Intelligence in Nature - Jeremy Narby [38]
Plants do not have brains, so much as act like them.
Later that day, I wandered through the streets of Edinburgh. The clouds had cleared, and the winter sun lay low on the horizon. The city and the volcanic cliffs overlooking it were bathed in pale light. I went over the morningâs conversation with Anthony Trewavas. We humans have different timescales from those in plants. Consequently, we do not see plants move and assume they are stupid. But this is an incorrect assumption caused by our animal nature. We do not see them move because we operate in seconds, rather than weeks and months.
I stopped on the sidewalk of the cobblestone street leading up to Edinburgh Castle and remained immobile. I breathed and watched people walk past. I tried shifting to a plantâs timescale, but my thoughts kept racing at animal speed. An image popped into mind of Trewavas sitting in an armchair, not moving, thinking about plants. He was acting like a plant to understand plants, and attributing intelligence to them. Like a shaman, he identified with nature in the name of knowledge. His eyes were shining.
Chapter 8
SMART SLIME
Seeing that plants can make decisions led me to look into other cases of intelligent behavior by brainless organisms. I focused on simple species in search of the basic conditions of intelligence.
Amoebas attracted my attention. Their name comes from the Greek amoibe, meaning change. These microscopic single-celled creatures mainly consist of a blob of protoplasm surrounded by a porous, flexible membrane. Amoebas move around by transforming themselves. They change the shape of their bodies by shifting their jellylike contents and stretching their membranes to form extensions known as pseudopods, or âfalse feet.â Amoebas are shape shifters, transformers.
Some amoebas have the capacity to merge with one another to form a single giant cell, with thousands or millions of nuclei. Known as true slime molds, these peculiar unicellular organisms can grow as big as a human hand. And if one of them is diced up, the pieces will put themselves back together. Creeping around slowly and engulfing food along the way, true slime molds act like giant amoebas. There are approximately one thousand species of true slime molds, and they occur around the world, in particular in temperate forests. In their visible, aggregate state, they look like glittering blobs of mucus, or spilled jelly. They can be white, red, orange, or yellow. Typically, a true slime mold changes shape as it crawls over damp wood, leaves, or soil, ingesting bacteria, molds, and fungi. Its entire body is covered by a layer of slime, which it secretes continually and leaves behind as it crawls forward. Though true slime molds are composed of only one large cell, and therefore lack nervous systems and eyes, they can move, navigate, and avoid obstacles. They can also sense food at a distance, and head unerringly toward it.
True slime molds defy categories. They move around to feed themselves, like animals. But they give rise to fruiting bodies containing spores, like fungi. Once their spores disperse to new habitats, they âgerminateâ into microscopic amoebas. The true slime moldâs life cycle is completed when these tiny amoebas merge into a single, giant cell. True slime molds spend their lives going between two kingdoms, fungi and animal, and between two scales, microscopic and macroscopic.
Scientists recently discovered that true slime mold, Physarum polycephalum, can consistently solve a maze. They found that when separate pieces of this bloblike organism are placed in a maze, they spread out and form a single cell, which fills all the available