As life has evolved, its complexity has increased exponentially, just like Moore’s law which states that the number of transistors on an integrated circuit doubles approximately every two years. Geneticists, Alexei Sharov at the National Institute on Ageing in Baltimore and Richard Gordon at the Gulf Specimen Marine Laboratory in Florida, have extrapolated this trend backwards and found that by the measure of Moore's Law, life is older than the Earth itself.
The application of Linear regression of genetic complexity on a log scale extrapolated back to just one base pair suggests the time of the origin of life 9.7 billion years ago. This cosmic time scale for the evolution of life has important consequences: life took ca. 5 billion years to reach the complexity of bacteria; the environments in which life originated and evolved to the prokaryote stage may have been quite different from those envisaged on Earth. Therefore they suggest that if life takes 10 billion years to evolve to the level of complexity associated with homo sapiens, then we may be among the first, if not the first, intelligent civilisation in the Milky Way, negating Drakes Equation.
On the semilog plot above , the complexity of organisms, as measured by the length of functional non-redundant DNA per genome counted by nucleotide base pairs (bp), increases linearly with time (Sharov, 2012). Time is counted backwards in billions of years before the present (time 0). Credit: arXiv:1304.3381 [physics.gen-ph]
Additionally they suggest that the evolution of advanced organisms has accelerated via development of additional information-processing systems: epigenetic memory, primitive mind, multicellular brain, language, books, computers, and Internet. As a result the doubling time of complexity has reached about every 20 years.
Sharov and Gordon also point out that astronomers believe that our Solar Nebula formed from the remnants of an earlier star, suggesting that life from this period might be preserved in the original gas, dust and ice clouds. In a form of Cosmic pansermia, life on Earth may be a continuation of a process that began many billions of years before the formation of our Solar System.
Ref: arxiv.org/abs/1304.3381: Life Before Earth
The Daily Galaxy via MIT Technology Review
Image Credits: graph, arXiv:1304.3381; top of page image courtesy of Shutterstock.com