Earth 7: Dinosaurs

Front 1

Ancient Times: source of myth

Back 1

Griffin: mines in gobi desert similar to protoceratops

dragons

Front 2

Dinosaur

Back 2

Well defined group of reptiles with upright posture that lived on land (or tres)

Front 3

Early scientific Studies

Back 3

Nicolas Stenos (1638-87): 1st to recognize fossils, tongue-stones actually shark teeth

Hint 3

Megalosaurus thigh bone first illustrated in 1677, then named as scrotum humanum in 1763

Front 4

Size range

Back 4

60 cm - 60 m

Front 5

Studies in Recent History

Back 5

Victorian England
early 1800
Reconstruction poor:
Dinos as giant dumb, slow lizards

Hint 5

Golden Era of Discoveries:
1870-1930
recons. much better:
with complete skeletons, but still dumb, slow lizards

Front 6

Dinosaur Rennaissance (1970s-today)

Back 6

Dinosaurs now viewed as smart, agile, possibly warmblooded creatures (at least most of them) that are more birdlike than lizard-like.

Hint 6

John Ostrom, prof at Yale studied Archaeopteryx, arguing birds come from dinosaurs
Robert Bakker (Ostrom’s student)
- Published book, The Dinosaur Heresies, challenging notions that dinos were dimwitted. Argued that many dinos were more like birds – fast, agile, warmblooded
- Probably not true of all dinos -->Stegosaurus
but many like Velociraptor.

Front 7

Edward Drinker Cope (1850-1897) vs Othniel Charles Marsh (1831-1899).

Back 7

--rivals, defamed each other.
--dinos in Colorado ensuing "dino rush"
--used camps like armies
--Discovered lots of complete dinos in western N. Am: some famous ones: Stegosaurus, Diplodocus, Triceratops, Brontosaurus (Apato-).

Front 8

Roy Chapman Andrews

Back 8

Expeditions in Central Asia (1920s-1930s), Gobi Desert of China & Mongolia.
-- Looking for early humans, which at that time were thought to have
originated in central Asia.
--Found lots of early mammal fossils & dinos, including Velociraptor, also nests & eggs

Front 9

William Buckland

Back 9

1st scientific description of a dino (1824)
- Interpreted as a giant, extinct lizard

Front 10

The Mantells (Gideon & Mary)

Back 10

1825: Described/named Iguanodon (Iguana + teeth)
- Reconstruction based on an Iguana. -Spike on nose should be on thumbs

Front 11

Richard Owen

Back 11

coined ‘dinosaur’ (1842)
- Means “Terrible Lizard”
- Included Buckland’s dino and Mantell’s, as well as some other dinos; Owen recognized unique features that set them apart from other animals.

Front 12

Benjamin Waterhouse Hawkins

Back 12

Helped public beginning to become aware of these strange beasts.
- An artist, produced first reconstructions of dinosaurs, including several lifesize
sculptures of dinosaurs for the ‘Great Exhibition’ of 1851 in London (asort of ‘World’s Fair’).

Front 13

The scientific Method

Back 13

Four steps
1. Observations
2. Hypothesize (Come up with explanation for observations)
3. Predict (Come up with predictions based on hypothesis)
4. Test predictions by experiment

Front 14

Scientific hypotheses must be____

Back 14

testable

Front 15

Theories

Back 15

Closest to truth, evidence of positive results test after test.

Front 16

Deep Time

Back 16

The Geologic Time scale

Front 17

the Mesozoic Era

Back 17

Triassic (251-200 million yrs ago = Ma)
Jurassic (200-145 Ma)
Cretaceous (145-65 Ma)

Front 18

The age of the Earth

Back 18

4.6 Billion years (Ga)

Front 19

measuring age of the Earth

Back 19

Meteorites. Their time of formation dates
back to the age of the solar system (same with all the planets on
our solar system as well)

Front 20

Age of humans

Back 20

160,000 yrs old

Front 21

Human history

Back 21

5500 years

Front 22

Earth Before life

Back 22

Lot's of volcanic activity
Dim Sun
High levels of greenhouse gases
Meteorites vaporizing oceans
Days 5-6 hours long
Moon 15x closer

Front 23

Appearance of life on Earth

Back 23

3.5 Billion years ago in oceans
visible life: 600 million years ago
~2.3 bill:oxygen 10% of today's

Front 24

Percentage of life as microbial

Back 24

83%

Front 25

stromatolites

Back 25

Mounds of layered rock built by
bacterial communities

Front 26

Snowball Earth.

