Life Ascending

I admit, I was initially put off by the mere title of Nick Lane's new book, Life Ascending: The Ten Great Inventions of Evolution^{(amzn/b&n/abe/pwll)}. I'm one of those many biologists who is adamant about the absence of direction in evolutionary history, and ascending just sounds too much like life climbing the rungs of the ladder of life, so I picked it up in a somewhat prejudicial mood.

Have no fear, though, I was won over. Right at the beginning, he admits that it is a subjective list; his criteria for including the ten chosen evolutionary innovations are that it had to revolutionize the living world, that it was important to a significant subset of life today, that it was a product of biological (not cultural) evolution, and that it had to be iconic — it had to symbolic and arrestingly interesting to human beings. That's fair enough; one could write a book on just the evolved properties of prokaryotes, but yeah, operons and chemical sensing and secretion and motility are of vast importance, but they're only going to be iconic to a rather restricted set of readers. And since my own personal interests run more to metazoan innovations, I'm not going to complain about a book that gives my hobby horses a more substantial run.

Even better, though, what enlivens the book is the biochemist's perspective: Lane isn't so much interested in the superficial matters of morphology, but in the emergence of new properties in the molecular machinery of the cell, and how it affects the world around us. Somehow, it always thrills me when we drill down right to the interactions of molecules to explain how biology works.

So here are the ten evolutionary inventions Lane describes.

1. Origins of life: Where and how did life arise? A review of some of the models for abiogenesis.

2. DNA: What conditions would allow for the synthesis of nucleotides? Where did the genetic code come from?

3. Photosynthesis: The photosynthetic pathway is a combination of two very different functional pathways — what does this tell us about their evolution?

4. Complex cells: How did cells become more complex? A chapter on horizontal transfer and endosymbiosis — borrowing and stealing and kidnaping by ancient cells.

5. Sex: Why do we have sexual reproduction? A question that focuses on the cytological and genetic machinery.

6. Movement: How do organisms get around? Cytoskeletons and motor proteins, and where they came from.

7. Sight: How did vision evolve? A fairly wide-ranging discussion of opsins and crystallins and Hox genes and the weird glow of black smokers.

8. Hot blood: Another chapter with a little taste of everything: respiration, metabolism, insulation, and how a key feature of our physiology affects everything.

9. Consciousness: Where did our awareness come from? You won't be surprised to learn that Lane is a materialist — the answer lies in the wiring of the brain.

10. Death: Why do all organisms die, and why do we even have genes that contribute to senescence and death?

So the topics aren't that biased: only three exclusive to multicellular animals, and six that are about eukaryotes almost exclusively — and even in those our prokaryotic heritage is discussed. And really, when you're talking about genes and biochemistry, you can't get away from the fact that you are dealing with genuinely universal processes.

The book is also a fun read, deep enough to give you some substance, yet clearly written with the general public in mind. If you aren't a biologist or biochemist, don't shy away — you will be able to read this book, and you will learn a lot from it. When I was reading it, I was thinking this would be a really enjoyable text to build a freshman seminar course around. The chapters are readable and each one addresses an interesting topic in biology, bringing up both current research and pending questions, and it's meaty enough to spark some good discussions.