Scientific American 2014 09 Special Issue Evolution.pdf

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HOW WE BECAME HUMAN
SPECIAL EVOLUTION ISSUE
ScientificAmerican.com
September 2014
The
Remarkable
7-Million-Year
Story of Us
EVOLUTION
eVOLUtION
the human saga
HARD
TO KILL
Climate Shifts
Made Us Adapt
INSIDE
TEAM
HUMANITY
Outcompeting
the Rest
(MOSTLY)
MONOGAMOUS
The Power
of a Partner
FUTURE
PATH
How We Are
Evolving Now
© 2014 Scientific American
ON THE COVER
Humans have been evolving for more than
seven million years, and we continue to
change. This special issue takes stock of
the latest insights into that odyssey—past,
present and future.
Illustration by Katy Wiedemann.
September 2014
Volume 311, Number 3
EVOLUTION
the human saga
36 Evolution Rewritten
Startling new findings are upending much of what scientists
thought they knew about our beginnings.
By Kate Wong
40 WHERE WE CAME FROM
42 Welcome to the Family
The road from ancient ape to modern human is far more com­
plex—and interesting—than anyone imagined.
By Bernard Wood
48 Climate Shocks
Our forebears had to cope with rapid climate fluctuations
that ultimately favored modern traits.
By Peter B. deMenocal
54 If I Had a Hammer
Tools were not enough to forge our species. A radical new
theory holds that luck also played a big role.
By Ian Tattersall
60 WHAT MAKES US SPECIAL
62 Powers of Two
Monogamous coupling might have been the best move
our ancestors ever made.
By Blake Edgar
68 One for All
The uniquely human ability to cooperate on a vast scale
has deep evolutionary roots.
By Frans de Waal
72 The “It” Factor
Experiments comparing children with chimpanzees suggest
that a key quality of humans is our capacity for innovation.
By Gary Stix
80 WHERE WE ARE GOING
82 The Networked Primate
What price do we pay for never having to be alone or bored?
M.I.T.’s Sherry Turkle argues that we are losing something
fundamental to our humanity.
Interview by Mark Fischetti
86 Still Evolving (After All These Years)
INGO ARNDT
Getty Images
Our species has changed at a fast pace in the past 30,000 years,
and we show no sign of slowing down.
By John Hawks
September 2014, ScientificAmerican.com
1
© 2014 Scientific American
DEPARTMENT S
4 From the Editor
6 Letters
12 Science Agenda
To bolster the nation’s high­tech labor pool,
eliminate community college tuition.
By the Editors
14
14 Forum
Requiring medical researchers to test males and females
in every experiment is a bad idea.
By R. Douglas Fields
19 Advances
Hints of supersymmetry. Cheaper, safer solar panels.
Plastic finds a home in Arctic sea ice. Taste receptors
fight bacteria. What birds understand about thought.
32 The Science of Health
Doctors can now readily cure hepatitis C, but the price
of treatment is prohibitively high.
By Jessica Wapner
35 TechnoFiles
Digital orchestras could replace live musicians
in concert.
By David Pogue
92 Recommended
24
A primer on the universe. Scientific answers to absurd
hypothetical questions. Ways to gain self­control.
Bringing back the recently dead.
By Clara Moskowitz
94 Skeptic
How the survivor bias distorts reality.
By Michael Shermer
96 Anti Gravity
For a tasty treat, try arthropods.
By Steve Mirsky
98 50, 100 & 150 Years Ago
100 Graphic Science
Exactly how much do humans differ genetically
from chimps and other primates?
By Kate Wong
ON THE WEB
Scientific American
Chronicles: World War I
92
Our Web site features an archive of news articles and analyses
published in the magazine throughout the First World War.
Go to www.ScientificAmerican.com/sep2014/wwi
A. & F. MICHLER
Getty Images
(heart)
Scientific American (ISSN 0036-8733), Volume 311, Number 3, September 2014, published monthly by Scientific American, a division of Nature America, Inc., 75 Varick Street, 9th Floor, New York, N.Y. 10013-1917. Periodicals postage
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Copyright © 2014 by Scientific American, a division of Nature America, Inc. All rights reserved.
