Category Archives: Biology

BOOK REVIEW: Astrobiology by David C. Catling

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Astrobiology: A Very Short IntroductionAstrobiology: A Very Short Introduction by David C. Catling
My rating: 4 of 5 stars

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This book explains how life came about on Earth and what that might mean for life elsewhere in the universe. It may seem odd that life’s origins on Earth is relevant to this otherwise extraterrestrial sub-discipline, but that bit of biology offers insight into what is necessary for life—at least life as we know it. There is also the question of whether life originated entirely within Earth’s primordial soup, or whether there was an extraterrestrial ingredient necessary.” [Note: we aren’t talking about an advanced civilization placing creatures here so much as raw materials frozen in space dust or a meteorite. This is the idea of panspermia that once had a substantial following.]

If you’re interested in whether there might be life beyond our planet, this little introduction will give you the basic insights into where it might be found and what it might be like. Though the book deals with a highly technical subject, it’s written with the non-expert in mind.

The book consists of eight chapters. The first chapter defines the subject of “astrobiology,” which is important as it’s not exactly a household term—and is arguably an ill-chosen term to boot. However, chapter one also defines life and outlines what are the necessities for the development of life. The second chapter explores what type of celestial body life might reside upon–or in. We tend to think narrowly of other planets like ours, but what about moons or meteorites, or even space dust? More broadly, this chapter gives the reader a primer on cosmology and astronomy as is relevant to the development of life. Chapter three evaluates the conditions which proved conducive to spawning life on Earth. This is followed by a chapter that looks at how the Earth provided an environment in which life could flourish, even allowing for the evolution of intelligent lifeforms. Chapter five explains how genes and the chemistry of life contribute to the perpetuation of life.

Chapters six and seven both answer the question of where we might expect to find extraterrestrial life. The former discusses promising locales for life within our solar system and the latter is about the space beyond. Needless to say, chapter six is a great deal more specific; it actually proposes nine celestial bodies in the solar system that could theoretically harbor life, and expounds upon which are most and least promising and why. Chapter seven is more about what kinds of places we might expect to find life, and where we might direct our investigations. While scientists are finding new planets all the time, it is a relatively new capability and these distant bodies are only discovered through indirect evidence. The last chapter is a brief one that discusses “controversies and prospects.” With respect to controversies the primary contender is the Rare Earth hypothesis that suggests that life may not be so common as we expect by virtue of the massive number of solar systems out there. As for prospects, that is just a couple of pages on the most likely contenders at the time the book was written.

The book has about a dozen illustrations, mostly explanatory diagrams and all in black-and-white. It also has a two-page further reading section. However, that’s it as far as ancillary matter is concerned.

I found this book to be interesting and a good way to get up to speed on the basic concepts necessary to understand the search for extraterrestrial life. I’d recommend it for others who’d like to do the same.

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BOOK REVIEW: Touch by David J. Linden

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Touch: The Science of the Sense that Makes Us HumanTouch: The Science of the Sense that Makes Us Human by David J. Linden
My rating: 5 of 5 stars

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“Touch” is a neuroscientist’s perspective on the human sense of touch, and the profound impact it has on life in our species.

It’s a short book, only about 200 pages of substantive text, arranged into eight chapters. The first chapter considers the role that our sense of touch plays in our lives as social animals. There are a number of studies described in this chapter, but I’ll cite only two that I think give an idea of what the chapter is all about. The first considers why a person holding a cold coffee is likely to be viewed more negatively than if that same person was holding a hot coffee after a handshake. The second reports that survey takers in a mall were more likely to gain compliance if they engaged in gentle, casual, and non-creepy touch—e.g. fingers to forearm.

The second chapter explores the combination of sensors we have in our skin—particularly in our fingers–that allow us to conduct feats of dexterity that (while we take them for granted) are phenomenally difficult. For all the billions put into robotics research, robots are nowhere close to being able to complete tasks that any five-year old can do. The third chapter examines how humans are uniquely geared to be able to give and recognize a particular type of touch sensation, the caress. Throughout the book there are a number of interesting stories, some of them are scientific case studies and others… not so much. This chapter begins with the story of a man on trial for flying into a rage because his girlfriend couldn’t get the pressure right when engaging in manual stimulation. (The author was actually on the jury.)

The fourth chapter delves more deeply and explicitly into sexual contact. Whereas chapter 3, dealt largely with hand against random skin, this chapter deals in genitals and erogenous zones more specifically. There are also a number of fascinating cases / stories herein. A lot of the chapter deals in how we experience and interpret pleasure.

Chapter five explains a specific type of sensation, that of temperature. It considers why crushed chili feels hot but crushed mint feels cool to the skin. While the focus of the book is on human anatomy, physiology, and social interaction, there are many cases from other species throughout the book. This chapter offers a prime example. It explains how Vampire Bats have a unique ability to sense infrared. This is of benefit to them, since they only take blood meals and, therefore, need to be able to sense where the blood is flowing and has the least insulation (fur) over it.

