Download Philosophie Zoologique – 200: Lamarck in

ARTICLE
PHILOSOPHIE ZOOLOGIQUE - 200: LAMARCK IN RETROSPECT
KAMALES KUMAR MISR A*
J. B. Lamarck is considered as one of the renowned evolutionists. He was the first scientist to
explain evolution as a vertical phenomenon and considered man as the end product of evolution.
Lamarck, originally a believer in constant world, became an evolutionist after studying the fossil
and recent mollusks of France in the year 1799. Lamarck published his book Philosophie
Zoologique in 1809 and is being misunderstood till today. It is time to evaluate Lamarckian
perception from present day concepts of evolution. The paper depicts his personal life, his
emergence as an evolutionist, his contribution on evolution, and post-Lamarckian discussions.
Moreover, Lamarckism is analyzed from the angle of various inheritance systems. The idea of
Lamarck is also addressed in the light of Baldwin effect, genetic assimilation, somatic selection
hypothesis, internal selection, gene duplication, and evolutionary novelties. Lastly, an evolutionary
model is proposed to elucidate Lamarckian concept based on the contributions on modern
evolutionary modalities.
Introduction
D
escent of complex organisms with modifications
is the central theme of evolutionary theory which
moves with the time. Evolutionary thoughts are
constantly enriching our knowledge time and again. The
central purpose of evolutionary biology is to provide a
rational explanation for the gradual appearance of
extraordinary complex and intricate organization of all kinds
of living forms. A long argument continues to address the
mechanism of evolution. As Mayr1 viewed that a true
theory of evolution must postulate a gradual transformation
of one species into another. Analysis of the history of
evolutionary theories reveals that J. B. Lamarck should be
considered as a true “First Evolutionist”.
Background of a Naturalist
Jean Baptiste Pierre Antoine de Monet, Chevalier de
Lamarck was born on August 1, 1744, in the village of
Bazentin-le-Petit, Picardie, in the north of France in an
impoverished aristocratic family. He was the eleventh child
*
198
Department of Zoology, Bethune College, 181 Bidhan
Sarani, Kolkata 70 006, Email: [email protected]
of his father Philippe Jacques de Monet de La Marck (died
in 1759) and mother Marie-Françoise de Fontaines de
Chuignolles.
His family had with a centuries-old tradition of military
service in the French army. Lamarck’s eldest brother was
killed in combat at the Siege of Bergen-op-Zoom, and two
other brothers were still in service when Lamarck was in
his teenage years. He was admitted to the Jesuit seminary
at Amiens around 1750s. After the death of his father,
Lamarck bought himself a horse, and rode across the
country to join the French army, which was in Germany in
the summer of 1761. Lamarck showed great physical
courage on the battlefield in the Pomeranian War with
Prussia, and he was even nominated for the lieutenancy.
Lamarck’s company was left exposed to the direct artillery
fire of their enemies, and was quickly reduced to just
fourteen men and no officers left. One of the men
suggested that the puny, seventeen year-old volunteer
should assume command and order a withdrawal from the
field; but although Lamarck accepted command, he insisted
they remain where they had been posted until relieved.
When their colonel reached the remains of their company,
this display of courage and loyalty impressed him so much
SCIENCE AND CULTURE, MAY-JUNE, 2011
that Lamarck was promoted to officer on the spot.
However, when one of his comrades playfully lifted him
by the head, he sustained an inflammation in the lymphatic
glands of the neck, and he was sent to Paris to receive
treatment. He underwent a complicated operation, and
continued his treatment for a year. He was awarded a
commission and settled at his post in Monaco.
After working as a bank clerk in Paris for a while,
Lamarck began to study medicine and botany and in
Monaco he encountered Traité des plantes usuelles, a
botany book written by James Francis Chomel. Lamarck
was getting a reduced pension of 400 franc and he wanted
to pursue a profession. He studied medicine for four years,
but gave it up under his elder brother’s persuasion. He
was interested in botany, especially after his visits to the
Jardin du Roi, and he became a student under Bernard de
Jussieu, a notable French naturalist. Under Jussieu, Lamarck
spent ten years studying French flora. In 1778, he
published some of his observations and results in a threevolume work, entitled Flore française. The book received
great acclaim, in part thanks to the support of Buffon.
