The fourth installment of what started out
in the spring of 2012 as a hand-written essay about a number of controversial
issues that I’d been stewing over for years—in particular, “problems” with
current speculations regarding the origin of life, quandaries raised by the
very nature of biological complexity, and what I saw as the shortcomings of a
neo-Darwinian insistence on natural selection being almost solely the cause of
all evolutionary change. Four years of subsequent evolutionary research have confirmed
my suspicions that neo-Darwinism has presented an oversimplified picture of
what is actually a very complex subject—one not so simple and clear-cut as
authors like Richard Dawkins would have us believe. This short section is the
first of several historical overviews that reveal how various biological fields
have been strongly affected by the prevailing attitudes of earlier, formative
times. Throughout this work I’ll be attempting to show how the slew of amazing
advances in recent decades point to an entirely new way of viewing life…and
how the strictly materialistic stance taken by almost all contemporary
biologists doesn’t square with a bigger picture gradually being revealed by all
their new findings. (The next section will look into the failings of scientific
materialism, with its over-reliance on purely reductive thinking.)
III.
The Modern Synthesis
The
most developed science remains a continual becoming, and in every field
nonbalance plays a functional role of prime importance since it necessitates
re-equilibrium.
Jean
Piaget, The Development of Thought
The bedrock
assumptions upon which Darwin’s theory of evolution
by natural selection rests are that there can be random variations in
genetic material and that these can lead to improved chances for survival. The
late paleontologist and evolutionary biologist Stephen Jay Gould, summarizing
its main tenets:
First, that all organisms produce more
offspring than can possibly survive; second, that all organisms within a
species vary, one from the other; third, that at least some of this variation
is inherited by offspring. From these three facts, we infer the principal of
natural selection: since only some of the offspring can survive, on average the
survivors will be those variants that, by good fortune, are better adapted to
changing local environments. Since these offspring will inherit the favorable
variations of their parents, organisms of the next generation will, on average,
become better adapted to local conditions.
During the
period Charles Darwin and Alfred Russel Wallace were shoring up their
ground-breaking theories, neither they nor anyone else had any idea how
inconceivably complex the manifold workings of life actually were. As an illustration
of how little was understood it that era: German biologist Ernst Haeckel, a
contemporary and great admirer of Darwin’s, believed that the cell (still a
little-known entity) was “not composed of any organs at all, but consist[ed]
entirely of shapeless, simple, homogeneous matter…nothing more than a
shapeless, mobile, little lump of mucus or slime….”
While Darwin
and Wallace were occupied with refining their ideas, a congenial and
self-effacing Austrian friar was growing pea plants in his abbey’s garden.[1]
Over the course of eight years, Gregor Mendel patiently reared almost 30,000
plants while piecing together the foundation of modern genetics.[2]
Due to a
number of adverse historical circumstances, Mendel’s far-reaching insights went
unrecognized for nearly half a century. Significantly, after all his
painstaking labor and meticulous recording of data, the priest’s findings were
made known solely through two public lectures followed by a paper submitted to
the Proceedings of the Natural Science Society of Brünn. Aside from that one obscure 1866 publication, Mendel
personally distributed 40 reprints of the treatise to suitable people and…his
seminal research quickly all but
disappeared. It was ignored by fellow botanists; they were confused about the
object of it all… perceived the work as being merely about hybridization (the
controlled breeding of animals being
an important feature of their day-to-day lives), and were put off by Mendel’s
perplexing reliance on numbers. It seems odd today, but scientifically rigorous
experimentation involving statistics was a foreign concept to biologists of
that era.
His efforts
were largely forgotten until 1900, when three European plant physiologists,
independently performing similar experiments, simultaneously brought to light
the friar’s enormous contribution to science. Mendel’s treatise, Experiments with Plant Hybrids, had been
published seven years after the first edition of On the Origin of Species came out but, despite an apocryphal story that Darwin owned a copy but never read it, there is no evidence
he was aware of the work.[3]
(Some scholars believe that Darwin, whose mathematical skills were poor, would
likely not have recognized its implications.) Mendel, long in poor health, died
at only sixty-one. All his papers, all his scrupulous documentation, were
carted out to a hill behind the abbey shortly after his death…and summarily
burned.[4]
The discovery
of genes as discrete units of inheritance had a huge effect on accelerating
evolutionary research. In the 1920s and 30s, following the acceptance of chromosome theory, a new discipline
emerged: population genetics (the
study, heavy on statistical analysis, of how traits arise and move through
populations). Thanks largely to work by two Britons—statistician Ronald Fischer
and biologist J.B.S. Haldane—and American geneticist Sewall Wright, Mendelian
genetics and the concept of evolution by natural selection were finally
integrated: a unification that became feasible only after it was finally recognized that the gradual, steady
modification called for by Darwin’s theory was entirely compatible with
Mendel’s axioms. This paved the way for an end to various disagreements that
had been building for some time. These conflicts were for the most part put to
rest during the course of an international symposium held at Princeton in 1947,
shortly after WW II’s travel restrictions had lifted. It became known as the modern Darwinian synthesis.