Back 26

700-600 million years ago
Earth was almost entirely entombed in ice. Glaciers at the equator!

Front 27

Appearance of land plants

Back 27

425 Ma.

Front 28

Dinosaurs appear

Back 28

230 Million years ago.

Front 29

Fossils

Back 29

the remains of ancient life

Front 30

Sediments

Back 30

Sand, silt, mud, clay, dust, and other less familiar materials.

Front 31

Making Fossils

Back 31

Death
(Bacterial decay)
....disarticulation?
Burial
(Bacterial decay)
permineralization: filling gap in bone
Replacement bone with diff mineral

Front 32

Body fossils

Back 32

the body of the animal (usually bones, can be soft parts as well).

Front 33

Trace fossils

Back 33

record the behavior of the animal. In the case of dinosaurs, we are
usually talking about footprints or trackways.

Front 34

lithify

Back 34

turn into stone

Front 35

Igneous

Back 35

these form from the cooling of magma or lava. Except for
the occasional unlucky dinosaur that happened to fall into a lava flow,
its unlikely you’d find dino fossils in igneous rocks!

Front 36

Sedimentary

Back 36

these form from the lithification of sediments. This is the best place to find dinosaur fossils.

Front 37

Metamorphic

Back 37

these are rocks that form from igneous or sedimentary
rocks at high temperatures and pressures – usually deep under the
surface of the Earth. It is possible you might find a dinosaur fossil in a
sedimentary rock that has been cooked and squeezed, but unlikely (the high temperatures and pressures usually destroy the fossils). Often fossils that are preserved in metamorphic rocks are themselves highly altered.

Front 38

Determining geological time

Back 38

• Relative Dating: How old one rock is relative to another rock.
• Absolute dating: How old the rock is in years

Front 39

Biostratigraphy

Back 39

the use of fossils to tell time
>Used for subdividing time
(eons, eras, periods, epochs)
>relative dating of rocks that contain same species (age within the range of species lifetime)

Front 40

5 Laws of Relative Dating

Back 40

1. Original horizontality.
2. Superposition.
3. Lateral Continuity.
4. The Law of Cross-cutting
5. The law of fossil succession

Front 41

Natural selection

Back 41

an explanation for how species evolve; it is a mechanism
for evolution.

Hint 41

3 component
1.Variation
2. Selection
3. Inheritance

Front 42

Evolution

Back 42

A fucking FACT!

Front 43

Nested hierarchies

Back 43

where species can be grouped together into larger groups (e.g. genera), those groups can be grouped together into even larger groups (e.g. families), and so on.

Front 44

cladograms or phylogenies or trees

Back 44

Diagrams of nested hierarchies

Front 45

Gondwana

Back 45

Supercontinent about 700 million years ago

Hint 45

It included the present southern continents of Africa, South America, Arabia, India, Australia, and Antarctica.

Front 46

Pangaea

Back 46

Supercontinent about 250 million years ago.
About 180 million years ago, Pangaea started to break up.

Hint 46

Evidence: shared dinosaurs
Then isolated species as continents drifted apart before colliding with others

Front 47

3 types of plate boundaries,

Back 47

Divergent boundaries = sea floor spreading centers.
Convergent boundaries = subduction zones and continental collisions.
Transform boundaries = lines where plates slip sideways, past one another.

Front 48

2 different ways to describe the outer layers of the earth

Back 48

(1) by composition – crust vs mantle
(2) by strength – lithosphere vs asthenosphere

Front 49

Crust

Back 49

made of the lightest rocks. They are “floating” on the heavier mantle
rocks.

Front 50

Lithosphere

Back 50

plates that include both crust and upper mantle (whatever rocks are cool enough to act rigidly over geologic time)

Front 51

Asthenosphere

Back 51

deeper mantle rocks (solid, but hot enough to flow slowly)

Front 52

Oceanic crust

Back 52

sea floor spreading
thin (“floats” low)
Yes, easily subducts
young (0-200 Ma)

Front 53

continental crust

Back 53

volcanoes and accretions
thick (“floats” high)
No, too buoyant
old (0-4000 Ma)

Front 54

monophyletic group

Back 54

Defined by the presence of evolutionary novelties.

