Tag: illustration

Plants Move

(featuring an illustration by Sarina Mitchel)

Big brains are essential to our success as a species. That’s how we dominated this planet, so we tend look there to understand the secrets of intelligence. Yet, this perspective blinds us to other species’ achievements. Take plants, for instance. They don’t have brains at all, yet they make up over 82% of Earth’s biomass (source). They range in size from single celled algae to the largest organism on earth (learn about Pando here). Many of our greatest discoveries in chemistry, medicine, and material science amount to finding some plant that already solved a problem better than we could. Yet, we tend to see them as material resources rather than intelligent living beings. I suspect we underestimate plants because, from a certain perspective, they don’t do very much. They just sit there, letting food and water come to them. What’s so smart about that?

This perspective says more about human impatience than anything else. Plants can climb and tunnel and build. They search their environment for resources, relocate to prime spots, and wrestle with each other for access. They capture prey, hide from predators, and actively defend themselves from attackers. They can transform themselves dramatically, switching between totally different strategies depending on time of day, time of year, and environmental conditions. Plants are very active. It’s just on a different time scale than we’re used to. Plant movement is most obvious over hours, days, and years, though in some cases they move dramatically in just seconds.

Brains allow us to move quickly, which gives us a big advantage over plants, but I don’t think it makes us “more intelligent.” It’s better to say we found different strategies, specializing in different kinds of intelligence. Plants are slow and stationary because that’s energy efficient. It allows them to thrive in otherwise barren environments. Animals can’t do this. We all depend on plants for survival. Our extravagant, free-moving lifestyle is only possible because plants do the slow, hard work of capturing energy and nutrients from the air and soil, making concentrated fuel for our activity. Plants don’t need brains to live the way they do, and they don’t let that stop them from adopting all sorts of complex behaviors and lifestyles.

This is possible in part because plants often root themselves to the ground. That may seem like a poor choice, since it limits their options dramatically. They have to commit to one environment for their whole lives. Either that spot provides what they need, or it doesn’t and they’re doomed to die there. But there’s a major upside to this strategy: their lives are much more predictable than ours. This makes it possible for evolution to carefully plan responses to just about every threat or opportunity a plant might encounter in its lifetime. This is a different kind of intelligence than what we’re used to, one focused on exquisite design and finely crafted behavioral scripts, rather than spontaneity. Plants do respond in the moment, though, and even rooted to the ground they can be surprisingly mobile.

The most common and obvious way that plants move is through growth. Animals can’t really move until they’ve grown a body, but plants move by growing. They use their senses to track and follow the sun, water, and chemical nutrients they depend on. They feel the pull of gravity, the strain caused by the wind, and physical touch along their bodies. They change their shape by growing cells larger, faster, or in thicker layers on this side, but not that side. This allows them to reinforce themselves and stay upright, grope and crawl around obstacles to reach food, navigate wide open spaces with roots or runners, or wrap around trellises to pull themselves toward the sun.

Plants can also move by shifting water around their bodies in a process known as turgor. Cells with more water swell, while those with less shrink. By shifting water between cells in its stalk, a sunflower can rotate throughout the day to track the arc of the sun. Morning glories and lotuses use similar methods to hide and protect their delicate flowers at night, then unfurl them into extravagant displays to attract pollinators during the daytime. Although turgor is much slower than muscle contraction, it’s still fast enough to react to animals. The touch-me-not mimosa, sundew, and venus fly trap all move quickly in response to physical touch. A few species, like hairy bittercress and the squirting cucumber, are much more dramatic. They build up pressure behind a catch mechanism, then suddenly launch their seeds into the air with explosive force.

Plants are also masters of using weather and animals to help them move. Plants have evolved specialized seeds that travel great distances, allowing whole populations of plants to migrate and colonize new territory. You’ve probably encountered helicopter seeds that gracefully twirl through the air, dandelion seeds that ride the wind on floofy parasols, and burrs that hitch a ride on your pant leg. The energy for this motion doesn’t come from the plant itself, so should that even count? As an engineer, that sort of practical laziness just makes the design more impressive to me. The plant doesn’t bother capturing and reshaping energy for this, because it doesn’t have to. All it has to do is build the seed in the right shape and “let go” at the right moment.

