Origin of Life Experiments

Stanley Miller
Stanley Miller and the origin of life experiment

Abiogenesis, the development of life from nonliving material, requires a source for the elements of life and requires a source of energy used in the chemical reactions that would eventually produce organic materials. All organisms are composed mostly of carbon, hydrogen, nitrogen, and oxygen, all of which were present in Earth's early atmosphere as carbon dioxide (CO2), water vapor (H2O), and nitrogen (N2). Energy was also present on early Earth in the form of lightning, volcanism, and ultraviolet radiation.

During the 1950s an organic chemist named Stanley Miller showed that amino acids could be produced by circulating a mix of gase,s approximating the early atmosphere, in a closed glass vessel and exposing the mixture to periodic electrical sparks to simulate lightning. More recent experiments, scientists have successfully synthesized all 20 amino acids found in organisms.

Miller's experiment showed that simple amino acids could be produced from non-living materials but amino acids are monomers and the chemicals of life such as DNA and protein are polymers. Polymers are produced by the linking together of monomers in a process called polymerization. How this process occured on the Earth is difficult to explain for compounds that were most likely found within the water which causes depolymerization. However, researchers have shown that concentrated amino acid solutions will polymerize to form protenoids when heated. Perhaps this may have occured around submarine vents where volcanic activity superheats oceanic water. Proteins created through this process would also be able to aggregate into microspheres, which as discussed before grow and divide just like cells. In this scenario the newly produced microspheres would be the protobionts--the intermediary between the inorganic compounds and organic living organisms.

Chapter Contents:

8.0: Deep Time: Precambrian Earth

8.1: The First Crust and the Development of Continents

8.2: The Development of Earth's Atmosphere

8.3: The Development of Earth's Hydrosphere

8.4: The Origin of Life

8.5: Origin of Life Experiments