Study finds new answers to age-old question: What is life?

WASHINGTON - In a new collection of essays, experts from all walks of life - philosophy, science, and molecular evolution - present a variety of perspectives on defining life.

According to David Deamer at University of California, Santa Cruz, a definition is required to help determine what is and is not life as scientists begin to develop artificial life forms in the laboratory.

And to investigate what appear to be life forms on other planets in the future.

Mark Bedau, Reed College (Portland, OR) and the University of Southern Denmark (Odense), relies on the Program-Metabolism-Container (PMC) model to define minimal chemical life.

According to Bedau, this integrated triad of chemical systems is all that is needed for a living organism to maintain its existence, grow, reproduce, and evolve.

Antonio Lazcano, National Autonomous University of Mexico, and colleagues present an historical perspective of the many definitions of life put forth over the years and why they have been unsatisfactory.

Steven Benner, Foundation for Applied Molecular Evolution and The Westheimer Institute for Science and Technology (Gainesville, FL) describes how chemical structures capable of Darwinian evolution might be useful as universal biosignatures.

Deceased Ukranian scientist Sergey Tsokolov asserts that feedback loops should be an essential component of any definition of life. Life could not exist in the absence of negative feedback, concludes Tsokolov.

“Our authors rose to the challenge, and their ideas and perspectives are genuinely new. It was a pleasure to work with them and help them wrestle with this difficult and complex problem,” said Deamer.

The essays appear in Astrobiology. (ANI)