Friday, May 03, 2013

Our marvelous kluge

kw: book reviews, nonfiction, physiology, brain, evolution

For the handful of people who actually follow this blog, the past nine days without a post indicate the difficulty I had finishing the latest book. While I enjoyed it and learned much, it was rough sledding, which I'll get into. I also find that, having retired, I am busier than when I was working, so for these few months at least, I have only written to review a book.

This common illustration of the Ascent of Man represents what most people think of as Evolution. As described in The Brain: Big Bangs, Behaviors and Beliefs by Rob DeSalle and Ian Tattersall, evolution works more like one of those massive multiplayer quest games. Imagine the players being all species of animals, from flatworms and beetles and clams and fish to birds and frogs and squids and primates and cattle. As the "players" move through the game, this one will encounter some new charm or tool or whatever, and that one will encounter something else. "Picking up" the new gewgaw may increase the survival of that kind of animal. After some time passes (lots of it!) some players will have gathered a number of such items, more might have gained one or two, even more have nothing new, and many have in one way or another "lost" and vanished from the game.

But what, exactly, is winning? Attaining the greatest percent of the biosphere? Certain species of termite seem to have won that hands down. Of course, in the context of The Brain, the biggest brain is thought of as the "winner", and many folks confidently expect humans to get brainier in the future.

The authors emphasize repeatedly that there was no preordained big brained "winner" of the "smarts lottery". Looking further back than the ape in the picture above, many of us learned that there is a "lizard brain" deep in our skulls, covered over with a "mammal brain", and finally covered over with the famed "gray matter" that makes us human, but with certain lizardly and "primitive mammal" mental quirks. Not really.

True, we are the current expression of 3.5 billion years or more of biological evolution. However, so is every other species on Earth! Your pet dog or cat, the robin in the yard, the worms in the dirt, the ants invading your kitchen, and the bacteria that help all of them digest their food, all have the same 3.5 billion-year evolutionary descent. Every leaf on a tree can be traced back to the same root. Humans are, as regards brains, the "lucky ones". If we succeed in bombing ourselves to smithereens, though, "lucky" isn't really the right word for it.

Well, the above is my take on it. The authors' take is detailed and comprehensive, showing (as well as we may know) how many features of the brain were developed and appended to what came before. The jargon gets a bit dense at times, but it seems the authors' attitude must be, "The readers are adults. They'll catch on, or look up what they must." We even find an occasional long chemical name, for no good reason I can determine. Lazy readers won't get far.

So, starting with the lowliest animals—and even with plants, which have some rudiments of cell-to-cell communication—we are led through the development of nerve nets, nervous systems, clusters of ganglia, brains, and the higglety-pigglety addition of features and structures to brains of all types, insofar as they tended to improve the lot of the animals possessing them. Along the way, we learn certain principles of evolutionary study, such as the importance of an out-group to clarify how to structure a portion of an evolutionary tree.

Natural selection is strict. Every feature of every creature has to be adaptive or it (the feature) will vanish. It can take many generations, but just as the human race is evolving toward having 28 teeth instead of 32, and losing our appendix, stuff we don't need is being done away with. That goes for the many parts of our brains. We have 'em because they are useful. At the end, the singular new feature that is, so far as we know, not present in any other Earthly animal, is our capacity to create and manipulate symbols.

Yes, I know that certain great apes have been taught to communicate using Yerkish or ASL, but the level of discourse possible with any of them is very, very limited. None of them created something like Yerkish; human experimenters did so. And transcripts of "conversations" that go for more than two or three exchanges make it clear that apes' intellect stops well before the level of a human 2-year-old. Abstract reasoning is beyond young human children, and much further beyond apes. Not only so, the behavioral clues gathered by anthropologists indicate that symbol manipulation, that is, language skills that we take for granted, were probably not present in our cousins the Neandertals or the earlier Homo heidelbergensis. The Neandertals (the book uses the word Neanderthals), though their average brain size was slightly larger than ours, apparently had a qualitatively different brain. They were very, very bright and capable, but there were no Neandertal Spinozas or Mozarts or Picassos or Feynmans. Hey, I just thought of a title for a great book for someone competent to research and write it: Did Neandertals Dance? I am betting they didn't.

