David Quammen

This is a review of the Blinkist summary of the original book. I found that I Have two copies of the full book plus another book titled “The tangled wing” as well as the kindle version. And I’m wondering how good the Blinkist summarty is. But I’m reasonably happy with what I’ve seen today.....and happy to give it 4 stars].
The concept of a tree of life has a long history among scientists and naturalists.The concept can be traced back to Aristotle. He mentioned the progressional development of animals in his book History of Animals, written in the fourth century BCE. However, Aristotle suggests that progress in nature is akin to ascending a ladder; living organisms start out as elements such as earth, water and fire, and gradually evolve into plants, animals and then humans.
As the French botanist Augustin Augier wrote in 1801, an illustrated “tree appears to be the most proper way to grasp the order and gradation” of plant life......The tree of life may have reached its apex with the gifted illustrator and biologist Ernst Haeckel......In the latter half of the 1800s, Haeckel published multivolume books......But unlike Augier’s tree, Haeckel drew evolutionary trees that illustrated the precise lineage of living things. He produced a tree of vertebrates, mollusks, plants and mammals, just to name a few.....Along with his influential drawings, Ernst Haeckel is also responsible for coining such enduring terms as “ecology,” “phylogeny” and “ontogeny.”
Starting in 1831, Charles Darwin spent nearly five years aboard the HMS Beagle, journeying down past the Canary Islands and along the coast of South America to the Galapagos Archipelago......It’s worth noting that Darwin had largely sorted out his ideas regarding evolution shortly after he returned from his trip. Entries in his notebooks between 1837 and 1838 show him ironing out the details of how species adapt to their environment and pass on favorable traits to their offspring. But when it came to announcing his ideas publicly, Darwin delayed........In February 1858, Wallace was hoping to publish a paper on his own evolutionary ideas, and through a mutual associate the paper ended up in Darwin’s hands.
that summer, Darwin agreed to join up with Wallace and give a presentation at the Linnean Society.......The weather was sweltering and their presentation so boring that it was all but ignored. Nearly a year and half later, Darwin’s book made the splash that the presentation with Wallace had failed to create.
Our understanding of evolution really changed when scientists began looking to molecules for insight...Of particular importance were the separate discoveries made by Russian zoologist Constantin Merezhkowsky (1905) and American biologist Ivan E. Wallin.
Merezhkowsky proposed that plant cells got their chloroplasts–specialized organelles that enable photosynthesis–by absorbing and internalizing a bacterium.
plant cells were once the same as animal cells, but then they absorbed photosynthetic bacteria and became plant cells.
American biologist Ivan E. Wallin was also looking into a microscope (mid 1920’s) and seeing what looked like bacteria. But rather than chloroplasts, Wallin was looking at mitochondria, which is the organelle, or tiny organ, that gives energy to cells by burning nutrients and oxygen. Clearly, Wallin thought, this represented another case of symbiosis. And he too would eventually be proven correct. [I had not been aware that these ideas were explored so early and had the impression that it was Lyn Margulis who had come up with the idea and doggedly fought to have it accepted.].
By the 1960s, a few scientists were keeping alive the wild idea that, at some point in history, cells had captured and incorporated bacteria.......In 1966, American biologist Lynn Margulis was suggesting that even the wiggly things on cells, like the flagella or cilia that help them move, also came from captured bacteria.......Our understanding of how plant and animal cells developed dramatically changed as the field of molecular phylogenetics began taking shape.
It was around 1957, when Crick was theorizing about how proteins are built from DNA information, that he also theorized that these proteins, packed with long lines of hundreds of varying amino acids, might contain useful information about their genetic lineage......Crick’s casual suggestion is how molecular phylogenetics began. Bacterial “fingerprinting” further changed our understanding of evolution.
Carl Woese’s 1977 paper, which described the work he’d been doing in “fingerprinting” methanogens, peculiar organisms that tend to show up in swamps as well as in more extreme environments, but he found that they could not be classified as euks or proks–they are something else entirely, a category that would eventually become known as archaea.
Woese’s fingerprinting methods would continue to uncover major revelations.
upon closer inspection, Doolittle and Bonen confirmed that chloroplasts were indeed captured bacteria that’d been incorporated into plant cells.....Soon, the same team proved that mitochondria had also started out as a bacteria.
Regardless, mainstream science was not ready to accept these head-spinning developments, for it suggested that the history of life is reliant upon something that isn’t supposed to happen: horizontal gene transfer.
If Woese, Bonen and Doolittle were correct, genetic material had been routinely absorbed from one species by another, no reproduction necessary. The tree had begun to get tangled.
In the 1990s, there were competing trees of life, and they no longer resembled trees at all.
In the early eighties, scientists faced solid evidence that life was more of a mosaic, or a compound of converging elements, than previously believed......As a result, new models of evolution–new trees–began springing up in an attempt to express this new understanding.