What does all this tell us about intelligence? For one thing, life doesn’t need a brain to navigate obstacles, seek out resources, climb, glide, follow a daily routine, catch prey, or even launch projectiles. Plants are full of amazing behaviors that are completely mindless, yet elegant, successful, and highly optimized. We’ll never understand those behaviors by studying brains or Deep Learning algorithms, but they tell us a lot about ourselves. Our brains do not replace the kind of embodied intelligence we see so clearly in plants, they merely extend it. We depend very much on the same evolutionary design and “script-making” that governs the plant kingdom. Under the hood, much of what makes us intelligent comes down to the cells of our bodies, dynamically shifting chemical concentrations and patterns of growth, very much like plants do.

I hope to share several more posts about plants and fungi in the future, because there really is a lot to say. If you’re interested in going deeper on the topic of plant intelligence, I highly recommend the 1996 film Microcosmos. It explores the plants and tiny creatures in a meadow with some extraordinary macro and time-lapse photography. No other movie has given me a more vivid and profound sense of awe at how alive the world is, at every scale. Sadly, the streaming options are limited right now, but it’s worth it if you can get your hands on it.

As always, I’d love to hear your thoughts. What are your favorite examples of plants being amazing? Are there other kinds of “mindless intelligence” you’d like to see me write about? How do you think about the intelligence of plants and animals? How are they similar and how are they different? Let me know in the comments.

Beyond Blueprints

(featuring illustrations by Sarina Mitchel)

Imagine your skull is a cockpit. A tiny You sits in front of a view screen and a dashboard, watching the world go by, pulling levers, and pushing buttons. Your body is a robot, precision engineered to protect you, keep you informed, and respond to your every command. It’s a complex and sophisticated machine, but not intelligent. It does what you tell it to do. Its shape and function were exquisitely designed by God or evolution, and encoded as DNA. That molecule represents the full blueprints for the machine. Now that the design has been perfected, all you have to do is follow the instructions step by step to make the ultimate human tool: your body.

That was probably very easy to imagine. The concept shows up all the time in the media, whether we’re talking about the literal giant robots from Power Rangers, or the psychological metaphors from movies like Inside Out. This way of conceiving the mind comes naturally to us, in part because that’s how it feels to be a person, sometimes. Great thinkers like René Descartes built whole philosophies around this duality of body and mind / soul. It has come to shape how our society works in many profound ways. Unfortunately, science tells a different story.

Perhaps the first clue that something is off is how human-centric this picture is. Life was around for billions of years before people or brains came onto the scene. Even single-celled organisms perceive the world and quickly respond in ways that show awareness of their situation and how the world works, no brains necessary. When cells band together to make bodies, they often have tiny brains (like insects) or no brains at all (like plants). Humans are among the small minority of species who are entirely dependent on their big brains for survival. Does that mean that we’re one of the only intelligent species on this planet? Are all the others just empty robots with no one in the pilot seat?

Some might think of DNA as a blueprint that specifies every detail about how to build and operate a living thing, but the reality is much more complicated than that. It’s better to think of DNA as a family’s collection of cookbooks, passed on from generation to generation. They’re full of ingredient lists, recipes, and instructions. The family wouldn’t know how to cook at all without those books, so they’re critical to survival. They include all of the family’s daily staples and seasonal favorites. Even if, in theory, the family could get by on a more exotic diet, they don’t. Their cookbooks cover the full range of cuisine that they’re comfortable with, and they don’t often branch out.

And yet, there’s plenty of interpretation involved. What should the family cook for dinner tonight? Which recipes and books are more popular, and which go unused? How do they manage the pantry, and what do they do when they don’t have all the right ingredients? Just because the recipe says one thing, it doesn’t mean they have to do it that way. In fact, the recipe books are littered with sticky notes which suggest variations. They mark which parts of the recipe to skip, which ingredients to go heavy on, and recommend substitutions. The family can even mix and match parts from multiple recipes, or exchange recipes with friends to try something new.

