Get Smart

THE artist – if she or he can be called that – was right-handed and used a shark's tooth. They had a remarkably steady hand and a strong arm. Half a million years ago, on the banks of a calm river in central Java, they scored a deep zigzag into a clam shell.

… It was found etched into the shell of a fossilised freshwater clam, and is around half a million years old – making the line by far the oldest engraving ever found. The date also means it was made two to three hundred thousand years before our own species evolved, by a more ancient hominin, Homo erectus.

… it was made deliberately, and yet, unlike tools, the mark has no obvious function. It may have been a decoration, or a practice run for a decoration on another object.

… "Regardless of intent, the very process of rendering a geometric form would seem to indicate the workings of a mind no longer tethered solely to the here and now, but capable of a uniquely abstract form of conscious 'wandering'," Edelman says.

The etch also suggests H. erectus was integrating different domains of knowledge – thought to be a key stage in the evolution of our creative minds. ¹

The discovery that plants have their own kind of intelligence is both fascinating and challenging finds Anil Ananthaswamy. ²

Root intelligence: Plants can think, feel and learn ³

It wasn't until 1992 that his idea of widespread electrical signalling in plants received strong support when researchers discovered that wounding a tomato plant results in a plant-wide production of certain proteins – and the speed of the response could only be due to electrical signals and not chemical signals travelling via the phloem as had been assumed. The door to the study of plant behaviour was opened. ⁴

Plants produce ethylene to regulate everything from seed germination to fruit ripening. They also release it when stressed – when under attack by predators or being cut by humans, for example – and nearby plants can sense it. "Ethylene is the plant equivalent of a scream," says Murch.

…

In the past decade, researchers have been making the case for taking plants more seriously. They are finding that plants have a sophisticated awareness of their environment and of each other, and can communicate what they sense. There is also evidence that plants have memory, can integrate massive amounts of information and maybe pay attention. Some botanists argue that they are intelligent beings, with a "neurobiology" all of their own. There's even tentative talk of plant consciousness. ⁵

There is even evidence that plants have long-term memories. Mimosa pudica, the touch-me-not plant, can close its leaflets when touched, but this defensive behaviour requires energy, therefore the plant doesn't indulge in it unnecessarily. When Mancuso and colleagues dropped potted mimosas on to foam from a height of 15 centimetres, the plants closed their leaves in response to the fall. But after just four to six drops they stopped doing this – as if they realised that the fall posed no danger. However, they continued to close their leaves in response to a physical touch, which would normally presage being damaged or eaten. "Even after one month, they were able to discriminate and be able to understand whether the stimulus was dangerous or not," says Mancuso. ⁶

A root is a complex assemblage. There's the root cap, which protects the root as it navigates through soil, but also senses a wide range of physical properties, such as gravity, humidity, light, oxygen and nutrients. Behind this is the meristem, a region of rapidly dividing cells. Further back is the elongation zone, where cells grow in length, allowing the root to lengthen and bend. And between the meristem and the elongation zone is a curious region called the transition zone (see diagram). Traditionally, it was thought to have no purpose, but Baluska and Mancuso think it is actually the nerve centre of the plant. ⁷

Nevertheless, Chamovitz and others don't dispute that plants are extremely aware of their environment, and are able to process and integrate information in sophisticated ways. In fact, a plant's awareness of its environment is often keener than an animal's precisely because plants cannot flee from danger and so must sense and adapt to it. For instance, while animals have a handful of photoreceptors to sense light, plants have about 15. "Plants are acutely aware of their environment," says Chamovitz. "They are aware of the direction of the light and quality of the light. They communicate with each other with chemicals, whether we want to call this taste, or smell, or pheromones. Plants 'know' when they are being touched, or when they are being shook by the wind. They integrate all of this information precisely. And they do all of this integration in the absence of a neural system." ⁸

This is all very clever, but it's not intelligence, says Chamovitz: "I don't like the term plant intelligence. We don't even know what intelligence is for humans. If you get five psychologists together you will get 20 different definitions." ⁹

[Question:] This photograph was taken on 22 June this year in north Pembrokeshire, UK. There were aircraft trails in the sky – but all of them were absolutely straight. So what is this?

[Answer:] That is undoubtedly an aircraft condensation trail (contrail), made quite deliberately. The dense knot in the bottom left is where the aircraft was climbing (or descending) almost vertically, concentrating the contrail in one spot. The aircraft levelled off, then turned abruptly before starting the circle. Once it had arrived back at the knot, it closed the loop by descending (or climbing) steeply. ¹⁰

EVOLUTION, we have always been told, results from natural selection sifting through countless random variations over millions of years.

That's not good enough, says Andreas Wagner, a systems biologist at the University of Zurich in Switzerland. Natural selection can explain which adaptations survive over time, he argues, but it falls far short of explaining where those adaptations originate.

For over a decade, Wagner has been looking for an answer that would satisfy him. ¹¹

Imagine a vast library, one so big that it contains every possible sequence of letters. Most of the books are gibberish, filled with words like "erwtvaiwq" or "avbqse", but you can also find Hamlet and On the Origin of Species. This is the book's core metaphor, used, for example, to describe how most strings of amino acids make non-functional proteins – Wagner's gibberish – but some make working enzymes and a few make brilliant ones.

The problem is that the library is so vast (there are more than 10130 different proteins made from just 100 amino acids) that the odds of evolution stumbling across the specific "book" it needs – an enzyme that can disarm a synthetic toxin, for example – are practically zero. Something else must guide evolution through the library. ¹²

Wagner tells us … instead of looking for a single meaningful book in the entire library, evolution is looking for any one of many functionally equivalent ones. ¹³

That's not all: the structure of the library makes it easy for evolution to move from one meaningful book to another. When Wagner and his colleagues tried browsing adjacent "books" – proteins that differ by a single amino acid – they found that most worked just as well as the original. The same was true when they changed another amino acid, and another. In fact, you could move, step by step, from one end of the library to the other without changing the meaning.

This allows populations to accumulate a lot of genetic variation while still remaining viable. In Wagner's metaphor, readers spread into many different rooms of the library. And that's where the big pay-off comes. By wandering far afield, you come to rooms with very different sorts of books nearby. In real terms, you end up in places where changing just a few more amino acids gives you a protein with a radically different function – an evolutionary breakthrough, close at hand.

And the more hidden variation the population accumulates, the more likely that this will happen. As Wagner puts it, "while you walk along one of these trails, the innovation you are searching for will appear at some point in a small neighborhood near you". ¹⁴