Monday, December 17, 2012

Thumbs Down: Ancient Clues or Cultural Constraints?

Last week at Harvard's Sackler Museum I photographed and took notes on what I considered to be a remarkable artifact of ancient Egypt--a single wooden arm. Several things about it fascinated me. First, its superb form, the dimensions stylized but perfect. Second, the fact that it was flat on the inside part, where it would have been attached to a larger sculpture. Third, the fact that it was made from wood, ostensibly a rare and precious commodity in a desert country. Perhaps the most amazing feature of this arm, which belonged to a striding figure, was its partially fisted hand with a beautifully tapered thumb aimed straight downward. My "find" merited several minutes of observation and a return visit.

Call me naive. I am. And easily swayed by the visual. But I found this particular object fascinating, inviting me to think on it more.

Fast forward to today when I stopped at the MFA for lunch with my friend Nancy Berliner. Waiting for our noontime rendezvous I was cornered by a herd of school kids guess where? In the ancient Egyptian rooms.

Taking a minute to observe what was there, I found myself mano a mano with a whole series of wood sculptures of striding figures, all proportioned stylistically but beautifully, all with hollow arms articulated at the shoulder, and all with thumbs pointed elegantly downward. It occurred to me that my Sackler arm was perhaps not that unique, in fact I considered the possibility that it may have been an ancient copy of an ancient copy of an ancient copy. Maybe the downturned thumb means something and maybe it's just a style. A stylized constraint that was de rigeur for Egyptian statuary of a certain time and place.

Why am I writing about it here in the context of botany instead of in my other blog, (Scientist/Artist) where I explore the connections between art and science, cognition and aesthetics? Why is it here in Botany Without Borders?

In my opinion the copy of copy of copy syndrome is emblematic of much of my experience as a botanist. Lucky to be ensconced in the botanical libraries at Harvard, I familiarized myself with classic texts that reached back hundreds of years. Studying many of these texts it became apparent to me that the scientific images in them persisted, almost identically, in series of editions by generations of authors from all over Europe. Images we had come to take for granted in the late 20th century had, in many cases, originated in the 17th century or earlier. There were even examples of images copied from Greek texts by the Roman Dioscorides, that had persisted all the way into our own time! This represented a deeply conservative strain in science that I came to understand only gradually, a mindset with unmistakable consequences.

If a picture is worth a thousand words imagine the hidebound character of a science meant to enlighten and discover. Imagine my response when I came to understand that the accepted concept of species, evidence for evolution, was a pre-Darwinian phenomenon that glided over the inconvenient fact of descent with modification.

Last month I reviewed a paper on the fascinating Galápagos Islands, the spot where Darwin had one of his "eureka" moments about the evolutionary process. The authors of the paper I was reading used dozens of journal pages to discuss the fact (to them) that no new species of their study group exist in the Galapagos. They didn't deny evolution in their paper, just implied that it didn't happen in their neighborhood, not with the species they studied. The pile of words, descriptions, measurements, dates, elevations, and specimen numbers was a kind of filibuster intended to make their point.

In the same way, thousands of wood arms were manufactured in ancient Egypt, but the artisans didn't dare waver from the stylistic constraint determined by unwritten, perhaps unspoken cultural rules.

Whether we are doing art or science or anything in between I think it's our job to learn the rules, then learn why we have them, and finally, to apply critical thinking to our decision about just how much we want to figure them into our practice. The alternative is to continue, potentially at least, misguiding generations to come.

Thursday, December 6, 2012

Apical Dominance, Symmetry, and Christmas Tree Genomics?

Yesterday's New York Times featured an article on breeding the perfect Christmas tree using RNA sequencing. The perfect (dead) tree would presumably retain its needles for longer than the ones we see now in our living rooms. Probably it would have more idealized proportions (perfectly obconical) and other traits that we consider desirable in holiday icons. You've gotta wonder.

