Final Exam Flashcards
(218 cards)
1
Q
Renewal of Life after the end-Ordovician mass extinction
A
evolutionary radiation came of brachiopods and bivalves but trilobites did not recover
2
Q
Renewal of life in ocean - Ordovician
A
- coral-stromatoporoid reefs flourished and increased in size
- ecological succession by rugose and tabulate corals which colonize seafloor then other animals populated reefs
3
Q
Stromatoporoids
A
colonial sponge-like animals
4
Q
tabulate corals
A
all colonial animals
5
Q
What were the new nektonic animals in the Ordovician?
A
ammonoids
- widespread index fossils
- evolved from straight nautiloids in Early Devonian
6
Q
Eurypterids
A
swimming arthropods
- relatives of scorpions with brackish and freshwater species
7
Q
Devonian was…
A
“the age of fishes” since they diversified
8
Q
Ostracoderms
A
jawless fish + bony skin + paired eyes
9
Q
Acanthodians
A
jawed fish
- fins supported by sharp spines + paired fins
10
Q
Gill bars…
A
- supported gills in primitive fishes
- modified gill bars led to jaws
11
Q
Placoderms
A
predators
- first dominated freshwater environments then expanded into Late Devonian seas
12
Q
Who were the first sharks in the Mid-Devonian?
A
Cladoselache
13
Q
Ray finned fishes v. Lobe finned fishes
A
ray-finned:
bones radiate from fins to support fish
lobe-finned:
lungfishes capable of air-breathing
14
Q
Lungfish burrowing
A
served as an adaptation to drought
15
Q
Animals living on land - Devonian
A
tetrapods [body fossils in rocks of Middle to late Devonian]
- amphibians return to water to lay eggs
16
Q
Land plants allowed for evolution of…
A
amphibians
17
Q
Tiktaalik
A
- first known tetrapod
- carnivorous
- intermediate between amphibians and lobe-finned fish
18
Q
Land Plants - Devonian
A
- invaded land by developing rigid stem and root systems
Vascular Plants: - tubes deliver water and nutrients
19
Q
Cooksonia
A
Middle Silurian vascular land plant
20
Q
Spores allowed for…
A
wider range for reproduction
21
Q
Lycopods
A
club mosses that evolved during Early/Middle Devonian
22
Q
Early Devonian spore plants were…
A
restricted to marshes and needed water for reproduction but seeds changed that since they were already fertilized and did not need as much water
23
Q
Silurian-Devonian reefs were composed of
A
- tabulate corals
- rugose corals
- stromatoporoids
24
Q
Effect of land plants on rivers:
A
Early Devonian root traces show plant roots stabilized sediments –> meandering streams
25
Devonian glaciation
increase in forests led to weathering , decrease in atmospheric CO2, led to cooling and mass extinction
26
End-Devonian Extinction
- global climate change [cooling caused by plants]
- forests formed carbon sinks
- oceanic anoxia from organic input
- extinctions happened in stages
- 75% species lost [mostly corals + invertebrates/vertebrates]
27
What periods are in the Late Paleozoic?
Permian and Carboniferous
28
Carboniferous consisted of...
more moist environments but they eventually dried up
29
The Carboniferous Period in comparison to Permian Period
Carboniferous - abundant swamps with later glaciations
- some orogeny's where rivers were going off of them forming deltas going into the sea
Permian - drying, arid environments
- continents started getting together forming Pangea which then caused arid interiors [moist air masses were not making it into the interior] = more desert conditions
30
What was abundant in the Late Paleozoic?
Ammonoids such as sea lilies
31
Brachiopods are
productids with cone-shaped shells that helped make reefs
1. Epibenthic = on the surface
2. Suspension feeders
32
When did sharks begin?
