A review by davidr
Life's Edge: The Search for What It Means to Be Alive by Carl Zimmer

4.0

"We cannot make artificial life because we cannot agree on what life is. We cannot find life on Mars because we cannot agree what life represents". --Radu Popa

Scientists still cannot agree on a definition of life. That is because life comes in so many forms and structures; there is no single definition that can encompass them all. That is the central theme of Carl Zimmer's book.

Zimmer's writing is excellent! He is a science columnist for the New York Times. He wrote a number of books. I really enjoyed his book [b:She Has Her Mother's Laugh: The Powers, Perversions, and Potential of Heredity|36391536|She Has Her Mother's Laugh The Powers, Perversions, and Potential of Heredity|Carl Zimmer|https://i.gr-assets.com/images/S/compressed.photo.goodreads.com/books/1511221974l/36391536._SY75_.jpg|58083603]. I expect to read additional books he has written.

The early portion of his book discusses what is a human. When did humans first evolve? Zimmer writes a number of interesting anecdotes about primate behaviors and their reactions to death. One hundred-thousand years ago, homo sapiens began carrying out funerals. This demonstrates that people understood that diseases and injuries cause death.

Zimmer writes about flowers that were buried by Ice Age squirrels 30,000 years ago in Siberia. Scientists have nurtured them back into healthy plants. He writes about hibernating bats. He writes about Covid-19. Famous Hungarian biochemist Szent-Györgyi said that self-reproduction is not a requirement for life. As a humorous aside, he gave as an example that a single rabbit cannot reproduce.

The tail end of the book discusses the origin of life. Some scientists believe that the most important components or requirements for life are shell membranes called "liposomes". They act as containers for life's molecules. Scientists have made liposomes by adding water to meteorites. Other scientists find that visiting the Kamchatka Peninsula is a great place to study early-Earth-like conditions. The peninsula is packed with active volcanoes, crater lakes, hot springs and ponds.

This is just a small sample of all the topics discussed in this book. The author does not try to be humorous. Instead, he captivates the reader with an amazing assortment of stories about scientists who have tried to define the edge between the non-living and life. Highly recommended!