Georges-Louis Leclerc, Comte de Buffon mentored Lamarck
and helped him in getting membership to the French
Academy of Sciences in 1779 and a commission as a Royal
Botanist in 1781 at the royal botanical garden, the Jardin
des Plantes, which was not only a botanical garden but a
center for medical education and biological research. The
job helped him to travel to foreign botanical gardens and
museums. In 1788, Buffon’s successor at the position of
Intendant of the Royal Garden, Charles-Claude Flahaut de
la Billaderie, comte d’Angiviller, created a position for
Lamarck, with a yearly salary of 1,000 francs, as the keeper
of the herbarium of the Royal Garden. In his two years of
travel, Lamarck collected rare plants that were not available
in the Royal Garden, and also other objects of natural
history, such as minerals and ores, that were not found in
French museums. Aside from a stint as tutor to Buffon’s
son during a tour of Europe in 1781, Lamarck continued
as an underpaid assistant at the Jardin du Roi, living in
poverty. In 1793, Louis XVI and Marie Antoinette went
to the guillotine, the old Jardin des Plantes was reorganized
as the Musée National d’Histoire Naturelle (National
Museum of Natural History), which was to be run by
twelve professors in twelve different scientific fields.
Lamarck, who had called for this reorganization, was
appointed a professor of the natural history of insects
and worms (that is, of all invertebrates), a subject he knew
nothing about. Lamarck received the official title of
“Professeur d’Histoire naturelle des Insectes et des Vers”,
with a salary of nearly 2,500 francs per year. On September
VOL. 77, NOS. 5–6
26, 1794, Lamarck was appointed to serve as secretary of
the assembly of professors for the museum for a period of
one year.
Personal Life
Lamarck married and widowed four times. On August
8, 1778, he married Marie Anne Rosalie Delaporte.
Lamarck’s first son, André, was born on April 22, 1781,
and he made colleague André Thouin the child’s godfather.
On January 7, 1786, his second son, Antoine, was born,
and Lamarck chose Antoine Laurent de Jussieu, Bernard
de Jussieu’s nephew, as the boy’s godfather. On April 21
of the following year, Charles Rene, Lamarck’s third son,
was born. René Louiche Desfontaines, a professor of
botany at the Royal Garden, was the boy’s godfather, and
Lamarck’s elder sister, Marie Charlotte Pelagie De Monet
was the godmother. Lamarck’s wife gave birth to three
more children before dying on September 27, 1792. The
following year on October 9, he married Charlotte Reverdy,
who was thirty years his junior. In 1797, his second wife
Charlotte died, and he married Julie Mallet the following
year; she died in 1819. He is rumored to have married
(and been widowed) a fourth time, but no documentary
evidence exists to support this. The two daughters who
attended his deathbed were left penniless at his death;
one surviving son was deaf and incapable and another
was insane. Only one son, Auguste, was financially
successful as an engineer, and only he went on to marry
and have children himself.
Pre-Lamarckian Thoughts
Pre-Lamarckian heritage have no distinct bearings on
evolutionary thinking of man. Impact of religion eclipsed
evolutionary thinking, because there was a contradiction
between God and evolution. Researches on physics,
cosmology, geology, etc. dominated the scientific fields.
There was no conceptual proposition in biological
sciences. Buffon and Linnaeus were two great naturalists
in eighteenth century. The seventeenth and eighteenth
centuries experienced an almost total revolution in man’s
concept of nature. This was the ‘age of reason’. Peoples
tried to understand reasons behind everything. Discoveries
in various fields, especially on physical laws, infinity of
time and space, cosmological evolution, discredited the
Bible as a source of scientific explanation. Further,
discoveries in the biological sciences too posed serious
challenges to the creationist-interventionist interpretation,
which include fossil evidence, heterogeneity of flora and
fauna, propositions of Linnaean hierarchy, adaptability of
organisms, etc.
199
Two major problems demanded scientific explanation
during pre-Lamarckian period 1.
1. The origin of diversity with seemingly orderly
arrangement in a natural system.
2. Superb adaptation of all organisms to each other
and to their surroundings.
More and more problems were identified about the
discontinuity between species and higher categories,
extinction and survival of species, existence of vestigial
organs and the role of God. Now, creationism became an
insignificant solution to the scientific community.
