“What problem with prebiotic Earth was solved by the emergence of life?”—D. Eric Smith
Could the answer lie in the flow of energy?
Lightning is the Earth’s solution to the problem of regulating electrical energy as it builds up in the atmosphere. Hurricanes solve the problem of releasing heat energy that builds up in warm tropical oceans. In the same way, the emergence and evolution of life may be the Earth’s most efficient solution to the problem of dissipating the energy constantly generated inside it.
Ultimately, origin-of-life research could reveal the extent to which the emergence of life and biological processes are governed by universal principles on the order of the laws of motion, gravity, and thermodynamics. It has already provided important insights into how biological systems produce and regulate growth and change.
Global climate change
Climate affects biology, and biology affects climate. Until recently, models for studying climate change have largely ignored energy flows through biological and ecological systems. Incorporating these interconnections will enhance the models.
Cures for diseases
While studying life’s origin, Harold Morowitz and his colleague Vijayasarathy Srinivasan stumbled upon a clue to a medical mystery—how Mycobacterium tuberculosis bacteria survive for years inside the human respiratory system, imprisoned by the body’s immune cells and deprived of the oxygen and nutrients they normally depend on.
Two ancient genes possessed by the bacteria may provide the answer. The genes are crucial players in the reductive citric acid cycle, but in the oxygen-rich environment in which the bacteria normally live, only the oxidative citric acid cycle would be needed. Why then have these genes persisted? The answer could be that they’re the organism’s secret weapon, allowing it to switch back to the reductive cycle when trapped inside the body. If correct, this could open new avenues to therapies for tuberculosis and other diseases.
Life on other planets
Shedding light on the emergence of life on Earth will help us come up with an answer to another question with profound implications: Is there life elsewhere in the universe?
• The building blocks of life are easier to make and more common than once thought.
• Many scientists believe that life emerged on Earth almost immediately once the environment allowed it around 3.8 billion years ago.
• Life forms on Earth have been found to thrive under a wide range of extreme conditions.
• As the number of planets discovered around other stars grows rapidly, it appears increasingly likely that Earth-like conditions, extreme or not, are common throughout the universe.
Could this mean that life on Earth and throughout the universe is inevitable?
Harold Morowitz | view bio
Morowitz is a biophysicist at the Santa Fe Institute and George Mason University’s Krasnow Institute, is preparing laboratory experiments to test the catalytic properties of transition metal-ligand complexes common when life began.
D. Eric Smith | view bio
Morowitz’s colleague D. Eric Smith is using advanced statistical mathematics and computational modeling to determine the chemical pathways on early Earth most likely to have led to self-replicating and metabolic processes
George Cody and colleagues in the Geophysics Laboratory of the Carnegie Institution of Washington, D.C., are performing experiments at high temperatures and pressures on potentially prebiotic chemistry at high temperatures and pressures to see how chemical reactions could have produced the reductive citric acid cycle at thermal vents.
Shelley Copley | view bio
At the University of Colorado, with the goal of developing a model for the origin of the genetic code, Shelley Copley and her research group are investigating precisely how RNA may have evolved from early chemical reaction networks.
At the University of Illinois Urbana-Champaign, Zaida Luthey-Schulten and her group are performing artificial life research that includes computer simulations of ribosomes, the cell's protein-building machinery; the differences in ribosome structure in the three main branches of the Tree of Life; and their role in the early evolution of protein synthesis.
The goal of other artificial life researchers is to synthesize simple living organisms in the laboratory. At Los Alamos National Laboratory, Steen Rasmussen is attempting to assemble a proto-cell.
At the University of Illinois Urbana-Champaign, physicist Nigel Goldenfeld and Carl Woese (discoverer of the archaea), molecular biology and evolution researcher were working with colleagues to investigate the role of horizontal gene transfer, or gene sharing, in producing the Universal Genetic Code.
Penny J. Boston | view bio
Penny J. Boston, a speleologist at the New Mexico Institute of Mining and Technology, is conducting research on the geomicrobiology of caves and mines, astrobiology, and extraterrestrial speleogenesis.
Robert M. Hazen | visit website
The role of minerals in the origin of life is the focus of recent research by Earth scientist Robert M. Hazen at George Mason University and the Carnegie Institution’s Geophysics Laboratory.
Ariel D. Anbar | view bio
Ariel D. Anbar, a biogeochemist in the School of Earth & Space Exploration and the Department of Chemistry & Biochemistry at Arizona State University, is interested in the past and future evolution of the Earth as a habitable planet and how this can inform the search for inhabited worlds beyond Earth.
Geochemist Michael Russell, a research scientist in the Planetary Chemistry and Astrobiology Group at NASA’s Jet Propulsion Laboratory, is investigating the emergence of life and oxygenic photosynthesis in hydrothermal systems on wet, rocky, sunlit planets.
Larry S. Crumpler | view bio
Crumpler is a research curator at the New Mexico Museum of Natural History & Science, studying New Mexico volcanoes as well as geology and volcanism on other planets. He is a member of the Mars Exploration Rover science team.