At this point, I am going to chase another rabbit. I like the book and recommend it, but it does show marks of overspecialization on the part of the authors. They needed some more broadly-based scientists to check it. I hope this doesn't sound like sour grapes or piling on, but here goes:
  • In the second half of the book, where the authors are wholly comfortable with the material, there is only one deficiency. They do not mention the Mirror Test. Humans over the age of 18 months, the great apes, one or two species of monkey, bottlenose dolphins, orcas, elephants, and at least one species of bird, the European Magpie, can all recognize themselves in a mirror. This indicates a level of self-awareness that might be called consciousness, though many bridle at that notion for nonhuman animals.
  • Working back to front: on p. 174 in an illustration of the limbic system in 3 animals, the Olfactory Bulb in the 3 labels is called the Optic Bulb in the main caption. Proofreading needed.
  • On p. 142, we find the sentence, "Many bacteria have light-sensing cells that help them orient…" Bacteria are single-celled. They don't have cells, they are cells. They have light-sensing chemicals, perhaps even localized within the cell.
  • On p. 135, they state that magnetotactic bacteria sense up and down magnetically, because the natural magnetic field is horizontal. The key sentence is "The magnetosomes allow the bacteria to orient North-South, so theat they are parallel to the earth's surface." Not so. Earth's magnetic field is horizontal only at the magnetic equator. Everywhere else it dips. Throughout most of the U.S., and at similar latitudes in Europe and Siberia, and in South America and southern Africa, the dip is in the 40°-60° range. The dip is vertical at the geomagnetic poles. The bacteria can follow the dipping field either toward or away from light. Bacteria from very near the geomagnetic equator would find the field useless for guiding vertical motion.
  • On p. 105, an unusual typo appears: "A micrometer is one billionth of a meter…'. No, it is a millionth of a meter. I don't know if this was an author error, but since most folks do their own typesetting these days, I think it was.
  • I find two problems on p. 85. Firstly, the reason creatures that molt are called Ecdysozoa is stated "…because a hormone called ecdysone is involved in the molting". The two "ecdy" words are related, but in this way: εκδύομαι, or ecdyomai, is the Greek word for "undress". Secondly, it is stated that Barnacles are Bryozoans. Whoo, boy! These are in different phyla. Barnacles are arthropods, essentially like crayfish hiding in a cone-shaped shell, without claws. Bryozoa are "moss animals", more similar to sponges.
  • Now for something truly extraordinary. On p. 58 it is stated that the number of connections in a human brain is about 100 trillion (1014). That's right. Then we find, "Using the area of axons as a guide, the number of potential connections in a human brain has been estimated to be more than 10 to the 76th power. That is a 1 with 76 zeroes after it, a number in the same range as the number of particles in the known universe." I must conclude that the authors are entirely ignorant of both astronomy and physics! Whoever did this "estimate" is worse. Brain connections are made via synapses, and a synapse has a volume of about one cubic micron. That means a cubic millimeter could contain a billion synapses. So far so good. A small, 1,000 cc brain contains one million cubic millimeters, so if that brain were nothing but synapses (no room left for axons, dendrites and so forth), there would be a million billion of them, or 1015. The largest human brains are about 2,000 cc in size, so at most, the number of connections must be quite a bit less than 2x1015. This error, a factor of about 1051, is in magnitude the largest error I have ever encountered in print!
Enough of that. I have a chemist friend who is pretty unaware of anything except chemistry. Chemical IQ: 180; all other kinds of IQ: about 80. A little more thoughtful proofreading would have helped The Brain a great deal. It makes me wonder if the 5 people who wrote the blurbs on the back book jacket actually read the book. Maybe they're equally over-specialized and just didn't notice.

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