Watch any nature show and at some point you’re sure to hear the soft-voiced narrator (usually David Attenborough or someone doing their best Attenborough impersonation) marvel at the “boundless variety” of life, of its seeming infinitude of shapes, colors, forms, and its tenaciousness in colonizing apparently every niche of our planet, no matter how harsh or isolated. Or as theorist Ian Malcolm puts it:
If there is one thing the history of evolution has taught us, it’s that life will not be contained. Life breaks free, it expands to new territories and crashes through barriers, painfully, maybe even dangerously . . . Life finds a way.

One takes a risk in arguing with the world’s favorite fictional chaos theorist (OK, admittedly, a minor risk), but that’s just what Astrobiologist Charles S. Cockell does in his new book The Equations of Life, which is basically a big “Not so fast, Mr. Life-Finds-A-Way” in your open shirt and tight jeans . . .” As he succinctly puts it in his introduction: “physical laws restrictively drive life toward particular solutions . . . outcomes aren’t always predicable, but they are limited.” In other words, if life often does “find a way,” it’s only while driving around a relatively restricted and tiny neighborhood sharply hemmed in by the laws of the universe.

If that sounds a bit dull, or makes one worry that Cockell is a spoilsport ruining our sense of wonder at life’s myriad expressions, Cockell closes his introduction with a reassuring promise: “The unity of evolution and physics brings a new richness to our view of life, an appreciation that within the simplicity of rules that govern and limit the forms of living things there is a remarkable beauty.” That beauty, and Cockell’s own sense of wonder at it, pops up repeatedly as he makes a methodical, clear, and highly persuasive bottom-up argument.

Cockell works through various scales as he makes his case, moving back and forth from microscopic to macroscopic as he examines for instance why life uses DNA to carry its code, employs electron transport to garner/harness energy, or has carbon has its base element; why water seems a requisite of life’s existence; and, more whimsically, why fish don’t have propellers and land creatures have legs rather than wheels. In each case he goes beyond simply explaining why things are as they are, exploring why possible alternatives, such as silicon-based lifeforms (with a reference to Star Trek’s Horta) are unlikely or impossible. Toward the end he closes with an exploration of what these strictures mean for the search for other life elsewhere in the solar system/universe. This last section is obviously more speculative, but it’s hard to find a flaw in his reasoning that if we do find life elsewhere, it’s much more likely to be similar in its base construction and processes than not — more likely to be carbon-based, more likely to take certain forms, more likely to need water as a base medium.

It’s all fascinating and explained in such an easy-flowing, lucid and enthusiastic style, one that leaps at times into the lyrical, that it’s easy to forget one is reading some sophisticated science. Even when Cockell refuses to shy away, as most do, from presenting the reader with the equations that give the book its title, ranging from the simple P = F/A (pressure equals force divided by area) that drives the shape of a mole’s paws to the more complicated k=Ae (Ea/RT) (trust me, it’s more complicated) to these that Cockell uses to explain why a ladybug’s legs are a ladybug’s legs:

F = 2π γR + π γ (2cosø/h-1/R) R2 + dh/dt 3πηR4/2h3
G(ø) = sinø [4/3(l/r)2cos2 + sin2ø
NA≤9π2r8E2/64F2l6
W = F2NAlg(ø)/2πr2E

Looking at that last group (which required several minutes of hunting around for the right symbols on my keyboard) will surely make some eyes water or roll back in the head, but Cockell, even as he gives us the equations, reminds us each time that it’s not important that the reader follow the specific physics as represented by the formulae. What’s key is the understanding that despite the seeming complexity and variety of life, we can boil evolution’s choices down to some simple (despite what it looks like above) universal rules. If that seems a crude sort of reductionism, Cockell argues “There is beauty in physical simplicity . . a stunning elegance and maybe even charm in physical equations manifested in the living form .” And I can guarantee you won’t look at a ladybug or a mole or really any other creature the same way. Highly recommended.

This was a very interesting book overall, but unfortunately it was not super enjoyable as it was hard to get into. I really appreciated the fact that this book includes references. This is a great addition for readers that want to explore a bit further.

I received an ARC via NetGalley in exchange for an honest review.

This is a hard book to review. It's filled with interesting scientific discussion on many topics, but the author's main concern seems to be developing a thesis his examples do not support. As a chat with an interesting guy about math, science and biology, it's a fine book. But in between the chats there is a lot of stuff that doesn't make sense.

