Shadows of Forgotten Ancestors

You can see that the process tends to be adventitious, opportunistic—not foresighted, not with any future end in view. The evolving molecules do not plan ahead. They simply produce a steady stream of varieties, and sometimes one of the varieties turns out to be a slightly improved model. No one—not the organism, not the environment, not the planet, not “Nature”—is mulling the matter over.

This evolutionary shortsightedness can lead to difficulties. It might, for example, cast aside an adaptation that is perfectly suited for the next environmental crisis a thousand years from now (about which, of course, no one has a glimmering). But you have to get from here to there. One crisis at a time is life’s motto.

ON IMPERMANENCE

If we lived forever, if the dews of Adashino never vanished, if the crematory smoke on Toribeyama never faded, men would hardly feel the pity of things. The beauty of life is in its impermanence. Man lives the longest of all living things … and even one year lived peacefully seems very long. Yet for such as love the world, a thousand years would fade like the dream of one night.

KENKO YOSHIDA, Essays in Idleness (1330–1332)¹⁹

* The silent “gh” in such English words as thought and height, or the silent “k” in knife or knight, were likewise once sounded out, but today are little more than a vestige of the evolution of language Something similar is true for the circumflex and cedilla which are in the course of being phased out in French, and for recent simplifications of Chinese and Japanese The nonfunctional genetic sequences, however, are not just a few letters here and there, but reams of obsolete and/or garbled information—something like a confused account in ancient Assyrian on how to manufacture chariot axles, set in more recently generated nonsense information* Before the method of radioactive dating was invented, the physicists simply had no way to get the timescales right Darwin’s son George became a leading expert on tides and gravity—in part to refute the claim that the history of the Moon proved the Earth to be too young for much biological evolution Several different radioactive clocks found within samples from the Earth, the Moon, and the asteroids; the abundance of impact craters on nearby worlds; and our understanding of the evolution of the Sun all independently and definitively point to an Earth about 4.5 billion years old.The technique is also being used to take tiny quantities of DNA from the remains of ancient organisms—bacteria from the gut of a preserved mastodon, for example—and make enough copies so they can be studied It has even been proposed that preserved somewhere in amber may be the remains of a bloodsucking insect that bit a dinosaur, from which we may one day learn about dinosaur biochemistry or even—this point is keenly debated—reconstruct, and in a way resuscitate, dinosaurs extinct for 100 million years In the best of circumstances, this does not seem to be a prospect for the near future

Chapter 6

US AND THEM

Let there be no strife, I pray thee, between me and thee … for we be brethren.

Genesis 13:8

There are no compacts between lions and men.

HOMER, The Iliad¹

Whether there were many instances of the origin of life on Earth or only one is a deep and perhaps impenetrable mystery. For all we know, there may have been millions of dead ends and false starts, unmourned ancient genealogies snuffed out as new ones arose. But it seems very clear that there’s only one hereditary line leading to all life now on Earth. Every organism is a relative, a distant cousin, of every other. This is manifest when we compare how all the organisms on Earth do business, how they’re built, what they’re made of, what genetic language they speak, and especially how similar their blueprints and molecular job orders are. All life is kin.

In our imagination, let’s cast our eyes back to the earliest organisms. They could not have been so purebred and pampered a line of self-replicating molecules as contemporary DNA or RNA—superbly efficient in the replication and proofreading of their messages, but reproducing only under the meticulously controlled conditions upon which modern organisms insist. The first living things must have been rough-and-ready, slow, careless, inefficient—just barely good enough to make crude copies of themselves. Good enough to get started.