11. Great Dying Flashcards
What percentage of marine species died out in the Permian mass extinction?
90-95%
When did the Permian extinction occur?
End of the permian
What was diversity of terrestrial life like before the Permian extinction?
High diversity, esp of insects, amphibians, reptiles and mammal-like reptiles
What was diversity of land plants like before the Permian extinction?
Very diverse, but arranged in characteristic belts based on lattitude
What were the 6 main types of marine life in the late permian?
Attached, burrowing, hiding, crawling, swimming, predating
What marine life type was characteristic of the permian?
Shelly fauna
What is the Triassic fossil record like?
Very poor
What types of species are seen in the Triassic fossil record?
Very limited number of species, all very abundant and environmentally tolerant
Why are few specialist species seen in the Triassic fossil record?
Specialists were wiped out by the Permian Extinction
What factor has overwhelming support as the cause of the Permian extinction?
Global warming
What temp difference is seen prior to the Permian extinction?
Rise of approx 6° at the equator, but higher at higher latitudes
What main systems sustains our ocean circulation?
Pole-to-equator temperature gradient
How did uneven temperature rise affect the oceans in the Permian?
Reduce temp gradient and reduce or stop ocean circulation
How would a reduction in ocean circulation lead to mass extinction?
- Dead organisms settle rather than being carried away
- Oxygen used up for decay
- Leads to cold, anoxic water which is hard for organisms to survive
- Pos feedback loop where more organisms dying amplifies the effects
What are some possibilities for the cause of the warming pre Permian extinction?
- Oxidation of uplifted coals at the South pole releasing CO2 into atmosphere
- Siberian traps releasing CO2 and greenhouse gases
- Methane hydrates
What data makes the Siberian traps an unlikely main cause for the heating?
Lots of Carbon-13 at the surface, too light to be explained by Siberian Traps
Describe the suggested warming cycle of the permian.
1 Siberian traps cause CO2 warming
2 Melted Methane hydrates cause negative C13 excursions
3 Methane Warming
Why is warming questionable as the only reason the Permian extinction was so severe?
Because similar heating has taken place in other periods without such dire consequences, 6° at the equator is not that severe
Why did the heating of the Permian have such a severe affect?
Permian geography? Land masses and ocean environments were connected - stuff in one affects them all
How does our current level of global warming compare to that of the Permian?
We have experienced a 3° rise in temp in about 100 years, while the Permian was 6° in 100,000-1 million years.
Half the rise but in <0.1% of the time
Why might the Permian extinction have been far less severe if the world then looked like now?
Ocean anoxia in one sea might not affect anoxia specialists in unconnected seas
Why is it concerning for us now that global mixing had such a large impact on the Permian extinction’s severity?
We (humans) are increasing global mixing at rates higher than any other in history
How do humans accelerate global mixing?
Transport of cargo, direct movement of species, forcing species from natural habitats
What groups of life are the most common biological invaders?
Plants, then fish, then birds
How do biological invaders affect disease?
Invaders often propagate diseases that are fatal to native species
Which environmental processes do invaders commonly impact?
Productivity, decomposition, hydrology, geomorphology, nutrient cycle etc
Which invaders affect frequency of fires ?(and thus largely impact landscape and ecosystems)
Plants and grasses