Plants have evolved for the past several hundred million years through the interaction of their genetically-controlled anatomy and the challenges of a harsh terrestrial environment. One feature of plants that I always teach my students is apical dominance. Apical dominance describes a primary feature of plant growth---the tips grow toward sunlight. Apical dominance is apparent in our "typical" Christmas tree-like conifers. The tip of the tree, its highest point, is also its narrowest point. 

The phenomenon of apical dominance is mediated by the release of hormones by cells at the tip. The hormones quiet growth in regions closest to the tip so that the tree can focus its energy and resources on growing upward. This enables the individual tree to out-compete others in the forest that might otherwise block its sunlight, vital for photosynthesis.

As a result of apical dominance the conifers we use for Christmas trees present with a nice symmetrical shape where branches radiate outward in increasingly wide whorls as they gain distance from the apex and its "do not grow" hormonal messages. While this phenomenon is most apparent in "christmas trees" we can detect it in all kinds of trees and woody shrubs. It just takes a little bit of looking at.

"Looking" is what I'm thinking about here. It is an unusual feature of our visual culture that stresses unwavering symmetry as a signal of beauty. I wonder why that is. If we consider the arts of east Asia, particularly China and Japan, we see a completely different approach. There, natural beauty is seen in plants, rocks, and landscapes whose symmetry is slightly (or a lot) perturbed by interferences. Holes, bends, reversals, crookedness. These are the features that make a rock or a bonsai or a tea bowl special.

Would our steroid-injected visual culture benefit from an appreciation of the crooked, the stunted, and the asymmetrical? I think so. For one thing it might give us a little more appreciation for those imperfections that lie just beneath the surface of our supercharged lifestyle.

I know that aesthetics is big business all around the world, not just in the United States. But I wonder whether we should re-assess our mass-produced approach to Christmas tree beauty. Instead of pouring resources into developing a "perfect" (dead) tree for our living rooms over the holiday season, maybe we should plant some trees that will live into the future. Some more greenery in all its imperfection might go far toward preserving our soil, our climate, and our sanity. 

Monday, December 3, 2012

Resource Allocation, Innovation, and Risk: A Botanical Model

The other day Lucy and I were talking about how her Mac Book (circa 2007) is practically obsolescent. It's an amazing thought actually, given the dazzling technological innovations that have emerged from Apple since then. In spite of a closetful of used and practically useless products from the last 20 years, we are joined at the hip to our iPhone 5 devices. It appears that Apple's strategy to allocate resources to innovative, growing product lines has provided brilliant results. In spite of what seems to be planned obsolescence in all of its devices, Apple continues to evolve to the delight of enthusiastic customers. What's it all about?

Our conversation got me to thinking about plant growth, resource allocation, and innovation and how, in a not-so-random way, it is related to the Apple phenomenon. 

If you think about a tree for example, the growing tips are buzzing with molecular activity and resource allocation. At the growing tips (where meristem tissue resides--roughly analogous to human stem cells) the tree is investing most of its resources, sugars, minerals, protective tissue, and as the leaves emerge, water. At the same time it is exactly at these meristematic areas that the tree faces the most risk. Predators, wind, desiccation, and UV exposure are some of the many adaptive challenges faced by meristematic buds, the growing tips of the plant. 

It's also in the buds where tissue differentiation occurs. Leaves, branches, or flowers may emerge from a meristematic bud. And ultimately, in buds that differentiate into reproductive tissue, meiosis occurs. Meiosis produces sperm and eggs; it's the basis of reproduction and genetic change. So it's in the vulnerable buds where genetic innovation, the engine of evolution, occurs. In the same way, new product lines that shape the evolution of a company emerge from older iterations. 

The growth that emerges from buds, whether leaves, branches, or flowers, is the part of the tree that's the most exposed, the most vulnerable. It's the part of the plant the encounters all the harsh realities of the physical world. It is out at the tender buds and emerging soft tissue that the tree survives or dies. In a similar way, new product lines are vulnerable to market choices and customer satisfaction. The tree takes a calculated risk with new leaves. Apple takes a calculated risk with new products. 

