The Origins of Life: Other Ideas

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Transcript The Origins of Life: Other Ideas

THE ORIGINS OF LIFE
Other ideas
Panspermia (aka cosmozoan)
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Life came from somewhere else and
seeded Earth
The support for this depends up on
evidence that life exists elsewhere than on
Earth
and the evidence that it may travel through
open space
© 2008 Paul Billiet ODWS
Exobiology
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Mars Viking Probe (1976)
revealed conflicting evidence
of life
Mariner Probe (1997) did not
reveal any more evidence
Tantalising evidence of water
on Mars
Venus has inhospitable
conditions (surface
temperatures of over
+400°C)
Viking
© 2008 Paul Billiet ODWS
Water and geothermal energy is the key
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The moons of Jupiter
and Saturn could
provide the right
conditions
Europa appears to be
covered in ice
Io shows volcanic
activity
Titan has organic
molecules present
© 2008 Paul Billiet ODWS
Europa
Life can survive in outer space
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Bacteria, inadvertently left
on a lunar probe
Collected and cultured
successfully after nearly 2
years in space
Meteorites of Martian origin
show that its early
atmosphere would have
been similar to Earth’s early
atmosphere
They also showed
(debatable) evidence of
bacteria transported by
meteorites
© 2008 Paul Billiet ODWS
Surveyor 3
Alien Earth
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Life has been shown to
exist on Earth in very
inhospitable conditions
that could exist on
other planets
Antarctic dry valleys
Mid-ocean ridges
earth science australia
© 2008 Paul Billiet ODWS
Antarctica
Earliest evidence of life
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The origin of the Earth itself is estimated as
4.5 billion years
Earliest evidence of life processes 3.9 billion
years ago
This leaves little time for biochemical
evolution
© 2008 Paul Billiet ODWS
The eternal question
If it can be shown that life came from an
extraterrestrial source the question still
remains…
How did life evolve in the first place?
© 2008 Paul Billiet ODWS
Special creation
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The non-scientific hypothesis
Some supernatural being brought life into
existence from nothing
Literal interpretation of religious documents
9:00am on 23rd October 4004BC
© 2008 Paul Billiet ODWS
Intelligent Design
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Creationists have tried to imply that life is so
complex and specialised that it could only
have come about through the design of a
supernatural creator
Once created it remained the same through
time
They accept microevolution
They reject the fact that new species can
come about by the natural selection of
chance mutations
© 2008 Paul Billiet ODWS
Special creation is based on belief
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As these ideas are developed from a
theological view point they are impossible to
test
Creationists focus on trying to disprove the
theory of evolution rather than by testing their
own hypothesis
A scientific fact is an observation that has
been repeatedly confirmed and for practical
purposes is accepted as true
Special creation fails this criterion
© 2008 Paul Billiet ODWS