Front 55

paraphyletic group

Back 55

Taxa in paraphyletic groups are defined by the lack certain
novelties that are found in other groups.

Front 56

Notochord

Back 56

Stiffened rod along back
• allows more efficient movement
• their movement is sinuous: e.g., salamander, fish

Front 57

Gills slits

Back 57

ancestrally functioned as filter feeding

Hint 57

Vertebrate gills consist of
• soft, blood-filled filaments used in gas exchange: take
up oxygen, release carbon dioxide, as water flows past.
• gill arches: hard, bony ‘struts’ allow gills to stay open.
• Gill slits: holes in either side of the body to let the water out

Front 58

the hagfish and the lampreys

Back 58

earliest vertebrates lacked true bone and were jawless.
have cartilaginous skeletons,

Front 59

Vertebrates have two types of bone:

Back 59

Axial bone (aka endoskeletal bone):
• Starts out as cartilage (flexible in nose, ears), then gets calcified.

Hint 59

Dermal bone: ‘bone on skin’: plates and scales.
• forms directly as bone

Front 60

Gnathostomes

Back 60

jawed vertebrates

Front 61

gnatha

Back 61

paraphyletic group
o jawless vertebrates

Hint 61

An extinct group: ostracoderms
• important feature: “shell-skins” (“ostraco-derm”)
= bone on outside of body (i.e. dermal bone)

Front 62

Where do jaws come from?

Back 62

Derived from 2 sets of gill arches. (Remember these? See above – they are bony structures used to support gills)

Hint 62

Placoderms = early, extinct gnathostomes
o Note dermal skeleton.
o Note that teeth are not ‘real’ teeth, but extensions of dermal armor.

Front 63

There are two types of gnathostomes

Back 63

Chondrichthyes (sharks and rays) &
Osteichthyes (bony fish)
--Novelty: Air bladder

Hint 63

There are two main groups of Osteichthyes
1. Ray-finned fishes (=Actinopterygii)
• “ray-fin” made of membrane strengthened by small spines
2. Fleshy-limbed vertebrates (=Sarcopterygii)
• Fleshy fin = lobes of muscle and bone

Front 64

The fleshy-finned (or –limbed) fish include two groups

Back 64

1. Lungfish & Coelacanths
2. Tetrapods

Front 65

Tetrapods

Back 65

amphibians, reptiles (including birds), & mammals

Hint 65

Novelties dealing with gravity, locomotion, and sensory reception.

Front 66

Tetrapod Novelties

Back 66

Vertebral struts 4 lateral strength
Four limbs w/ fingers & toes 4 support
Stapes: bony sound-carrying bridge to inner ear evolved from upper jaw support no longer needed

Hint 66

Hip and Shoulder girdles anchor (transfers force) to vertebrae
--for loco, and support
--shoulder evolved from dermal outer armor once part of skull in fish
--pelvis from back fin support

Front 67

Tetrapods

Back 67

amphibians, reptiles (including birds), & mammals

Hint 67

Novelties dealing with gravity, locomotion, and sensory reception.

Front 68

Tetrapod Novelties

Back 68

Vertebral struts 4 lateral strength
Four limbs w/ fingers & toes 4 support
Stapes: bony sound-carrying bridge to inner ear evolved from upper jaw support no longer needed

Hint 68

Hip and Shoulder girdles anchor (transfers force) to vertebrae
--for loco, and support
--shoulder evolved from dermal outer armor once part of skull in fish
--pelvis from back fin support

Front 69

Tetrapods divided into two groups

Back 69

"Amphibians” and Amniotes

Front 70

Amphibians

Back 70

Need water for fertilization
• Female lays eggs in water; eggs are fertilized externally -- i.e. males fertilize eggs after they’ve been released by females.
~~Need water for early development, e.g. the tadpole stage of life.

