“There are millions of different species of animals and plants on earth—possibly as many as forty million. But somewhere between five and fifty billion species have existed at one time or another. Thus, only about one in a thousand species is still alive—a truly lousy survival record: 99.9% failure!” ~David Raup Mass Extinction! Presented by: Livia Montone ([email protected])
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“There are millions of different species of animals and plants on earth—possibly as many as forty million. But somewhere between five and fifty billion species have existed at one time or another. Thus, only about one in a thousand species is still alive—a truly lousy survival record: 99.9% failure!”~David Raup
How do you define “Mass Extinction”?• Any substantial increase in the amount of
extinction (ie. lineage termination) suffered by more than one geographically widespread higher taxon during a relatively short interval of geologic time, resulting in at least temporary decline of standing diversity. (from Sepkoski, 1986)
How do you define “Mass Extinction”?• Any substantial increase in the amount of
extinction (ie. lineage termination) suffered by more than one geographically widespread higher taxon during a relatively short interval of geologic time, resulting in at least temporary decline of standing diversity. (from Sepkoski, 1986)
• An extinction of a significant portion of the world’s biota in a geologically insignificant period of time. (from Hallam and Wignall, 2000)
Outline
• Geologic Time Scale
• Background and mass extinctions
• Phases of extinction
• Biological causes of extinction
• Physical causes of extinction
• Geochemical Toolbox
• The Big Five
A side note about time units vs. rock units…
Time Units (ie. periods of time)
• Eon• Era• Period• Epoch • Age
• Rock Units (ie. sequence of rocks)
• Eonothem• Erathem• System• Series• Stage
Phases of Mass Extinction
Biological Causes of Extinction
• Minimum Viable Population and the Problems of small populations– Demographic Stochastity– Genetic Deterioration– Social Dysfunction– Extrinsic Forces
GAMBLER’S RUIN!
GAMBLER’S RUIN Results$10
Trial # # of flips # pos. # neg.
1 158 74 84
2 14 2 12
3 192 91 101
4 24 7 12
5 432 211 221
$5
1 147 71 76
2 23 9 14
3 15 5 10
4 241 118 123
5 45 20 25
GAMBLER’S RUIN Results
$10 Trial 2 $10 Trial 4
$10 Trial 5
GAMBLER’S RUIN Results
$5 Trial 3$5 Trial 2
$5 Trial 4
Survivorship Curve
Proposed Physical Causes of Extinction
Mass Extinctions• Global climate change• Global sea level change• Change is salinity of