Extinction Events & Survival of Humankind
An extinction event (also known
as: mass
extinction or extinction-level event) is a sharp
decrease in the number of species
in a relatively short period of time. Over 99%
of species that ever lived on the planet Earth are
now extinct. In the past 540 million years there have been five
major extinction events
where over 50% of animal species alive died.
1.
Ordovician-Silurian
extinction,
439 million years ago,
caused by a drop in sea levels as glaciers
formed: 25% of marine families and 60% of
marine genera.
2. Late Devonian
extinction, 364
million years ago, cause unknown: 22% percent
of marine families
& 57% of marine genera.
3.
Permian-Triassic extinction,
251
million years ago, likely an asteroid impact or
flood volcanism
& loss of O2 in the seas, killed 95% of
all species.
4.
End Triassic extinction,
199-214
million years ago, caused by massive floods of
lava erupting from
the central Atlantic magmatic province
removing 22% of marine families, 52% of marine
genera. Vertebrate deaths are unclear.
5.
Cretaceous-Tertiary
extinction,
about
65 million years ago, likely caused by asteroid
impact
creating the Chicxulub
crater of Yucatan Peninsula & Gulf of Mexico. The
extinction killed 16%
of marine families, 47% of marine genera
& 18% of land vertebrate families, & the
dinosaurs.
A more recent event that hit in the Siberian
wilderness...
1908 Tunguska Event... a meteor impact that flattened 770
sq.mi.
identified as a
near
Earth Object impact*
that could be a sterilizing event eliminating all life?
Some plans
that may insure the Continuity
of Human Species in an
apocalyptic event:
2. Moon Vault
