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MAY BE THE EARTH’S

OLDEST FOSSILS ARE

3.5 BILLION YEARS OLD

THE CONCLUSION, substantially earlier and it confirms that
MADE BY it was not difficult for primitive life to
RESEARCHERS AT form and to evolve into more advanced
microorganisms.”
THE UNIVERSITY
OF WISCONSIN- Schopf added that the research shows,
MADISON AND UCLA, if the conditions are right, “It looks
SUGGESTS THAT like life in the universe should be
EXTRATERRESTRIAL widespread.”
The new study looked at fossilized
LIFE MIGHT DEVELOP microorganisms that were found in
MORE EASILY THAN Western Australia in 1992. Schopf has
THOUGHT. been studying these fossils since their
discovery and has published several
papers about them, determining their
How common is life in the universe? age at 3.465 billion years. Geoscience professor John Valley, left, and research scientist Kouki Kitajima
This is a hard question for scientists to collaborate in the Wisconsin Secondary Ion Mass Spectrometer Lab in Weeks Hall
answer definitively, since we only have In previous research, Schopf and his
one data point: Earth. colleagues established that the origin
of the fossils was biological, which was types of isotopes. and just 250 million years after Earth
But a new study published in the somewhat controversial. Some critics The work was painstaking, as the fossils formed.
Proceedings of the National Academy argued that the oddly shaped cylindrical are each only about 10 micrometers The team said this new study
of Sciences on some of Earth’s oldest fossils were just odd minerals that only wide, meaning eight of them could fit strengthens the case for life existing
fossils has shown that a diverse group look like biological specimens. along the width of a human hair. elsewhere in the universe because it
of organisms had already evolved on our However, subsequent research in 2002 The team analyzed eleven microfossils would be extremely unlikely that it arose
planet nearly 3.5 billion years ago, much confirmed the fossils’ biological nature. and were able to separate the carbon quickly on Earth but did not develop
earlier in Earth’s history than thought. Research published in the journal Nature from each fossil into its constituent anywhere else.
found that the remains of iron-eating isotopes and measure their ratios.
The researchers say the new findings bacteria dated back to between 3.8 “This is something we all would like to
mean it might be easy for life to develop billion and 4.3 billion years ago. The results indicated they were find out,” Valley said.
and evolve, which would increase “characteristic of biology and metabolic
the likelihood that life is widespread Schopf teamed up with John Valley, function,” Valley said in a statement.
throughout the universe. a geoscience professor from the They found several different types
University of Wisconsin-Madison who of organisms, a primitive but diverse
“By 3.465 billion years ago, life was has been working for 10 years to refine group,” Schopf said. Two of the species
already diverse on Earth; that’s clear,” J. a technique called secondary ion mass appeared to have performed a simple
William Schopf from UCLA, lead author spectroscopy, or SIMS. This device form of photosynthesis, another
of the new study, said in a statement. shoots an ion beam on a surface and, in apparently produced methane gas, and
a vacuum, collects and analyzes ejected two others appear to have consumed
“This tells us life had to have begun secondary ions, searching for specific methane and used it to build their cell
walls.
In short, these fossils represent a
“community” that lived together and
“were a significant component of
Earth’s early biosphere,” the team
wrote, and were comprised of primitive
photosynthesizers, methane producers,
and methane users.

Because several different types of
microbes were shown to be already
present by 3.5 billion years ago, this An example of one of the
means life started much earlier than microfossils discovered in a
that. Earlier studies by Valley have sample of rock recovered from
shown that liquid water oceans existed the Apex Chert. A new study used
on Earth as early as 4.3 billion years sophisticated chemical analysis to
An epoxy mount containing a sliver of a nearly 3.5 billion-year-old rock from the ago, more than 800 million years before confirm the microscopic structures
Apex chert deposit in Western Australia is pictured at the Wisconsin Secondary Ion found in the rock are biological. J.
Mass Spectrometer Lab in Weeks Hall. Jeff Miller the Western Australian fossils studied William Schopf
in this research would have been alive,