Human Origins: 7 million years and counting

129 Pages·2018·2.37 MB·English

by  New Scientist

Human Origins
7 million years and counting
NEW SCIENTIST
Contents
Series introduction
Contributors
Introduction
1 Distant origins
2 On to two legs
3 Lucy and her sisters
4 Bigger brains
5 Our closest cousins
6 Global conquerors
7 Civilization and beyond
8 A special species
9 Shaped by our world
10 Unanswered questions
Conclusion
Fifty ideas
Glossary
Picture credits
Series introduction
New Scientist’s Instant Expert books shine light on the subjects that we all wish
we knew more about: topics that challenge, engage enquiring minds and open up
a deeper understanding of the world around us. Instant Expert books are
definitive and accessible entry points for curious readers who want to know how
things work and why. Look out for the other titles in the series: The End of
Money
How Your Brain Works
The Quantum World
Where the Universe Came From
How Evolution Explains Everything about Life
Why the Universe Exists
Your Conscious Mind
Machines that Think
Scheduled for publication in 2018: How Numbers Work
A Journey Through The Universe
This is Planet Earth
Contributors
Series Editor: Alison George, New Scientist
Editor: Michael Marshall, freelance science journalist based in Devon, UK
Instant Expert Series Editor Jeremy Webb, New Scientist
Guest contributors
Justin L. Barrett is a professor of psychology and chief project developer for
Fuller Theological Seminary’s Office for Science, Theology, and Religion
Initiatives. He is the author of Born Believers: The Science of Children’s
Religious Belief (2012). He writes about our natural receptivity to religious ideas
in Chapter 7.
Michael Bawaya is a the editor of American Archaeology magazine. He lives in
Albuquerque, New Mexico and writes in Chapter 6 about human migration into
the Americas.
David Begun is a professor of anthropology at the University of Toronto,
Canada. He is author of The Real Planet of the Apes (2015) and writes here
about the dawn of the apes in Europe in Chapter 1.
Ara Norenzayan is a professor of psychology at the University of British
Columbia in Vancouver, Canada. He is the author of Big Gods: How Religion
Transformed Cooperation and Conflict (2013). In Chapter 7 he discusses
religion’s critical role in helping societies grow.
Mark Pagel is a professor of evolutionary biology at Reading University, UK, a
fellow of the Royal Society, and author of Wired for Culture: Origins of the
Human Social Mind (2012). In Chapter 8 he describes why teaching is critical to
our cultural evolution, and asks why language evolved.
Pat Shipman is a palaeoanthropologist and retired Adjunct Professor of
Biological Anthropology at Pennsylvania State University. Her latest book is
The Invaders: How Humans and Their Dogs Drove Neanderthals to Extinction
(2015). Her work on the relationship between humans and wolves appears in
Chapter 5.
Thanks also to the following writers and editors:
Robert Adler, Claire Ainsworth, Shanta Barley, Colin Barras, Emily Benson,
Alyssa A. Botelho, Catherine Brahic, Ewen Callaway, Andy Coghlan, Kate
Douglas, Alison George, Jessica Hamzelou, Jeff Hecht, Bob Holmes, David
Holzman, Jude Isabella, Ferris Jabr, Dan Jones, Alice Klein, Will Knight, Roger
Lewin, Mairi Macleod, Phil McKenna, Rachel Nowak, Jan Piotrowski, James
Randerson, Kate Ravilious, David Robson, Michael Slezak, Laura Spinney,
Mićo Tatalović, Jeremy Webb, Clare Wilson, Sam Wong, Aylin Woodward, Ed
Yong, Emma Young.
Introduction
There can be no more profound question than ‘Where do we come from?’ Since
our ancestors figured out how to think, we humans have wondered about our
origins, but it is only within the last few centuries that we have tackled the
question scientifically.
The story of the study of human evolution is an epic one, full of
extraordinary discoveries, daring adventures and (often) spectacularly vehement
arguments. It encompasses a swathe of technical disciplines, and forces us to ask
deep questions about who we are as a species. This book is your introduction to
the subject.
The first seven chapters tell the story of human evolution in chronological
order, beginning with the earliest primates, moving through the earliest ape-like
hominins, and concluding with the rise of modern civilization. The final three
chapters then step back to ask the three biggest questions: what is so special
about us, how did we get that way, and what do we still not know?
That last point is a crucial one. We should admit in advance, with apologies,
that no reader will get to the end of this book and find that they understand how
humanity evolved. Our understanding of human evolution has been upended, or
at least seriously complicated, by a swathe of remarkable discoveries made since
the year 2000. So you won’t find the ultimate truth here, but you will find plenty
of facts, our best explanations for them and, we hope, the right questions to ask.
Michael Marshall, Editor
1
Distant origins
The story of our origins begins tens of millions of years ago. In the wake of a
mass extinction that wiped out all the dinosaurs – except for birds – and a host
of other creatures, a new group of animals arose. They were small and probably
seemed utterly insignificant at first. But they would spread to every continent
and ultimately change the face of the planet. They were the primates.
The story of primate evolution spans 55 million years and hundreds of
species. But from the point of view of our own evolution, there are four key
steps:
1 The original primates
2 The ‘higher primates’ or ‘simians’ – the group that includes monkeys
3 The apes, especially chimpanzees
4 The rise of hominins like us.
In this chapter we will focus on the first three steps. The following six chapters
will cover the hominins.
Meet Archie
Our distant ancestors most likely evolved in Asia, in a hothouse world newly
free of dinosaurs. More than 55 million years ago, in the lush rainforests of what
is now east Asia, a new voice was heard in the animal chorus: the cry of the first
primate.
A fossil unveiled in 2013 might give us an idea of what this crucial ancestor
looked like. Archicebus achilles is the earliest primate skeleton ever found (see
Figure 1.1). It also strongly suggests that our lineage evolved in Asia, several
million years earlier than we thought, and links the evolution of primates to the
most extreme episode of climate change of the last 65 million years.
FIGURE 1.1 The evolution of the primates, apes and hominins: Archicebus achilles is the oldest primate
found so far. Analysis of the fossil places it in the tarsier lineage but it may yet turn out to be a human
ancestor.