It's a chicken-and-egg problem: Which came first, metabolism (which makes life run), or life (which makes metabolism work)? Today, scientists from the University of Cambridge have published research that indicates that the blueprints for metabolism can be found way before life actually emerged.

The researchers figured this out by simulating ancient Earth's oceans in the laboratory. These "oceans" contained all the building blocks of life, matching the original source of all living beings on our planet. When the researchers examined the chemical reactions in these ancient oceans, they found that those events closely match the same reactions that take place in our bodies to create energy. These chemical processes may be the ancestors to our own metabolism.

Iron was of particular interest to the researchers, as it acts as a catalyst to facilitate many of these reactions, much as enzymes serve as catalysts in our bodies. They also found that iron can cause reactions that switch biochemical pathways on and off, which would eventually lead to cells' ability to react to their environments.

The researchers performed over 4,000 experiments to test their hypothesis, and they all pointed toward a chemical origin of metabolism.

The findings give yet more detail to our picture of how the world — and humanity — evolved, and could have implications for the creation-evolution debate, as intelligent design proponents have pointed to human metabolism as evolutionarily inexplicable.

The researchers have published their paper on the ancient metabolism-like reactions in a recent issue of Science Advances. Their press release is available at Phys.org.

Photo: University of Liverpool | Flickr