Genesis for Non-Theists

Creation narratives are lively stories.  In the Bible, God creates the universe and earth in six days. In other traditions, creatures are dismembered, huge eggs hatch, birds create land. Even science’s own creation narrative starts with a Bang and once earth takes shape, the first organic molecules appear relatively quickly, within a billion years. 
But at that point the scientific story of life slows way down. Life remains at the stage of single cells for the next two billion years. What was happening to our smallest, oldest ancestors all that time? Why did it take so long to move beyond the stage of one-only? Was evolution on hold?

From “Oldest bacteria fossils” to “Multi-cellular eukaryotes” 2 billion years later, life on earth was single-celled.

What took so long was the creation of the building blocks for being alive. It’s a creation story with parallels to the first chapters of Genesis. Here’s the biblical sequence: plant life emerges on the third day, including “fruit trees bearing fruit in which is their seed,” followed over the next three days by creatures of the water, air, and land, including man and woman. A few verses later we read about the Garden of Eden and, symbolically, the beginnings of sex and death.

Here briefly is science’s version: life evolved from the simplest cells to cells with a nucleus that enclosed the protected “seed” of DNA. This change set in motion the end of one kind of immortality, the beginnings of sex and death, and the emergence of a new immortality.

The process was slow because the changes were huge.

Like the Bible, science has a name for our first ancestor. LUCA, our “last universal common ancestor,” was a single-celled organism, a kind of bacterium, from which all life on earth is descended. Inside LUCA was a floating coil of DNA, sections of which have been passed down to every living thing.

Our common ancestor, a cell with DNA but no nucleus

LUCA reproduced simply by dividing, with one set of genes in each new cell. The new cells were identical, a long line of Adam clones without an Eve.

LUCA’s membrane enclosed only watery liquid and the genes. Gradually LUCA’s descendants “ate” and absorbed other bacteria. Some of these bacteria turned into the nucleus of the cell that absorbed them. They became the container for the cell’s genes. Such cells advanced from  prokaryotes (before a nucleus) to eukaryotes (a true nucleus, and pronounced “you carry oats”). The nucleus was a seed, a seed that provided the DNA with a chemical environment of its own and helped grow more complex DNA and much larger cells.
Sex, Death…

Cells get a nucleus–and more.

Early cells were, in their own way, immortal. The genes in both prokaryotes and early eukaryotes would reproduce and then the cell would split into two identical cells, as bacteria still do. Did such cells die? Eventually, but only from accident or the environment. In this Eden, cells did not get older. They became their own offspring and could theoretically live forever.

Eukaryotes, however, found a new way to reproduce. One would rub up against another eukaryote and portions of their DNA sets would be inserted into the other—the original sex act. With this exchange of DNA, genetic variation sped up, at last. So did natural selection.
In the next step, sex became specialized. As some early organisms became multi-celled, such as algae, they reproduced not by division of the whole parent organism but, as with us, by means of specialized germ cells (not the disease kind of germ but the creative kind, as in the “germ of an idea”).
No longer was the parent reincarnated in a clone, as in bacteria. It was left behind, and it aged and died. As in Genesis, the co-mingling of different living things brought sex and death. Cellular life moved beyond Eden.
…and Immortality
So we have lost the immortality that the prokaryotes enjoyed. But we have found it in another, more complex form. Our immortality runs through the genetic line of our children and other blood  relatives. It turns out that it is not the body, the soma, that is the crucial package. It is the germ cells that carry the DNA forward. 
But is this an adequate and satisfying idea for us humans who dream of living forever? Is the continuity of DNA a meaningful form of immortality? Here is one answer from Harvard biology professor George Wald, in his 1970 lecture on “The Origins of Death.”
We already have immortality, but in the wrong place. We have it in the germ plasm; we want it in the soma, in the body. We have fallen in love with the body. That’s that thing that looks back at us from the mirror. That’s the repository of that lovely identity that you keep chasing all your life. And as for that potentially immortal germ plasm, where that is one hundred years, one thousand years, ten thousand years hence, hardly interests us.
I used to think that way, too, but I don’t any longer. You see, every creature alive on the earth today represents an unbroken line of life that stretches back to the first primitive organisms to appear on this planet; that is about three billion years. That really is immortality. For if the line of life had ever been broken, how could we be here? All that time, our germ plasm has been living the life of those single celled creatures, the protozoa, reproducing by simple division, and occasionally going through the process of syngamy — the fusion of two cells to form one — in the act of sexual reproduction. All that time, that germ plasm has been making bodies and casting them off in the act of dying. If the germ plasm wants to swim in the ocean, it makes itself a fish; if the germ plasm wants to fly in the air, it makes itself a bird. If it wants to go to Harvard, it makes itself a man. The strangest thing of all is that the germ plasm that we carry around within us has done all those things. …
I, too, used to think that we had our immortality in the wrong place, but I don’t think so any longer. I think it’s in the right place. I think that is the only kind of immortality worth having — and we have it.

