Final Exam part 3 Flashcards
(119 cards)
where are the oldest stromatolites found
In the fig tree formation
where are the earliest shelly animals known?
the late Neoproterozoic; Namibia
what organisms were present in Ediacharan times, “ediacharan organisms”
- large size organisms
- no hard body parts
- no mineralized parts.
- a lot of diversification within the organisms: including exo and endoskeletons
What is Cloudina?
oldest endo and exoskeleton
where was Cloudina discovered?
upper Proterozoic of Namibia
What is the structure of Cloudina
smooth appearance, tube like worm consisting of calcium carbonate; structure similar to that of Nnidarians, had spicles distributed through the soft tissue.
What was the abandoned assumption about the Precambrian/Cambrian boundary
It was thought that this boundary could be determined by the presence of lack there of exoskeletons, but this was proved wrong because of developments in the fossil record.
what are Trace fossils
fossils of unknown organisms; considered tubular worms
where are trace fossils located in the stratigraphic record
late Proterozoic/ late Vendian
What are the 5 stages of late Proterozoic-early Cambrian
Nemakit-Daldynian Tommotian Atdabarian Botomian Toyonian
What is the index fossil for the Precambrian/Cambrian boundary
Trichophycus pedum- this organism moved on the sediment and below the surface so organisms started digging under the sediment, an evolutionary step in the stratigraphic record and a dividing factor between the two boundaries.
Did Ediacarans live above or below the surface?
They lived above the sediment, organisms started digging under the sediment in the Cambrian and Edicarans are in late Precambrian
Why did organisms start living/digging underground; what is the significance of learning to dig underground
To hide for predators; underground they found new sources of nutrients which allowed for the diversification of trace fossils
what was the significance of trace fossils
the had something to do with the Agronomic revolution
what was the tommotion stage and what is its significance
it is the second stage between the late Proterozoic and early Cambrian, the earliest faunas occur in this stage
what is the latouchella
tommotian fauna; first gastropod
what is the structutre of latouchella
looks like a gastropod; coiled and slightly curved
what is the tommotion fauna
diverse group of organisms that evolved skeletons
what was the relationship between tommotion fauna and stromatolites
tommotion fauna were stromatolites’ first predators and the they led to significant decrease of the stromatolites
what are sclerites
long row of appendiges that played a protective role against small predators
what are the tree main tectonic structures
- Canadian shield- vistas of ancient rocks in Precambrian periods
- North American Platform
- Mobile Belt- oceans where techonomic movements occur
describe the evolution of earth’s climate
alternating succession between greenhouse and icehouse climate start as greenhouse
what is the relationship between the earth’s climate and the rate of evolution
there is higher evolution rate during greenhouse periods
what is the Sauk transgression
sea-level fluctuation which led to new ecological niches