2
Scientific American, September 2014
© 2014 Scientific American
From the Editor
Mariette DiChristina
is editor
in chief of
Scientific American.
Follow her on Twitter @mdichristina
A
Humanity’s Journey
s I type, I am In the cavernlIke mccarran aIrport In
Las Vegas. Frank Sinatra is crooning through the
speakers. People are bustling along with their
bags, tucking into a sandwich before boarding for
their flights and, of course, foolishly dropping
their hard-earned money into the ringing, glowing slot machines.
I’ve just come from giving a keynote at the Amaz!ng Meeting,
the annual gathering of evidence-based thinkers run by the
James Randi Educational Foundation. The irony of the location
for such a meeting is not lost on me. At. All.
Not for the first time, I’m marveling at how some seemingly
unremarkable primates evolved into an ingenious species dis-
playing a series of similarly fascinating contradictions today. We
are clever and silly, poetic and crass, playful and brutal. We con-
template our mortality, selflessly share knowledge with others
and consume resources even when we know it’s unsustainable.
In every way, we are a remarkable species, but our rise to
dominance on this planet was by no means a given. In this, our
annual single-topic issue, we explore “The Human Saga” of our
species’ evolution. The articles probe the narrative arc of human
history, from where we began to what the future may hold.
Surely one important key for our success to date is our unique
ability to cooperate in large, well-organized groups—at a rate
and more expansively than other animals. See “One for All,” by
primatologist Frans de Waal, starting on page 68.
Today’s climate is being influenced by human activity, but
perhaps it is a surprise that past rapid swings in climate may
have helped shape human adaptability, advances in stone tools
and our varied diet, as environmental scientist Peter B. deMeno-
cal describes in “Climate Shocks,” beginning on page 48.
We are not done adapting. Although some believe humans
are no longer subject to natural selection, “Still Evolving (After
All These Years),” by anthropologist John Hawks, starting on
page 86, explains why that is not so. He details why humans
actually have evolved rapidly in the past 30,000 years as we have
switched from hunting and gathering to agriculture. As we look
ahead, we note with no small satisfaction that the human mosa-
ic in all likelihood will only continue to grow more colorful.
2 0 1 4 S C I E N C E I N AC T I O N W I N N E R
Congrats to Kenneth Shinozuka
of Brooklyn, N.Y., winner of the
$50,000
cientific American
Science in Action prize, part of the
S
Google Science Fair. To protect his beloved grandfather, who suffers
from Alzheimer’s and is prone to wandering, he paired a wearable
foot sensor with a Bluetooth-enabled wireless circuit and a smart-
phone app. The result can ease the anxieties of families everywhere.
Kenneth, a finalist in the 15–16 age category in the Google Science
Fair global competition, will join the others at the awards event on
September 22 at the company’s headquarters in Mountain View,
Calif. As chief judge since the fair’s founding, I am again looking
forward to seeing all the student scientists in action.
—M.D.
BOARD OF ADVISERS
Leslie C. Aiello
President, Wenner-Gren Foundation
for Anthropological Research
Kaigham J. Gabriel
Corporate Vice President,
Motorola Mobility, and Deputy, ATAP
Director, Medical Informatics and
Systems Division, and Professor, Virginia
Bioinformatics Institute, Virginia Tech
Director, Sage Center for the Study of Mind,
University of California, Santa Barbara
Lawrence M. Krauss
Director, Origins Initiative,
Arizona State University
Director, Hedonia: TrygFonden
Research Group, University of Oxford
and University of Aarhus
Robert E. Palazzo
Dean, University of Alabama at
Birmingham College of Arts and Sciences
Michael Shermer
Michael Snyder
Publisher,
Skeptic
magazine
Professor of Genetics, Stanford
University School of Medicine
Co-director, Clean Energy Incubator,
and Associate Professor,
Department of Mechanical Engineering,
University of Texas at Austin
Roger Bingham
Harold “Skip” Garner
Morten L. Kringelbach
Carolyn Porco
Co-Founder and Director,
The Science Network
CEO, Burrill Equities LLC
and Burrill Media, LLC
G. Steven Burrill
Leader, Cassini Imaging Science
Team, and Director, CICLOPS,
Space Science Institute
Director, Center for Brain and Cognition,
University of California, San Diego
Professor of Physics, Harvard University
Michael E. Webber
Michael S. Gazzaniga
Steven Kyle
Arthur Caplan
Professor of Applied Economics and
Management, Cornell University
David H. Koch Institute Professor,
Department of Chemical
Engineering, M.I.T.
