Final Exam Flashcards
Renewal of Life after the end-Ordovician mass extinction
evolutionary radiation came of brachiopods and bivalves but trilobites did not recover
Renewal of life in ocean - Ordovician
- coral-stromatoporoid reefs flourished and increased in size
- ecological succession by rugose and tabulate corals which colonize seafloor then other animals populated reefs
Stromatoporoids
colonial sponge-like animals
tabulate corals
all colonial animals
What were the new nektonic animals in the Ordovician?
ammonoids
- widespread index fossils
- evolved from straight nautiloids in Early Devonian
Eurypterids
swimming arthropods
- relatives of scorpions with brackish and freshwater species
Devonian was…
“the age of fishes” since they diversified
Ostracoderms
jawless fish + bony skin + paired eyes
Acanthodians
jawed fish
- fins supported by sharp spines + paired fins
Gill bars…
- supported gills in primitive fishes
- modified gill bars led to jaws
Placoderms
predators
- first dominated freshwater environments then expanded into Late Devonian seas
Who were the first sharks in the Mid-Devonian?
Cladoselache
Ray finned fishes v. Lobe finned fishes
ray-finned:
bones radiate from fins to support fish
lobe-finned:
lungfishes capable of air-breathing
Lungfish burrowing
served as an adaptation to drought
Animals living on land - Devonian
tetrapods [body fossils in rocks of Middle to late Devonian]
- amphibians return to water to lay eggs
Land plants allowed for evolution of…
amphibians
Tiktaalik
- first known tetrapod
- carnivorous
- intermediate between amphibians and lobe-finned fish
Land Plants - Devonian
- invaded land by developing rigid stem and root systems
Vascular Plants: - tubes deliver water and nutrients
Cooksonia
Middle Silurian vascular land plant
Spores allowed for…
wider range for reproduction
Lycopods
club mosses that evolved during Early/Middle Devonian
Early Devonian spore plants were…
restricted to marshes and needed water for reproduction but seeds changed that since they were already fertilized and did not need as much water
Silurian-Devonian reefs were composed of
- tabulate corals
- rugose corals
- stromatoporoids
Effect of land plants on rivers:
Early Devonian root traces show plant roots stabilized sediments –> meandering streams
Devonian glaciation
increase in forests led to weathering , decrease in atmospheric CO2, led to cooling and mass extinction
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]
What periods are in the Late Paleozoic?
Permian and Carboniferous
Carboniferous consisted of…
more moist environments but they eventually dried up
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
What was abundant in the Late Paleozoic?
Ammonoids such as sea lilies
Brachiopods are
productids with cone-shaped shells that helped make reefs
1. Epibenthic = on the surface
2. Suspension feeders
When did sharks begin?
In the Devonian
The Devonian consisted of…
crinoids, sea lilies, sea urchin, shark relatives + jaw fish + bryozoan + ammonoids + echinoids + blastoids
Crinoidal Limestone
made of parts of crinoids
Bryozoans
sheet-like colonial animals, trapped in sediment in mounds
- important contribution to limestones
- they slowed down water and collected suspended material
Fusulinids
Late Carboniferous foraminifera
- long + index fossils for Upper Carboniferous-Permian
Index Fossils qualities
- easily identifiable
- abundant
- widespread
- short-lived
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
Reef
wave-resistant biogenic structure
Helicoprion
the Permian fish with the buzzsaw mouth
- ate squid and other soft body platonic animals
- common ancestor with sharks
Late Paleozoic Continental Life
Extensive coal swamps dominated by lycopods
- they took CO2 of atmosphere and oxygen went up
- sphenopsids
- seed ferns
cordaites
gymnosperms
Sphenopsids
- sprouted off roots
- did not live in coal swamps
- grew on levees and floodplains
Seed Ferns
-Carboniferous
- abundant
- small bushy plants
- large and treelike ones [Glossopteris]
Why are seeds important?
they can travel + endure for a long time
Cordaites
Upland plants
Gymnosperms
“naked seed” plants
- formed woodlands
- includes conifers [cone bearing plants]
Gymnosperms dominated terrestrial environments in…
Permian
What winged insects were in the Carboniferous period?
Giant dragonflies
Mayflies
Arthropleura
largest known land invertebrate
- arthropod
What caused Carboniferous insects to be so great in size?
too much oxygen
Reptiles
- amniote eggs [protects embryos]
- did not need water
- can lay eggs on land and aquatic environments inside
- rare fossil eggs from Paleozoic
What is the ancestor of therapsids?
Dimetrodon
Therapsids
- more related to modern mammals than reptiles
- upright stance + complex jaws + endothermic
- had some hair apart from scales
Endothermic
can regulate their body temperature
Ectothermic
depend on outside environments
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
In the Early Carboniferous, [Paleogeography]
there was a high sea level
- warm and shallow seas
- abundant limestone
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
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
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]
Order of Orogenies
- Taconic Orogeny - Late Ordovician
- Acadian Orogeny - Devonian
- Alleghenian Orogeny - Permian
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
Oscillating glaciers during Carboniferous Period led to changes in…
sea levels
Global unconformity in marine sediments caused by
a drop in sea level during Carboniferous Period
Unconformity
surface of non-deposition or erosion
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
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
More C12 implies
warmer temperatures [more organic carbon locked up in geological reservoirs being released]
- releasing light carbon
End of Permian meant that
oxygen was very heavy and light at the beginning of the Triassic as a result of glacial melting
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
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]
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
What animal survived the end of permian mass extinction?
Lystrosaurus since they lived in burrows
The Early Mesozoic era was a
reboot of life
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
There was all grazers at the end of
Permian
Deposit Feeders v. Suspension Feeders
Deposit Feeders = burrowing through sediment
Suspension Feeders = more on the surface
Hexacorals
dominant reef builders
- evolved from soft bodied anemones in Triassic
- resembled rugose corals
All modern corals started in the
Triassic
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
Phytoplankton
- dinoflagellates, calcareous nannofossils
- ammonoids = rapid evolution + great index fossils
Nannofossils
coccolithophores
Belemnoids
squid-like relatives of ammonoids
- straight with consideration inside and soft bodied over them
Osyters started in the
Triassic
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
Marine reptiles
placodonts
- blunt toothed shell crushers with broad armored bodies
First Marine Reptiles [early Triassic]
Nothosaurs