Woese updated the Big Tree in 1987 and 1990, but it started with three main branches, Eukarya, Bacteria and Archaea, all stemming from a mysterious area labeled “Common ancestral state.”....What was really provocative was that Woese’s 1990 tree also suggested that Archaea and Eukarya have common ancestry. By extension, this meant that all plants and animals, including humans, have lineage that includes the archaea Woese discovered only a few years before.
However, what Woese didn’t foresee was that the nineties would witness an avalanche of evidence supporting horizontal gene transfer (HGT)......As a result, many scientists saw that the tree of life wasn’t a tree at all, and new illustrations began to emerge to reflect this. Some suggested that the tree was actually closer to a web, or perhaps a coral reef, with layers of interwoven sections.....For decades, many scientists resisted anything that strayed too far from the old Darwinian way of thinking about evolution. But by the end of the twentieth century, there was too much evidence to ignore.
Evidence of horizontal gene transfer has changed the way we think about evolution.
Consider the long history of clues about horizontal gene transfer (HGT)......In 1928, an English civil servant named Fred Griffith discovered that one type of dead bacteria could come alive when mixed with a second type of bacteria.......When the bacteria was resurrected, it came back as that second type of bacteria! A transformation like this wasn’t supposed to be possible.
Anoother example is one of the more significant documentations of antibiotic-resistant bacteria that took place in Japan following World War
These days, it’s more widely understood that bacteria can contain something known as transferable resistance factors, which are capable of quickly going from one species to another, no Darwinian inheritance necessary.
For a while now, it’s been becoming clearer that the real agents of survival are the genes rather than the organism hosting the genes......After all, there are certain proteins, such as tryptophanyl-tRNA synthetase, that can be found in humans and cows, as well as in bacteria.......In 1997, Ford Doolittle, along with his colleague Jim Brown, made 66 different trees to track 66 proteins like this one; they showed how such genes have their own lineage, a lineage independent of particular species or specific organisms. Sometimes genes move horizontally because, as Doolittle put it, genes have “their own selfish interests.”
Darwin couldn’t have known that HGT was even an option. So he still deserves credit for getting science on the right path with evolution; he just didn’t deduce the mechanism behind evolution correctly–nor could he have!
Many questions remain, but it is clear that our concepts of species and individuality are less stable than we thought......Tests at the University of Rochester showed that Wolbachia bacteria, a group of parasitic bacteria, showed up in the genomes of a range of insects and invertebrate animals such as head lice and crustaceans. It was concluded that the bacteria targeted ovaries and testes and was passed to offspring through infected eggs. Perhaps most surprising was how it affected fruit flies: the insect’s own genome was found to contain almost the entire genome of the bacteria.
Some of the most recent evidence suggests that, over the course of millions of years, “alien” genes have been incorporated into “the deepest cellular identity of plants, fungi and animals.” They’ve moved from chloroplasts and mitochondria and can now be found in the essential genomes of complex creatures.
And then there are all the microbes that inhabit the human body.....But these aren’t invaders –they’re essential to your health, well-being and critical functions, such as digesting food.
So are you an individual or actually a network of organisms? Some scientists go so far as to question whether the idea of an “organism” is still valid.
The key message in these blinks: A lot has happened since the publication of Charles Darwin’s 1859 book, On the Origin of Species. Since then, it’s been proven that genetic material doesn’t require reproduction in order to be passed to another organism. In the past few decades, horizontal gene transfer, the process of genetic material being passed and absorbed through symbiosis, has been proven to be a major factor in the evolution of life on our planet. Given the fact that this has occurred even between distantly related species, it is apparent that all life on Earth is a lot more closely entwined than we’d previously thought.
My take on the book. I was familiar with most of the concepts although I now have a better understanding of horizontal Gene transfer. (I remember in 1965, in my genetics classes, we were being taught about jumping genes in native corn in America ......though the mathematics of calculating links between alleles was a bit beyond me. So we have come a long way since then).....and I was certainly not aware of the work of Merezhkowski and Wallin much earlier. So did I learn some new things. Yes! Certainly did. Interesting stuff. Four stars from me.… (more)

I won't pretend I understood everything, but this was pretty interesting--it includes a great deal of biographical information about a number of scientists, and discusses their discoveries, and the developing, and sometimes abandoning of theories. One worries that some of one's beliefs would be considered ridiculous by the scientific community; this book makes it clear that the "ridiculous" opinion isn't confined to those outside the community. But that's a trivial point. What's interesting is the tracing of Horizontal Gene Transfer and other discoveries, and the fact that many scientists, while borrowing Darwin's fame (beginning their papers with "On the Origin of . . ." or, slightly less blatant, just "origin of . . ."), are critical of how much he was unaware of, to the detriment of future discoveries.
Narration by Jacques Roy is perfect.… (more)