The Immortal Jellyfish

The Immortal Jellyfish

There is a species of small jellyfish that will, when it is sick or injured, instead of dying, regenerate itself. It will sink “to the bottom of the ocean floor, where its body folds in on itself—assuming the jellyfish equivalent of the fetal position. The bell reabsorbs the tentacles, and then it degenerates further until it becomes a gelatinous blob. Over the course of several days, this blob forms an outer shell. Next it shoots out stolons, which resemble roots.” These stolons grow into new jellyfish.

The description is from Nathaniel Rich’s article, “Forever and Ever” in the New York Times Magazine (Dec. 2, 2012). Over two years, one lab colony of such jellyfish rebirthed itself ten times. The jellyfish’s official name is Turritopsis dohrnii and its not-surprising nickname is the Benjamin Button jellyfish. As different from us as it may look, our genetic makeups are surprisingly similar.

We view death as part of the definition of life, as a boundary that all living things share. But death, it turns out, is not absolute. The clichés that “you live and then you die” and “life is short” tap into more complexity than they were intended to. Bacteria , for example, divide in two: individual bacterium may be destroyed or die from illness, injury, or antibiotics, but most of them form identical clones, which then clone again and again. And as for life being brief, Buffalograss, a prairie plant resistant to weather extremes, sprouts underground stems which in some locations may have been growing for the last 15,000 years. Among individual plants, the Bristlecone Pine named Methuselah in California, is coming up on its 5000th birthday. And Wikipedia’s lengthy “List of Longest Living Organisms” begins with a note that “This list is incomplete.”

Today the immortal jellyfish is a specialty of Dr. Shin Kubota at Kyota University’s Seto Marine Biological Laboratory. Kubota spends much of his days feeding, caring for, and observing his wards. A prolific researcher, Kabuto is also spiritual and a little eccentric. His expressed goal is to become young again himself, even to achieve immortality, or at least to point a way towards a cure for cancer.

In what ways might our knowledge of rejuvenating jellyfish and other exceptions to the rule of death change our perspective on our mortality? Not surprisingly such reports encourage daydreams of life-prolonging gene splicings. But they also complicate and enrich our view of the vulnerabilities and persistence of living things.

“Getting Dead”

If you get hold of John King’s fine book Reaching for the Sun: How Plants Work, be sure to read the startlingly titled last chapter, “Getting Dead.” These pages are quietly designed to dislodge a bit of our complacency about how all life ends. Most people assume that death  comes to plants in much the same way it comes to humans, as the extinguishing conclusion that arrives in one of a few ways in a fairly predictable time frame.

King sets us straight. “Some kinds of organisms appear to be immortal.” Bacteria divide in two; pieces of sponges become new sponges; such clones never “die.” Buffalo grass sprouts underground stems which may have been growing for the last 15,000 years. As for individual plants, the oldest known specimen is a Bristlecone Pine named Methuselah in California, coming up on its 5000th birthday. (That means it sprouted when the Egyptians were building the pyramids and has breathed the same air as all the history ever since. Methuselah in the Old Testament lived a mere 969 years, and his age was mythic. The tree of the same name has lived almost 5000 years and is real.)

King’s point is that dying is not the looming Grim Reaper for plants that it is for us, and that once a plant has done its best to meet its primary directive of reproduction, dying varies greatly depending on the environment. Most plants fall into one of two categories. Some live one or two years, bloom once, and die. The grains and vegetables that we eat are examples. Such plants die through senescence, a built-in program for decay in all or part (autumn leaves) of the plant. Other plants, including trees, shrubs, and perennial flowering plants, produce seed repeatedly.  These multi-blooming plants are more like us, King explains, than the blooming-once plants; they produce seed often and they don’t die by program.  Instead, they–like humans–get worn down, worn out, infected, failing. They and we get old, in other words. Death from attrition and vulnerability, not design.

Reading King’s chapter, I found the fact of dying becoming less monolithic than it has seemed in the past. We think of life and death as a pair, like salt and pepper, but it’s not that simple. Death, the noun, is always “dying,” the verb, always a variable process for “getting dead.” Dying seems less conspiratorial to me now, and more part-euthanasia, part-scavenger, coming around for different purposes, with many different procedures, sooner or later or almost never.