Science: Steps Toward Life

Nearly everyone wants to know how life on earth began, says Biochemist Sidney W. Fox of Florida State University, but most scientists who conjecture about it merely theorize. They do not test their ideas by actual experiments. Dr. Fox and a few others have been experimenting, and in Science Dr. Fox tells what luck they have had so far in charting the secret paths followed by nature in the creation of life.

Gases to Protein. Astronomers believe that the atmosphere of the early, lifeless earth had no free oxygen in it, but was made of gases like methane, hydrogen and ammonia. Scientists have also proved that when this gaseous mixture is put in a flask with a little water in the bottom, and an electric discharge is passed through it, the chemical reaction produces an accumulation of amino acids in the water. Since amino acids are the building blocks out of which proteins are made, and proteins are the chemical framework of all life on earth, the first chemical step toward life could have come about naturally on the primitive earth, pushed by lightning flashes or perhaps cosmic rays.

Nature’s next step toward life must have been to make proteins out of accumulated amino acids. Reasoning that parts of the primitive earth’s surface may have been fairly hot, Dr. Fox mixed together the 18 amino acids common to the proteins of all living organisms and heated them gently. He got “proteinoids” that behave very much like proteins found in nature. They are digested by natural enzymes and eaten by bacteria. If polyphosphoric acid is added to the mix, the reaction takes place at only 160° F., well below the boiling point of water.

Protein to Cells. The next step in the life-creating process, according to one theory, is the organizing of protein molecules into cells that grow by absorbing smaller molecules in the water around them and multiply by dividing. How did nature make cells, with their permeable walls and juicy insides, out of assorted protein molecules? Dr. Fox does not think this is difficult; he has done something very like it himself. He dissolved in hot water some of the proteinoids that he made by heating amino acids. When he cooled the solution, billions of microspheres appeared, about the size of cocci (round bacteria) and looking very much like them. They shrink when salt is added, and this suggests that they are hollow and that their walls are slightly permeable like the cell walls of bacteria.

Dr. Fox does not claim that his microspheres are alive, but he thinks that something like them may have been a step in nature’s progression toward life. If amino acids were continually raining down from the sky, it is natural to suppose that considerable quantities of them accumulated on fairly hot parts of the young earth’s surface. The heat made them react, as in Dr. Fox’s lab; after they had turned into proteinlike molecules, heavy rain dissolved them and washed them into the sea. There they cooled and formed microspheres, each of which packaged together a great assortment of proteins and similar chemicals. This process may have been repeated billions of times in different places, generating during each repetition many billions of microspheres. Eventually, one of them happened to have in its membrane the proper chemical wherewithal for a dim sort of life. Once this spark was alight, the great parade of evolution, from bacteria up to man, was a natural consequence.