Hint 70

 Frogs
 Salamanders & newts
 Caecilians (limbless amphibians – ancestors did have limbs,
they’ve since lost’em)

Front 71

Amniotes

Back 71

Novelties:
1. Amniotic egg. water enclosed
2. Internal fertilization.
3. “Waterproof” skin. keratin skin cells
4. Improved lungs. more complex

Hint 71

include the reptiles (including birds), the mammals, and their
extinct relatives

Front 72

Amniotes divided into two groups

Back 72

reptiles (w/ 2 subdivisions)
*Anapsids
*diapsids
mammals and relatives (extinct)
*synapsids

Hint 72

distinguished by # of temporal fenestra
*Anapsids: 0
*synapsids: 1
*Diapsids: 2

Front 73

Reptiles

Back 73

Two living groups: the turtles and the diapsids.

Hint 73

Reptiles are characterized by one novelty: a hole directly below the eye,
in the roof of the mouth, called the suborbital foramen. Its function is
unclear.

Front 74

Diapsids are divided into two groups

Back 74

#1: Lizards and snakes & kin (e.g., ichthyosaurs and plesiosaurs
• #2: Archosaurs, includes crocodiles, pterosaurs, & dinosaurs

Hint 74

• Novelty of diapsids? The diapsid skull condition!

Front 75

Archosaurs

Back 75

novelties
#1: Thecodonty
• Teeth deeply rooted in sockets; surrounded by bone
• Convergence: mammals are also thecodont.
#2: Antorbital fenestra
• Hole in front of eye, between nostril and eye socket
#3: Mandibular fenestra
• opening in side of lower jaw

Front 76

Ornithodira (pterosaurs & dinosaurs)

Back 76

Novelties:
1: “Mesotarsal” ankle
2: Digitigrade stance
3: Long metatarsals
4: Very long tibia and fibula = long calves

Front 77

Dinosaur Clade

Back 77

Novelties
1: Narrow track gait; erect posture
2: Ilium forms a lip over the hip socket
3: femur with inturned head
4: Expanded Ilium
5: A ‘123’ hand; digits 4 and 5 are reduced.
6: 234 foot (note big toe = pointed back)

Hint 77

Types of Dinosaurs:
saurischians (lizard-hipped)
ornithischians ('bird'-hipped)

Front 78

Lagosuchus

Back 78

closest relative of dinosaurs:
small (> 1m long), bipedal (meaning it walked on two
legs), and a predator.

Front 79

Early Dinosaurs

Back 79

middle Triassic (tho no fossils yet):
Instead, we first see dinosaurs appear in the Late Triassic, 230-200 million years ago. Approximately 20 species are found, widely distributed throughout Pangaea

Hint 79

Herrerasaurus
Lesothosaurus
Coelophysis
• Small (~1-2 meters or less in length)
• Bipedal
• Agile, fast runner, may have been able to jump

Front 80

Late Triassic ecosystem dominated by.....

Back 80

early Archosaurs (neither croc or dino)

non-mammalian synapsids.

Front 81

Ornithischians

Back 81

novelties generally reflect adapations to one of three areas:
herbivory (large belly, gastrolith, chew)
defense (size, armor, groups)
sociality (male combat, display, comm

Hint 81

novelties:
Reverse pubis
Predentary bone
Low jaw joint
cheeks (shared by most)

Front 82

Ornithischia division

Back 82

Early ornithischians
Genasaurs (2 subdivisions)
*Thyreophorans (armored)
*Cerapods

Front 83

Thyreophorans

Back 83

2 mian groups:
ankylosaurs
stegosaurs

Both quadrupedal and hoofed

Hint 83

Stratigraphic Range: ~130 million years, Early Jurassic to Late Cretaceous. Steg. abundant in Jurassic. Anky. abundant in Cret.

Front 84

Thyreophorans were among the earliest dinosaurs to be discovered and
described

Back 84

1st: Hylaeosaurus in 1833, Gideon Mantell
Scelidosaurus in 1861, Richard Owen
Stegosaurus, In 1877, O. C. Marsh

Front 85

Thyreophoran Novelty

Back 85

Bony armor, called scutes or osteoderms. Scutes occur in rows parallel to midline of body, on lateral and dorsal surfaces of the animal

Front 86

Stegosaurs

Back 86

Novelty: Plates and spines along the back.