Emergence of an Evolutionist
In his initial days, Lamarck was originally an
essentialist. He used to belief the concept of constant
world. Originally he was not a thinker on evolution although
the term was in the air. In his initial discourse (for the
year 1799) as a professor of the ‘inferior animals’ (later
known as ‘invertebrates’, the term coined by Lamarck
himself), Lamarck believed that species are unchanging and
there is no possibility of evolution. Interestingly, in the
next year discourse, Lamarck came with essential points
of his new evolutionary theory which was further explained
in his book 2. What had induced Lamarck in changing his
idea at the age of 55 years? As Mayr1 observed that an
old man had ‘to abandon is previous world view and
replace it by one that is so revolutionary that it had not
been held by anyone previously’. From the late 1790s,
Lamarck took over the charge of mollusks collection and
carefully studied both the fossil and recent mollusks in
the Paris Museum after the death of his friend
Bruguière 3. He observed that many of the living mussels
and marine mollusks had analogues among fossil species.
He found that the modern species extended far back into
the Tertiary strata and he established chronological series
terminating in a recent species. This observation led
Lamarck to think about that many phyletic series had
undergone a slow and gradual change throughout time 1.
During the studies on comparative anatomy of animals in
Paris Museum, he found discontinuities among the various
morphological types, insects, mollusks, worms, vertebrates,
etc. and thought separate graded series should exist for
each category. “I speak of an almost irregularly graduated
series of the principal groups (masses) such as the great
families; a series which assuredly exists among the animals
as well as plants; but which, when the genera and
particularly the species are considered, forms in many
places lateral ramifications, the endpoints of which are
truly isolated” (Discours XIII: 29) 4. In his book he
200
recognised two entirely separate lineages of animals, one
leading from the infusorians to the polyps and radiarians,
the other one, containing the majority of animals, arising
from worms (Fig. 1). Later, Lamarck 5 recognised an even
much larger number of separate lineages 6.
Infusorians,
Polyps,
Radiarians
Worms
Annelids,
Cirrhipedes,
Molluscs
Insects,
Arachnids,
Crustaceans
Fishes,
Reptiles
Birds
Amphibian Mammals
Monotremes
Cetacean
Mammals
Unguiculate
Mammals
Ungulate
Mammals
Figure 1. Lamarck’s figure ‘showing the origin of the various
animals’ (Philosophie zoologique, p. 179).
What had disturbed Lamarck’s thinking was the
problem of extinction. Origin and extinction were the then
central theme of scientific debate. Scientists and elite
peoples were believer in constant and created world, thus
they could not explain properly the facts of extinction and
new origin.
Several explanations were put forward. Firstly, extinct
animals are those that were killed by Noah’s Flood or some
other catastrophe. Second explanation was that the extinct
species might be surviving somewhere in unexplored areas
of Earth. Thirdly, it is thought that it is the work of man.
Lamarck thought that extinction is only a pseudo-problem.
According to him, “fossils … might have changed since
that time and have been converted into the similar species
that we now actually find?” 2 (p. 45). Lamarck thought
that no organism ever extinct; … simply drastic
transformation took place with change beyond recognition7.
He emphasised that evolutionary change was the solution
to the problem of extinction. His idea on evolutionism had
strong support from his earlier geological studies 8 .
Lamarck’s logic was that since a species is in complete
harmony with its environment and since the environment
constantly changes, a species must likewise change forever
in order to remain harmonious balance with its environment.
This is the basic philosophy of evolution which is not
acceptable to now a day’s non-Darwinist. Lamarck viewed
SCIENCE AND CULTURE, MAY-JUNE, 2011
it from another angle, that it would be possible for an
intelligent creator to design a perfect organism in a static
world of short duration, but in a constantly changing
environment (drastic and catastrophe too) how could
species have remained perfectly adapted to such changing
scenario? Lamarck had clearly recognised the importance
of the environment and the adaptation of the organism.
Contribution of Lamarck
In his first six years as professor, Lamarck published
only one paper, in 1798, on the influence of the moon on
the Earth’s atmosphere. Lamarck began as an essentialist
who believed species were unchanging; however, after
working on the mollusks of the Paris Basin, he grew
convinced that transmutation or change in the nature of a
species occurred over time. He set out to develop an
explanation, and on 11 May 1800 (the 21st day of Floreal,
Year VIII, in the revolutionary timescale used in France at
the time), he presented a lecture at the Muséum national
d’histoire naturelle in which he first outlined his newly
developing ideas about evolution.
In 1801, he published Système des Animaux sans
Vertebres, a major work on the classification of
invertebrates. In the work, he introduced definitions of
natural groups among invertebrates. He categorized
echinoderms, arachnids, crustaceans and annelids, which
he separated from the old taxon for worms known as
Vermes. Lamarck was the first to separate arachnids from
insects in classification, and he placed crustaceans into a
separate class from insects. His classification of the
mollusks was far in advance of anything proposed
previously. Lamarck broke with tradition in removing the
tunicates and the barnacles from the Molluska.
