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GEOL 2155 > Mid Term #2 > Flashcards

Mid Term #2 Flashcards

1
Q

What are the different types of fossils found during the Precambrian?

A

Unicellular, and are rarely preserved

Hard to differentiate between species

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2
Q

Precambrian Subdivisions

A

Hadean (4.6-3.8 Ga)
Archean (3.8-2.5 Ga)
Proterozoic (2.5 Ga - 542 mya)

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3
Q

Orogenic Events

A

Result in the formation of metamorphic rocks under extreme pressure and heat

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4
Q

Evidence for Formation of Oceans

A

Pillow Basalts in Isua formation (greenland)

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5
Q

Isua Formation

A

Greenland

Oldest evidence of life due to high carbon 12 content

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6
Q

How do you measure isotope ratios?

A

Mass spectrometry

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7
Q

Mass spectronomy

A

Transform sample into a gas (digested in acid, vaporize with laser)
Pass down tube filled with inert gas (He)
Deflect with magnet
Collect and count different ions at other end

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8
Q

Where are the oldest stromatolites?

A

Warawoona Group

Western Australia

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9
Q

Fig Tree Formation

A

Stromatolites
Prokayotes
Pristane and Phytane (products of decomposition of chlorophyll)

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10
Q

Where does the understanding of ancient atmosphere come from?

A

Geochemistry of rocks and minerals

Certain minerals are stable in anaerobic conditions but not in the presence of Oxygen

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11
Q

Atmosphere of Archaen

A

Very limited amount of oxygen (compared to now)

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12
Q

Archaen rocks Geochemistry

A

Contained weathered mineral grains, so erosion was taking place (some sort of atmosphere present)

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13
Q

Banded Iron Formation composition

A

Iron-oxide minerals (hematite and magnetite)

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14
Q

Banded Iron Formation interpretation

A

Rusting of ocean

Precipitate minerals out of ocean due to reaction of Fe with O2

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15
Q

Red Beds

A

Terrestrial deposits
Formed when iron oxide minerals are exposed to O2
First occurs same time decrease in BIF

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16
Q

Precambrian Atmosphere

A

Primarily anoxic until 2.5-2.0 Ga, see change in geochemistry of rocks

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17
Q

Early Proterozoic Fossils

A

Gunflint Chert

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18
Q

Gunflint Chert

A 
Ontario (2.1 Ga)
Stromatolites
Light Carbon
Pristane and Phytane
Increase in diversity of Prokaryotes
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19
Q

Pristane and Phytane

A

Stable products from decomposition of chlorophyll

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20
Q

Appearance of Eukaryotes

A

First appear 1.8 Ga
Require O2 for metabolism
Some reproduce sexually (increased variability)

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21
Q

Eukaryotes

A

Primarily distinguished by their size

Prokaryotes usually 10-60 micro milimeters

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22
Q

Metaphytes

A

Macroscopic Fossils

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23
Q

Macroscopic Fossils

A

Algae

First occurrence 1.25 Ga

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24
Q

Algae

A

Eukaryotic
Photosynthetic
No complex organs/tissues (not plants)