Hint 86

Function of plates?
1. Protection? NO (fragile, muscle att)
2. Thermoregulation? Probably not
3. Display? Most likely (scare off)

Front 87

Ankylosaurs

Back 87

Novelties:
1: A dorsal shield.
2: secondary palate that separated air passage from food
passage; allowed them to breathe and eat at the same time

Front 88

Two clades of ankylosaurs:

Back 88

Ankylosaurids:
* horns on face
* clubbed tail made w/ 2pairs of scutes
Nodosaurids:
* no horns on face
* no clubbed tail, but spikes on side

Front 89

Cerapods

Back 89

Novelties:
1. Gap between front and back teeth (diastema)
2. Uneven enamel thickness:
enamel on the upper teeth is thickened on the outside;
lower teeth enamel concentrated on inside. As teeth grind together,
enamel is sharpened; creates ‘self sharpening blade’

Hint 89

two groups:
A. Ornithopods
B. Margin heads (Marginocephalia)

Front 90

Ornithopods

Back 90

Novelties:
Kinetic Skull:
special joint in their upper jaw that allows the sides of the upper jaw to swing outwards. This causes the teeth to rub against each other

Hint 90

3 groups:
* “early ornithopods”,
* “iguanodontids”,
-- hadrosaurs (the only monophyletic one of the three).

Front 91

early ornithopods

Back 91

Heterodontosaurus
1 to 1.5 m in length, Bipedal
Possesses differentiated teeth, just as mammals do (fangs, incisors)
Possessed well developed arms & hands, Early Jurassic

Hint 91

Oryctodromeus cubicularis
3 members at end of a Cretaceous-aged fossil burrow
in Montana
7 feet long and 70 lbs, bipedal
Shovel-like beak, strong shoulder muscles, suggests it was adapted
for digging. <--parental, burrowing

Front 92

The “iguanodontids” & hadrosaurs (= the Iguanodontia); late Jurassic to
late Cretaceous

Back 92

These ornithopods could reach up to 12 m in length, and most probably walked on all four legs, though perhaps ran on two (as the video I showed in class suggested). They are characterized by:

Hint 92

Novelties:
Loss of upper front teeth
Expanded nasal openings
hand specialization
* Iguanodon's tumb spike
* flexible 5th digit
* Digits 2-4 modified into hooves

Front 93

Hadrosaurs, a.k.a. the ‘duck-billed dinosaurs’

Back 93

Novelties:
* Dental batteries (dentagenesis?)
* Duckbills” – highly modified upper anterior mouth, so that is looks like a flattened ‘bill’.
* Extremely enlarged, warped nasal bones and nasal passages for display/sound making

Hint 93

Hadrosaur Behavior:
1. Nested: craters, 7m apart, covered
2. Cared for young: fossils found

Front 94

Margin-heads (Marginocephalia)

Back 94

Novelty:
Margin of bone at back of skull
(also characterized by simple row of heterodonts)

Hint 94

Two groups:
1. Pachycephalosaurs = “Thick skulled lizards”
2. Ceratopsia = “Horned faces”

Front 95

pachycephalosaurs

Back 95

bipedal, ran fast
large, 3ft--25ft 1.5 tons

Evolutionary novelty:
Two skull types: Flat heads & Full domed heads

Hint 95

Thickened skull is very dense bone
Strong neck muscles – avoid violent rotation or even dislocation of head on neck (whiplash)
Vertebral joints give strength to back – prevent torque
of back and injuring spinal cord (paralysis!)
Sexual dimorphism

Front 96

Ceratopsia

Back 96

Novelty:
Rostral bone: beak-like bone

Hint 96

Groups of ceratopsians: psittacosaurs, “protoceratopsids”, ceratopsids

Front 97

Psittacosaurs

Back 97

• Primitive ceratopsians
• Small (4-6 feet long)
• Facultatively Bipedal
• Fast Runners?
• Primitive leaf shaped teeth (how did it digest plant matter?
Gastroliths!)

Hint 97

Spectacular psittacosaur find reported within the last few years, from famous early Cretaceous fossil beds in the Liaoning region of China

Front 98

“Protoceratopsids” + Ceratopsids

Back 98

Novelties:
1. Frill = large margin at back of skull
2. Dental batteries

Front 99

Protoceratopsids

Back 99

paraphyletic, and generally smaller than the ceratopsids. They lack horns.

Front 100

Ceratopsids

Back 100

Some had the largest skull known from any animal on land – 2.7 m high! (= almost 9 feet!), with a frill 1.5m long ( = 5 feet!)

Hint 100

Novelties:
Horns
--defense/combat= puncture wounds
--display=dimorphism, allometry