Nick Lane 2015. Life Ascending. The ten great inventions of evolution London: Profile Books, 34 pp.

Nick Lane’s tour of his choice of the 10 iconic and transformative evolutionary advances in the history of life on earth. The first 8 chapters are: the origin of life; DNA; photosynthesis; the complex cell; sex; movement; sight; hot blood. Most of this territory is covered more powerfully and with more up to date material in his more recent The Vital Question (2015).

But worth reading just for the last two chapters.

Chapter 9 Consciousness Nick Lane isn’t afraid to pass judgement, positive and negative, on the big names in the field.

I have rarely come across a field where the main protagonists refer so little to each other …

And Nick Lane agrees that Julian Jaynes is obviously daft to assert that the Homer of the Iliad was not consciously aware while just a hundred or few years later the Homer of the Odyssey was.

Nick Lane would, I think, find a lot in common with Carlo Rovelli on consciousness. Both empirical, which is surely an increasingly important approach where problems are increasingly challenging.

The first thing we must do is dispose of the idea that consciousness is anything like it seems. it’s not.

and

You are the music while the music lasts [T.S. Eliot]

(Rovelli would perhaps only add that his theory that the arrow of time that is entropy gives us more.)

They both agree that consciousness is all in the timing - tens to hundred millisecond scale over which incoming signals are integrated into an awareness, a model of nearby reality. Images which fly past faster than that are seen but not consciously registered. This matches roughly the ~40 Herz frequency with which groups of neurons fire, a phenomenon apparently correlated with conscious experiences in some experimental settings (cf Christof Koch & Francis Crick; also Gerald Edelman coming from a different (immunological) perspective.

Chapter 10 Death explores the Peter Medewar proposal that we have accumulated a “graveyard” of genes that are selected for since they promote reproduction early in life even thought they can often be fatal later on (when it doesn’t matter to selection). But Nick Lane shows that this is not so simple: ageing is not the same thing as age-related disease. A single base change in a mitochondrial gene (common in Japanese populations, not elsewhere), halves the risk of hospitalisation among those older than 50! (Tanaka, M., Gong, J.-S., Zhang, J., Yoneda, M. & Yagi, K. (1998) Mitochondrial genotype associated with longevity. The Lancet 351, 185–186.) NB doesn’t extend maximum life, but increases “health span”. The mutation causes a small but life-long reduction of free radical leak from the cell during respiration. (Increasing the population of mitochondria per cell has the same effect, and is a consequence of low calorie diets.)

Also of great personal interest is rapamycin, an immunosuppressant effective in transpant patients (but not at The Alfred?!) which has been put forward as an “anti-ageing” drug. In transplant patients it does not cause increased bone loss or increased cancer risk. Other than noting “broad spectrum attack” possible deleterious consequences of rapamycin not explained by Nick Lane. To investigate further …