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25
Bitter Spring Formation
``` Central Australia Most diverse Proerozoic microfossil assemblage Cyanobacteria Bacteria Algae? ```
26
Ediacaran Fauna
Multicellular eukaryotes burst onto scene 580 mya
27
First Hard Parts
Tommotian Fauna Small shelly fauna 545-520 mya
28
Tommotian Fauna
High abundance, relatively low diversity | Early Cambrian
29
Why did animals develop Hard Parts?
Response to predators Increase in size Locomotion
30
Charles Doolittle Walcott (1850-1927)
Excavated >60,000 specimens from Walcott quarry | Named more than 100 of the 170 known species
31
The Burgess Shale
Marine shale Middle Cambrian Age (505 mya) Access by 11 km hike UNESCO world heritage site (1984)
32
Depositional Setting of Burgess Shale
Fine-grained calareous mudstones (low energy/ below wave base) Thought to be at base of steep drop off Storm deposits
33
Preservation at Burgess Shale
Excellent
34
Preservation Requirements
Stagnation or incomplete recycling Rapid burial Rapid diagenesis (chemical alteration/conversion
35
Algae of Burgess Shale
Marpolia | Yuknessia
36
Marpolia
Filamentous strands, no evidence of hold-fast
37
Yuknessia
Long, unbranched fronds, from central hold-fast
38
Sponges of Burgess Shale
Vauxia
39
Vauxia
Named after Walcott's thrid wife, Mary Vaux
40
Worms of Burgess Shale
Priapulids
41
Onychophora
Velvet Worms | Aysheaia
42
Trilobites of Burgess Shale
Olenoides
43
Olenoides
Benthic
44
Arthropods of Burgess Shale
``` Sidneyia Alalcomenaeus Yohoia Burgessia Marrella ```
45
Sidneyia
Up to 13 cm long Benthic Fed on small trilobites
46
Alalcomenaeus
Stalked eyes Probably pelagic Up to 6 cm
47
Yohoia
2 cm long Benthic scavenger/predator Articulated cranial 'appendages'
48
Burgessia
``` Extremely common Very small (1 cm max) ```
49
Marrella
``` Stem Arthropod Most common taxa Up to 26 body segments, each with a pair of legs Legs used for walking and breathing Benthic scavenger ```
50
Chordata of Burgess Shale
Pikaia
51
Pikaia
Classification not universally accepted | Presence of antennae and an external cuticle is problematic
52
Oddities of Burgess Shale
Hallucigenia Opabinia Wiwaxia Anomalocaris
53
Hallucigenia
Up to 3 cm long | Not sure which end is the head, or how the organism moved or ate
54
Opabinia
Five eyes: Ventral, posterior facing mouth, proboscis | Possible pelagic, but a bottom feeder
55
Wiwaxia
``` Bilaterally symmetrical Covered in small sclerites Up to 5 cm long No sign of eyes or tentacles Unknown method of movement ```
56
Anomalocaris
``` Name means abnormal shrimp First 'super-predator' Up to 2 m long Compound eyes on stalks Mouth consisted of 32 overlapping plates in a ring that could crush prey (NO JAWS) Two large arms extended anteriorly Fan shaped tail, stabilizing shape Swam using dorso-ventral body undulations ```
57
Significance of Burgess Shale
One of the best early windows into Cambrian ecosystem Demonstrates body plans, life habits, and phyla One of the few sites to preserve soft tissue
58
Difficulty in the Burgess Shale
It's only one locality
59
Chengjiang Fauna Geologic Setting
Mudstones from Qiongzhusi Formation | Represent a shallow sea with a muddy bottom
60
Depositional Environment of Chengjiang Fauna
Shallow water ,200 m | Close to terrestrial sediment input - affected by tide
61
Preservation of Chengjiang Fauna
Chemical and environmental conditions that allow for exceptional preservation Three Dimensional fossils Soft Tissue preserved
62
Faunal Composition of Chengjiang Fauna
Similar taxa to Burgess Shale: Sponges, Arthropods, Anomalocaris, Hallucigenia
63
Fana of Chengjiang Fauna
Myllokunmingia | Haikouichthys
64
Myllokunmingia
3 cm long Chordate Angathans
65
Chordate
Notochord Pharyhngeal gills V-shaped myomeres
66
Haikouichthys
3 cm long Chordate Cartilage in cranial region - Vertebrate Intestines and gonads
67
Agnathas
Jawless fish
68
Hagfish and Lampreys
Last remaining agnathans
69
Implications of Chengjiang Fauna