What happens to older parts of the plant? In trees, older tissue becomes woody through a process called lignification. An insoluble, non-permeable, practically indigestible molecule called lignin invests every woody cell. Subsequently, the cells die. Dead woody cells are far from useless. They support the tree and conduct water and nutrients that nourish new growing cells at the tip. Similar to an evolutionary tree, where branching occurs, a "decision" is made to render the ancestor extinct. It's a rare tree that sprouts fresh buds from branching points that go back 10, 20, or 30 years. 

We see this kind of growth process in many types of organisms, notably fungi and lichens. If you've ever looked at a colony of mold or a rotting log, you may notice that growth patterns are roughly radial. It's at the edges of the growth circle that resources are obtained and processed, and it's the cells at the edge that keep fighting their way into the substrate. As the fungus grows outward, similar to the tree, it encounters the vicissitudes of a harsh and unknown environment. Analogous to leaves, which produce nutrients through photosynthesis, apical fungal cells and new product lines are the driving force of growth and differentiation. 

I don't know if the Apple folks had a botanist working for them but someone somewhere must have looked at a plant and come up with the inspiration for growth form of unparalleled success. 

Sunday, December 2, 2012

Plants as a Model for Urban Transportation

I've been thinking about how we can use our knowledge of plants as a model for urban transportation systems. It's a tantalizing concept. Plants, like cities, are open systems that interact with their environment. Taken from that commonality there's a lot we can learn from plants about how to plan urban transportation systems.

What are some of the goals for transportation systems? Efficacy of movement, low emissions, energy efficiency, safety, low noise levels.

Think about the city. Tens of thousands of people move in and out of the city every day. Inside the urban boundaries they circulate in large and small arteries, pause, and continue on their journey. Along with the people there is the movement of vehicles that carry them or, in the case of bicycles, which they propel themselves. The city also imports all kinds of materials into itself day and night. All of the imports (and exports) are carried in vehicles of every sort. They are taken to nodes, points of activity, and they are processed there. 

Plants import countless molecules of water and nutrients every day. These molecules circulate and are utilized inside the plant body through transportation, change, and excretion. Molecules of various sizes are imported, organized, stored, and built into larger (or smaller) units. All of this happens "passively," that is, there's no noise, no emission, and no use of energy outside of sunlight or the breakdown of molecules like starch that are the products of photosynthesis.

Plant transportation systems have evolved for hundreds of millions of years so that the plant body, the analogue of the urban area, is built elegantly, minimally, and conservatively. Growth for its own sake never occurs on without the concomitant development of an infrastructure. 

Plants are well known for their efficiency in retaining resources like water in dry climates. In addition, plants are built to withstand physical, chemical, and mechanical emergencies like flooding, freezing, and breaking. These are the kinds of emergencies we may be seeing more in our urban areas as climate change continues. How can we develop urban transportation infrastructures that utilize these models?

One objective is to recognize diversity. How many types of transportation actually exist in the city? What do they accomplish? What infrastructure is needed to maintain them while ensuring the goals of safety, efficiency, and other desirable "quality of life" features? 

Another objective is to encourage smart development, not just growth. Do new areas of growth go along with new developmental moves? For example, is infrastructure for alternative modes of transportation like pedestrians and bicycles in place? Are there limits to scalability? For example, can goals like safety and efficiency be met or exceeded even as capacity for transport expands? 

Finally, how can we improve accessibility and efficiency for every part of the city and every population? How can we improve emissions standards? Lower energy use? And how to maintain or improve convenience of movement and transfer of people and materials?

A closer look at plant anatomy, and a study over a range of different kinds of plants, would inform these questions and I think, lead to creative new solutions for transportation problems.