Exam III Flashcards
What are spontaneous generation and panspermia?
spontaneous generation: belief that life spontaneously arose from rotting meat
panspermia: life seeded by chemical compounds or spores from meteorites
What are the necessary traits, composition, conditions, and components for life?
traits: open systems, cell membranes, reproduce, complex dna info storers, changes and mutations
composition: carbon, hydrogen, nitrogen, sulfur, and phosphorous
conditions: deep ocean hydrothermal events
components: proteins, nucleic acids, organic phosphorous compounds, a container lol (#tupperwareformyskinsack)
What did the Urey-Miller experiments reveal about the origin of life?
amino acids need UV radiation or lightning or charged surfaces to zap acids together into chains
Why are hydrothermal vents thought to be where life began?
warm, deep, anaerobic (no oxygen)
What is a prokaryote?
simple single that’s a proud asexual
Why are earliest fossils (prokaryote fossils) rarely found?
soft bodied, microscopic
What are stromatolites?
mat like colonies of photosynthetic cyanobacteria
How do eukaryotes differ from prokaryotes?
eukaryotes are complex single cells that sexually reproduce, have organelles and variable evolution
What were the Ediacarans?
large metazoan organisms (multicellular, eukaryotic) that came after snow ball earth (end of proterozoic eon), related to increase in oxygen and warm marine areas
similar to jellyfish, corals, and worms
What is the importance of small shelly fauna?
the shells evolved to protect soft tissue, increasing probability of preservation
Know the 5 steps to complex life.
- prokaryotic bacteria
- eukaryotic cells
- multicellular soft bodied organisms
- tiny, shelled organisms
- large shelly animals
When did the Paleozoic Era begin?
542 Ma
What is the order of Paleozoic periods?
Cambrian, Ordovician, Silurian, Devonian, Carboniferous (Miss, Penn), Permian
What are cratonic sequences and how do they form?
definition: deposition sequences bounded by unconformities
how they form: transgressions and regressions of epicontinental seas
top: erosion
regressive sediments
maximum sea level
bottom: transgressive sediments
What are epicontinental seas?
Shallow seas that flood broad, low-lying areas of continents
Why are quartz sandstones important resources?
used to make glass
used for hydraulic fracturing by propping opening fractures
What was the location and climate of Laurentia?
equatorial, tropical
What is a clastic wedge and how does one form?
an expansive wedge shaped deposit of gravels, sands, and muds eroded and extending from the mountain front
form during orogeny bc of continental collision
Know about the Cambrian Explosion represented by Burgess Shale. How were the fossils preserved?
as mostly soft parts
60,000 specimens collected
What formed reefs in the early Paleozoic?
stromatolites and archaeocyathids “ancient cups”
What are the other dominant organisms of the early Paleozoic?
trilobites: euryptids
brachiopods
graptolites: planktonic bois
Why did so much salt accumulate in the Michigan Basin?
it was a hot shallow lagoon basin with a narrow neck restricting ocean flow
Why do black shales form?
bc high organic content gets buried with low oxygen in warm, high water
Why don’t black shales form in the ocean today?
the ocean today has mixing currents
What resource is associated with black shales?
oil/natural gas
How did reefs evolve in the middle paleozoic?
grew immensely in epicontinental seas
honeycombs and sunbursts (tabulate and rugose), petroleum storer
How are corals used to interpret Earth’s past?
paleo-equator locator
What key invertebrates were common in mid-Paleozoic oceans?
blastoid and crinoids
euryptids
cephalopods
What are some key differences between the 5 groups of fish?
ostracoderms: bony skinned, jawless
ancanthodians: spiny fish with jaws and teeth
placoderms: plate skinned fishes with jaws
chrondrichthytes: sharkes with cartilage skeletons
osteichthes: lobe finned or ray finned
Bony fishes gave rise to what, which gave rise to what?
Bony fishes gave rise to lobe-finned fish, which gave rise to amphibians.
What is a tetrapod?
4 legged vertebrates
evolved from lobefin fish in late Devonian
What is the fossil evidence of the first plants?
spores, Ordovician 450 Ma (plants probably derived from stonewarts pond weed)
What is the advantage of seed-bearing plants vs. spore-bearing plants?
seeds survive harsher, drier conditions and can be dispersed further
Which orogeny was responsible for the modern Appalachian Mts.? What caused it?
Alleghenian Orogeny, caused by collision of Gondwana and Laurentia
What are cyclothems and what caused them?
cyclothems: cyclic repetition of marine and coal bearing, non marine strata
shows advance/retreat of seas/glaciers
How does coal form and why is it abundant?
- plants buried
- bacteria turned to muck (peat)
- compressed by rock
- carbon compressed
abundant bc rising seas buried swamps
What are the primary coal-forming periods?
Miss, Penn (latter)
How did South Dakota’s Wind Cave form?
jointed Mississippian Pahasapa Limestone
How does Pangea differ from Rodinia (compare them on a map)?
Pangea: larger, fewer continental shelves and epicontinental seas, south pole glaciation, mid latitude deserts, C SHAPED
rodinia: idk clumpy
What was the climate of Pangea like?
colder on south pole, hot dry in the middle
Given an assemblage of fossils (including index fossils), what part of the Paleozoic are they from?
early: shells, anomalocaris (large shrimp pinching pitch), stromatolites
middle: euryptids, cephalopods, blastoids, crinoids, tabulate and rugose, idk fish lol
late: brachiopods, reptiles and amphibians and shit
Amphibians evolved into reptiles: what trait allowed reptiles to conquer more environments on land compared to amphibians?
reptiles could reproduce without returning to water, amniote egg
What is the difference between synapsid and therapsid reptiles?
synapsids: based on temporal openings in the skill, cold blooded
therapsid: reptiles with mammalian traits, warm blooded and hair and stuff
Plants: What types of plants made up coal-forming swamps?
lycopsid trees
Why did insects get so large in the Pennsylvanian?
hella oxygen
Which Paleozoic extinction event was the worst, and what caused it?
the late Permian one (Great Dying)
caused by climate change related to formation of Pangea (frigid polar regions, no more shallow seas, Siberian Traps flood basalts)
When did the Mesozoic begin and end? What is the order of Mesozoic periods?
251 Ma - 65 Ma
Triassic, Jurassic, Cretaceous
What is the result of Pangea breaking apart? What ocean forms as a result of the break up?
North America and Gondwana split (rifting and extension creates mountains and basins)
North Atlantic ocean forms
Gulf of Mexico evaporates forming salt. Why is this important for the oil industry?
salt domes form and trap oil
How did orogenies change western North America?
caused compression and deformation (hella orogenies)
accretion of exotic terrane
Which orogeny led to the modern Rocky Mts.?
Laramide orogeny
What is the evidence for the environments of the Mesozoic?
red rock country (triassic was hella dry)
(morrison formation indicated movement into jurassic when things finally got wet again)
western interior seaway for movement into cretaceous as everything started melting
What is the Western Interior Seaway?
epicontinental sea that spanned gulf of mexico to the Arctic (100 m highter than today)
jurassic-cretaceous
Why was sea level so high in the mesozoic?
increased rate of seafloor spreading
What rock types are associated with the seaway (South Dakota)
sandstone, black shale, carbonate limestone (including chalk!)
What are coccoliths and what type of rock do they form?
microscopic plankton that form chalk
What is the significance of the Deccan Traps?
greatest volume of continental basalt on earth (.5 million km3 of lava) #indiavsthehotspot
What was Cretaceous climate like and why?
higher temps, no glaciers
high sea floor spreading rates, low albedo, water expands at high temps