Chardates and vertebrates had evolved, and were diversifying by 522 mya
70
What is an Invertebrate
Member of Kingdom Animalia - Eukaryotic and Heterotrophic | Lacks a vertebral column and skull - no cartilage or bone
71
Invertebrate Phylums
Porifera Cnidaria Echinodermata Arthropoda
72
Porifera
Sponges
73
Cnidaria
Corals and Jellyfish
74
Echinodermata
Starfish, Sea Urchins, Sand Dollars, Crinoids and Sea Cucumbers
75
Arthropoda
Insects, Crustaceans, Centipedes, Millipedes and Chelicerates
76
Fossil Sponges
Tend to be preserved as piles of siliceous spicules
77
Fossil Coral
Calcium carbonate skeleton preserves
78
Fossil Echinoderms
Relatively rare | Preserved as series of calcareous plates
79
Fossil Arthropods
Record is better for those groups with harder exoskeletons (trilobites)
80
What is a Trilobite?
Joined exoskeleton composed of chitin | Function of appendages vary by body region
81
Trilobite Anatomy
Dorsal surface divided lengthwise into an axial and two peural lobes Single pair of antennae Compound eyes
82
Tagmata
Group of arthropod segments with similar function
83
Trilobite Tagmata
Cephalon, thorax and pygidium
84
Trilobite Life Habits
Exclusively marine Varied feeding habits: predators, scavengers, deposit feeders Primarily benthic, although Proetida was pelagic
85
Trilobite Ontogeny
Molts
86
Fossil Molluscs
Outstanding fossil record due to presence of calcium carbonate shells
87
Mantle of Molluscs
2 folds of skin Secretes shell Mantle cavity contains gills
88
Shell
3 Layers
89
Layers of Shell
Periostracum Prismatic Nacreous
90
Periostracum
Thin organic layer between the shell proper nad the environment Composed of protein conchiolin
91
Prismatic Layer
Columnar crystals of calcium carbonate | Form in the extrapallial space, between periostracum and mantle
92
Nacreous Layer
Planar crystals of Calcium carbonate | Formed directly from the underlying mantle
93
Shell Growth
Periostracum and prismatic layer grow from the edge of the existing shell
94
Feeding Anatomy
Radula: tongue like organ | Eat by boring, grazing or harpooning
95
Polyplacophora (Chitons)
7-8 dorsal plates (shell valves) Radula reinforced with magnetite Stratigraphic range at least late Cambrian to recent
96
Gastropods
``` Diverse and disparate Specialized radula With or without shell Developed circulatory and nervous system Opeculum ```
97
Opeculum
Trap door, pull soft parts into shell and closes off for protection
98
Class Cephalopoda
Marine predators/scavengers Foot: Jet propulsion 3 subclasses
99
3 Subclasses of Cephalopoda
Nautiloidea Coleoidea Ammonoidea
100
Nautiloidea
2 pairs of gills, no suckers
101
Coleoidea
Squid and octopus
102
Ammonoidea
Extinct
103
Locomotion of Cephalopoda
Funnel, derived from foot, water propelled out via muscular contraction of mantle cavity Lateral fins: stabilizers
104
Types of Sutures
``` Orthoceratitic Agoniatitc Goniatitic Ceratitic Ammonitic ```
105
Orthoceratitic
Completely lack lobes and saddles, or gently rounded lobes and saddles Cambrian to recent
106
Agoniatitic
Simple lobes and saddles | Early-Mid Devonian
107
Goniatitic
More pronounced and numerous lobes and saddles (8) Late Devonian-Permian Rare in Triassic and Cretaceous
108
Ceratitic
Tips of most lobes are subdivided to give a saw-toothed appearance Rare in Carboniferous, Permian and Cretaceous Common during Triassic
109
Ammonitic
Complex subdivided lobes and saddles Common during Jurassic and Cretaceous Also found during Permian and Triassic
110
Goniatites Characteristic of ...
Paleozoic
111
Ceratites Characteristic of ...
Triassic
112
Ammonites Characteristic of ...
Jurassic -Cretaceous
113
Bone
Composed primarily of Calcium phosphate | Intramembranous or endochondral
114
What purposes do bone serve?
Support Protection Movement Mineral Storage
115
Types of Bone Cells
Osteoblast Osteoclast Osteocyte
116
Osteoblast
Production of new bone
117
Osteoclast
Remove/dissolve existing bone
118
Osteocyte
Maintains existing bone
119
Types of Bone Growth
