In this century dominated by biology and in which genetics has managed to unravel the most intimate secrets of living matter, Lynn Margullis appears as a breath of fresh air for the scientific community. With her peculiar ideas about the planet and her defense of the Gaia hypothesis, according to which the Earth is a gigantic self-regulating ecosystem, this biologist has opened new windows to the knowledge of one of the great questions of science: what is the lifetime? What is it that makes this third planet in the solar system so radically different from the rest of the known universe?
–You argue that life cannot be explained only in terms of physics and chemistry. Isn’t it to think that there is a kind of soul that differentiates the living from the inert to depart from science?
-To understand life, as to understand science, it is necessary to place it in its cultural context. Anyway, even scientifically, it is naive to think that life is just a physical phenomenon. When an organism dies, the nucleic acids, the proteins, all the molecules, are still there, but there is something that has radically changed: what is missing is the organization. Life is that organization, that process. It is a flow of matter and energy. DNA alone does not explain life. A living being is not distinguished by its chemical material, but by its behavior.
–The history of life on Earth still has many gaps. Can we really understand it with current knowledge?
-Life is a phenomenon of about 4,000 million years, almost as many as the Earth itself, and is actually a property of the entire planet. He is the one who has maintained the environmental conditions that are favorable to him during all this time. About 2 billion years ago the first organisms other than bacteria appeared, the protoctists. Much later, about 500 million years ago, animals, plants and fungi, organisms considered superior, emerge. Human ancestors are unimportant on the geological scale: three million years. That is, half of the history of life has been occupied exclusively by bacteria, and more than three-quarters, the organisms that make up the microcosm. That is why its study is so important, and that is the reason why all living things are linked to each other by history.
–The vision of life as a whole is not accepted by many scientists. Why are these ideas so suspicious?
-Vladimir Vernadsky (1863-1945) published a work in French in 1929 in which he spread the term biosphere. He did with space what Darwin had previously done with time. To understand life, one must understand the cycles of matter and energy on our planet. If Darwin said that all living things are linked to each other, Vernadsky went one step further: life is closely linked to the surface of the Earth; specifically, restricted to a strip of 20 kilometers. No living being can develop its entire life cycle outside the biosphere. This is a fact. However, someone has understood that Gaia is a living superorganism, which is a simplification of the theory and endows the Earth with a component of will that scientists reject. What Gaia really means is that the Earth is a huge ecosystem that regulates, for example, the concentration of reactive gases on a global level.
–How has the human species conception of life on Earth changed in this century?
-Sir Fred Hoyle said in 1948: “When we are able to take a photograph from outside the Earth, a powerful idea will take shape.” I don’t believe almost anything Hoyle says, but this is a great phrase. The images sent by Apollo twenty years later made us understand that life cannot be hidden. Apart from the atmospheric, astronomical and oceanographic evidence, everything on Earth indicates that it is a living planet.
–And what future awaits the planet? In particular, what future does the human species have?
-Life is an almost indestructible phenomenon that has lasted for more than 3,500 million years; therefore, it will continue to exist at least until the Sun goes out. The most normal thing is for humans to become extinct. Of all the thousands of species that lived in the Cambrian, about 500 million years ago, today none survive. The same thing will happen to the human species. But life will endure after the extinction of humanity.
–However, it has been said that the planet is in danger …
-This is a good example of the arrogance of the human being. We are absolutely dependent on microorganisms, which we despise, although they provide us with everything we need to live: they regulate gases and temperature and recycle waste products. We believe that environmental problems only concern the human species, because we always see everything from our perspective, although it is almost inevitable. When Armstrong stepped on the Moon, he was not alone, because microorganisms traveled with him: the bacteria from his mouth, his intestines, his skin, etc. Human beings think that evolution only affects us. It’s so silly – like thinking that when one dies, the whole world dies.
–But we have introduced important changes in the environment that have effects even on a planetary scale …
-We have extended the biosphere, for example, by building skyscrapers, but we have not slowed down evolution. Even genetic manipulation is actually a merit of nature itself. Genetic engineering uses restriction enzymes, genes from bacteria, etc. Products that have been working for billions of years.
–Let’s go back to the beginning. Why after so many years of biology studies have we still not been able to define life?
-In the question there is a linguistic trap. According to the rules of grammar, you would have to respond with a name, one thing. But life on Earth, more than a name, is a verb. It is a process through time that repairs, maintains, recreates and transcends itself. Life exists to reduce the physical gradient, the solar gradient. Thus, spontaneously, complexity is created. It is difficult to define. An American Supreme Court judge once stated that he might not be able to define obscenity, but he sure could recognize it when he saw it. We all have that ability to recognize life. Life recognized itself long before there were books on biology.
Cristina Ribas
This interview was published in May 1997, in number 192 of VERY Interesting
