By Robert Hazen, George Mason University
The idea of spontaneous generation of life comes from the fact that we see new growth in the spring after winter, when life seems to have died around us. This idea is not such a strange one; but it was soundly trounced by Louis Pasteur, the great French chemist. He was instrumental in abolishing these ideas and leading us to a new way of thinking about life’s origins. What were they?
Louis Pasteur
Louis Pasteur was born in 1822. He was the descendant of generations of tanners, and so had a great deal of practical chemical experience in his family’s background. As a boy, he was only interested in drawing, and thought he wanted to become an artist, but he excelled at school as well. Eventually, he attended university in Paris and shifted his focus to physics and chemistry. He went on to become the founding director of the Pasteur Institute, an institute founded in his name and in his honor.
Pasteur made major contributions to crystallography, to the understanding of fermentation—which was, of course, a subject of great interest to the French wine and beer industry—but his major discovery, the thing that really established his fame in France, was the discovery of the germ theory of disease. In other words, he is the one who discovered that microbes cause infectious diseases; and, of course, once we found the cause of a disease, we became much closer to finding a cure.
Pasteur was unique in his ability to focus his keen scientific intellect on problems of great social concern and he saw his science in the context of a much larger world.
This is a transcript from the video series The Joy of Science. Watch it now, on Wondrium.
No Life Can Occur Without Prior Life
When it came to the idea of spontaneous generation of life, Pasteur did not accept it.
He conducted a brilliant series of experiments to show that when water was boiled, it could be sterilized. In order to do so, he sealed some beakers and kept some open to the air, and then he boiled the water. What he found is that when we boil the water and seal the container, it became sterilized, or pasteurized. It would not allow other life to form.
Setting the Stage for Newer Ideas
On the other hand, if we kept the beaker open, then eventually microbes would get in and start contaminating that water. These ideas had tremendous practical consequences; his development of pasteurization transformed the production and preservation of food. For example, it revolutionized the distribution of milk, and of beer, at that time in the 19th century and really changed the whole way food is transported and stored.
Interestingly, in the process of developing pasteurization, Pasteur also introduced the dictum that no life can occur without prior life. With the idea of spontaneous generation of life thrown out of the window by Pasteur, the stage was set for the advent of another idea—the one proposed by Charles Darwin.
Charles Darwin
Darwin developed the theory of evolution by natural selection, and wrote the following to a colleague in a letter: “If we could conceive, in some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, et cetera present, that a protein compound was chemically formed, ready to undergo still more complex changes.”
Here, Darwin realized that life’s origin, however it occurred, depends on three key resources. First, life requires water—that’s Darwin’s ‘warm little pond’. Second, life requires energy. Perhaps the Sun, perhaps it was lightning, or maybe it’s the Earth’s inner heat. Then, life requires chemicals: carbon, oxygen, hydrogen, sulfur, perhaps with some nitrogen and phosphorous thrown in. This is so one can make those molecules of life; remember the lipids, the carbohydrates, proteins, nucleic acids. We need all those basic building blocks.
Later on, in the early 20th century, several scientists went on to expand on these ideas that were contained in Darwin’s letter. Most notable amongst these researchers was the Russian chemist, Alexander Oparin, who lived from 1894 to 1980.
Alexander Oparin’s Ideas
In 1922, while he was still in his 20s, Alexander Oparin proposed the idea that life arose from a body of water that gradually became enriched in organic molecules. This is the so-called Oparin ocean, sometimes known as the primordial soup. One just has to gradually build up supplies of organic molecules dissolved in the ocean. Somehow, he argued, these molecules became self-organized into a chemical system that could duplicate itself, and that was the first life form.
As intriguing as these ideas were, and they were certainly subject to testing in the lab, it wasn’t until the years following World War II that a systematic, experimental approach to the study of this primordial soup was devised and implemented.
Common Questions about Louis Pasteur and the Idea of Spontaneous Generation of Life
Louis Pasteur’s major discovery, the thing that really established his fame in France, was the discovery of the germ theory of disease. In other words, he is the one who discovered that microbes cause infectious diseases.
In the process of developing pasteurization, Louis Pasteur also introduced the dictum that no life can occur without prior life. With the idea of spontaneous generation of life thrown out of the window by Pasteur, the stage was set for the advent of another idea, the one proposed by Charles Darwin.
Alexander Oparin proposed the idea that life arose from a body of water that gradually became enriched in organic molecules. This is the so-called Oparin ocean, sometimes known as the primordial soup.
