by LINDSEY VALICH
The first signs of life emerged on Earth in the form of microbes about four billion years ago. While scientists are still determining exactly when and how these microbes appeared, it’s clear that the emergence of life is intricately intertwined with the chemical and physical characteristics of early Earth.
“It is reasonable to suspect that life could have started differently—or not at all—if the early chemical characteristics of our planet were different,” says Dustin Trail, an associate professor of earth and environmental sciences at the University of Rochester.
But what was Earth like billions of years ago, and what characteristics may have helped life to form? In a paper published in Science, Trail and Thomas McCollom, a research associate at the University of Colorado Boulder, reveal key information in the quest to find out. The research has important implications not only for discovering the origins of life but also in the search for life on other planets.
“We are now at an exciting time in which humankind is searching for life on other planets and moons, as well as in other planetary systems,” Trail says. “But we still do not know how—or even when, really—life started on our own planet. Research like ours helps identify specific conditions and chemical pathways that could have supported the emergence of life, work which is certain to factor prominently into the search for life outside of our planet.”
The importance of metals in the emergence of life
Research into life and its origins typically involves a variety of disciplines including genomics, the study of genes and their functions; proteomics, the study of proteins; and an emerging field called metallomics, which explores the important role of metals in performing cellular functions. As life evolved, the need for certain metals changed, but Trail and McCollom wanted to determine what metals may have been available when microbes first appeared billions of years ago.
“When hypotheses are proposed for different origin-of-life scenarios, scientists have generally assumed all metals were available because there weren’t studies that provided geologically robust constraints on metal concentrations of fluids for the earliest times of Earth’s history,” Trail says.
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