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Enter Stanley Miller. In 1952 this 32-year-old chemist decided to test the prevailing
theory and see if life could be produced from Urey’s mix of chemical compounds. Miller
carefully sterilized long sections of glass tubing, flasks, and beakers. He built what
looked like a sprawling erector set of support poles in his lab and clamped flasks, beakers,
and connecting glass tubes to this structure. He filled one large beaker with sterilized water. He filled other flasks with the three gasses Urey had identified as part of Earth’s early
atmosphere—methane, ammonia, and hydrogen sulfide.
Miller slowly boiled the beaker of water so that water vapor would rise into his enclosed “atmosphere” of a labyrinth of glass tubes and beakers. There it mixed with the three
other gasses in swirling clouds in a beaker labeled “atmosphere.”
Miller realized he needed an energy source to start his life-creating chemical reaction.
Since other scientists had determined that the early atmosphere contained almost continual
rolling thunder and lightning storms, Miller decided to create artificial lightning in his atmosphere. He hooked a battery to two electrodes and zapped lightning bolts across the “atmosphere” chamber. A glass pipe led from this chamber and past a cooling coil. Here water
vapor recondensed and dripped into a collection beaker that was connected to the original
water beaker.
After one week of continual operation of his closed-cycle atmosphere, Miller analyzed
the residue of compounds that had settled in the collection beaker of his system. He found
that 15 percent of the carbon in his system had now formed into organic compounds. Two
percent had formed actual amino acids (the building blocks of proteins and of DNA). In just
one short week, Miller had created the building blocks of organic life! Virtually all scientists were amazed at how easy it was for Miller to create amino acids—the building blocks
of life.
In 1953 the structure of the DNA molecule was finally discovered. Its structure fit well
with how Miller’s amino acid molecules would most likely combine to create longer chains
of life. This was another bit of evidence to support the idea that Stanley Miller had discovered of how life on Earth began.
Fun Facts: There are 20 types of amino acids. Eight are “essential amino
acids” that the human body cannot make and must therefore obtain from
food.
More to Explore
Davies, Paul. Fifth Miracle: The Search for the Origin and Meaning of Life. New
York: Simon & Schuster, 2000.
Gallant, Roy. The Origins of Life. New York: Benchmark Books, 2000.
Jenkins, Steve. Life on Earth: the Story of Evolution. New York: Houghton Mifflin,
2002.
MacDougall, J. D. Short History of Planet Earth: Mountains, Mammals, Fire, and Ice.
New York: John Wiley & Sons, 1998.
Morgan, Jennifer. From Lava to Life: The Universe Tells Our Earth Story. Nevada
City, CA: Dawn Publications, 2003.