Endochondral | Intramembranous
120
Endochondral Bone Growth
Cartilaginous precursor is remodeled by bone cells (called ossification) Long bones are endochondral - limbs, ribs Determinate in mammals and birds Indeterminate in fish, amphibians, turtles and lizards
121
Intramembranous Bone Growth
Bone grows directly from precursor cells | Includes: Dermal Bone and Sesamoid bones
122
Dermal Bone
Many bones of the skull, pectoral girdle and any bones formed in the skin
123
Sesamoid Bone
Associated with areas of mechanical stress: patella, pisiform)
124
What is an agnathan?
A Vertebrate that does not have Jaws
125
What are Jaws?
Cartilagenous or bony structures derived from gill arches that are often used to support teeth
126
Earliest Vertebrates
Haikouichthys
127
Earliest Agnathans
Conodonts
128
Conodonts
``` Large eyes 5 cm long Tooth elements show evidence of microwear Similar in appearance to lamprey Evolve rapidly Cambrian - Triassic Global marine distribution ```
129
Ostracoderms
All jawless vertebrates with external body plates
130
First Ostracoderms
Astraspids and Arandaspids | Ordovician
131
Astraspids and Arandaspids
``` 20 cm long Mobile tail covered in bony plates Cranial shiels composed of plates Mouth containes bony plates Presence of lateral line system ```
132
Lateral Line System
Sensory system found in many aquatic vertebrates Series of sensory cells that link to the central nervous system Provide spatial awareness via vibrations in surrounding water
133
Later Ostracoderms
Hereostracans Anaspids Thelodonts
134
Hererostracans
Diversify during Silurian and Devonian | Differentiated from astraspids and arandaspids by possession of only a single branchial opening on each side
135
What are Heterostracans United by?
Single broad dorsal head shield Single broad ventral head shield Numerous smaller plates linking the two
136
Anaspids
Silurian and Devonian Verterbral column bends ventrally in caudal fin Ventral fin folds
137
Thelodonts
Isolated scales during Ordovician Abundant scales and body fossils during Silurian and Devonian Diverse scale morphologies
138
What are Bony Shields United By?
Large head shield that covers gills dorsally | Ventrally located branchial openings
139
Bony Shields
Ordovician - Devonian | Wide variety of head ornamentation and shield morphologies
140
Early Agnathan Diversity
Originate in Cambrian Diversify during Ordovician Peak diversity during Silurian and Devonian Decline during Carboniferous
141
Early Agnathan Life Habits
Active swimmers | Body shape suggests most were living close to he bottom as grazers and predators
142
Early Agnathans Evolutionary Trends
Reduction of cranial and body plates Development of pectoral and accessory fins Increase tail surface area Increase in size
143
The Devonian and Agnathans
Still diverse but have been supereseeded by gnathostomes Jawed fish take oker in terms of diversity and abundance Agnathans occupy peripheral niches since the Carboniferous
144
Why are Jaws Important?
Breakdown of food | Prey capture
145
The Evolution of Jaws
Derived from ancestral brachial gill arches
146
1st Arch
Mandibular arch | Composed of Palatoquadrate adn Meckel's Cartilage
147
2nd Arch
Hyoid Arch | Most prominent element is the Hyomandibula
148
Evolution of Jaws Theory
Mandibular arch from a single anterior ancestral gill arch (Serial) Mandibular arch from several ancestral gill arches (Composite)
149
Other Names for Palatoquadrate
Quadrate in reptiles | Incus in mammals
150
Other Names for Meckel's cartilage
Articular in reptiles | Malleus in mammals
151
Other Names for Hyomandibula
Columella in reptiles | Stapes in mammals
152
Types of Jaw Suspension
Amphistylic Hyostylic Autostylic
153
Amphistylic
Palatoquadrate attached to neurocranium both anteriorly and posteriorly
154
Neurocranium
Portion of the skull enclosing/supporting the brain (braincase) Common in early gnathostomes
155
Hyostylic
