Survivors and the Terminator

The story of biological evolution recounts the ways that most plants and animals have changed over time as small bodily variations improved their odds of survival. But what about those species, fitted successfully to stable environments early on, that have changed very little? Are any such ancient species (besides the microbes) still around today?

Yes. In Survivors: The Animals and Plants that Time Has Left Behind, Richard Fortey tracks down some present-day creatures that look much like their fossilizeds ancestors from millions of years ago. Oddly, their stories of sameness impress me with as strong a sense of evolution’s power as the stories of other species, including ours., that have changed to adapt.

Horseshoe crabs, after half a billion years, still crowd the beach. (delaware-surf-fishing.com)

Horseshoe crabs, after half a billion years, still crowd the beach.
(delaware-surf-fishing.com)

In the opening chapter, Fortey is on a beach in Delaware on the night of the annual horseshoe crab orgy, when thousands of male horseshoe crabs come ashore to clamber on top of the females. Horseshoe crabs have  been scrambling up beaches for 500 million years.

In the darkness along Delaware Bay the scratching percussion of the crabs provides an unmusical accompaniment on an imaginary journey backwards in time: to an era well before mammals and flowering plants; a time before the acme of giant reptiles, long before Tyrannosaurus; backwards again through an extinction event 250,000,000 years ago that wiped nine-tenths of life from the earth; and then back still further, before a time of lush coal forests to a stage in the earth’s history when the land was stark and life was cradled in the sea.

firmoss (newfs.s3.amazonaws.com)

Four hundred mya, plants like this Norwegian Huperzia moved from the water to land and were among the first to acquire the crucial, stiffened water-conducting tubes that enabled them to stand upright and compete for light.
(newfs.s3.amazonaws.com)

In the other chapters, Fortey describes the velvet worm in New Zealand, the lovely Norwegian fir moss, the not-so-lovely lungfish. The photo captions here mention their particular keys to adaptive success.

It helps that their environments have changed very little. “Survival is about endurance of habitat.” One habitat that endures is the tidal flat, where the shallow sea meets the muddy shore. Organisms here can burrow, find oxygen in the water and air, find food through filtering or scavenging. Here are horseshoe crabs, snails, small fish, many plants. “This habitat does seem like a good place to be for an organism with conservative tendencies. If its own place survives, then so will the beast. It is the right place to weather mass extinctions that affect many other environments more severely.…Stick-in-the-muds last longest.”

As for the durable species themselves, a few characteristics recur. “Many…seem to have long life spans.” Horseshoe crabs take a decade to mature. And some enduring animals invest more resources in fewer progeny by producing “relatively large eggs or few offspring.” But there are no fool-proof formulae. “[T]he luck for old timers will eventually run out. It always does.”

lungfish (media-web.britannica.com)

In Australia, Fortey finds the lungfish that dates back 400 mya, “the great survivor among the vertebrates, the animals with backbones.” With lungs, these sea creatures, in the transition to the land, can gulp air when the river runs low on oxygen.
(media-web.britannica.com)

What about humans? When will our time run out? Fortey doesn’t make guesses, but he has a hard label for us.

[Early man] may have hunted edible mammals and birds to the point of obliteration even in his earliest days; he was the first species that deserves to be called the Terminator….The extinction event that is happening right now is the first one in history that is the responsibility of a single species. There’s no meteorite this time, no exceptional volcanic eruptions, no ‘snowball earth,’ just us, prospering at the expense of other species.

He is confident about the survival of only one type of organism. “I am not worried about the survival of bacteria. They will be there to rot down the last bodies of the last humans, and then the wheel of life will have turned full circle.” So ends the book.

 

Growing Old Brings Frailty and Illness. Unless You’re a Lobster

I look at my being alive as one instance of the larger wonder of organic life. Over millions of years, cells and plants and animals have come to life anew and functioned for as long as needed to create offspring. Gradually, features that give the individual and thus the species the best odds for continuity are honed. I am part of that long sequence and I see my being alive now, my body, my membership in a society and culture, and my eventual death in that context.

But what about my aging—senescence? The wrinkling and weakening, the deteriorating of knees, hearing, muscle, brain, and heart? Where do such changes fit in? Perhaps because I’m going through them at age 73, it’s sometimes difficult not to see such decline as pointless. The certainty of death is hard enough; aging as a prelude can feel demeaning.

lobster (anvilcloud.blogspot.com)

(anvilcloud.blogspot.com)

I think this way even though I know that different species live and die in many different ways. Some plants live one year, others come back every season. Bacteria clone themselves and don’t die from age but from hostile organisms and conditions in their environment. Seabirds age very slowly; as long as they can fly, they can usually avoid predators.  Lobsters don’t age; they can continue to grow and remain fertile for 45 years or more in the wild, dying only when they can no longer molt and grow a larger shell.

