Paleozoic Diversity and Mass Extinctions Flashcards
1
Q
What are the causes mass extinction
A
- Radical environmental changes on large scales
2
Q
What happens during mass extinctions
A
- extinction of both marine and terrestrial life
- Tropical organisms tend to be hit hardest
- species in many different phyla are affected, usually phyla survive
3
Q
What did the Ordovician Marine community look like
A
- Major transgression lead to new habits
- which leads to new episode of diversification
4
Q
Define End-Ordovician Mass extinction
A
- More than 100 families of marine invertebrates extinct
5
Q
What are the causes of End-Ordovician mass extinction
A
- Extensive glaciation
- Queenston Clastic Wedge
- Cool water overstressed marine primary producers
6
Q
What did the Silurian and Devonian Marine Communities look like
A
- Brachiopods, gastropods, corals and others rebounded
- Silurian and Devonian were periods of major reef building
7
Q
Define the End-Devonian Mass Extinction
A
- Global collapse of reef communities
- Tropical marine groups severely affected
8
Q
Why was there are collapse of reef at the End-Devonian mass extinction
A
- loss of environment due to continental collisions
- black shale deposits
- Glacial sediments
9
Q
What did the Carboniferous and Permian Marine communities look like
A
- Brachiopods and ammonoids recovered quickly after end-Devonian extinction
- decline of Stromatoporoids and tabulate
- Bony fish expanded
10
Q
Define the end-Permian mass extinction
A
“The great dying”
- 96% of marine invertebrate species
- 65% of land animals
- 70% vertebrates and 33% insects
extended over million of years
11
Q
What were the causes of the End-Permian Mass Extinction
A
- Volcanism in Siberia ( damaged the ozone layer)
which causes climatic effects like:
-global warming - deep sea anoxia and increased seawater CO2
