The Tangled Tree: A Radical New History of Life by David Quammen: A review

"Science itself, however precise and objective, is a human activity. It's a way of wondering as well as a way of knowing. It's a process, not a body of facts or laws. Like music, like poetry, like baseball, like grandmaster chess, it's something gloriously imperfect that people do. The smudgy fingerprints of our humanness are all over it." - David Quammen in The Tangled Tree

In The Tangled Tree, popular science writer David Quammen gives us the history of a field of study called "molecular phylogenetics." 

Have I lost you already? Well, hang with me a bit longer; this is actually pretty interesting.

In the late 1970s, a research team at the University of Illinois announced that they had identified a "third domain" of life. This "domain" was made up of single-cell microbes which they called archaea. They were genetically distinct from what were then the only two recognized lineages of life: prokaryotes, which include bacteria, and eukaryotes, which include plants and animals. This team was headed by Carl Woese, who Quammen calls "the most important biologist of the 20th century you've never heard of." (Even more interestingly for me, the team included as his chief assistant George Edward Fox, then a post-doctoral researcher and soon to be a researcher in biochemistry at the University of Houston, where he still serves.)  

Quammen spends a lot of time describing the life's work of Woese, who, in his telling at least, was the guiding force behind the discovery. Woese was undoubtedly a major contributor to the science of molecular phylogenetics, which essentially describes how evolution occurs at a molecular level and is not just vertical between parents and children but can also be horizontal (between species) through something called "horizontal gene transfer" (HGT). Unfortunately, late in life Woese turned into a bit of a crank who harbored resentments over slights - for example, the fact that he was overlooked for the Nobel Prize.

Science is a human activity and humans are notably imperfect.

One of the most intriguing offshoots of this new science for me is what it does to the old concepts (at least since Darwin) of species, individuals, and the evolutionary tree of life.

First of all species: We think of species as being discrete, separate, identifiable. In reality, each "species" is a mosaic of species. Each living being is not so much a species as a community of species which live together in symbiotic relationships.

Which brings us to the individual: Humans, for example. By the estimate of one research group, each human body contains 37 trillion human cells and 100 trillion bacterial cells! (Another study puts the ratio closer to 1/1.) We are host to other fellow travelers as well - nonbacterial microbes like virus particles, fungal cells, archaea, and other teeny bits of life. And all of these play their role in helping us to function. In helping us be human. These "others" that are a part of us make up an estimated 1% - 3% of our body mass.

And about that tree: As Darwin drew it, it has distinct branches and twigs, but this isn't really how evolution works. In fact, the branches and twigs are all tangled and grown together, so that one species - human, for example - may be composed of more than 10,000 actual species living in our guts, our hair, our mucus membranes, our skin...

Have I blown your mind now?

This is truly an amazing story and Quammen does a commendable job of telling it in a way that can be (at least partially) understood by a reader with scant scientific training. He also gives us the personalities of the scientists who pioneered the new field, but one could argue that he is too gentle with them at times. Woese did turn quite paranoid late in life and grew to hate Charles Darwin, feeling that Darwin was hogging all the acclaim that he (Woese) deserved. And then there was Lynn Margulis, one of the women researchers who featured prominently in the book. She made important contributions early on, but she, too, turned quite dark at the end of her life, becoming a 9/11 truther. Quammen tends to present these as sort of lovable quirks of personality.

Still, a fascinating book, divided into mercifully short chapters which make it easier to absorb. Moreover, each chapter ends in something of a cliffhanger that makes you want to keep turning those pages. And so I did and was surprised when it ended at 65% on my Kindle. The rest is all acknowledgements, notes, and bibliography.  

My rating: 4 of 5 stars