For one example, there is a long description of how a ladybug can walk up a smooth vertical wall. It's fascinating in its own right, but it has nothing to do with the subtitle, "How physics shapes evolution." It elucidates physical principles that could be used by a human designer. The reason a ladybug has setae is not that they are the best way to adhere to surfaces, but that random mutation and natural selection resulted ladybugs with setae surviving and reproducing better than some ancestral form without setae.

If physics could prove that there was only one way to solve a biological problem, it would be fair to say that physics had shaped evolution. But there are many ways to climb smooth vertical surfaces, and many creatures that thrive without that ability. It's true that any evolutionary solution must be consistent with physical principles, but everything in the physical universe must be consistent with physical principles, so that's an empty statement. And his deduction from that, that if extraterrestrial life is found it will be similar to terrestrial life--because it is determined by the same physical principles--is faulty. In places with different gravity, ambient temperature and pressures, and other factors of physical environment, I would expect entirely different design approaches.

If evolutionary designs were optimal, then again it would make sense to claim that they had been shaped by physics, or at least by the science that made the designs optimal. But evolutionary systems have clear design flaws, that reflect their biological history, not physical principles. It is true that the same solutions have often evolved independently, which is some evidence that they are in some sense optimal. But even distant relatives on the tree of life share tools that might influence design choices independent of physical principles. For example, while eyes have evolved independently, all eyed creatures share an ancestor with opsins and the PAX6 gene; a creature in need of an optical sense organ without those tools might have come up with an entirely different solution.

Moving from subtitle to title, what the author calls "the equations of life" have the opposite problem. Instead of observing biological designs and deriving the physical principles that make them work; the author applies equations from physics and claims to find evidence for them in life. The first equation is the power law, such as Max Kleiber's observation that metabolic rate of a wide range of creatures seems to be approximately proportional to its mass raised to the 0.75 power.

But this is not an equation so much as a rough curve that seems to roughly fit a large number of creatures over a wide range of masses. But lots of other curves fit equally well, this is nothing like a precise relation. Moreover, there are many creatures far from the predicted curve. As a physiologist (someone who studies the physics of biological systems) Kleiber's main interest was in asking why deviations occur. He did not treat the precise shape of the "main sequence" as revealing some deep physical principle. He was asking a biological question, why are some groups of creatures significantly different from average.

Now a physicist might well be interested in whether the relation was a true power law, or just a slightly less than proportional relation. If it were a true power law, then it might reveal some interesting connection between mass and metabolism. But the author of this book merely lists a lot of biological relations that seem to have rough power law shapes (my Dad, another physiologist, used to say, "everything looks linear on log-log paper," which is the same thing as saying, "everything looks like a power law"). It takes more than eyeballing shapes to make useful insights in either physics or biology.

The fact is biology has taught a lot to physicists. Perhaps the most famous example is entomologist Antoine Magnan who asked his engineer assistant André Saint-Lagué to calculate the aerodynamics of insect flight. In Magnan's 1934 book on insects, he recorded the conclusion that flight is impossible. Since insects clearly do fly, it meant that the current knowledge of aerodynamics was faulty (it would be over four decades before Torkel Weis-Fogh--a zoologist not a physicist or aeronautical engineer--discovered the key principle that allows insects to fly).

There are many examples in The Equations of Life in which observing biological systems has led to interesting extensions of physics. There are no credible example of the application of physical principle leading to progress in biology--the best the author can offer are things like the power law example.

Reading this book will teach you a lot of physiology, and some interesting facts about biology and physics. But the material is organized to support an argument, and it doesn't support that argument. That makes in annoying to read at times, and means it is unconvincing in its broader conclusions.

Well, that was a pretty informative read. A little difficult to get into at times (although I suspect half of it was because I was trying to read it when I was too tired), but definitely informative.

To be honest, I’m not that well-versed in equations in general. I can solve basic linear equations with two unknowns, that kind of thing; just don’t ask me to memorise really complex ones. So, I admit that, at first, I was hesitant to request this book, thinking that maybe it’d be out of my reach. Fortunately, while it does deal with equations, it’s not just page after page filled with numbers and symbols, and the author does explain what each term of each equation stands for. In the end, this was all fairly understandable, both the math and the writing itself.

