Intelligence in Nature - Jeremy Narby [30]
I followed her into her office and asked about her work. She explained how she micro-injected DNA into nematode gonads in order to induce mutations in their eggs. She had several nematodes stuck on an oily slide and invited me to sit down at the microscope to take a look.
Once I got the swing of the apparatus, I focused on a single worm. The nematode was alive and moving. It looked like a transparent, Byzantine snake. Its internal organs had the intricacy of a racing-car engine, and it moved like a ballerina, ending each sideways weave with a flick at the tip of its body. I understood more clearly why the nematodeâs scientific name includes the Latin word for elegant. I admired the nematodeâs beauty for several minutes, feeling amazed that a creature with a brain of only three hundred neurons could move with such grace.
I found the experience thrilling. I turned to Monique Zetka and thanked her sincerely. As the quality of nematodes is not a frequently discussed subject, and as some people get uneasy taking such tiny creatures seriously, I asked with some hesitancy whether she liked nematodes.
She seemed embarrassed by the question and simply said, âThey are pretty nice.â Scientists sometimes view their business as keeping a cold gaze in the face of natureâs elegance and beauty. I thanked her again and let her get on with her work.
I tried discussing my newfound enthusiasm for invertebrates with people around me, but often they just laughed. Many Westerners place themselves above âlowlyâ creatures such as nematodes. But humans are part of nature. Like so many other animals, we have eyes, noses, ears, mouths, teeth, brains, digestive tracts, skin, gonads, and so on. We are affiliated to even the simplest creatures.
The first animals were invertebrates. Animals with backbones and skulls only appeared about 500 million years ago. First came fish, then amphibians, reptiles, birds, and mammals. We humans are mammals. We belong to the order of primates, which includes marmosets, monkeys, apes, and chimpanzees.
Humans have several distinctive features, the most obvious of which is that we are the only living primates who walk full-time on two legs. According to the fossil record, some of the first bipedal primates belonged to a now-defunct genus called Australopithecus. These precursors of humanity lived about three and a half million years ago and had brains one-third the size of our own. Apart from their near-human posture, they were very much like chimpanzees, with similar diets and similar brain size. The first true hominids, commonly known as Homo habilis, appeared about two million years ago. They stood upright and had brains half the size of our own. Since then, hominid brains have continued to expand.
The fossil record is patchy and hard to interpret. Paleontologists do not agree on many details. When did the first Homo sapiens appear? Some believe that the roots of our species might extend back over four hundred thousand years. Others think that our immediate ancestors were a separate African species called Homo rhodesiensis, and that one should only apply the label Homo sapiens to fossils less than two hundred thousand years old. Some paleontologists believe that there have been different varieties of archaic Homo sapiens, including Homo rhodesiensis, Homo antecesor, and Homo heidelbergensis, from whom both modern humans and Neanderthals derived. Others view Neanderthals as an entirely separate offshoot of Homo rhodesiensis.
Our stocky Neanderthal cousins lived mainly in Europe and had a brain volume that was slightly superior to our own. Like us, they buried their dead, made musical instruments, and produced efficient hunting tools. Neanderthals were serious predators. Analysis of their fossilized bones reveals that they had a heavy meat diet. Nevertheless, Neanderthals were also quite different from us. Their skulls were oval shaped, not round. Their foreheads were