Modern stromatolites in Shark Bay, Western Australia

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Chapter 6 The Origin and Evolution of Life on
Earth
Modern stromatolites in Shark Bay, Western
Australia
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Modern stromatolites in Shark Bay, Western
Australia
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500 million year old stromatolite fossils at
Lester Park in Saratoga, NY
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Microfossil (?) in rocks with age of 3.5 billion
years
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Akilia Island, West Greenland rocks 4 billion
years old
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3.9 billion year old (3.9 Ga) banded iron
formation (BIF) on Akilia Island in Western
Greenland. The fractionated 56Fe isotopic value
suggests the presence of biology on the Earth at
3.9 Ga. ?56Fe describes the 56Fe/54Fe isotopic
ratio
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Prof. Stanley Miller inspecting his experiment to
simulate an early Earth atmosphere with lightning
as a possible source of prebiotic molecules
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Image showing short strands of RNA (red)
contained within a lipid pre-cell (green circle),
both of which formed with the aid of catalysis by
clay minerals beneath them.
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Steps that may have led to life on Earth
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ALH84001 meteorite was found in the Antarctic and
is known to have come from Mars
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Pseudo-fossil in Martian meteorite, ALH84001
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Ejection Ages
0.73 ? 0.15 Ma 1.16 ? 0.06 Ma 2.8 ? 0.3 Ma
4.1 ? 0.4 Ma 11.0 ? 0.7 Ma 14.7 ? 0.9 Ma 19.8 ?
2.3 Ma
Christen et al. (2005) Mars ejection times and
neutron capture effects of the nakhlites
Y000593 and Y000749, the olivine-phyric
shergottite Y980459, and the lherzolite NWA1950.
Antarct. Meteorite Res., 18, p. 117-132.
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Ediacaran sea floor at 550 million years ago
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Cretaceous-Tertiary boundary layer (65 million
years old)
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50 ka Meteor Crater in Arizona, USA
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Impact of Shoemaker-Levy 9 onto the planet
Jupiter in 1994
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Primate Phylogeny
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Figure modified after Gagneau et al. (1999)
Proc. Natl. Acad. Sci. USA, 96, 7077-7082.
Ages from Kumar and Hedges (1998) Nature, 392,
917-920 Pearson (2006) Nature, 441, 260-261.
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Current estimates describing human evolution
Ardipithecus
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Questions

• Have we earned the self-anointed distinction of
  being Chosen?
• Did we deserve to win? Did they deserve to die?
• Are the selection processes in evolution based
  on merit?
• How much did dumb luck contribute to our being
  here today?
• Did we, the Winners, triumph over the now
  extinct Monsters because they were obviously
  inferior?
• If so, what criteria distinguished winners from
  losers in the past?
• What criteria will distinguish winners from
  losers in the future?
• Do those criteria have a Divine source?
• Or, are those criteria displayed every day on
  the Serengeti Plain?
• What do our virtual realities reveal about our
  inner selves?
• Will virtual realities contribute to selection
  pressures in the future?

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Are we the product of Divine handiwork?
Are we the descendants of Monsters?
TIME August 15, 2005