What do a single cell, a simple organism, a Nobel Prize-winning scientist have in common? Each has a life story.
In 2007, scientists discovered spherical and ellipsoidal forms preserved in the ancient sandstone slabs of Western Australia. They were microfossils, impressions just a few millionths of a meter long, beyond invisible to the unmagnified eye. But whatever they were, they were old. Their chemical traces—carbon, sulfur, nitrogen, and phosphorous—date back approximately 3.4 billion years. Because carbon and nitrogen are common elements in all living things, these newfound forms were once alive. They were bacteria. They fed off sulfur compounds. They clung to sand grains in the sediment. Dr. David Wacey from the University of Western Australia concluded that “early life was very simple, just single cells and small chains, some perhaps house in protective tubes.”[i] This could be the story of the first life on earth.
How many lives have come to pass on this planet? An estimated one hundred billion human beings have existed.[ii] But we are just one species of roughly two million that are known. Many more have yet to be undiscovered. The National Science Foundation’s “Tree of Life” project estimates that there could be between five and one hundred million species present today.[iii] Then there are the extinct. One popular claim holds that 99.9%of all species are long gone.[iv] Life has been present here on Earth for over three billion years. Who knows how fruitful and multiplicative each species has been during its existence?
Despite the unknowable number and unimaginable variety of its forms, there is essential unity to life. Every individual has descended from a common ancestor.[vi] We all take part in evolution, the process of change in genetic composition of a population due to both random and nonrandom mechanisms. Our genes either do or do not endure, and those genes that have higher-than-average frequencies within the population can be considered fitter. Evolution is an ongoing process of determining “What is more fit?” We contribute data to this survey by shepherding our genes to the next generation. So it goes, from generation to generation. The arrow of time points forever forward; we must survive and pass on. Because of the deep influence of evolution—from genes to species—patterns are conserved. Genetic information is coded in the same basic molecular language: A, C, G, and T or U.[vii] All individuals are composed of cells, the smallest basic unit of life. And the story of a life—of your life and all life—will unfold in a somewhat predictable way.