The book doesn’t simply deal with equations either, and delves into astrobiology and basic atomic and particles physics (electrons -are- subatomic particles, after all, and knowing what part they play in atomic interactions is useful to understand what exactly happens at the biological molecular level, too). In fact, I found that a couple of chapters do fit in nicely with quantum theory, if you’re interested in that as well, since they explain essential interactions at shell level. I hadn’t studied chemistry since… at least 21 years, but this sent me back to my old classes, and I realised that I still possessed the required knowledge to get what the author was talking about. Which is great, because 1) I’m interested, 2) I like it when I grasp something that old me would’ve dismissed as ‘too hard’, 3) did I say I’m interested?

Last but not least, the book also contains a list of references that I’ll try to check at some point. Not all of them, of course, but since he points to Sean B. Carroll and his works on evo-devo, that’s a win in my little world.

All in all, this was a set of really interesting and intriguing theories, theories that make a lot of sense when you think about it and take time to observe nature around you. (Why did animals develop legs and not wheels? Well, inequal terrain and all that… Logics, logics…) And if you’re wondering about the possibility of other forms of life, either carbon-based on other planets or not even carbon-based, the author also explores this, going to demonstrate why it may or may not work (hence why a basic lesson in chemistry is provided). A solid 4.5 stars for me (I just think it dragged slightly in the last chapter).

Finally a science book that is not afraid to show some equations! An extremely enjoyable reading, that show the connection between complex scientific concepts with real life examples. Reading the volume requires concentration, and some mathematical basis, but it is definitely worthwhile

I thought this book was written well and explored a lot of topics. While it's called The Equations of Life, it only deals with a few equations, though that didn't bother me. I found that the author is great at explaining how simplified equations can lead to surprising consequences in terms of what kind of life we can expect. He also devotes some time to astrobiology, which is an interesting field of research right now (particularly because we don't know what's out there). Overall, the book was a pleasure to read, and I recommend it to people who enjoy reading about science and physics.

Is biology universal?

Sitting under my rock as I do, I had no idea there were astrobiologists. For a couple of decades now, apparently. One of them, Charles Cockell has written a book called The Equations of Life. Not only does it examine extraterrestrial life, but it firmly places physics underlying all of biology. Biology is totally dependent on physics.

Every lifeform seems to work along basic principles of physics or quantum physics. It’s all about processing electrons for their energy. The basic building blocks of life, amino acids, sugars and fatty acids are apparently raining down on planets all over the universe. Asteroids transport them. And water, which we like to think is our extraordinary trump card, is found commonly all over. The ingredients for life are everywhere. So there must be life out there, and there must be work for astrobiologists.

Cockell finds that life is pretty much going to be carbon-based, regardless of the planet or galaxy. Silicon-based life is possible, for example, but is just unlikely because of silicon’s inherent weaknesses. Silicon-based life is probably doomed to be primitive. Carbon however, is not only everywhere, it binds with everything appropriate to life. It’s the odds-on favorite for creating life. And will win the Darwinian battle.

The book takes a very long time to get to the good stuff. There is a lengthy examination of the ladybug, and how its wings and legs express physics equations. There is an in-depth examination of anthills and the sociology of their builders. These are interspersed with physics equations, partially explained, barely applied, and skippable. There is a great deal of basic biology and chemistry, including a long discourse on the periodic table. It is, despite Cockell’s efforts, rather flat.

Back in outer space, we do not know if the DNA/RNA system is universal, or how a DNA/RNA mutation system might perform in other environments, gravities, atmospheres, climates and seasons. But at the physics level, it is easier to predict. It’s the relationship of atmosphere to gravity to body mass that dictates it. This does not limit lifeforms; it enhances variations. Anything is possible, as long as it obeys the laws of physics. So, Cockell says, if there were a small planet with lesser gravity, and a thicker atmosphere, the top animals might be flying beings of human size. Maybe they wouldn’t have invented the automobile and burnt up all the carbon. Maybe they’d have really advanced flying machines. That’s the fun part of astrobiology. There is far too little of it in The Equations of Life.

Meanwhile, back on Earth, while we can’t say biology is universal right now, we can say that physics is. Everything that acts can be reduced to an equation. Is that good news. or what?

David Wineberg

Powerful! The ideas and theories are amazing and the author added the references. Great book and excellent candidate for any library from colleague to university.