum?

Answer 34

The depression or (as in dinosaurs) the hole in the pelvic girdle into which the hind limb articulates.

Question 35

Between the shoulder and elbow is the largest bone in the forelimb, called the what?

Answer 35

Humerus.

Question 36

Between the elbow and the wrist are two parallel bones called what?

Answer 36

The radius and ulna. In most tetrapods, the radius is the thinner of the two.

Question 37

The bones in the wrist are called what?

Answer 37

Carpels.

Question 38

The bones between the wrist and fingers are called what?

Answer 38

Metacarpals.

Question 39

Finger bones are called what?

Answer 39

Phalanges.

Question 40

Between the hip and knee is the largest bone in the hindlimbs, called what?

Answer 40

Femur.

Question 41

Between the knee and the ankle are two parallel bones called what?

Answer 41

Fibula and tibia. The tibia is the bone that forms our shin. If you’ve ever broken a bone in your leg or ankle, there’s a good chance that you broke your fibula, which is the thinner or the two lower leg bones.

Question 42

The bones in the ankle are called what?

Answer 42

Tarsals.

Question 43

The bones between the ankle and toes are called what?

Answer 43

Metatarsals.

Question 44

The bones in the toes are called what?

Answer 44

Phalanges (the same name as the bones in the fingers).

Question 45

What are the two major groups of dinosaurs?

Answer 45

Saurischians and Ornithischians.

Question 46

Saurischian dinosaurs are those that share an evolutionary ancestor that had a pubis that …?

Answer 46

Extended downwards and forwards, towards the ribcage.

Question 47

Ornithischian dinosaurs are those that share an evolutionary ancestor that had both …?

Answer 47

a special beak-forming bone in the lower jaw (called the predentary) and a pubis that extended downwards and backwards, towards the tail.

Question 48

“Saurischian” means “__”, and “ornithischian” means “__”.

Answer 48

“Lizard hipped” and “bird hipped”.

Question 49

Birds are part of a special group of saurischian dinosaurs that changed their pubis from …?

Answer 49

Extending forward to extending backwards.

Question 50

What are the two major groups of saurischian dinosaurs?

Answer 50

Sauropodomorphs and theropods.

Question 51

What are Sauropodomorphs?

Answer 51

They were large herbivores with elongated necks and relatively small heads.

Question 52

What are Prosauropods?

Answer 52

An early group of sauropodomorphs and were the first group of large-bodied herbivorous dinosaurs to evolve.

Question 53

What are Sauropods?

Answer 53

They were a later group of sauropodomorphs. Many sauropods attained truly gigantic size, and the group includes the largest animals to ever walk the earth. Sauropods stood on four robust and columnlike legs. Sauropod vertebrae (particularly the cervical vertebrae) are filled with complex air sacks, which helped to reduce weight. The teeth of sauropods are usually simple and peg-like.

Question 54

What are Theropods?

Answer 54

They were bipedal saurischian dinosaurs that shared a carnivorous ancestor. Many theropods were carnivorous and have serrated blade-like teeth and sharp hooked claws, but some were herbivorous and a few lack teeth altogether. Birds are a kind of theropod, making theropods the only group of dinosaurs that is not completely extinct.

Question 55

All known ornithischian dinosaurs are thought to have been primarily herbivorous. What are two adaptations that they have?

Answer 55

1. The backwards extending pubis, which gives ornithischians their name, was an adaptation
   that created more space in the ribcage. This extra space was probably filled by extra-large digestive organs. Plant matter is much harder to digest than meat, and most herbivores need larger stomachs and intestines than do carnivores.
2. The beaks, which all ornithischians possess, are also herbivorous adaptations that helped ornithischians to chop off large mouthfuls of vegetation.

Question 56

What are the five major groups within the ornithischians?

Answer 56

Ornithopods, pachycephalosaurs, ceratopsians, stegosaurs, and ankylosaurs.

Question 57

What are ornithopods?

Answer 57

Ornithopods include a wide range of dinosaurs that lack armor and that either walked bipedally all the time or assumed a bipedal stance when running. Many ornithopods are small antelopesized dinosaurs, but some, like the iguanodonts and hadrosaurs, grew to be multi-ton giants.

Question 58

What are iguanodonts?

Answer 58

Iguanodonts are large ornithopods with a spikeshaped claw on each hand.

Question 59

What are hadrosaurs?

Answer 59

Another group of large ornithopods, hadrosaurs, are the famous “duckbilled dinosaurs”. Hadrosaurs evolved late in the history of dinosaurs, but were highly successful. Some hadrosaurs have elaborate boney crests, and all hadrosaurs have strikingly large beaks in the front of their mouths and dense, tightly packed rows of small teeth in the rear of their mouths. Together, these teeth form large chewing surfaces and are collectively referred to as dental batteries.

