What is life?

The question has confounded human beings since we have been around. We can accept that golden retrievers, oak trees, and bacteria are alive, but when we start talking about origins, “alive” becomes a tricky term. Attempting to define life, we often look for the cutoff point – the moment 3.7 billion years ago when non-life ended and life began, when a batch of self-replicating molecules became a microorganism, when chemistry became biology.

In 1952, scientists Stanley Miller and Harold Urey attempted to recreate this moment. They crafted a chemical cocktail to mimic the elemental composition of our planet's primordial seas, and they submitted this mixture to an electrical charge. They waited and watched, and found that their experiment produced the same amino acids that serve as the building blocks for all life on Earth. However, although the Miller-Urey experiment created amino acids, it did not generate life.

In a recent paper in the Journal of the Royal Society Interface, scientists Sara Imari Walker and Paul C.W. Davies argue that Miller and Urey might have been looking for life in the wrong places. By confining the search for life's origins to the realm of chemistry, as Miller and Urey did, we make the mistake of ignoring the critical role of information. Walker and Davies argue that the capacity for information processing and storage might be the defining property of life on Earth. In living beings, information flows in two directions – we receive information from our environment, and we actively respond to that information.

You can throw flour, sugar, and eggs in an oven, but you won't get a cake. Life is more than the lucky product of a stew of elements; biology is more than complex chemistry. The chemical ingredients for life were replicating in that primordial stew, but abiotic self-replication (like we see in viruses) is completely passive. Biological self-replication (like we see in bacteria), on the other hand, is the result of active information control. According to Walker and Davies, the origins of life lie in that information.

Read more at LiveScience.com

Find the original article in the Journal of the Royal Society Interface