Professor, Harvard Law School
Professor of Microbiology and
Immunology, Weill Medical
College of Cornell University
Professor and Head of
Engineering and Public Policy,
Carnegie Mellon University
Co-director, Center for
Neuroengineering, Duke University
Director, Program for Evolutionary
Dynamics, and Professor of Biology and
of Mathematics, Harvard University
Vilayanur S. Ramachandran
Director, Division of Medical Ethics,
Department of Population Health,
NYU Langone Medical Center
Director, Center for Computational
Genetics, Harvard Medical School
Distinguished University Professor,
University of Maryland College Park
and Johns Hopkins Bloomberg School
of Public Health
David J. Gross
George M. Church
Professor of Physics and Permanent
Member, Kavli Institute for Theoretical
Physics,University of California, Santa
Barbara (Nobel Prize in Physics, 2004)
Mallinckrodt Professor of
Physics and of Applied Physics,
Harvard University
Co-chairman, Applied Minds, LLC
Robert S. Langer
Lisa Randall
Steven Weinberg
Martin Rees
Lene Vestergaard Hau
Lawrence Lessig
John P. Moore
Astronomer Royal and Professor
of Cosmology and Astrophysics,
Institute of Astronomy, University
of Cambridge
Regents Professor of Soil Science
and Agroecology, Washington
State University
Director, The Earth Institute,
Columbia University
Chair, Advisory Council,
National Center for Science Education
Director, Theory Research Group,
Department of Physics,
University of Texas at Austin
(Nobel Prize in Physics, 1979)
Professor of Chemistry and
Chemical Biology, Harvard University
Director, Global Viral Forecasting Initiative
Chairman, Foundation for the Defense
of Democracies, and Venture Partner,
Lux Capital Management
Professor of Quantum Optics,
Quantum Nanophysics, Quantum
Information, University of Vienna
George M. Whitesides
Rita Colwell
John Reganold
Danny Hillis
Nathan Wolfe
Richard Dawkins
Daniel M. Kammen
M. Granger Morgan
Founder and Board Chairman,
Richard Dawkins Foundation
Drew Endy
Professor of Bioengineering,
Stanford University
Director, Center for Information
Technology Policy, Princeton University
Class of 1935 Distinguished Professor
of Energy, Energy and Resources Group,
and Director, Renewable and Appropriate
Energy Laboratory, University
of California, Berkeley
Partner, Khosla Ventures
CSO, Allen Institute for Brain Science
Jeffrey D. Sachs
R. James Woolsey
Miguel Nicolelis
Eugenie C. Scott
Anton Zeilinger
Vinod Khosla
Edward W. Felten
Martin A. Nowak
Terry Sejnowski
Christof Koch
Professor and Laboratory Head
of Computational Neurobiology Laboratory,
Salk Institute for Biological Studies
Jonathan Zittrain
Professor of Law and of Computer
Science, Harvard University
4
Scientific American, September 2014
Illustration by Nick Higgins
© 2014 Scientific American
Letters
editors@sciam.com
“There are plenty
of arguments with
which one may
oppose capital
punishment, but
suggesting that
lethal injection is as
barbarous as gassing
or electrocution
is unwarranted.”