In the Devonian
33
The Devonian consisted of...
crinoids, sea lilies, sea urchin, shark relatives + jaw fish + bryozoan + ammonoids + echinoids + blastoids
34
Crinoidal Limestone
made of parts of crinoids
35
Bryozoans
sheet-like colonial animals, trapped in sediment in mounds
- important contribution to limestones
- they slowed down water and collected suspended material
36
Fusulinids
Late Carboniferous foraminifera
- long + index fossils for Upper Carboniferous-Permian
37
Index Fossils qualities
1. easily identifiable
2. abundant
3. widespread
4. short-lived
38
Late Paleozoic Marine Life
There was a higher Mg-Ca ratio in the seawater:
- caused more aragonite algae and sponges
- important builders of Late Carboniferous and Permian reefs
39
Reef
wave-resistant biogenic structure
40
Helicoprion
the Permian fish with the buzzsaw mouth
- ate squid and other soft body platonic animals
- common ancestor with sharks
41
Late Paleozoic Continental Life
Extensive coal swamps dominated by lycopods
- they took CO2 of atmosphere and oxygen went up
- sphenopsids
- seed ferns
cordaites
gymnosperms
42
Sphenopsids
- sprouted off roots
- did not live in coal swamps
- grew on levees and floodplains
43
Seed Ferns
-Carboniferous
- abundant
- small bushy plants
- large and treelike ones [Glossopteris]
44
Why are seeds important?
they can travel + endure for a long time
45
Cordaites
Upland plants
46
Gymnosperms
"naked seed" plants
- formed woodlands
- includes conifers [cone bearing plants]
47
Gymnosperms dominated terrestrial environments in...
Permian
48
What winged insects were in the Carboniferous period?
Giant dragonflies
Mayflies
49
Arthropleura
largest known land invertebrate
- arthropod
50
What caused Carboniferous insects to be so great in size?
too much oxygen
51
Reptiles
- amniote eggs [protects embryos]
- did not need water
- can lay eggs on land and aquatic environments inside
- rare fossil eggs from Paleozoic
52
What is the ancestor of therapsids?
Dimetrodon
53
Therapsids
- more related to modern mammals than reptiles
- upright stance + complex jaws + endothermic
- had some hair apart from scales
54
Endothermic
can regulate their body temperature
55
Ectothermic
depend on outside environments
56
Late Paleozoic Paleogeography
- continents clustered near each other
Third Orogeny:
- Gondwanaland collided with Eurasia
- started to form Pangea which was together by the end of the Permian
- Appalachians = Alleghenies Orogeny
57
In the Early Carboniferous, [Paleogeography]
there was a high sea level
- warm and shallow seas
- abundant limestone
58
In the Late Carboniferous, glaciation...
expanded and sea level dropped as a result of carbon burial
- plants and other amps produced so much carbon which changed CO2 ratio
59
In the Permian, Pangea
was almost complete
- the interior was low moisture + evaporites and dunes
- reduced carbon burial led to higher atmospheric CO2 and global warming ended the glaciation
60
Alleghenian Orogeny
- the last of the three orogenies for the Appalachians
- development of valley and ridge [thrust faults and Blue Ridge Provinces in the Appalachian Mountains]
- completed flesh deposition in foreland basin, continued molasses deposition [filling the foreland basin]
61
Order of Orogenies
1. Taconic Orogeny - Late Ordovician
2. Acadian Orogeny - Devonian
3. Alleghenian Orogeny - Permian
62
Cyclothems and Coal
cycles in coal beds containing marine sediments - slight changes in sea level [transgressions and regression]
- think about rivers going down to ocean forming deltaic deposits, marginal marine environments
- swamps producing and burying a lot of carbon especially with sediments from mountains
1. sea levels up and down = burying of coal
2. sea level high = no coal production
3. sea level low = some coal being produced but would have to bury it
transgressions caused deposition of marginal marine peat on top of continental deposits then overland by marine sediments
63
Oscillating glaciers during Carboniferous Period led to changes in...
sea levels
64
Global unconformity in marine sediments caused by
a drop in sea level during Carboniferous Period
65
Unconformity
surface of non-deposition or erosion
66
What caused the drop in sea level during the Carboniferous Period?
There was a global climatic cooling during the mid-Carboniferous caused by weakening of greenhouse warming
- led to ice age
- the expansion of glaciers caused sea level to drop
67
Late Permian Anoxia
anoxia = low oxygen tones in oceans in partly related to organisms but more about temperature where it started going up going into the Permian
68
More C12 implies
warmer temperatures [more organic carbon locked up in geological reservoirs being released]
- releasing light carbon
69
End of Permian meant that
oxygen was very heavy and light at the beginning of the Triassic as a result of glacial melting
70
Frozen Methane [methane hydrate]
- major greenhouse gas
- produced by Archean prokaryotes and symbionts in herbivores
- stored frozen on sea floor under tundra and on continental slopes
- once thawed it becomes a major contributor to global warming
71
End of permian was caused by:
- Late Permian Flood Basalts in Siberia
- Basalts flows and traps in one given area:
Siberian Traps
Producing a lot of CO2 and it got worse [Terrestrial environments + forests burnt up]
72
End of Permian was REALLY BAD since...