Continuing the examination of specific kinds of sensation, chapter six is about pain. This is where the neuroscientific perspective offers some interesting insight. In particular, because it considers why soldiers who had multiple gun wounds could do their job on the battlefield with nary a peep of complaint, but then would raise holy hell about a bad blood stick a few days later in the hospital. The case of a medic who was badly shot up but not cognizant of it until later is discussed in some detail.

Chapter 7 deals in the itchy, and asks and answers the question of whether or not itchiness is a particular case of low-intensity pain. By low intensity, I’m not speaking of the compulsive behavior sometimes spurred by such sensations.

Chapter 8 is also highly neuroscience influenced. It deals with various illusions of sensation, and how these illusions come about through the interaction of sense and the brain. While the most famous example of such an illusion is phantom limb pain experienced by amputees, Linden addresses less traumatic and more work-a-day tactile illusions for most of the chapter. (This may be because there are a number of popular works of neuroscience that deal in phantom limbs—most notably V.S. Ramachandran’s books.)

I enjoyed this book. It conveys significant technical detail, but does so in a fashion that is easy for a non-expert to follow both because of readable writing and the use of stories. The author uses frequent graphics to help clarify points, and the graphics (mostly line drawings and graphs) do their job by being easy to follow and interpret.

In short, the book was highly readable, concise, and informative. I’d recommend it for anyone interested in the sense of touch.

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You’re So Evolved: Love Poem to a Hominid

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Baby, I dig your bipedal ways
You could chase down wounded game for days
And walking around on just two feet
You can forage in the mid-day heat
When it’s too hot for those big ole cats
Who bully their way through our habitat

 

My dearest, it simply makes me drool
When I see you working with a tool
Thumbs opposable, and shoulders free
I’m awed when you throw stones at me
Just imagine how I shed a tear
When I see you chuck a pointy spear

 

And that prefrontal cortex, oh my lord
You could plan the move of a nomadic horde
One day you’ll be able to add, and subtract
You’ll think–and paint–in the abstract
You just need vocal cords of greater dexterity
To express yourself with heightened clarity
[not in grunts and stone throwing]

 

True, you’re not the strongest of the apes
And while tigers race you barely traipse
Monkeys climb, swinging tree to tree
You lack arm strength and dexterity
Still, there’s something about you that I just can’t deny
Though you share sixty percent DNA with a fruit fly
You’re so evolved

BOOK REVIEW: Gulp by Mary Roach

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Gulp: Adventures on the Alimentary CanalGulp: Adventures on the Alimentary Canal by Mary Roach
My rating: 5 of 5 stars

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This week I’m [improbably] doing two book reviews about works devoted to the human digestive tract. (Before you conclude that I’ve got a colon fetish, let me explain that I was spurred to this research by life events. I did some advanced yoga cleansing practices and wanted to learn more about the science of what was going on down below.) In addition to this book, Mary Roach’s “GULP,” I’ll be soon posting a review of Giulia Enders’s “GUT.” The two books have more in common than their monosyllabic titles beginning in “gu” and the fact that they each came out within the past couple years. They’re both light-hearted romps down your digestive tract. However, they’re also different in several key ways. GULP is quirkier; GUT is perkier, but more importantly the two books have different thrusts (yes, there’s just that much interesting stuff to learn about digestion (and the lack thereof)—which make the two books complementary. Cutting to the chase, I’d recommend both books, but if you only read one book about your alimentary canal this year, I hope my reviews will help you determine which one is for you.

Explaining how Roach’s book is “quirkier” will tell one a lot about Roach’s book and how it differs from Ender’s work. (And since Ender’s writing style could be described as quirky itself, it’ll help clarify that as well.) By “quirky,” I mean that Roach’s book is built around a set of narrow questions that address topics of a bizarre or strange nature. In GULP one will read about whether your pet really wants “paté in beef gravy” [spoiler: it does not], whether the story of Jonah and the whale is BS, how smugglers use their digestive tracts illicitly, what are the benefits of Fletcherizing (chewing your food more thoroughly—much more thoroughly), whether Thanksgiving dinner can split one’s stomach open (like it feels it does), and what’s the worst case flatulence scenario.

This isn’t to say that one doesn’t learn something about the basic science of digestion as one is reading about extreme cases of tasting skill, stomach fistulas, flatulence, constipation, and overeating. One does, but this book isn’t organized to educate one about the alimentary canal systematically and generally. It’s a work of creative nonfiction designed to make the reader keep saying “huh, I never would have thought” and it does an outstanding job of it. You may not have given much thought to some of these topics, but you’ll be craving answers by the time you get past the chapter heading. There’s a reason that Roach’s works top the charts of pop science books. She finds the interesting questions and the most fascinating examples.

