Research into which metals were present at the time life first formed on earth is shedding new light on the possible origin of life both here and potentially on other planets. The team behind the new, sometimes unexpected findings believes their research will move those looking into the origin of life on earth one step closer to answering one of the universe’s biggest mysteries by providing them with a tool they didn’t previously have.
Origin of Life One of the Universe’s Biggest Mysteries
Most scientists agree that life likely originated on earth at least 300,000 years after the planet first formed. However, few if any agree completely on how the otherwise lifeless materials our planet is made of combined to form those first microscopic living, breathing organisms. Many theories have been proposed, ranging from a mixture of pre-biotic chemistry and tremendous amounts of energy to the arrival of pre-biotic proteins and other organic building blocks from asteroids and comets, but none have been proven definitively to be true.
In recent years, scientists have reassessed this question by taking a more forensic approach by trying to determine the environment of the early earth around the time they believe the first ancient life forms sprang forth. Think of it like a crime investigator gathering all of the circumstantial evidence they can to explain something they know happened without having an actual video recording of the event in question.
Much of that science involves studying and understanding genetics, while others have focused on proteins and their building blocks like peptides to pinpoint how life could have emerged from raw material. Now, a new team from the University of Rochester has found some rather exciting results about the availability of various metals around the dawn of that first life that is moving all of the science around the origin of life closer to a final answer.
How Ancient Life Put the Pedal to the Metal
“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,” says Dustin Trail, an associate professor of earth and environmental sciences at the University of Rochester. “But we still do not know how—or even when, really—life started on our own planet.”
Fortunately, Trail explains, research into what metals were available when life started, and how living organisms depend on metals for all sorts of biological processes, is helping to identify what he describes as the “specific conditions and chemical pathways that could have supported the emergence of life.”
Specifically, Trail and his team analyzed the fluid compositions in the earth’s outer layer (dubbed the lithosphere) as it existed billions of years ago. That’s because the earth is estimated to be around 4.4 billion years old, so looking back this far is the only way to study the environmental characteristics present when life first sprung up. Think of it as studying the crime scene to better understand what happened.
Of course, researchers cannot measure the exact metals that were present at this ancient time, but they can infer which ones were available to those first burgeoning forms of life by studying these lithospheric fluids. Understanding the nature of the lithospheric fluids present at the time of first life allowed Trail and his team to figure out which metals would be available and which ones would not, since these fluids are the only pathway metals can take to get from the interior of the planet to its exterior. Its information Trail says is critical to solving the mystery.
“When hypotheses are proposed for different origin-of-life scenarios, scientists have generally assumed all metals were available,” says Trail, “because there weren’t studies that provided geologically robust constraints on metal concentrations of fluids for the earliest times of Earth’s history.” Now, he says, his teams’ research is providing that tool.
For example, their research has already proved valuable by determining the availability of copper, or in this case lack thereof, in the time life may have first formed. This evidence goes against a number of “origin of life” models which depended on copper to help fuel the pre-biotic soup of chemicals that may have given birth to the first life forms. Without copper, these models and theories become significantly less likely to be the answer. Think of it as our ancient crime investigator eliminating a number of suspects from her list. It doesn’t leave her the answer to who did it, but it shortens the list of suspects quite a bit.
Effect of Metals on Origin of Life Could Aid Search for Extraterrestrial Life
The researchers behind these latest findings say that their insights into the metals available to earth’s first living organisms may have other benefits as well. For instance, Trail says that along with a better understanding of early earth, the type of findings made by his team research “is certain to factor prominently into the search for life outside of our planet.”
In the end, whether hunting for life in another star system or the origin of life here on earth, the researchers behind these exciting finds believe their work in understanding which metals were and were not available at the time of life’s origin will be critical to help find all of those answers.
“Our research shows that metals…may function as important links between the ‘solid’ Earth and emerging biological systems at Earth’s surface,” Trail explains. “Experiments designed with this information in mind will result in a better understanding of how life originated.”