Impacts 2

Question 1

What defines a mass extinction?

Answer 1

1. at least 30% of species extinct
2. broad range of ecosystems affected
3. extinction happens quickly in geological timescales (1 million yrs)

Question 2

What is a species

Answer 2

A group of organisms capable of interbreeding

Question 3

Ordovician Extinction

Answer 3

450 Ma
60-70%

• Glaciation of Gondwana
• Configuration of plates to South Pole
• moss absorbing CO2

Question 4

Devonian Extinction

Answer 4

360 Ma
75%

• climate and sea lvl change
• low oxygen lvls
• volcanic activity? Supernova?

Question 5

Permian Extinction

Answer 5

250 Ma
Great Dying
95%

• volcanism (siberian traps)
• massive climate change (one of biggest contributors)
• Pangea supercontinent
• impact?
• anoxia, sea level fall

Question 6

Triassic Extinction

Answer 6

200 Ma
70-80%

• volcanoes (eruptions had SO2)
  -> acid rain
• climate change
• impact? three craters in a row…

-> dinos rlly took over afterwards

Question 7

Cretaceous Extinction

Answer 7

66 Ma
75%

• Asteroids
• volcanism
• sea level fall

Question 8

What are the causes of mass extinctions

Answer 8

Usually involves multiple!

• Biological (background extinctions)
• Plate tectonics (change climate and sea lvl)
• volcanism (causes ->
• climate change
• extraterrestrial events (asteroid, gamma radiation burst, galactic cycles)

Question 9

What are some of the supercontinents

Answer 9

Pangea
Rodina
Nuna

Question 10

What happens to biodiversity when supercontinents form

Answer 10

decreases
- competition, virus, easy to wipe out

Question 11

Explain the difference btwn ice and green house

Answer 11

ice house has ice present at the poles

Question 12

Describe Pangea

Answer 12

in the permian world

• huge and dry, caused carboniferous rainforest collapse
• vast deserts, arid wastelands
• fewer niches and continental shelves

Question 13

what is ocean stagnation
and which extinction is this associated with?

Answer 13

associated with end permian extinction

• polar waters unable to sink
• anoxia: lack of oxygen cuz low circulation

Question 14

What causes sea level to fall? What extinction is this associated with?

Answer 14

associated with end permian extinction
there were less mid ocean ridges

Question 15

Siberian traps

Answer 15

erupted during end permian extinction

• 2-3million km basalt lava = CO2 and methane
• continued erupting for 2 million years
• set fire to the largest coal, oil, gas deposits on Earth

-> greenhouse gases = climate change

Question 16

What does clathrate contain? What extinction was this associated with?

Answer 16

in deep ocean, contains methane

-> methane = stronger greenhouse gas than CO2
-> melting of this happened in end Permian extinction

Question 17

What caused a large decline in ammonites and a major extinction of plants

Answer 17

end triassic extinction

Question 18

Index fossils called _____ from Cambrian went extinct during ____

Answer 18

Conodonts, end triassic extinction

Question 19

Aftermath of permian extinction led to the rise of ____

Answer 19

dinosaurs