Last Ape Standing The Seven-Million-Year Story of How and Why We Survived

226 Pages·2013·2.27 MB·English

by  Chip Walter

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Contents
Author’s Note
Introduction
Chapter One The Battle for Survival
Chapter Two The Invention of Childhood (Or Why It Hurts to Have
a Baby)
Chapter Three Learning Machines
Chapter Four Tangled Webs—the Moral Primate
Chapter Five The Everywhere Ape
Chapter Six Cousin Creatures
Chapter Seven Beauties in the Beast
Chapter Eight The Voice Inside Your Head
Epilogue: The Next Human
Acknowledgments
Notes
Bibliography
Footnotes
A Note on the Author
By the Same Author
Plate Section
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For Cyn. My compass and my Gibraltar.
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Author’s Note
Despite its academic-sounding name, a good deal of brawling often goes
on within the field of paleoanthropology. That it explores the deep past
and counts on bits of ossified bone grudgingly revealed or scraped out of
the earth doesn’t help the inexactness of the science, or the
disagreements it generates. Although all researchers in the field work
hard to bring the objectivity of the scientific method to their work, its
nature involves a lot of guesswork. So while one scientist or group of
scientists may think that the unearthed fossils of a particular creature
demand that it be classified as a new species, others might feel just as
strongly that it is simply a new example of a species that has already
been discovered. Some scientists find good reason to have created the
classification Homo antecessor, for example. Others, just as reputable,
and just as thorough in their thinking, argue no such species ever
existed.
No one really knows. The evidence is too sparse and too random. We
are making up these names as a convenient way of organizing the chaos
of discovery over the past 180 years. It’s not as though the creatures
themselves went by the nomenclatures we have made up. Nor can we
comprehend what we don’t know. We can never say if we have
discovered the fragmented evidence of 80 percent of our direct
ancestors and cousin human species, or 1 percent.
Too often, being human, we may give the impression we understand
more than we do, or that we have just about figured it all out. We
haven’t, as you will see. One of the reasons this book is relevant is
because the human family tree, or more precisely, our very limited view
of it, has changed so much in just the past five years.
Advances in genetics, innovations in radiocarbon dating, together
with plain old scientific creativity and elbow grease have greatly
improved our guesswork and helped flesh out the discoveries we have
made. There would be no hope, for example, of having even the
remotest idea that a wisdom tooth and the end of a pinkie finger found
in a Siberian cave three years ago belonged to an entirely new species of
human (scientists call them Denisovans) with whom we and
Neanderthals may share a common ancestor. This paltry evidence even
revealed we mated with them! Nor would we have learned that billions
of humans (including, very possibly, you) have Neanderthal mlood
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running in their veins. But we now know these astonishing things are
true, even as they have turned assumptions once taken as gospel entirely
on their heads.
Still, despite these advances and the exciting discoveries they have
made possible, the illumination of our past is a little like trying to find a
set of car keys in the Sahara with a flashlight.
I bring this up now to clarify a point: we don’t know exactly how
many other human species have evolved over the past 7 million years—
27 or 2700. We likely never will. But I have tried to arrive at an arguable
and acceptable number that makes the larger point that, despite the
disagreements that take place within the field, the story of how we came
to be is a good deal more intriguing and complicated than we thought
even a few years ago. And that makes the story even better.
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Introduction
Over the past 180 years we have so far managed to stumble across,
unearth, and otherwise bring to light evidence that twenty-seven
separate human (hominin, to use the up-to-date scientific term)1 species
have evolved on planet Earth. As you may have noticed, twenty-six of
them are now no longer with us, done in by their environments,
predators, disease, or the unfortunate shortcomings of their DNA. The
lone survivor is a peculiar, and peculiarly successful, upright walking
primate that calls itself, a little self-importantly, Homo sapiens sapiens,
the wise, wise one. In most circles, we simply call them you and me.2
Of all the varieties of humans who have come and struggled and
wandered and evolved, why are we the only one still standing? Couldn’t
more than one version have survived and coexisted with us in a world as
big as ours? Lions and tigers, panthers and mountain lions, coexist.
Gorillas, orangutans, bonobos, and chimpanzees do as well (if barely).
Two kinds of elephants and multiple versions of dolphins, finches,
sharks, bears, and beetles inhabit the planet. Yet only one kind of
human. Why?
Most of us believe that we alone survived because we never had any
company in the first place. According to this thinking, we evolved
serially, from a single procession of gifted ancestors, each replacing the
previous model once evolution had gotten around to getting it right. And
so we moved step by step (Aristotle called this the “Great Chain of
Being”), improving from the primal and incompetent to the modern and
perfectly honed. Given that view, it would be impossible for us to have
any contemporaries. Who else could have existed, except our direct, and
extinguished, antecedents? And where else could it all lead, except to us,
the final, perfect result?
This turns out to be entirely wrong. Of the twenty-seven human
species that have so far been discovered (and we are likely yet to discover
far more), a considerable number of them lived side by side. They
competed, sometimes they may have mated, more than once one variety