- Siberian flood basalt caused global warming
- Volcanisms ignited Carboniferous coal deposits [more CO2 and SO2]
- higher temperatures thawed methane hydrate on seafloor
- lower O2 in world oceans, acidic precipitation, ozone depletion
[more ultraviolet radiation meant all SO2 was breaking apart ozone particles]
- hot, dry, acidic, anoxic
- 96% extinction of species
73
What animal survived the end of permian mass extinction?
Lystrosaurus since they lived in burrows
74
The Early Mesozoic era was a
reboot of life
75
Life in the Early Mesozoic Era:
- molluscan were ruling in freshwater and marine environments
- bivalves and gastropods spreading into freshwater and marine ecosystems
- Stromatolites returned to shallow-water environments since their predators died off
- bivalves were abundant
- sea urchins evolved, some burrowed through sediment = deposit feeders
76
There was all grazers at the end of
Permian
77
Deposit Feeders v. Suspension Feeders
Deposit Feeders = burrowing through sediment
Suspension Feeders = more on the surface
78
Hexacorals
dominant reef builders
- evolved from soft bodied anemones in Triassic
- resembled rugose corals
79
All modern corals started in the
Triassic
80
Pelagic Realm
included anyone that is living its life in the open ocean so planktonic + nektonic + combination of both
1. phytoplankton
2. nannofossils
3. belemnoids
81
Phytoplankton
- dinoflagellates, calcareous nannofossils
- ammonoids = rapid evolution + great index fossils
82
Nannofossils
coccolithophores
83
Belemnoids
squid-like relatives of ammonoids
- straight with consideration inside and soft bodied over them
84
Osyters started in the
Triassic
85
Fishes that made it in the Triassic started developing
shell crushing abilities
- with peg-like teeth for shell-crushing
- simple jaws + scale covered bodies but also cartilaginous
86
Marine reptiles
placodonts
- blunt toothed shell crushers with broad armored bodies
87
First Marine Reptiles [early Triassic]
Nothosaurs
88
Plesiosaurus evolved from
nothosaurs
- came from terrestrial ancestors [with long necks for feeding]
- eating fish or squid
89
Long necks are an adaptation for
hunting fish
- covers more area so selection pressure allowed them to reach for fish and grab more easily
90
Ichthyosaurs
"fish lizards"
- soft fin
- biggest vertebrate eyes
91
Tree-forming gymnosperms:
1. Cycads
2. Cycadeoids
3. Ginkgo
- ferns produce spores that are very identifiable
- "fern spore spike"
92
Early Mammals:
- small
- evolved from therapsids
1. Thecodonts = dinosaur ancestors with legs directly beneath [not sprawling]
93
Thecodonts Descendants
1. Dinosaur morphs and dinosaurs
- bipedal, different skulls, highly developed teeth
2. Crocodilians
3. Pterosaurs
94
Pterosaurs
a. flying reptiles [first animals that flew]
- Late Triassic
b. not dinosaurs but does have common ancestor
95
Phytosaurs
- looks like alligator / crocodile
- aquatic animal
- predators + scavengers
96
Synapsids v. Diapsids
Synapsids = Dicynodonts
Diapsids = Dinosaurs
97
Largest known non-mammal synapsid in the Late Triassic
Lisowicia
98
Metoposaurs
large amphibians
99
What was the most common dinosaur in the Late Triassic?
Coelophysis
100
What are some possibilities as to why small dinosaurs buried rapidly?
1. land slide
2. flooding / pack hunting + drowned and got buried
101
Dinosaur Evolution
ornithischian ["bird hipped"] + saurischian ["lizard-hipped"]
- herbivores + carnivores
102
Sauropods
- largest dinosaur and land animals
- evolved to massive sizes from Late Triassic to Late Jurassic
103
Largest carnivore at its time was [Late Jurassic theropod]
Allosaurus
104
Archaeopteryx was considered the
first bird
105
When did Pangea begin to separate?