The modern
synthesis is basically a set of ideas that was assertively championed by bird taxonomist-cum-evolutionary
biologist Ernst Mayr and several of his chief collaborators in America, notably
paleontologist George Gaylord Simpson, expatriate Soviet geneticist Theodosius
Dobzhansky, and botanist G. Ledyard Stebbins—all prominent experts in their
fields. Up until that time, researchers working in disciplines such as paleontology,
systematics, and ecology were neither in close communication nor sharing their findings.
To some extent, these fields were all influenced by Darwinian theory even
though many of his ideas had long since fallen out of favor. The specific
disciplines’ views on evolutionary agencies and their relative importance had
diverged; each was starting to attribute different meanings to established
concepts and use different terminology to describe them. Of even greater
concern, paleontologists were actually at odds with the concept of natural
selection as a consequence of not seeing the gradual changes required by its
precepts reflected in fossil records. Those working with population genetics
were convinced they had finally found a way to connect the different
disciplines.
The symposium, considered a great success, united
many branches of biology under one common evolutionary umbrella that (according
to Gould) “validated natural selection as a powerful causative agent and raised
it from a former status as one of a contender among many to a central position
among mechanisms of change.” (This was the gathering’s intended goal.) Mayr
made clear that the intention of the synthesis
was simply a means to
designate the general
acceptance of two conclusions: gradual evolution can be explained in terms of
small genetic changes (“mutations”) and recombination, and the ordering of this
genetic variation by natural selection; and the observed evolutionary
phenomena, particularly macroevolutionary processes and speciation, can be
explained in a manner that is consistent with known genetic mechanisms.
The true significance and influence of natural
selection was still being debated until findings by Dobzhansky reaffirmed its
primacy—a critical, solidifying event in the movement’s early development. The
alliance thereafter commonly became known as neo-Darwinism.[5]
But, like Darwin and his contemporaries, Mayr and his esteemed colleagues had little notion of the real complexities
lying beneath the surface of their subject matter. The entire field of microbiology was
in its infancy…the helical structure of DNA still unknown. No embryologists had
attended the symposium and their findings would muddy the water for some time
yet. Perhaps due to the strong personalities and fervor of neo-Darwinism’s
promoters, from its outset the movement was infused with a zealousness that
made it notably resistant to change—an ironic misfortune, since all the
scientific branches concerned were in flux.
Only fifty years later, the
modern synthesis was in need of modernization.
©2016 by Tim Forsell draft
18
Jan 2016
[1] Properly speaking, he was from Moravia (a historic region in what is now the
Czech Republic). Many misconceptions surround Mendel and his work: for one, he
was a friar—not a monk—and lived not at
a monastery but at an abbey, among a
community of very talented and learned men.
[2] It was fortuitous that Mendel chose to work with pea
plants. By sheer good fortune, the traits he chose to follow were controlled by
genes found on different chromosomes and those traits also happened to denote
distinct, unambiguous features not typically displayed in such regular fashion.
Botanist Carl Nägeli (1817–91) was the only biologist to attempt repeating
Mendel’s experiments. Unfortunately, he chose to work with a plant in the
Sunflower family that reproduces asexually and thus did not demonstrate
Mendel’s results.
[3] Mendel and his peers were all well-acquainted with
Darwin’s work. (Mendel owned a copy
of Origin.)
[4] The complicated story of the “rediscovery” of Mendel’s
research is somewhat out of the scope of this work but historically
fascinating: Mendel’s obscure publication had been passed around by a few plant
breeders. Among those who had read the paper were Dutchman Hugo de Vries,
German Carl Correns, and Austrian Erich von Tschermak. Working independently,
each achieved in their own experiments results similar to Mendel’s. Correns
barely missed out on beating de Vries to publication and there is evidence that
both intended to claim discovery of what became
known as Mendel’s Law (the
3:1 ratio of dominant versus recessive characteristics generated by the
hybridization of two purebred strains). Coincidently, de Vries sent Correns a
copy of his newly-published article, written for a French journal, that made no
mention of Mendel. Correns was just then putting the last touches on his own
manuscript and, bitter at having been upstaged, hurriedly finished his own
paper and sent it to the German Botanical Society for publication. Correns made
a point of crediting Mendel with the 3:1 law’s discovery to undercut de Vries’
claim to priority; whether or not he intended to do the same is still debated.
But, unbeknownst to Correns, de Vries had already sent his paper to the German Botanical Society and, in this version, had
credited Mendel. Thus was Mendel’s work “rediscovered” and handed over to
science.
[5] George Romanes, a protégé of Darwin’s, “coined the
term neo-Darwinism to refer to the version of evolution advocated by Alfred
Russell Wallace and August Weismann with its heavy dependence on natural
selection…[rejecting] the Lamarckian idea of inheritance of acquired
characteristics” (a commonly held notion of the era that Darwin himself had embraced).