The causes of aging are complex and difficult to study definitively. Wikipedia’s “Senescence” introduces the range of theories and uncertainties. The approach that catches my attention the most is the study of aging in terms of natural selection and evolution. Here are three highlights that have struck me.

One is that certain harmful genetic mutations switch on later in life after an organism’s reproductive period has ended—many cancers, for example, in humans. Because they don’t impact the number or health of the offspring, such genes do no harm to the persistence of the species and so they are unlikely to be lost over the generations. The diseases of the elderly get passed along by the young.

Even more unfortunately, some mechanisms in our bodies boost our health when we’re young and then come back to bite us when we get older. Digesting calcium, for instance, builds strong bones early on but helps clog and stiffen arteries decades later. As long as such a function improves our fitness to make and raise babies, whatever damage it does later on doesn’t matter much in the very long run.

A third way in which selection seems indifferent to the pains of aging is partly statistical: even if natural selection did reduce the ravages of aging and prolong the fertile period, such organisms would nevertheless decline in numbers from accidents or predators as the years pass. The body invests its resources where they are the most effective for the future, in youth and early reproduction, not in a comfortable old age.

In these ways and others, aging apparently takes its cue from the importance of reproduction and from the danger of predators and other external forces. For primates, including me, we reproduce early because the big cats—leopards, jaguars, cougars, tigers—stalked us for millions of years in the forests and grass lands. And for most other species as well, reproduction early in the parents’ lives is the safest bet for species continuity. Still, the exceptions are fascinating. Lobsters in their suit of armor run little risk from ancient predators, so they can reproduce throughout their lives without ever aging into genetic irrelevance.

So. Does my basic and imperfect understanding of all this alter how I experience my weakening muscles, my declining sexuality, my distracted thinking, my reduced sense of taste? To an extent, yes it does. It’s the sense of pointlessness, of feeling disposed of by nature despite all its power to change things, that makes aging harder to bear. Knowing that the decline has its own place, though a melancholy one, in the organic pragmatism that brought me to being in the first place in some consolation.

 

“Comparison Is the Thief of Happiness”

“Comparison is the thief of all happiness*,” says former NFL star Joe Ehrmann in denouncing the pressures on boys to “be a man,” in the film The Mask You Live In. Messages overt and covert from fathers down to video games leave males of all ages struggling with loneliness and fury. Similar pressures, certainly, weigh on females and most other human groups. Comparing ourselves to others haunts and hurts us all.

comparison (fitzvillafuerte.com)

(fitzvillafuerte.com)

But there’s a catch: Comparison brings pleasure as well as pain. In How the Mind Works, psychologist Stephen Pinker concurs with the popular wisdom that “people are happy when they feel better off than their neighbors, unhappy when they feel worse off….You open your paycheck and are delighted to find you have been given a five percent raise—until you learn that your co-workers have been given a ten percent raise.” Happiness often lasts no longer than the tingle of the flattering comparison that brought it on.

So how are we to understand happiness if it is so frail, so dependent on where we stand in relation to others? Many people don’t puzzle over the nature of happiness very much; they view it as a self-evident goal that they can pursue, find, and remain in, as if it were a job or a house. “I just want to be happy.” I remember my surprise decades ago when a friend mentioned off-handedly that perhaps happiness is not the goal of life. The possibility had never occurred to me.

Happiness looks a little clearer quickly when we separate the two broad meanings of the word. One is satisfaction, as in “Overall, I’m happy with my life so far.” The other meaning is the emotional flush of joy or excitement, as in “happy dance.” Another kind of understanding of happiness and how to reach it, one that does not depend on comparison to others, is the practice of mindfulness that many find to be a path towards contentment and joy.

For me, the evolutionary perspective is also enlightening. If unhappiness comes at us in so many shapes while happiness remains so elusive, a reason may be that for any organism, many more things can go dangerously wrong than can go blissfully right. Pinker: “There are twice as many negative emotions (fear, grief, anxiety, and so on) as positive ones, and losses are more keenly felt than equivalent gains….[P]eople’s mood plummets more when imagining a loss in their lives…than it rises when imagining an equivalent gain….[H]appiness tracks the effect of resources on biological fitness. As things get better, increases in fitness show diminishing returns: more food is better, but only up to a point. But as things get worse, decreases in fitness can take you out of the game: not enough food, and you’re dead” (392).

So it’s not that happiness eludes us soley because comparisons steal it or we are incapable of finding it. It’s that we come into life in the first place equipped with alarm bells for all the gritty dangers and with only a selection of pleasures.

 

*Teddy Roosevelt is credited with the original version: “Comparison is the thief of joy.”