Early Triassic
106
Tethys Seaway
"ancestor" of the Mediterranean Sea
107
in Eastern U.S. we saw...
- rifting which created fault basins during Triassic-Jurassic [a lot of basalt caused rift valleys since tensional tectonics stretching apart the crust and the first valleys began to form, having basalt come out]
108
The Palisades
Late Triassic flood basalts from rifting
109
CAMP
Central Atlantic Magmatic Province
- formed at the end of the Triassic Period
110
Volcanism...
- global warming caused by volcanic activity, which released high volumes of CO2 during Triassic-Jurassic transition
- CO2 levels implied by increased number of fossils leaf stomates [cells that take in CO2]
- many plants and animals were unable to cope with abrupt temperature increase
111
End of Triassic Mass Extinction:
1. the break up of Pangea which led to extensive volcanism
2. global warming and ocean acidification
3. meteorite impact proposed as a factor but not accepted by all
4. about 60% extinction of all species continental and marine
112
Who survived the end of the Triassic mass extinction?
1. insects
2. land plants
3. dinosaurs
4. mammals
5. pterosaurs
6. ammonoids
113
Endemic
only live in that area and nowhere else
114
Mesozoic Era
- birds evolved from feathered theropod dinosaurs in Middle Jurassic
- most fossil birds are in Early Cretaceous rocks of China with abundant bird tracks in China + Korea + Japan + North America
- almost no fossils record for birds in Gondwana during Early Cretaceous:
1. Two early cretaceous birds in Gondwana [Catroavis + Kaririavis]
2. Early Cretaceous birds in Australia:
1 bone, 2 feathers, 2 tracks
115
Earliest known undoubted fossil bird [Late Jurassic in Germany] + oldest known bird
Archaeopteryx
116
Chalk is mostly from the
Cretaceous
117
Coccolithophores
calcareous phytoplankton composing chalks
118
Cretaceous World:
1. planktonic foraminifera's [index fossils]
2. plankton diversified
[diatoms (siliceous) + foraminifera + calcareous nannoplankton (coccolithophores)]
3. nekton = ammonoids + belemnoids persisted, teleost fish diversified as did marine reptiles including sea turtles
119
Teleost Fish
ULTIMATE bony fish
- dominant modern group
- symmetrical tail
- specialized fines
- short jaws
120
Life of the Cretaceous
- epibenthic bivalves = nudists
~ formed large tropical reefs
- predators reduced brachiopods and stalked crinoids
- flowering plants [angiosperms] in Early Cretaceous
- gymnosperms still dominant
121
Vertebrate Faunas
community similar to modern African savannah with abundant "duck-billed" dinosaurs [Hadrosaurs]
122
Pterosaurs were
flying vertebrates
123
Why were so many continental and marine vertebrates so big during the Cretaceous?
More abundant vegetation
124
Mammal Evolution Characteristics
pointed teeth + endothermic + large brains + suckled young + rear feet for grasping + tree climbing = burrowing
125
First mammals were in
Late Triassic
126
Purgatorius
rat-like mammal which was probably arboreal
- other mammals probably fossorial [burrowers]
127
Cretaceous Paleogeography
- Mid Cretaceous sea level high
- most continents isolated but seas opened in South Atlantic, Gulf of Mexico, Caribbean
- Tethys Seaway
- high sea level, associated with rapid seafloor spreading [divergence putting basalt on ocean bottoms] + long time with no margnetic reversal
~ rapid burial of carbon due to plankton conditions
~ sea level went up and became anoxic
- ice free arctic
~ high temperatures = lack of sea ice
- oceans stagnated = shallow marine black muds
~ expansion of normally thin oxygen-poor zones [anoxia]
128
The Late Cretaceous was the start of
the Rocky Mountains
129
Rudists went extinct before
late Cretaceous due to cooling
130
Cretaceous Mass Extinction
- dinosaurs but birds survived
- ammonoids
- mosasaurs and most other marine reptiles [but not sea turtles]
- reduction in gymnosperms and angiosperms
- 90% of calcareous nannoplankton and foraminifera went extinct
~ extinction blamed on combination of end-cretaceous volcanism + meteorite impact
131
End Cretaceous Volcanism
Deccan Plateau, India
132
Deccan Plateau volcanism
- preceded meteorite impact
- sudden cooling and warming weakened ecosystems
- instant collapse of ecosystems
133
Evidence of meteorite impact:
1. Microspherules
2. Craters
3. Heavy metal iridium
4. Shocked mineral grains
134
Chicxulub Crater:
1. Impact
2. Tsunami
3. Debris Transport
135
"Meteorite hit the right place to worsen this mass extinction..."
