In his book Life’s Edge
, Carl Zimmer is in search of what it means to be alive. He explores the boundary, brink, fringe, margin, and threshold that defines life. He takes us on a journey through the history of the concept, and when we think that he is on the verge of giving us the answer… [spoiler alert] although supercomputers are in use, the answer is not 42.
I was particularly interested in this book as it related to my career as a science teacher. For the first day of class in a new school year, I wanted my junior high students to be pumped and running to my class everyday for the rest of the year. While many teachers spend that first day going over their policies and procedures, setting up seating charts and explaining the upcoming course and curriculum, I chose to start right in. There would be plenty of time for these other tasks once I captured the students’ interest.
This is what I did. Prior to class, I’d pick up some fresh liver at the meat counter of the supermarket. Then I went to a local supplier of fish bait and purchased a supply of bait maggots. At school, I prepared a number of Petri dishes that contained the liver as the medium and then layered in a small number of maggots. When the students arrived for their first science class, they would be immediately encouraged to form small groups and to observe and write down all their thoughts. In my mind, there was no way when their parents asked them what they did in school today, that any of these young people would say ‘nothin’.
In follow-up classes, this first lesson gave me the opportunity to introduce terms such as observation and inference. At that time, one theme in the provincial Program of Studies (curriculum) was ‘characteristics of living things’. After looking at liver and maggots, we were off to a great start.
I also taught high school biology where I was able to remind students of their earlier exposure to defining what it means to be alive. At this level, we were able to discuss order versus randomness. Enthalpy and entropy. Oxidation, reduction, the storage and release of energy. The capacity to do work. Steady state and equilibrium. Now, instead of examining maggots on liver, the students made observations of a Traube Cell. I’ve put the reference to the article below. You can freely download a pdf of the original paper via the link provided.
Back to Life’s Edge
. I found myself entertained, bewildered, and amazed. Sometimes I was nodding my head in agreement, and at others fact checking as I had forgotten or never new the details. Zimmer tells us in his acknowledgments that he began this project with a series of interviews with “eight deep thinkers”. These conversations were turned into a podcast. Not satisfied to stop there, Zimmer expanded his research to develop this book. Just in case your curiosity needs further satisfying, there are 14 pages of Notes combined with a Bibliography of 28 pages. Zimmer’s book alone provided me with compelling information on a wide range of specific life-defining topics from the legal definitions of life and death to philosophical consideration about the definition of life. Zimmer tells us about astrobiology, he explains how experiments with liposomes ultimately led to the development of nanopore DNA sequencing and gave us the techniques to get our cells to take up the mRNA vaccines.
Amazingly, I found through Zimmer’s book that humans historically, but of course on a much bigger scale, have gone through the thought processes of the young students in my class. In both cases, there was a struggle to refine and define. Even as I write this review, I came across a new research paper on the molecular evolution of oxygenic photosynthesis. If the life’s edge is also a boundary, no doubt we will continue to push it.
Links of Interest
Traube Cell reference
: Ron Royer, and Ron Haaseth. “A Simple and Concrete Model for the Introduction of Cell Theory in the Secondary School.” The American Biology Teacher, vol. 48, no. 8, 1986, pp. 483–484. (free to download pdf)
Could Photosynthesis Be As Old as Life Itself?
Blast into Biology
Gerry’s Gene Scene - Astrobiology
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