Karteikarten
Proterozoic cont.. (19)
Karten in diesem Stapel (20)
- 1What are the most common fossils in the Proterozoic rock record?-Stromatolites
-Procaryote Microfossils
-Eucaryote fossils - 2☼What are stromatolites?☼Large, layered structures built up by mats of bacteria.
- 3What organisms are responsible for stromatolites?Cyanobacteria
- 4Do procaryote fossils occur in Proterozoic rocks?Yes - spheres and filaments of bacteria
- 5Do eucaryote fossils occur in Proterozoic rocks?Yes
- 6The first evidence for eucaryotes in the rock record is what?Eucaryote chemofossils (2.7 Ga)
Eucaryote body fossils - Grypania (2.11 Ga) - 7What trends are seen in the eucaryote body fossil record during the Proterozoic?Increase in cell size and diversity form 1.6 to 1.0 Ga
- 8What are acritarchs?~rounded, organic-walled planktonic microfossils
-Spinose & non-spinose forms
-Problematic, but most are kingdom protista - 9What are VSMs?-Vase-shaped microfossils
-Organic walls
=testate amobae (kingdom protista) - 10☼How did eucaryotes originate?☼-Through the procaryote symbiosis Hypothesis
-Several types of procaryote cells lived together for mutual benefits to form the 1st eucaryote cell.
-1st proposed by Lynn Margulis
(mitochrondria > purple bacteria) - 11Does the Proterozoic fossil record include only procaryotes (bacteria) and small eucaryote cells?No - contains some macrofossils
- 12What are metazoans?-Complex, multicellular animals
-All are consumers
- 1st ones had no shell, no teeth, and no skeletons - 13When do metazoans first appear in the fossil record?~650 Ma
- 14Did metazoans have hard parts?No - they were soft-bodied
- 15he 1st metazoans left behind what kinds of fossils?Traces + a few body fossils & chemofossils
- 16The 1st metazoans were likely what kinds of animals?a) Sponges - phlum porifera
b) Cnidarians - sea anemane/jellyfish relatives
c) Worms
d) possible Arthropods - 17The Doushantuo Formation of China is famous for having what kinds of fossils preserved?3-D, Phosphatized Embryos
- 18What are bilaterians? When did they first appear?-Bilaterally-symmetrical animals
-555 Ma - 19What is the significance of Cloudina fossils?-1st ever organism with hard parts
(Stacked icecream cone shaped) - 20When does Cloudina appear in the rock record?In the near-latest precambrian ~550 Ma