- gypsum and anhydrite bedrock at impact site
- debris reentering atmosphere caused heat
- impact force put aerosols into stratosphere
- combined with meteorite dust and soot to block sunlight for years
- acid precipitations [effects on sea life + soils]
136
What is the fastest running bird today?
Ostriches
137
What is a dinosaur?
bird-like animal that lived during Mesozoic Era
- closest common ancestor shared with crocodilians and birds
- modern birds are descendants of theropod dinosaurs
138
Saurischian v. Ornithischian
Examples of Saurischian [lizard-hipped]:
1. theropods
2. sauropodomorpha
Examples of Ornithischian [bird-hipped]:
1. cerapoda
2. ornithopoda
139
How do we known what we know about animals?
1. body fossils
~ bones, skin and feather impressions, eggs
2. Trace fossils
~ tracks, nests, tooth traces, burrows
3. living relatives
~ crocodiles, alligators, birds
140
What animal held evidence of live birth?
Ichthyosaurus
141
Who first noticed dinosaurs?
1. Native American tribes - legends on dinosaur remains
2. Chinese referred to dinosaur bones as long gu tou ["dragon bones"]
3. Scythian legend of friffin
142
Who studied dinosaurs?
Sir Richard Owen
- originator of the term "dinosaur" = terrible lizard
143
How long were dinosaurs alive?
Late Triassic - Late Cretaceous period for non-avian dinosaurs
144
Where did dinosaurs live?
- all continents
- highest abundance and diversity in the U.S., Mongolia, China, Canada, Europe, and Argentina
[more recent discoveries in Africa]
- terrestrial ecosystems:
[forest, deserts, Savannah's, swamps, river plains, seashores]
145
What did dinosaurs eat?
Plants + conifers + ferns + flowering plants
- Animals
- Cannibalism in a few species
146
Where did most evidence of dinosaur come from?
teeth + tooth traces + stomach contents + coprolites
147
How did dinosaurs raise their young?
- long term parental care in some species
- juveniles stayed in the nest until more than halfway grown
- denning behavior
148
How did dinosaurs go extinct?
1. Gradual decline related to Deccan Plateau
2. Meteorite Impact
149
The first skull discovered belonged to...
Velociraptor [think Jurassic Park]
150
Spinosaurus
largest theropod dinosaur
- semi-aquatic
151
What dinosaur held evidence of burring and denning?
Orcytodromeus
152
Mongolia
- weirdest theropod
- adapted to eating marshy foods + vegetation in swampy areas
153
Zulu Crurivastator
"Destroyer of Shins"
154
What do palm trees imply?
It implies that the environment in which they are in has warmer climate than normal ~ shows temperature gradient and if below, then it is cooler climate and there is no palm trees
155
What animal made it out of the Cretaceous?
turtles
156
Mass of mammals [increased or decreased] after the impact?
increased
- think of small crocodilians and odd mammals
157
What plant evolved in the Paleocene?
Legumes
~ mammals and other animals started eating these and drove coevolution between vertebrates and some of the plants that had survived the impact
158
What were some of the vertebrate survivors?
1. Crocodilians
2. Birds
3. Mammals
4. Turtles
159
What allowed whales to walk in water?
their bones were dense enough
160
Evolution of whales
1. Indohyus
- think cloven hook so deer + sheep + goats
2. Pakicetus
3. Ambulocetus
- "a whale that can walk"
4. Basilosaurus
- carnivorous
- greater in body size and reduction of the legs
161
Who is the closest relative to whales?
hippos
162
What are some modern marine vertebrates?
sharks and whales
163
Why did sharks start getting bigger?
They started growing to eat whales, which were also increasing in size
164
Sandy coasts offered new niches..