In 1802 Lamarck published Hydrogéologie, and
became one of the first to use the term biology in its
modern sense 9. In Hydrogéologie, Lamarck advocated a
steady-state geology based on a strict uniformitarianism.
He argued that global currents tended to flow from east
to west, and continents eroded on their eastern borders,
with the material carried across to be deposited on the
western borders. Thus, the Earth’s continents marched
steadily westward around the globe.
Lamarck published Recherches sur l’Organisation des
Corps Vivants in 1802, where he drew out his theory on
evolution 8. He believed that all life was organized in a
vertical chain, with gradation between the lowest forms
and the highest forms of life, thus demonstrating a path
to progressive developments in nature. Lamarck published
a series of books on invertebrate zoology and paleontology.
VOL. 77, NOS. 5–6
Of these, Philosophie zoologique, published in 1809, most
clearly states Lamarck’s theories of evolution. The first
volume of Histoire naturelle des Animaux sans vertèbres
was published in 1815, the second in 1822. He even found
time to write papers on physics and meteorology, including
some annual compilations of weather data. Lamarck also
anticipated the work of Schleiden and Schwann in cell
theory. During his lifetime Lamarck became controversial,
attacking the chemistry proposed by Lavoisier. In his own
work, Lamarck had favored a traditional theory based on
four elements 6. He also came into conflict with the widely
respected palaeontologist Georges Cuvier, who was not a
supporter of evolution.
Lamarck’s New Paradigm
Lamarck felt that two well known phenomena in the
world of organisms, which were originally, raised earlier,
need careful explanation.
Animals show a graded series of “perfection” :
Lamarck understood the gradual increase in “animality”
from the simplest animals to those with the most complex
organization, culminating in man. This idea he had
developed from studies on mollusks.
The amazing diversity of organisms : Anything
possible need has effectively taken place. “After a long
succession of generations…….individuals, originally belong
to one species, became at length transformed into a new
species distinct from the first” 2 (pp. 38-39). “These
changes only take place with an extreme slowness, which
makes them always imperceptible” 2 (p. 30).
Lamarck’s Theory
First law: “In every animal …. , the more frequent
and sustained use of every organ gradually strengthens,
develops and enlarges that organ, and gives it a strength
proportionate to the length of time it has been used; while
the constant disuse of such an organ imperceptibly
weakens and deteriorates it, progressively diminishing its
faculties until finally disappears” 2 (p. 113).
Second law: Inheritance of acquired characters.
“Everything which nature has caused individuals to acquire
or lose as a result of the influence of environmental
conditions to which their race has been exposed over a
long period of time – consequently, as a result of the
effects caused either by the extended use (or disuse) of
a particular organ…. is conveyed by generations to new
individuals descending therefrom, provided, that the
changes acquired are common to both sexes, or to those
201
which produce the young” 2 (p. 113). He stated that “with
regard to living bodies, it is no longer possible to doubt
that nature has done everything little by little and
successively” 2 (p. 11).
Misunderstanding
Injudicious readers of Lamarck’s work time and again
misunderstood him by the term ‘besoin’ into ‘want’ instead
of “need”, and a neglect of Lamarck’s carefully developed
chain of causations from needs to efforts, to physiological
excitations, to the stimulation of growth and eventually to
the production of structures 1. Even Darwin wrote to J. D.
Hooker on 11 January 1844 “Lamarck nonsense of …
adaptations from the slow willing of animals” because he
read mistranslation of the word besoin in to ‘want’ instead
of ‘need’, and Lamarck’s careful explanations.
Serious misunderstanding about Lamarck’s paradigm
is that the idea of a direct induction of new characters by
the environment. Lamarck himself rejected this
interpretation: “I must now explain what I mean by this
statement: The environment affects the shape and
organization of animals, that is to say that when the
environment becomes very different, it produces in the
course of time corresponding modifications in the shape
and organization of animals”.
Lamarck wrote, it is true, if this statement were to be
taken literally, “I would be convicted of an error; for,
whatever the environment may do, it does not work any
direct modification whatever in the shape and
organization of animals” 2 (p. 107). The above statement
shows that Lamarck was very much aware about the
ecological impact in the evolutionary process.