There are 17 chapters in GULP, and while they collectively take one on a tour of the alimentary canal, Roach devotes more space to some parts than others. She spends more time on what goes at the head end (smelling, tasting, chewing, and salivating) than does Enders. Also, please don’t think the book is low brow or that it appeals to the lowest common denominator (8-year-old boys?) when I tell you that there are three chapters on various dimensions of flatulence.

As I said, you may not have thought much about some of these questions, but you’ll learn something nonetheless. A prime example can be seen in the chapter on smuggling via the digestive tract. I’d read stories of cocaine mules dying when a condom burst in their stomach, but I had no idea about the extent to which items and materials are smuggled down there. It’s not just drugs. One guy was explaining how he smuggled knives. Really. Knives. Plural.

There are a few topics that are well covered by both books. Take, for example, constipation. Roach elucidates the topic using the case of Elvis Presley and others who’ve been literally terminally constipated. (Ender’s—on the other hand—considers the everyman’s constipation, though with amusing drawings and commentary.)

I’d recommend this book for readers interested in learning more about how their food makes its way through—particularly if you like learning about the strange cases.

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BOOK REVIEW: What is Life? by Addy Pross

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What Is Life?: How Chemistry Becomes BiologyWhat Is Life?: How Chemistry Becomes Biology by Addy Pross
My rating: 4 of 5 stars

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Dr. Pross’s book shares a title (but not a subtitle) with the seminal work by the renowned physicist Erwin Schrödinger from 1944. While Schrödinger addresses a wide range of topics on how life might be explained in terms of physics and chemistry, Pross’s focus is narrower. Pross asks—and proposes an answer for—the straightforward (but thorny) question of how abiogenesis could occur. Abiogenesis is life from the non-living. Darwin did an excellent job of explaining how we could get from single-celled organisms to the great complexity we see in our own bodies, but Darwin didn’t touch the question of how that very first ancestor became animated.

The subtitle of this work, “How Chemistry Becomes Biology,” gives one insight into how Pross proceeds. There’ve been many ideas about how life came to be on planet Earth over the years. For a time, the idea of panspermia—life arriving from an extraterrestrial source—was popular. Of course, the most popular belief has been that there was a force of life (i.e. an “élan vital”) breathed into non-living matter by a, presumably, supernatural force / entity. While the awe-inspiring nature of life made this idea appealing / believable, it took a hit from the Urey-Miller experiments. Said experiment exposed the four materials believed to have been the most common in our pre-biologic atmosphere (hydrogen, ammonia, methane, and water vapor) to lightning, and the result included a range of organic materials—including amino acids–the building blocks of… well, us, among the other life forms of the planet. Of course, Urey-Miller didn’t make abiogenesis a foregone conclusion, but the production of ever more complex self-replicating molecules under laboratory conditions has made it easier to digest the notion that life developed without any intelligent or supernatural push.

While Pross’s ideas are at the stage of hypothesis, he develops a compelling explanation that revolves around the idea of dynamic kinetic stability. “Dynamic Kinetic Stability” is a mouthful, and so it’s necessary to break it down. The best place to start is with the “stability” part. This is because the biggest problem for an abiogenetical theory of life is the Second Law of Thermodynamics. The Second Law tells us that entropy increases. There are many ways of restating this, such as that chemical reactions move to states that are of lower free energy. However, the most intuitive way is to say that a beer mugs break but do not spontaneously pop into existence. So if everything is getting simpler by deteriorating, breaking, and decomposing, how does one get / maintain a stable state of complexity? First and foremost, the answer involves adding a lot of energy and resources, but there’s more to it than that–as the author explains. “Dynamic” can also be explained in complex terms, but it’s most easily thought of as being like a river in that the river’s existence is stable, but it’s always a different river—ever changing water molecules arranged differently. (Critically, our bodies are the same way. Except for neurons, our cells are constantly being replaced.) The term “kinetic” speaks to how said replacement takes place; replication must be fast and decay slow.

The appeal of the ideas put forth by Pross is that they’re conceptually consistent with Darwinian Evolution. That is, an entirely new set of principles isn’t necessary to make sense of the origins of life. Pross argues that the self-replicating molecules that can most effectively put resources to use succeed in doing so, and—in the process–they drive others into extinction.

I found this book interesting and readable. The author uses good analogies to make his points (which often deal in complex matter) as clearly as possible. I can’t disagree with the other reviewers who’ve pointed out that the book is a bit repetitive and drags out a relatively simple statement of the argument. It’s not so egregious that I could say that it’s necessarily the result of a desire to pad the book out to a length necessary to sell in hard-copy form. (But it might have been.) The understanding of this topic is in its infancy, but that doesn’t mean this book isn’t a valuable contribution to popular understanding of abiogenesis.

I’d recommend this book for anyone interested in reflecting on from whence we came in a fashion that is open-minded to explanations that eschew the supernatural.

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