Question 60

What ae dental batteries?

Answer 60

They are tightly packed rows of small teeth in the rear of their mouths. Together, these teeth form large chewing surfaces.

Question 61

What are pachycephalosaurs?

Answer 61

Pachycephalosaurs were bipedal with short arms, unusually stout and strong tails, and armored skulls. Some pachycephalosaurs have thick, domed skull roofs and backwardspointing horns. They have sharp conical teeth in the front of their mouths, behind their beaks, and leaf-shaped teeth in the rear. These front teeth have led some palaeontologists to hypothesize that pachycephalosaurs might have been omnivores.

Question 62

What are ceratopsians?

Answer 62

Ceratopsians are another group that evolved late in the history of dinosaurs. Ceratopsians have large parrot-like beaks and skulls that are greatly expanded in the rear. In most ceratopsians, this rear skull expansion is taken to an extreme and a large boney frill, or neck shield, is present. Many ceratopsians have large horns and also possess dental batteries. Triceratops is easily the most famous of the ceratopsians and is one of the largest. Most large ceratopsians were quadrupedal and have short tails.

Question 63

What are stegosaurs?

Answer 63

Stegosaurs are a group of quadrupedal dinosaurs with rows of projecting osteoderm plates down their backs and long osteoderm spikes on their tails. Some stegosaurs also have osteoderm spikes on their backs and over their shoulders. Stegosaur front limbs are much shorter than their hind limbs. Stegosaurs were probably not fast runners, but they could probably pivot quickly and could rear up and stand on their hind legs. Stegosaur heads are small relative to their bodies and their snouts are narrow.

Question 64

What are ankylosaurs?

Answer 64

Ankylosaurs are the most heavily armored of all dinosaurs. Ankylosaurs are quadrupedal with short legs and wide ribcages. The backs and skulls of most ankylosaurs are covered in spikey protective osteoderms. Some anklosaurs also have large osteoderms on the ends of their tails, forming a mace or “tail club”. Unlike their relatives, the stegosaurs, most ankylosaurs have short snouts and broader, rounded beaks.

Question 65

Bones are the most common dinosaur fossils because …?

Answer 65

Bones decay less rapidly than do softer tissues.

Question 66

Define integument.

Answer 66

Body covering.

Question 67

Dinosaur skeletons that contain a lot of skin fossils are often called what?

Answer 67

Mummies.

Question 68

What is keratin?

Answer 68

Keratin is a tough but flexible material that also composes hair, feathers, fingernails, and the outside of claws, beaks, and horns.

Question 69

What was the first mummified dinosaur?

Answer 69

Hadrosaur specimens, found in Wyoming in 1910. These revealed that hadrosaurs were covered with scales and that scales from different regions of the body often had different shapes.

Question 70

Fossil scales are also known from which specimen?

Answer 70

Theropods, sauropods, ceratopsians, stegosaurs, and ankylosaurs.

Question 71

A major breakthrough in the study of dinosaur integument came in 1996, when a small ____ specimen with fossil feathers was discovered in ____. This little carnivorous dinosaur was called Sinosauropteryx.

Answer 71

Theropod and Liaoning, China.

Question 72

How were the feathers of Sinosauropteryx preserved?

Answer 72

The feathers had been preserved, because the dinosaur’s body was buried suddenly by extremely fine ash from a volcano.

Question 73

In 2012, feathers were first reported from the large tyrannosauroid ___.

Answer 73

Yutyrannus. At over a ton in weight, Yutyrannus is the largest known feathered dinosaur.

Question 74

Since this first discovery of dinosaur feathers, many other have been made in Liaoning. We now know that lots of small theropods had a covering of simple hair-like feathers and some, like ___, had feathered wings.

Answer 74

Microraptor.

Question 75

Could ornithischians have been fluffy as well?

Answer 75

A few tantalizing specimens unearthed over the last few years have suggested that some ornithischians might also have had feather-like integument. (Refer to study guide for details…)

Question 76

What modern animals have osteoderms? What dinosaurs?

Answer 76

Armadillos, crocodilians, and some lizards. Among dinosaurs, large osteoderms formed the plates and spikes of stegosaurs and the armor and tailclub ends of ankylosaurs. Some sauropods also have osteoderms, although it has been hypothesized that the osteoderms of sauropods were less important for protection and more important as mineral reserves.

Question 77

How do paleontologists utilize melanosomes?

Answer 77

Studies of modern birds have shown that feather color is influenced by the shape and arrangement of melanosomes - pigment cells within a feather. Black and gray colors result from long and narrow melanosomes. Brown and reddish colors come from short and wide melanosomes. White feathers have no melanosomes. Iridescence or ‘glossiness’, like the shiny black and blue feathers of crows and magpies, corresponds to narrow melanosomes that are aligned in the same direction.