This is getting a little too anthropomorphic. Cells don’t think about this sort of thing, because “thinking” isn’t how they do it. In reality, we’re talking about molecules, banging around together in chaotic but reliable ways according to the laws of physics. They don’t have any “intentions,” except maybe the ones implicit in their evolved recipes. But this is how they behave. Each cell is autonomous, responding to the environment with spontaneity. The DNA serves as a reference book, not a program. It isn’t even used to construct the cell. Remember, cells reproduce by dividing in half. Nature never builds a cell from scratch. Instead, half the family takes half the house, half the pantry, and a full copy of all the cookbooks. They wave goodbye, then carry on living as they always have, just as a separate cell with a separate fate.

DNA is a crucial resource, representing countless generations of acquired knowledge and wisdom. But it is not a blueprint, and that’s critical to how evolution works. Every cell and every organism lives an open-ended life, doing their best to survive with what they’re given. When circumstances change, life improvises and diversifies. The same genes may cause different behaviors in new contexts. When one way of living is blocked, old neglected genes may resurface, bringing back old ways of living. In stressful times, cells increase their own mutation rates, taking a risk to generate new variations which might get them out of a bind. This makes life far more flexible than if every aspect of design and behavior was explicitly laid out in the genome.

This becomes even more important for organisms with complex bodies. If DNA really was a blueprint, then building a human body would require precisely positioning and configuring each one of 37 trillion cells. Even if that process was 99.99999% perfect, there’d still be millions of errors. Luckily, this process is bottom-up, with each cell coordinating with its neighbors to figure out their relationships, what needs doing, and how to work together. That makes errors much more tolerable, since one cell can take over for another, or work around whatever defect is in the way. If the body were built from literal blueprints with no room for improvisation, then even a single cell out of line could potentially throw off everything that comes after. Errors would be much more likely to cascade and accumulate, potentially becoming fatal.

Perhaps the most astounding thing is that each cell in a body has a copy of the same set of cookbooks. They just read them differently, adopting a lifestyle to fit their place in the body. A bit like people in a society, each cell in the body tries to play its own role, and many different roles interact to make something much more than the sum of its parts. From many independent observations, decisions, and actions made locally by each cell, higher order structures and behaviors emerge. Cells make up organs and bodies. They manage bodily resources, capture and aggregate information about the world, and respond in coordinated ways. They perform extraordinary feats, like moving 37 trillion cells through space, gracefully and without damage.

Imagine you are a swarm of nanobots, clinging together to form a giant mecha. This mecha has evolved to do something useful, but its shape and function are only loosely defined. Each nanobot is a mindless automaton, operating independently within some constraints that are just specific enough for it to serve some purpose within the greater whole. These nanobots cluster to form dynamic structures, nested machines made of machines, in constant motion, building up to massive size and complexity. In order to manage this unwieldy bulk, the nanobots weave together into a neuromorphic computer. This specialized sub-processor simulates the world in real time, predicts what comes next, and carefully coordinates the timing of activity across this whole vast assemblage.

Part of that computer is responsible for imagining what it’s like to be the giant mecha. Its whole existence is within a simulated environment, extrapolated from the trillions of tiny motes of sensory data provided by the swarm. It watches the behaviors and emotions produced by the swarm, and uses them to tell stories about the values, needs, and intentions that guide the mecha’s behavior. It makes educated guesses about what the mecha will do next, which the swarm uses as hints to guide their behavior. As the only part of the mecha that is self-aware, and having no direct perception of the nanobots themselves, this simulation imagines itself to be in charge, and assumes the whole arrangement is for its benefit.

I know this is an uncomfortable image for many people. It’s not warm and fuzzy. It probably feels strange, maybe even disgusting. It’s not how we like to think of ourselves. However, “strange” and “disgusting” are also excellent words to describe living bodies, in all their infinite variety. Human beings are machines made of meat and bone. They are also unique souls, with meaningful lives, profound experiences, and extraordinary talents. The challenge is to see this not as a contradiction, but as two sides of the same coin. We can be the pilot in the cockpit, and the nanobot swarm.

What do you think? Is this a useful way of thinking about mind and body? Have you ever noticed moments when your body dominates your mind and the “pilot in the cockpit” illusion seems to break down? Or do you think I’m under-selling the power and importance of the brain? Is it right to say that “nobody’s home” in life without a brain, or is it more complicated than that? Any questions about this “cookbook” metaphor and what’s really going on in the cell? I’d love to hear from you. Please, join the conversation in the comments section.