Extinction: A large Scale Random Transformation

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Extinction A large Scale Random Transformation
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Co-Evolution Niches

• Any species living in a niche has evolutionary
  relationships with other species some casual,
  some crucial
• Therefore, the extinction of a species will have
  repercussions in the niches of all species which
  have co-evolutionary relationships with the newly
  extinct species

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New Evolutionary Niches Open
The Rats Become the Kings
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Implications

• Evolutionary Clock gets periodically reset
• Life recovers (relatively rapidly) to fill new
  ecological niches ? this empowers species
  diversification
• This means that survival of the fittest doesnt
  work on long timescales ? random catastrophe is
  MORE important
• Strangely, nature confirms that a new world will
  arrive out of the ashes of the old one

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Potential Triggers

• Asteroid Impacts sudden

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Gradual Large Basalt Outflows

• Large CO2 changes which can affect atmospheric
  and ocean chemistry (slow)

an oh shit event
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At least a dozen significant events
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Five Agreed Upon Major Events
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Many events of varying extinction percentage
amplitude
The struggle
Relatively stable
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65 Million years ago

• KT extinction (dead dinosaurs) triggered by
  asteroid impact.
• A 10km diameter asteroid, leaving a crater 200
  Km in diameter

• Impact caused acid rain, ash (from global forest
  fire) that directly blocked out the sun for
  months, severe global cooling (nuclear winter).

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Large Animals Perished

• Before the end of the Cretaceous, flight evolved
  independently three times
• Insects, flying reptiles, birds (avian dinosaurs)
• By the end of the Cretaceous 65 Mya, most
  dinosaurs along with other large marine reptiles
  and various invertebrates died out
• No land vertebrate larger than a large dog
  survived the KT boundary event

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Toba catastrophe 74000 BC The most recent
supervolcano.
Proximity to equator ability to affect all
latitudes of globe, and for tephra circulation to
be affected by trade winds.
Here is Toba, at 2 degrees north of the equator.
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(Probable) Climatic Effects of Toba
Ice core samples from Antarctica and Greenland
Global circulation of ash from Mount Pinatubo,
1991 atmospheric presence of Toba Tuff was
undoubtedly far more extensive.

• 6-year period of sulphur deposition far above
  normal levels
• sulphur and volcanic ash remained in atmosphere,
  blocking out substantial amounts of sunlight.
  Nuclear Winter for 610 years.

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Effect on Humankind (controversial theory)
Out of Africa Migration time line would place
humans in proximity to the worst effects of Toba.
Record shows that, 70,000 years ago, Homo
Sapiens were the only surviving humanoid.
-Homo sapiens is remarkable for lack of genetic
diversity in comparison to other primates ?
Something Happened
Bottleneck scenario Colossal
near-species-extinction level event leaves small
of individuals Remaining (est 5-10,000
breeding pairs of Homo Sapiens), who become the
genetic root of the species.
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Recent Extinctions

• Auroch (1627) Dodo (1662)
• Stellars Sea Cow (1768)
• Mascarene Island Giant Tortoise (1795)
• South African Cape Lion (1858)
• Quagga (1883)
• Passenger Pigeon (1914)
• Tasmanian Wolf (1936)
• Bali Tiger (1937) / Javan Tiger (1976)
• Kauai Oo (1987)
• Golden Toad (1989)
• Baiji White Dolphin (2006)
• Chinese Paddlefish (2007)
• Christmas Island Pipistrelle (2009)
• Vietnamese Rhinoceros (2010)
• Pinta Island Tortoise (2012)

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By 2050 - 2100?

• 50 of all species on the planet will be either
  endangered or extinct
• Habitat destruction
• Global Warming
• 25 mammalian species
• 15 bird species
• In The Future of Life (2002), E.O. Wilson of
  Harvard calculated that, if the current rate of
  human disruption of the biosphere continues,
  one-half of Earth's higher lifeforms will be
  extinct by 2100 we have operationally become GOD