~ sand dollars evolved from "sea biscuits" [urchins]
- we started seeing more compressed sand dollars so they glided into the sand so they streamlined and could quickly hide from predators
165
Urchins were
burrowers
166
When did sand dollars start?
Paleogene
167
How do marsupials differ?
- they have a pouch meaning that babies are born as embryos and stay in their moms such
168
Bats [present by early Eocene]
~ flight originated from the trees down
169
Ungulates
"hoofed animals"
- mostly herbivores
170
Types of Ungulates:
1. Perissodactyls
~ odd-toed
~ horses + tapirs + rhinos
2. Artiodactyls
~ even-toed
~ cloven-hoofed goats + sheep + pigs + deer + cattle
171
When did elephants start evolving?
Late Eocene
172
Mesenychids
dog-like carnivorous mammals
173
Diatryma
huge flightless birds with clawed feet and slicing beaks
174
Why are flamingos pink?
they like salty habitats and eat brine shrimp
175
Oligocene Mammals
~ horses in North America
~ Charles Darwin discovered horse teeth in South American from Pleistocene environment
176
What is the largest land mammal of all time?
Paraceratherium
177
What are some examples of large land mammals?
brontotheres + tapirs
178
When did carnivores evolve?
In the Eocene
Examples:
1. saber-toothed cats
2. bear-like dogs
3. wolf-like mammals
179
Paleogene Paleogeography
continents were a bit closer together but still similar to modern time
~ Atlantic and Pacific still connected
~ Madagascar disconnected
~ North and South America not together yet
Early Paleocene = warm climate but cooled later
180
Paleocene-Eocene Thermal Maximum [PETM]
- abrupt shift in oxygen isotope ratio
- shift in light carbon isotopes
181
Why was there a shift in light carbon isotopes?
The release of methane hydrate became positive feedback causing the melting of frozen methane so overall warming caused by a change in ocean pattern
With the melting of methane it became positive feedback loop becoming hotter and hotter
It will go negative and lighter
182
What epoch matches current level of atmospheric CO2?
Oligocene
183
Laramide Orogeny: The Rocky Mountains
- active igneous activity with active fold and thrust belt + low angle of subduction
1. thrust faults
2. compressive tectonics
[basalts got bent so oceanic lithosphere subducted resulting in volcanism]
184
Yellowstone hot spot
more than 20 successive forests buried in basalt lava flow
185
Gulf of Mexico
- result of Mississippi Embayment:
1. Thick Eocene deposits, Oligocene regression formed clastic wedge
2. important for petroleum source rocks and reservoirs
~ As sea level went down with cooling then you got progressively younger rocks going out the sea
3. Tom Canyon crates also with tsunamis and microspherules
[contributed to size of Chesapeake Bay]
186
What are microspherules?
melted glass where minerals have vaporized or turn into glass
187
Chesapeake Bay: Meteorite Impact Site
seismic profiling revealed basin filled with breccia, faults causing geologic hazard
188
Marine life of the Neogene World
- Miocene cetaceans + baleen whales
baleen whales had a tooth structure that basically served as a filter for phytoplankton - kind of a strainer]
- Miocene recovery of planktonic foraminifera
189
Terrestrial life of the Neogene World
~ grasses + herbs + weeds more widespread
~ required arid climate
~ cooler climate connected to Antarctic glaciation
190
Why did all of these organisms coevolve and become more diverse in the past 25 million years?
- they all ate each other essentially
- grasses, herbs, and weeds coevolved
- rats and mice + modern songbirds ate seeds
- modern snakes then ate the songbirds and rats + mice
191
Mammals in the Neogene World
- mammals adapted to open terrain
- even-to ungulates = artiodactyls
- elephants diversified and spread
- carnivorous mammals
- New World primates
192
Elephants diversified except in what two continents
1. Antarctica
2. Australia
193
New World Primates
- all the cattle we have today came from one species of Pleistocene which had ancestors in Africa [primates in the Americas had ancestry to Africa]
194
In the Neogene, we got the spread of
C4 grasses...
- C4 plants incorporated more C13 than C4 grasses
- there was more silica in grasses
- grasses began to expand and take o
195
How did silica affect graders' teeth and their evolution?
- teeth are made of apatite [5] and silica [7] so silica is much stronger, wearing out the teeth
196
Why did C4 grasses spread?