Palatoquadrate contacts the neurocranium anteriorly, but the jaw is suspended entirely by the hyomandibular arch Allows the palatoquadrate to rotate forward upon opening of jaw Common among modern sharks
156
Autostylic
Palatoquadrate fused to neurocranium Excludes hyomandibular arch from jaw suspension Found in Chimaerid sharks, lungfish and tetrapods
157
Placoderms
Armour plated monsters Silurian - Devonian Have bony plates that cover the cranial and branchial regions Lack teeth
158
How do Placoderms differ from jawless fish?
Cranial and trunk plates are mobile, nuchal gap
159
Early Jawed Fish
Acanthodians
160
Acanthodians
Akanthos Silurian-Permian Predominant feature is spines along edges of most fins
161
Earliest Gnathostome
Guiyu oneiros
162
Guiyu Oneiros
Silurion of China
163
Acathodians
Large head with light bony plates Body covered in small scales composed of bone and dentine Most have teeth
164
Evolution of Teeth
Thought to be derived from scales surouned oral region
165
Chrondrichthyans
Cartilaginous fishes Primarily known from teeth and spines Have hereocercal tails
166
Who developed the tooth whorl?
Early Chondrichthyans
167
Gnathostomes in order of First Appearance
Acanthodians Placoderms Chondrichthyans
168
Gnathostomes in order of their Hypothesized Occurence
Placoderms Chondrichthyans Acanthodians
169
Osteichthyans
Fishes with bony internal structure
170
Who did Osteichthyans evlove from?
Possibly Acanthodians
171
When did Osteichthyans first appear?
Silurian | Diversify during Devonian
172
What are the two groups of Osteichthyans?
Actinopterygians | Sarcopterygians
173
Actinopterygians
Ray-finned Fishes Fins supported by series of bony rays Majority of extant fishes
174
Basal Actinopterygians
Cheirolepis
175
Cheirolepis
``` Mid-Devonian 25 cm long Heterocercal tail Small overlapping scales that have a pega nad socket articulation Large gape ```
176
How did Cheirolepsis move?
Lateral undulation
177
How were Cheirolepis's teeth arranged?
Irregular on maxilla, premaxilla and Dentary
178
What are Neopterygians?
Subgroup of Actinopterygians
179
When do Neopterygians appear?
Permian | Diversify during mexozoic and cenozoic
180
What is characteristic of Neopterygians?
Homocercal tails, thinner, more flexible scales
181
Basal Netopterygians Jaws
Maxilla is hinged anteriorly, allowing for lateral expansion | This creates a suction by expanding the volume of the oral cavity
182
What are Teleosts?
Advanced Neopterygians
183
Teleost Jaws
Hinged premaxilla that swings forward
184
When do Teleosts appear?
Jurassic
185
Sarcopterygians
Lobe-finned fishes | Articulated bony elements support the fin
186
When did Sarcoterygians first appear?
Silurian
187
What are the two extant groups of Sarcoterygians?
Lungfish | Coelacanths
188
What are tetrapods descended from?
Sarcopterygians
189
Lungfishes
Diverse during Devonian Known for vast number of bones in skull Some could drag themselves over land using fins
190
Aestivate
Seal itself in a mucus cocoon and reduce its metabolism while awaiting the return of water
191
What taxa can aestivate?
African lungfish
192
When did coelacanths first appear?
Mid-Devonian
193
What challenges did taxa have when leaving the water?
``` Support Locomotion Feeding Respiration Sensory System Water Balance ```
194
Support
Skeletal adaptations to fight gravity
195
What skeletal adaptations were created?
Limbs and girdles
196
Locomotion
Development of the terrestrial limb system Limbs must develop new range of motion Joints must become mobile
197
Feeding
Develop the quadrate articular jaw joining
198
Respiration
Early tetrapod probably relied on buccal pumping for air exchange
199
Buccal Pumping
Suck air into throat and essentially swallow it
200
Sensory Systems
Lateral line system no longer useful | Development of auditory apparatus
201
Water Balance
Desiccation would have been a problem Early tetrapods lived close to water Wate would have been a necessity for reproduction

GEOL 2155 (3 decks)

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