Thursday, January 26, 2012

In Memory of Lynn Margulis

This essay will also be posted on my website at

One of the greatest evolutionary scientists, Lynn Margulis, died last November 22. In this essay I would like to reflect on her contributions to our understanding of the world. Not just of a narrow aspect of science, but the whole world.

Lynn was a child prodigy who began her university studies at age 14. In graduate school, she studied genetics, and married her fellow graduate student, Carl Sagan (who was as creative and large a thinker as she). She was not content to just learn what others said about genetics. She wanted to understand why some traits were inherited only through the mother’s side. These traits appeared to be passed on not through the chromosomes in the nucleus but through the mitochondria, which are tiny energy factories inside of most cells. Some plant traits appeared to be passed on through chloroplasts, the tiny green photosynthesis factories in many plant cells. This meant that mitochondria and chloroplasts had, and used, their own DNA. She wondered why they had that DNA. When she read about the work of some Russian scientists in the early twentieth century, she had her answer. Mitochondria and chloroplasts started off as bacteria, which moved into and took up residence inside of larger cells that already had nuclei. They did not consume the larger cell, nor did it consume them. Instead they formed a permanent partnership, which has been going on for billions of years. Mitochondria and chloroplasts began, she said, by symbiosis—cells living together. The result was the genesis of a new, complex kind of cell. She called this process symbiogenesis.

When Lynn Sagan (later Margulis) wrote her paper, it was rejected fifteen times. She was persistent. Finally it was published. At first her ideas were scorned. But in less than a decade, most biologists were convinced that she was right. When I went to hear her speak, while I was a sophomore at the University of California, Santa Barbara (it was the first scientific seminar I ever attended), she was well received, even though the professor who introduced her made some off-color jokes. At the time, I was a creationist, and I thought that there were only two alternatives to the origin of a complex cell: either gradual evolution, or sudden creation. Lynn Margulis presented a third alternative. Her view was entirely evolutionary, of course; but the host cell and the bacteria had evolved, separately and gradually, then suddenly merged together.

Today Margulis’s view of the origin of mitochondria and chloroplasts is a textbook standard. Scientists are working on an even more amazing example of symbiogenesis: many believe that the nucleus itself is the evolutionary descendant of a bacterium that moved into a larger cell that did not yet have a nucleus. I suspect that this idea would have been too wild even for Lynn in the early days.

In her final years, Lynn was looking for evidence that cilia and “flagella” of complex cells (such as paramecia) were the evolutionary descendants of spirochete bacteria. She had some good circumstantial evidence, but never did find proof.

She was also the principal biological champion of the “Gaia” view of the Earth, a view first proposed by atmospheric scientists James Lovelock. All of the organisms of the Earth form a single network of life. The Earth is therefore not just the home of life, but is alive. Not every component of the Earth is alive, of course; but neither is every component of a cell. A cell has living components, such as mitochondria, and nonliving components, such as water. But nobody would say that a cell is not alive. By the same reasoning, the Earth is alive.

Lynn was pugnacious. She was not afraid of a good scientific debate. And she was not afraid to be wrong. Clearly she was wrong in her assertion that HIV is not an infectious virus. But if she had never taken the risk of being wrong, would she ever have had the insights that changed modern biology?

I had a chance to talk with Lynn Margulis in 2004, as I was preparing my Encyclopedia of Evolution. She was 66 years old at the time, and could have retired comfortably and with renown. But she was still fighting for recognition of yet more of her insights. I mispronounced her name, and she corrected me: the emphasis is on the first syllable, Margulis. She said I would only be allowed to make that mistake once. I didn’t make it again. She enjoyed what I had written in my encyclopedia but was not afraid to point out what she considered errors. When I dedicated Life of Earth to her last year, she left me a phone message saying that the dedication brought tears of happiness to her eyes. She bought copies and left them for students to read at the University of Massachusetts, where she worked. I am glad to have brought a little joy and appreciation into the life of this great scientist.

