The Oldest Living Things On Earth

The photographer Rachel Sussman has been traveling the world to take pictures of the oldest living organisms on our planet. She described her journey in this TED talk, and now, at last, she’s created a gorgeous new book, The Oldest Living Things in the World, published by the University of Chicago Press.

Rachel asked if I would write an introduction to the book. After contemplating her photographs and thinking about what these strange Methuselahs mean for us and for science, here’s what I wrote:


It is easy to feel sorry for the gastrotrich. This invertebrate animal, the size of a poppy seed and the shape of a bowling pin, swarms by the millions in rivers and lakes. After it hatches, it takes only three days to develop a complicated body, complete with a mouth, a gut, sensory organs, and a brain. Having reached maturity in just seventy-two hours, the gastrotrich starts laying eggs. And after a few more days, it becomes enfeebled and dies of old age.

To squeeze a whole life into a week seems like one of nature’s more cruel tricks. But that’s only because we are accustomed to measure our lives in decades. If the ancient animals and plants featured in this book could look upon us, they might feel sorry for us as well. We humans marvel at the longest-living human on record, Jean Calment, who lived from 1875 to 1997. But for a 13,000-year-old Palmer’s oak tree, Calment’s 122 years rushed by as quickly as a summer vacation.

Palmer’s oaks, gastrotrichs, and all the species in between are the products of evolution. The head-swimming diversity of life is joined in an evolutionary tree made up of tens of millions of branches. And one of the most spectacular of that diversity’s dimensions is longevity. If natural selection provides Palmer’s oaks with millennia, why does it only spare a gastrotrich a week of existence?

Starting in the 1960s, evolutionary biologists have searched for an overarching explanation to account for all the different ways to grow old. The best-supported ones so far are variants on the old truth that a jack-of-all-trades is a master of none. An organism can collect a finite amount of energy, whether it’s a lion killing gazelles, a tulip capturing sunlight, or a microbe breathing iron at the bottom of the sea. It can use that energy to grow, to produce offspring, to defend itself against pathogens, to repair damaged its damaged molecules. But it has a limited budget. The energy spent on one task is energy that can’t be spent on others.

Molecular repair and pathogen defense are both good ways to live longer. But a long-lived organism that produces few offspring will not pass on many copies of its genes to future generations. The organisms that will succeed are the ones that do a mediocre job of keeping their bodies in order, leaving more energy for making babies.

This balance goes a long way to explaining why some species live long and some short. It may give scientists clues to how we humans might battle the burdens of aging, such as Alzheimer’s disease. But this balance is only part of the answer to why things live as long as they do. The environments in which species live may also be a part of the answer. In some places, life may simply run slower. Some lineages may evolve a way out of the binds that tie most species. They may escape the trade-offs that come with channeling energy in one direction or another, and be free to live longer.

The durable mystery of longevity makes the species in this book all the more precious, and all the more worthy of being preserved. Looking at an organism that has endured for thousands of years is an awesome experience, because it makes us feel like mere gastrotrichs. But it is an even more awesome experience to recognize the bond we share to a 13,000-year-old Palmer’s oak tree, and to wonder how we evolved such different times on this Earth.

12 thoughts on “The Oldest Living Things On Earth

  1. Nice. Creosote can get to be roughly as old as the Mojave yucca, and propagate in the same clonal circle pattern. That and cryptobiotic soil are all good reasons to tread lightly in the desert.

  2. The Ted Talk with Rachel Sussman was very informative though she did mention how David Attenborough was wrong about the blue whale being the largest living creature and that in actuality it is the honey mushroom. However, I think David Attenborough was talking in terms of the kindom Animalia. Anyway, I think it was a great lecture and I am sure the book is too.

  3. Not much to wonder about. Random walk plus selection for different environments, different bodies, different lifestyles, gradual divergence filling in all viable possibilities. I guess we can wonder about just exactly what those different paths were, but the fossil record of plants is spotty, or rather consists of a few spots. There’s little if any fossil record of such tiny, soft-bodied creatures as the gastrotrich. Maybe genetic comparisons will bring some enlightenment, or just more material to speculate about. Durable mysteries indeed.

  4. Not sure I agree on her definition of life-span in permafrost-living bacteria. Granted they take a loooong time to divide but once mitosis is over and done with I think it should be considered a separate (“new-born”) individual even if it’s genetically identical. I would use the same argument goes for a few of the clonal trees as well. Otherwise I think we should consider all asexually dividing species as ancient.

  5. At a DNA replication, the protons have to “choose sides,” and the proton code immediately after a DNA replication represents actually a nonstationary state from the quantum-mechanical point of view. The time evolution of the system and particularly the penetration of the potential barrier in the double-well potential represents a loss of the genetic code which should perhaps be considered as the primary cause of aging. The aging is thus a process which goes on continuously in the DNA molecule but gets “manifested” at the replications.” – (The Uncertain Gene, quoting Löwdin). The quantum level may be the place to look for dynamics of aging.

  6. A small typo, one extra damaged to repair in this sentence:

    “It can use that energy to grow, to produce offspring, to defend itself against pathogens, to repair _damaged_ its damaged molecules.”

    I very much like the description of the free radical theory of aging given in Nick Lane’s book “Oxygen: The Molecule that Made the World”.

    Basically, as we budget our energy usage, there’s a metabolic cost to the repairs too. That is, if the free radical theory of aging is correct, then our leaky mitochondria have doomed us from the start, and repairing damage incurs its own damage.

    I ran across this remarkable assertion in a wikipedia article on reactive oxygen species. I need to track down a proper reference for it, as it isn’t cited there.

    “It has been estimated that endogenous ROS produced via normal cell metabolism modify approximately 20,000 bases of DNA per day in a single cell. 8-oxoguanine is the most abundant among various oxidized nitrogeneous bases observed. During DNA replication, DNA polymerase mispairs 8-oxoguanine with adenin, leading to a G->T transition mutation. The resulting genomic instability directly contributes to carcinogenesis.”

    Birds and bats have disproportionately longer lives than us earthbound animals. It seems that their mitochondria are more efficient by necessity of the energy demands of flight, and so leak fewer free radicals/superoxide radicals.

  7. >An organism can collect a finite amount of energy, whether it’s a lion killing >gazelles, a tulip capturing sunlight, or a microbe breathing iron at the
    > bottom of the sea. It can use that energy to grow, to produce offspring, to >defend itself against pathogens, to repair damaged its damaged >molecules. But it has a limited budget. The energy spent on one task is
    >energy that can’t be spent on others.

    Yes, it’s true that this is a widely cited, popular theory of aging. But it’s clearly wrong, because animals LIVE LONGER the LESS food energy they take in. And they live longer the MORE food energy they burn in exercise.

    This theory should have been a non-starter.

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