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19 Cards in this Set
- Front
- Back
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What is the age of the earth?
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4.6 billions years
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What are Stromatolites?
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Layered mounds of sediment formed by cyanobacteria; cyanobacteria secrete a mucous-like substance to which sediment sticks, and as each layer of cyanobacteria gets buried by sediment, it colonizes the surface of the new sediment, building a mound upward
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What formation found in rocks is indicative of the oxygen revolution?
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banded iron
indicative of significant oxygen production by anaerobic bacteria and availability in oceans for oxidation of iron and silicon |
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What is ediacara fauna?
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unique assemblage of soft-bodied organisms preserved worldwide as fossil impressions in sandstone at the close of Precambrian time.
These fauna represent an important landmark in the evolution of life on earth - they immediately predate the explosion of life-forms at the beginning of the Cambrian |
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What is the Cambrian Explosion?
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Appearance of nearly all phyla by end of period - sponges, cephalopods, snails, trilobites, crinoids, sea cucumbers, inarticulate brachiopods
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What are the Burgess Shales?
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Famous for the exceptional preservation of the soft parts of its fossils (middle Cambrian)
One of the earliest beds containing the imprints of soft parts |
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What are some possible causes of the Cambrian Explosion?
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Environmental - breakup of supercontinent; end of late Precambrian glaciation
Biochemical - accumulation of O2; accumulation of sufficient CaCO3 for shell-building |
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What fauna appeared in the Ordovician?
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rapid spread of molluscs
jawless fish first vertebrates bones and armour plates proliferation of all forms of corals |
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What fauna appeared in the Silurian?
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first vascular land plants
elaboration of sponges dominance of brachiopods development of fishes earliest jawed fishes in late Silurian |
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What fauna appeared in the Devonian?
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earliest forests
all major groups of fish, early sharks some amphibians by end of period abundant brachiopods |
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What appeared during the Carboniferous?
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large trees, warm moist forests and swamps
3/4 of world's coal formed reptiles appeared abundant large amphibians abundant gastropods glossopteris ferns |
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What appeared during the Permian?
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reptiles develop rapidly - abundant
insects and amphibians spread mammal-like reptiles greatest known extinction at end of Permian |
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What was lost during the Permian extinction?
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50% of known families of animals
trilobites and blastoids completely disappeared brachiopods diminished (130 groups to 2) more than 3/4 of marine genera, reptile families, amphibians |
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What appeared during the Triassic?
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proliferation of reptile groups
first dinosaurs flying dinosaurs by end earliest mammal ancestors |
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What appeared during the Jurassic?
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maximum of dinosaurs
earliest birds tall cycads |
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What appeared during the Cretaceous?
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earliest flowering plants
earliest conifers largest pterosaurs |
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What is the K-T extinction?
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large scale mass extinction of animal and plant species, marking the end of the Mesozoic and beginning of Cenozoic (Cretaceous - Tertiary)
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What was lost during the K-T extinction?
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marine - 100% of ammonites, 93% marine reptiles, 83% plankton, 70% sponges, 65% corals
land - 100% non-avian dinosaurs and pterosaurs, 56% reptiles nothing larger than 25 kg survived |
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What is the order of the 5 major extinctions?
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Oldest to newest:
Ordovician Devonian Permian Triassic Cretaceous |
