30 | New Scientist | 28 March 2020
Books
Some Assembly Required:
Decoding four billion years
of life, from ancient fossils
to DNA
Neil Shubin
OneworldFantastic Fossils: A guide
to finding and identifying
prehistoric life
Donald R. Prothero
Columbia University PressIN 1871, a now-obscure biologist
called St George Jackson Mivart
published On the Genesis of
Species. As its title suggests, the
book was a riposte to Darwin’s
theory of natural selection,
published in 1859. Mivart had been
an avid Darwinian, but the more
he thought about it, the stronger
his doubts grew. In particular, he
couldn’t see how natural selection
could account for the appearance
of novel structures.
This was the start of a debate
that has raged ever since: just
what caused the major transitions
in the history of life? How, for
example, did birds evolve flight?
Or animals evolve to live on land?
The problem is that a small,
incremental step towards
structures such as wings, feathers
or lungs would appear to be
of little adaptive value, and so
wouldn’t have been selected for
by evolution. Ditto the sweeping
anatomical and physiological
changes required to take to the
air or colonise the land. As the late
palaeontologist and science writer
Stephen Jay Gould put it, what use
is 2 per cent of a wing?
Pretty much every major
transition hits this problem, and
creationists exploit it in their
attempts to discredit the theory.
Neil Shubin at the UniversityLaying the bones bare
Finding out how flight evolved or how animals colonised the land is all about
a collision of palaeontology and genetics, discovers Graham Lawtonof Chicago is well placed to answer
the question. As a palaeontologist,
he predicted the location of, and
then found, the fossilised remains
of Tiktaalik roseae, a 375-million-
year-old transitional form.
Tiktaalik is what we used to call a
missing link: it is an intermediate
stage between aquatic andterrestrial animals, and one of the
best pieces of physical evidence
for the theory of evolution.
The story of Tiktaalik’s hard-
won discovery in the Canadian
Arctic was the centrepiece of
Shubin’s excellent previous book,
Your Inner Fish. His latest book,
Some Assembly Required, plays to
his other specialism, molecular
biology, where he works to
understand how genetics andViews Culture
PHIL^ DEG
GINGE
R/ALAMYUniversity. Shubin and Prothero
were university classmates and
remain friends.
The buddies have produced very
different books. Fantastic Fossils
is an insider’s guide to finding,
collecting, identifying and
understanding fossils, including
a comprehensive walk through
the different life forms that fossil
hunters might hope to unearth,
from sponges to vertebrates.
There is a lot of ground to cover,
but enough “wow” moments
to keep you going, much like a
real-life fossil-hunting expedition.
Did you know, for example, that
the earliest turtles had shells
on their bellies rather than their
backs? Or that the 15-million-year-
old leaves in the fossil beds of
Idaho are so exquisitely preserved
they are still green? There is all
this and much more to enjoy in
both of these books. ❚developmental biology explain
such major transitions – for
instance, how a class of regulatory
genes called Hox orchestrate the
development of all body plans.
His new book is a skilful and
fascinating account of how his two
very different worlds produce a
coherent answer to the 2-per-cent-
of-a-wing question. Spoiler alert:
evolution rarely comes up with
anything truly new but simply
repurposes what is available.
Thus lungs evolved from swim
bladders, feathers from dinosaurs’
insulating fuzz, and so on. When
true novelty arises, it often comes
from an unlikely source: viruses.
Shubin covers both the
groundbreaking science and the
scientists who broke it, telling
a vivid and human story of the
excitement, frustration and often
sheer serendipity of progress.
Tiktaalik (and Shubin) also have
a cameo appearance in another
fine book by prolific author and
palaeontologist Donald Prothero
at California Polytechnic StateMolecular biology is
revealing deeper secrets
of ancient life like T. r ex“ As palaeontologist
and science writer
Stephen Jay Gould
put it, what use is
2 per cent of a wing?”