We can carry on Lynn’s legacy if we continue to think big about the world. When Lynn started, most scientists were trying to decompose the big picture down into component parts. But now, many scientists consider that the interactions of those components are the most important thing. An entire research institute, the Santa Fe Institute, is devoted to understanding complex interactions and emergent properties. Geneticists now know that humans and mice have about the same number of genes, and most of them are the same genes; the big difference between a mouse and a human is not the genes but the interactions among the genes. I like to think that Lynn contributed greatly to this important change in the scientific view of the world.

Announcement: I just posted a new YouTube video on It will be up soon. Darwin comments on…Newt Gingrich?

Also, please send comments about what you would like to discuss, and thanks for the comments received.

Friday, January 20, 2012

What Would You Do About…

Note: I am posting a new Darwin video on my YouTube channel StanEvolve. It is not showing up on the main channel page, but if you click on videos, you will find it. It is called Charles Darwin and airplanes. It is about the difference between science and religion.

Note: I am now on Twitter @StanEvolve.

In the previous post, I asked for your input of ideas for this blog. Due to a Blogger website error, you may have missed that posting. If you missed it, take a look at it. I really want to know your input.

But I will also be asking your advice about specific situations. To start: please let me know what you think I should do in the situation I describe below.

I wrote a book review for the National Center for Science Education, which was read by a long-term prisoner in California. He wrote a letter to me, laboriously and carefully and intelligently. We began exchanging letters about evolution. He shared some of his questions and observations, and told me about some conversations he had with his fellow prisoners. I could not send any of my books—prisoners cannot receive hardcover books—but I printed out my summary of the Origin of Species for him, as well as the PDF file of Life of Earth.

I began to notice in his letters that he was dedicated to communism. I suggested to him that communism failed in part because it made incorrect assumptions about human nature (capitalism also makes mistakes, but not the same ones). He wrote back and said he was familiar with the Lysenko story (click here for the Wikipedia summary), but that The Great Stalin and The Great Mao were not responsible for the collapse of communism: it was the fault of infiltrators. He was not angry at anything I said, nor am I at anything he said, and our correspondence will probably continue.

But it is clear to me that he is a fundamentalist communist as unaffected by evidence as any fundamentalist creationist. Fundamentalist faith deflects all contrary evidence by making special accommodations; for example, creationists may say that God nudged the organisms around in the Flood to make the fossils end up in an evolutionary order.

So, what would you suggest that I do? Should I mention to my correspondent that he is using the same patterns of thought that fundamentalist creationists use? My inclination is to simply not discuss such matters any further with my correspondent; I am sure other topics will come up from time to time. But if you think I should write to him about it, let me know—and let me know how—in the comment box.

I look forward to your input on this and other things, and your responses to one another, rather than just waiting for it to happen. I have learned much of what I know by simply listening to others. I have the habit of walking right up to clusters of colleagues and just listening. Sometimes I tell them that I just want to listen and learn. Sometimes it is gossip (which, according to some studies, is nearly always good gossip rather than malicious gossip), sometimes it is major scientific or political insights. In fact, I have learned some things from the intelligent prisoner with whom I correspond.

Saturday, January 7, 2012

For This New Year: Your Advice Requested

It appears that Blogger reposted my December 23 entry rather than the one that I submitted. I will try again with this message.

This blog has, in its three years of existence, been primarily an outlet for my ideas: the kind of one-directional flow that feels most comfortable to a university professor. I want to change this beginning in 2012.

I would like to begin directly requesting my readers to give me advice. There is always a comment box option, which several of you have used, but my default (like that of most professors) has been to just talk and then acknowledge those few people who raise their hands. But interaction is the successful way to go. The internet is set up to encourage interaction. That means you! I would like to know what topics you would be interested in hearing about. I will continue to post things that I learn (primarily about evolution) but I will try to remember to always request your responses. I am not running out of my own ideas, but there will be plenty of time and space for yours.

I got to be smart by listening to other people—not just at scientific meetings, but everywhere, such as family reunions; not just from science, but from fiction, and from hearing people’s stories. Sometimes I crash a conversation that is going on in the hallway, and when they look at me I just said I wanted to learn something from them.

Let me know in the comment box (now or in any future comment box) what you would like to see discussed in this blog. Also check my website for news and essays. One news item: The Chinese edition of Life of Earth has just been published. I think you have to be in Taiwan to buy it.