likely did others in either by murdering them outright or simply
outcompeting them for limited resources. We are still scrounging and
scraping for the answers, but learning more all the time.
If we hope to place our arrival on the scene in any sort of perspective,
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it’s a good idea to remember that every species on Earth, and every
species that has ever lived on Earth (by some estimates thirty billion of
them), enjoyed a long and checkered past. Each came from somewhere
quite different from where it ended up, usually by a circuitous, and
startling, route. It’s difficult to imagine, for example, that the blue
whales that now swim the world’s oceans, great leviathan submarines
that they are, were once furry, hoofed animals that roamed the plains
south of the Himalayas fifty-three million years ago. Or that chickens
and ostriches are the improbable descendants of dinosaurs. Or that
horses were once small-brained little mammals not much taller than
your average cat with a long tail to match. And the Pekinese lapdogs
that grace the couches of so many homes around the world can trace
their beginnings to the lithe and lethal gray wolves of northern Eurasia.
The point is, behind every living thing lies a captivating tale of how
the forces of nature and chance transformed them, step by genetic step,
into the creatures they are today. We are no exception. You and I have
also come to the present by a circuitous and startling route, and once we
were quite different from the way we are now.
Theories about our ancestry have been amended often because new
discoveries about how we came into existence keep emerging; several
times, in fact, while this book was being written. But however it played
out in the details, we know this: for every variety of human that has
come and gone, including those we think we have identified as our
direct predecessors, it has been a punishing seven million years. Survival
has always been a full-time job, and the slipperiest of goals. (It still is for
most humans on the planet. More than four billion people—nearly two
thirds of the human race—subsist each day on less than two dollars).
But luckily, for you and me at least, while evolution’s turbulent dance
rendered the last line of non–Homo sapiens DNA obsolete eleven
thousand years ago, it allowed ours to continue until finally, of all the
many human species that had once existed, we found ourselves the last
ape standing.
Not that we should rejoice at the demise of those others. We owe a
lot to the fellow humans that came before us—hairier, taller, shorter,
angrier, clumsier, faster, stronger, dumber, tougher—because every one
of us is the happy recipient of all the more successful traits that our
ancestors acquired in their brawl to keep themselves up and running. If
today we were to make the face-to-face acquaintance of an
Australopithecus afarensis or Homo ergaster or Paranthropus
robustus, what would we see? Intelligence, fear, and curiosity is my
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guess, for starters. And they would see the same in us because we truly
are kindred spirits.
This has ensured that many of the deft genetic strategies that made
those now departed human species once possible still remain encoded in
the DNA that you and I have hauled with us out of the womb and
blithely carry around each day into our personal worlds. The millions of
these creatures who came and strove and passed through the
incomprehensibly long epochs between their time on earth and the here
and now are, after all, us, or at least some of them were. We are a
marvelous and intriguing amalgamation of those seven million years of
evolutionary experimentation and tomfoolery. If not for the hard planks
of human behavior those others long ago laid down, we would be
naught.
So you can thank the lines of primates that in eons past found their
way into Africa’s savannas, then to Arabia and the steppes of Asia, the
mountain forests of Europe, and the damp archipelagoes of the Pacific,
for genetic innovations like your big toe, your ample brain, language,
music, and opposable thumbs, not to mention a good deal of your
personal likes and dislikes, fascinations, sexual proclivities, desires,
temper, charm and good looks. Human love, greed, heroics, envy, and
violence all trace the threads of their origins back to the
deoxyribonucleic acid of the humans who came before us.
Some might wonder what sense it makes to rummage through the
leavings of the past seven million years to try to piece together the story
of our peculiar emergence. The payoff is that it’s the best way to
understand why we do the startling, astonishing, sometimes sublime
and sometimes horrible things we do. We owe it to ourselves to unravel
the riddles of our evolution because we, more than any other animal,
can. If we don’t, we stand no chance of comprehending who we really
are as individuals or as a species. And only by understanding can we
hope to solve the problems we create. To not understand how we came
into this universe damns us to remain mystified by our mistakes, and
unable to build a future that is not simply human, but also humane.
This in itself, however, fails to answer the nagging question of why
our particular branch in the human family managed to find its way to
the present when so many others were shown the evolutionary door.
Plenty of other human species had a good run; many considerably
longer than ours. Some were bigger, some were stronger and faster,
some even had heftier brains, yet none of those traits was good enough
to see them through to the present. What events, what forces, twists,
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and evolutionary legerdemain made creatures like you and me and the
other seven billion of us who currently walk the earth possible?
Somehow only we, against all odds, and despite the brutal,
capricious ways of nature, managed to survive … so far.
Why?
Our story begins once upon a time, a long time ago …
Chip
Walter
Pittsburgh,
Pennsylvania
June 2012
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