May 2014
EXECUTION AND ETHICS
In describing the use of an experimental
cocktail to execute Dennis McGuire in Jan­
uary as having gone “badly” in “The Myth
of the Compassionate Execution” [Science
Agenda], the editors say, based on obser­
vations by the priest who gave McGuire
his last rites, that “McGuire struggled and
gasped for air for 11 minutes, his strained
breaths fading into small puffs” before
he died 26 minutes after the injection. As
a practicing anesthesiologist, I conclude
from this description that McGuire’s priest
probably witnessed the effects of airway
obstruction in an unconscious but not yet
dead subject, which may have been upset­
ting to the priest but would have been of
no consequence to McGuire.
There are a variety of drugs that cause
rapid loss of consciousness. In contrast, le­
thal gassing will often bring on distressing
breathlessness before permanent loss of
consciousness, and death by electrocution
may cause extreme pain. There are plenty
of arguments with which one may (and
personally I think should) oppose capital
punishment, but to oppose it by suggesting
that lethal injection is as barbarous as gas­
sing or electrocution is unwarranted.
Peter A. Bamber
Midgley, England
I would argue that there is a moral im­
perative for medicine to work on perfect­
ing a hasty and painless death. While doc­
peter a. bamber
midgley, england
tor­assisted suicides do not and should
not involve healthy people, even a termi­
nally ill patient’s body can put up a signif­
icant struggle to live under the effects of
adrenaline and the emotions related to
death. Although the method of adminis­
tration in doctor­assisted suicides and ex­
ecutions may need to differ, it seems that
the desired result in both cases would be
the same: a respectful death.
Talon Swanson
Seattle
While I endorse this article’s opinions
and am opposed to the death penalty, I
must disagree with the editors’ statement
that “scientific protocols for executions
cannot be established, because killing ani­
mal subjects for no reason other than to
see what kills them best would clearly be
unethical.” In the veterinary world, animal
euthanasia is sadly performed many times
a day, for many reasons.
Some years ago after fighting all day
for the life of my horse, Alex, I took him to
our local surgeon. It turned out he had
colic. We led him into my trailer, where he
was given a barbiturate, and he died with­
out a twitch. The mercy we give to our an­
imals and pets is the heavy price we pay
for their love and companionship.
Chris Stross
via e-mail
SUPERSYMMETRY PREDICTION
In “Supersymmetry and the Crisis in Phys­
ics,” Joseph Lykken and Maria Spiropulu
discuss hopes that evidence of supersym­
metry, which proposes that all known par­
ticles have hidden superpartners, will be
found at CERN’s Large Hadron Collider
within a year’s time—and the effects on
physics as a whole if it is not.
There is one approach to superpartner
discovery that the authors do not explore.
Many people think the framework of string
theory and its M­theory variant, with small
extra dimensions, is well motivated. To
make predictions from the 10­ or 11­dimen­
sional string/M theories, it is necessary to
project them onto a world with four space­
time dimensions, and some resulting de­
scriptions have had phenomenological
successes. Essentially all predict that some
superpartners of the electroweak gauge
bosons will be light enough to observe at
the LHC after its upgrade. Some also pre­
dict that gluionos, the proposed superpart­
ners of gluons, will be light enough to ob­
serve there.
Predictions based on such theories
should be taken seriously. I would like to
bet that some superpartners will be found
at the LHC, but I have trouble finding peo­
ple who will bet against that prediction.
Gordon Kane
Victor Weisskopf Distinguished
University Professor of Physics
University of Michigan
Lykken and Spiropulu write about a
crisis in physics that results if we fail to
discover supersymmetry. But they and the
editors of
Scientific American
have ne­
glected possibilities that I reported on in
your own blogosphere in 2012 (Scientific
American.com/sep2014/beyond­higgs):
that there is nothing whatsoever wrong
with the Standard Model, that it doesn’t
need fixing and that even adding quantum
gravity may not spoil it. That scenario is
more boring than all the wonderful ideas
being put forward but is much simpler.
Glenn D. Starkman
Professor of Physics and Astronomy
Case Western Reserve University
SECONDHAND VAPOR
In “Are E­Cigarettes Safe?” [The Science
of Health], Dina Fine Maron notes that
one of the concerns about e­cigarettes is
that they expose users and bystanders to
“unidentified dangers.”
As a bystander, I am concerned about
6
Scientific American, September 2014
© 2014 Scientific American

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