Extinction and Evolution: A Song of Ice and Fire Flashcards
(60 cards)
1
Q
What is the relationship between diversity and time?
A
Diversity is increasing over time
2
Q
Describe the Signor-Lipps effect
A
- you are unlikely to find the last individual of a species
- mass extinctions appear to begin sooner in the fossil record than was actually the case
- sampling bias/artefact
3
Q
Describe major glaciations
A
Ice lock up causes a drop in sea level (e.g. end-Ordovician by 100m)
4
Q
What does the locking up of CaCO3 create?
A
- calcium mineralisation
- carbon store
5
Q
What happens at the end-Permian?
A
A rich set of diverse body forms get obliterated due to heat
6
Q
What do the end-Permian cadavers create?
A
- organic-rich shales
- petroleum deposits
7
Q
Stromatolites
A
Layers of microbial mats with intermediate silting
8
Q
Reef building organisms can be used as
A
Indicators of marine diversity
9
Q
Reef gaps
A
- mark most mass extinctions
- reefs are either completely absent or much reduced
- due to temperature and CO2 changes (ocean acidification)
10
Q
Problems associated with sampling in deep time?
A
- Signor-Lipps Effect
11
Q
Mass extinctions
A
Key episodes of evolutionary history
12
Q
When did vertebrates arise?
A
Cambrian (Palaeozoic)
13
Q
When did jawed vertebrates arise?
A
Silurian (Palaeozoic)
14
Q
When did sharks arise?
A
Devonian (Palaeozoic)
15
Q
When did tetrapods arise?
A
Devonian (Palaeozoic)
16
Q
When did amniotes arise?
A
Devonian (Palaeozoic)
17
Q
When did therapsids arise?
A
Permian (Palaeozoic)
18
Q
When did dinosaurs arise?
A
Triassic (Mesozoic)
19
Q
When did mammals arise?
A
Triassic (Mesozoic)
20
Q
When did placental mammals arise?
A
Jurassic (Mesozoic)
21
Q
When did birds arise?
A
Jurassic (Mesozoic)
22
Q
When did snakes arise?
A
Cretaceous (Mesozoic)
23
Q
When did primâtes arise?
A
Paléogène (Cenozoic)
24
Q
When did hominids arise?
A
Neogene (Cenozoic)
25
What is necessary for the radiation of new or minor taxa?
Wiping out incumbent taxa
26
Describe the radiation of mammals
- originate in the Triassic
- rise to dominance after extinction of non-avian dinosaurs
27
Describe the end-Ordovician event
- oceanic cooling and anoxia
- prominence of globally-distributed transitional benthic faunas (disaster taxa)
- stages of succession
28
Give an example of a Benthic disaster taxa
Hirnantia
29
What caused elevated atmospheric CO2 levels to drop in the late Ordovician?
- weathering of lava flows
- rise of earliest land plants
30
What does dropping of CO2 in atmosphere cause?
- carbonic acid rain
- silicate dissolution forms bicarbonate ions
- run into ocean and locked up as CaCO2 in skeletons of marine calcifying organisms
31
Describe the end-Ordovician mass extinction
- ~100m sea level drop
- loss of first metazoans reefs
- loss of graptolites and other planktonic forms
- post-glacial temperature rise create rising sea levels and widespread marine anoxia
32
Describe the ramifications of the end-Permian mass extinctions
- ocean temp rises 5-15 degrees across latitudes
- ocean acidification, anoxia, reef loss and basically everything marine
- 1 death of >90% of species due to heat
- recovery took 8-9My
33
Describe the end-Permian event
- outpouring of >4millkm^3 of lava from Siberian traps over 2My
- eruption through organic-rich shales and petroleum deposits venting > 100,000Gt CO2 to the atmosphere through km-scale blowouts
34
Siberian traps
Large igneous province
35
When did the crucial end-Permian organic-rich shales and petroleum deposits arise?
Cambrian and Proterozoic
36
Describe the immediate ramifications of the end-Permian
simple marine ecosystems not seen since the Proterozoic (i.e. stromatolite communities)
37
Describe the Permian-Triassic disaster t’axa
- stromatolites
- bivalve Claraia
- herbivore Lystrosaurus
38
Describe Lystrosaurus
- herbivore
- burrowing habit
39
Lilliput Effect
Tendency of disaster taxa to be small
40
Describe the recovery after the Permian-Triassic event
- tepid ocean
- hot arid conditions
- slow recovery
41
Describe the end-Permian effect on plants
- no evidence for a familial-level mass extinction at end-Permian
- several My for planet recovery of lost gymnosperm forest ecosystem
42
The organisms that survived the end-Permian extinction were those that would
Go on to found modern ecosystems
43
Describe the end-Cretaceous mass extinction
- killed non-avian dinosaurs (gigantosaurs, pterosaurs, ammonites and various marine reptiles)
- unusually profound and immediate effect on plant life
44
Describe the end-Cretaceous event
- extra-terrestrial impact on Yucatan peninsula of Mexico
- tidal waves
- >180km crater ring
- dust cloud caused several months of near darkness
- outpouring of ~1millionkm^3 from Deccan Traps
- burned through immense oil fields in Gulf of Mexico, releasing CO2
45
How is the end-Cretaceous Chixulub crater traced
- geomagnetic anomalies
- ring-like Cenotes distribution
46
Cenotes
Limestone caverns
47
end-Cretaceous disaster taxa
- synchronous fern spike
- adaptation to dark
48
How was the end-Cretaceous impact defined?
- fossil deposit laid down by seismically-induced tidal wave in Montana
- sturgeon and paddlefish
- tiny glass spherules in gills drawn in by breathing as ejecta hit the site (within 30mins)
- within 45mins of impact
49
Other end-Cretaceous impact effects
tiny glass spherules (molten sand grains) from impact ejection are seen where they fell, with own impact craters
50
Seiche
Seismically-induced tidal wave
51
Deccan Traps
Large igneous province
52
Describe the after effects of the Deccan Trap outpouring
- 0.5My of warming in late-Cretaceous
- 0.8 degrees cooling in last 50,000y
-
53
Megafauna
Gigantic animals
54
Cenozoic disaster fauna
Small birds and mammals
55
Describe the general characterisation of the last 66my of earth’s history
- progressive cooling
- falling CO2
- weathering of large igneous provinces
- changes associated with industrial Revolution
56
How is deep time studied
In 10my bins
57
Describe the relationship between R and ΔT
Moderate to strong correlation
58
R
Extinction rate
59
ΔT
Magnitude of change in temperature
60
What is the ΔT of the big five mass extinction events (IPCC, 2021)
>5.2