Global climate change led to warmer growing seasons
197
Ice Age Evidence
1. Erratic boulders
2. Glacial till and basins associated with glaciation [for example the Great Lakes which represent where there was a continental glacier that caused deep enough holes in parts of that area and left enough melted water which formed the Great Lakes]
3. Depression of land
4. Glacial scouring [lower parts of mountains of northeast U.S. are smooth while the top has been scraped by glacial activity]
5. lowered sea level [exposed continental shelves + allowed elephants to travel to the Americas and horses to Asia allowing evolution]
6. Changes in biota
198
What is used to reconstruct vegetation changes with glacial and interglacial times?
Fossil Pollen
- it shows that there is more boreal to deciduous mixed forest
199
Ice Age: Oxygen Isotopes
- ocean was enriched in O18 ["heavy"] during glaciations
- Eccentricity and Obliquity cycles followed same pattern that heavy will be cool and lighter will be warm
- Great Lakes remained when ice sheets melted back [as they melted they formed huge lakes]
- climate impacts felt globally [Sahara expanded and rainforests were restricted isolating gorilla ancestors during Pleistocene] --> they were pushed farther north and during glaciations, they were pushed down to forest ecosystems near the equator [move with cycles]
200
When was the last glacial maximum?
35000 - 10000 years ago
201
When did the Northern Hemisphere glaciation and Ice Age begin?
Northern Hemisphere - 3 may
Ice Age - 2.5 may
202
Milankovitch Cycles
Precession + Obliquity + Eccentricity
When all 3 come together, it may cause glaciation or deglaciation
203
Tectonics and Mountain Building
- assembling of California
- California Coastal Range = accreted terranes, divided by faults
204
Yellowstone Hot Spot
- oldest ones are farther away
- plate moving southwest and mover over hot spot
- hot spot within a continental plate
- northwestward movement
- Columbia river basalt coming from subduction of plate that is forming the cascades
205
Formation of Caribbean Island Arc [oceanic-oceanic]
Caribbean plate started interacting with North American plate
oceanic under oceanic forming volcanic rocks + volcanism
206
The Great American Biotic Exchange
- Isthmus of Panama
North and South American mammals developed separately but Pliocene uplift of isthmus connected continents which allowed exchange of terrestrial fauna
207
Himalayan Mountains
- India continent collided with Eurasia continent and whatever oceanic crust was between them was affected [oceanic environment got thrust up by collision]
- Tibetan Plateau
Nothing was being subducted so it just kept going up leading to mountain building
- no marine material was left or what ocean was once between them
208
Human Evolution
earliest apes = Sahelanthropus [non-human apes + humans]
209
Hominins as index fossils
- not good as index fossils since they are rare
210
Australopithechines
"intermediates" between human and non-human apes
- as grasslands developed, apes started spending more time on the ground which led to increase in brain size relative to body size
211
Homo
2.5 to 2 mya:
- larger skull + thigh and pelvis bones similar to australopithecines + developed stone tools
- 10 -15 species recognized but decreased to one species of homo [homosapiens]
- Neanderthals = Homo neanderthalensis [stone tools + burial + genome mapped + interbred with homosapiens]
212
Homosapiens
Mitochondrial DNA originated in Africa
- migrated to Asia and Australia
- interbred with related human species
- made cave paintings + longest continuous human culture in Australia
213
When did human migrate to North America?
about 23 000 years ago and move south through Central and South America by at least 13 000 years ago [may have followed elephants]
214
Sixth Mass Extinction beginning
large-mammals extinction in North America started about 12 000 years ago
Examples being:
1. American elephants
2. large beavers
3. horses
4. North American camels
5. giant armadillos + giant ground sloths
215
Hypothesis for 6th Mass Extinction
1. Overkill Hypothesis:
human hunting led to mass extinction of large mammals
2. Overchill Hypothesis:
rapid climate change altered habitats and triggered mass extinction of largest animals
216
Megafaunal Extinctions
Habitat alternation and overhunting
- human introduced invasive species [dogs, rats]
217
Development of Agriculture
- hypsithermal interval
[warmer today allowing development of agriculture]
- atmospheric Co2 increase since 1960s
218
Impacts of Climate Change
1. sea level rise
2. change in plant communities
3. desertification
4. changes in precipitation
5. species migrations + extinctions
