[2005/06/03] He¡¯s Ba-a-a-ck: Lamarck Puts Pressure on Darwin – and ID, Too?
He¡¯s Ba-a-a-ck: Lamarck Puts Pressure on Darwin – and ID, Too? 06/03/2005 To historians of
evolutionary theory, Lamarck is a 19th-century loser. His hypothesis
of ¡°inheritance of acquired characteristics,¡± according to high school
textbooks and common knowledge, was debunked by experiment, and overturned
when Darwin proposed natural selection as a mechanism for evolution.
Why, then, does Massimo Pugliucci (Dept. of Ecology and Evolution, State
University of New York at Stony Brook, NY) give Lamarck good press in a
book review in Nature?1 Why does he put Darwin on
defense, charging that a ¡°broader view of inheritance puts pressure on the
neo-darwinian synthesis¡±? Pugliucci favorably reviewed
the book Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral,
and Symbolic Variation in the History of Life by Eva Jablonka and
Marion J. Lamb (Bradford Books, 2005), a ¡°lamarckist¡± polemic:
The authors argue that there is more to
heredity than genes; that some hereditary variations are
non-random in origin; that some acquired information is
inherited; and that evolutionary change can result from
¡®instruction¡¯ as well as selection. This may sound rather
revolutionary, even preposterously close to lamarckism.
But Jablonka and Lamb build on evidence from standard research in
evolutionary and molecular biology, and their case should be examined on
its merits, rather than being dismissed by a knee-jerk reaction.
(Emphasis added in all quotes.)
He quickly
quenches any alarm that he or the authors want to revive the kind of
lamarckism that taught direct inheritance of acquired
characteristics, or ¡°direct adaptive feedback from the soma to the germ
line¡± – for example, that a lumberjack¡¯s strong arms would be inherited by
his baby boy. ¡°That version of lamarckism is dead,¡± he assures us,
¡°killed off by our understanding of molecular biology, and nobody is
attempting to revive it.¡± But that first meaning of lamarckism is
not all that Lamarck taught:
The second meaning is actually closer to
the core of Lamarck¡¯s ideas, which are rarely, if ever, read
by modern biologists. The suggestion is that some
heritable, adaptive changes come not from natural selection, but
from the action of evolved internal systems that generate non-random
¡®guesses¡¯ in response to environmental challenges. Examples
are not hard to find, contrary to the assumed wisdom of standard
neo-darwinism. Consider the existence of ¡®hotspots¡¯
that make mutations in certain regions of the genome much more
likely than in others. Or the impressive ability of some
bacteria to increase the mutation rate of a specific gene
involved in the metabolism of a given amino acid when that amino acid
becomes scarce in the environment.
Pugliucci
acknowledges that ¡°Jablonka and Lamb are surely taking a gamble in
labelling their position as lamarckist,¡± but he sides with them in
one shocking point: ¡°they are correct to point out that no modern
biologist is a darwinist in the sense Darwin would have understood –
not least because Darwin included a lamarckian mechanism of the
first (now frowned upon) type in his theory, as he had no solution to
the problem of heredity¡±. Having disabled the alarm, Pugliucci now offers
the neo-lamarckism of Jablonka and Lamb as the evolutionary answer to the
intelligent design movement:
If one accepts this bold, expanded
version of heredity and evolution, it turns out that
evolution can proceed very rapidly and phenotypic modification
can precede genetic changes.... Indeed, changes at the genetic
level will often simply stabilize adaptive modifications that
are initiated through phenotypic plasticity [i.e., acquired
characteristics], epigenetic control mechanisms, or
behavioural and symbolic means [i.e., social/language
communication from parent to offspring]. This is a framework
that would greatly help to solve old problems in evolutionary
biology, such as the origin of novel structures, and even the appearance of what ¡®intelligent
design¡¯ proponents refer to, rather nonsensically [sic], as
¡®irreducible complexity¡¯. This wouldn¡¯t require the
abandonment of neo-darwinism, but rather its expansion beyond what
Ernst
Mayr contemptuously labelled ¡®bean-bag genetics¡¯.
So Pugliucci offers not an either-or choice of
lamarckism vs. neo-Darwinism, but an expanded synthesis beyond that
thesis-antithesis dichotomy. For empirical support, he points to the
¡°partial failure of the originally ultra-reductionist, gene-centred
approach that gave us genomics,¡± saying that ¡°the interesting
stuff is going on at the level of large gene networks¡±, ¡°not of individual genes, partly because there is widespread
functional redundancy in the genome.¡± Presumably, this pool
of functionality can be drawn on by environmental cues to optimize
solutions to problems. Realizing his viewpoint will probably
anger the hard-core selectionists, like Richard Dawkins
and George Williams,
he draws on a defense, in closing, that has been used by several
intelligent design proponents as strategic realism about changing the
minds of the old guard:
The clamour to revise neo-darwinism
is becoming so loud that hopefully most practising evolutionary
biologists will begin to pay attention. It has been said
that science often makes progress not because people change their
minds, but because the old ones die off and the new generation is more
open to novel ideas. I therefore recommend this and the other
books I mentioned on the future of evolutionary theory to the
current crop of graduate students, postdocs and young
assistant professors. They¡¯ll know what to do.
They¡¯ll know what to do, all right:
they¡¯ll chuck Chuck and baptize Jean-Baptiste into the dustbin of
discredited prophets, and embrace intelligent design. Like
Sutherland in the next article below, Pugliucci and his champions
believe that specified complexity and optimization can emerge
spontaneously, without purpose or direction, as long as there is a
need. But that fallacy is not just with neo-Darwinism and its
reductionist genomics; it is with any theory that fails to
include information as a fundamental property of the
universe. No combination of chance and natural law will produce
information. Think of a blank DVD and one containing microscopic
pits encoding the latest Star Wars movie: they have the same mass
and physical properties. It is the information content that makes
all the difference when you insert them into a DVD player.
Similarly, to believe that the information content in the genome and in
all the gene networks and epigenetic controls to which Pugliucci refers
could have arisen by naturalistic means cannot be done without assuming
naturalism at the outset. All our common experience teaches that
information arises only from intelligent causes. What
this book review does, despite its dismissive ridicule of intelligent
design, is strengthen the strategic posture of ID. It advertises
the weaknesses of the Darwin camp to the enemy. The ¡°clamor to
revise neo-darwinism¡± has risen to a fever pitch within the Darwin
camp, and can no longer be ignored, except by the Old Guard who have
grown deaf with age. The phrase ¡°irreducible complexity¡± has
rattled the evolutionary generals: ¡°Quick: we need a counterattack,¡±
they strategize. ¡°How¡¯s the neo-Darwinian antidote
working?¡± ¡°Too weak,¡± the technician responds; ¡°Their weapons have developed immunity to it, and we¡¯ve found it
incapable of protecting our own soldiers. It¡¯s not as potent as we
thought it was.¡± ¡°Anything else in our strategic arsenal?¡± ¡°Nothing new, General. Most of our weapons were forged
in the 19th century.¡± ¡°Well, then, did anything work well before
Chairman Charles?¡± ¡°We could resurrect an older weapon used with
partial success from time to time, even by Darwin,¡± a lieutenant
responds. It was invented by General Lamarck.¡± ¡°We can¡¯t use
that; it¡¯s broken. Everybody knows that.¡± ¡°We¡¯ve got to do
something, General. Let the young recruits try it and see if they
can get parts of it to work this time.¡± The intelligent
design strategists, like Gideon spying around the tents of Midian (see
Judges
7), are listening in on all of this. Can a loaf of barley
bread overturn ten thousand tents? It can, either when the tents
are made of wind held together by fog, or when there is supernatural
power in charge. It appears the I.D. camp has both advantages.