The list of evolutionists
prior to Lamarck was believer
in static world. Lamarck
replaced this concept of
world by a dynamic one and
explained that entire balance
of nature was constantly in
flux. Lamarck was the first
man
to
bridge
the
evolutionary
gap
by
considering man as the end
product of evolution even
before the discovery of a
hominid or even a primate
fossil. He envisaged that
“some
quadrumanous
animals, especially one of the
202
most perfect of them ……use their feet only for walking
and to give up using their hands like feet…..that these
quadrumanous animals would at length be transformed into
bimanous, and their thumbs on their feet would cease to
be separated from the other digits when they use their
feet for walking” having upright posture “to command a
large and distant view” 2 (p. 170) …. “an animal
organization approaches that of man the more perfect it
is” (p. 171). The strong critics of Lamarck, Georges Cuvier
refuted the theory. At that time no one could expect himself
to be in a fossil lineage. Cuvier died in 1832 and first
hominid fossil (Pliopithecus) was not discovered until
1837. This is imaginative Lamarck, the first perfect
evolutionist.
World between Lamarck and Darwin
Philosophie zoologique was a sign of the first
breakthrough to evolutionism. The concept depicted in this
book was refuted time and again until 50 years when
Darwin came with substantial evidence. Darwin had
burgeoning facts at his disposal of the scientific
contribution in biology to prove evolution from various
angle. Still none had accepted the theory of evolution
unconditionally. Most of the contemporary scientists
agreed to some of the contents of the complete theory.
Table 1 shows how far close the views of Lamarck and
Darwin was and contemporary scientists.
Six major theories could be recognized in between
propositions of Lamarck and Darwin 1. Most of these
theories were controversial, which either state about the
inheritance or effect of use and disuse (e.g. orthogenesis,
aristogenesis, mutationism, direct induction, stochastic
variation, saltationism, etc.).
TABLE 1. Comparison of Evolutionary theories by contemporary evolutionist (modified
after Mayr, 1991).
Evolution
as such
Common
descent
Gradualness
Populational
speciation
Natural
Selection
Lamarck
Yes
Yes
Yes
Not spelt
Not explained
Cuvier
Yes
Sometimes
No
No
No
Darwin
Yes
Yes
Yes
Yes
Yes
Haeckel
Yes
Yes
Yes
?
Partly
Neo-Lamarckian school
Yes
Yes
Yes
Yes
No
T. H. Huxley
Yes
Yes
No
No
No
de Vries
Yes
Yes
No
No
No
Weismann
Yes
Yes
Yes
?
Yes
T. H. Morgan
Yes
Yes
No
No
Unimportant
Synthetic theory
Yes
Yes
Yes
Yes
Yes
SCIENCE AND CULTURE, MAY-JUNE, 2011
Baldwin effect : The Baldwin effect, also known as
Baldwinian evolution or ontogenic evolution, is a theory
of a possible evolutionary processes 10. The Baldwin effect
functions in two steps. In the first step, phenotypic
plasticity allows an individual to adjust to a partially
successful mutation, which might otherwise be utterly
useless to the individual. The second step, if enough time
is provided, evolution may find an inexorable mechanism
to replace the plastic mechanism 11. Morgan12 and Osborn
13 independently arrived at the similar ideas, which
explained that phenotypic plasticity is the ability of an
organism to adapt to its environment during its lifetime.
Pleiomorphism or “phenotypic plasticity” is a phenomenon
in which a given genotype may develop different states
for a character or group of characters in different
environments due to “genotype-environment interaction”.
This effect is similar to the concept of “canalization” 14,
which describes the containment or limitation of phenotypic
variation by developmental mechanisms. He added that a
trait can be canalized against environmental disturbance,
genetic perturbations, such as mutations, or both.
Post-Darwinian Lamarckism
Some critics of Charles Darwin tried to explain organic
evolution on the basis of Lamarckian concept. Packard in
1884 proposed a term “neo-Lamarckism”, which covered a
number of heterogeneous ideas 15. Most of the so-called
neo-Lamarckian views (theories) dealt with mental forces.
Interestingly, no two neo-Lamarckians had the same views,
thus a consensus “Neo-Lamarckism” was never
established. The important neo-Lamarckian views were,
Geoffroyism, psycho-Lamarckism, etc. All neo-Lamarckians
supported the inheritance of acquired characters and
believed that something experienced and gathered by one
generation could be transmitted to the next generation and
subsequently heritable 16 . Until mutation and
recombination were considered to be the principal forces
in evolution, neo-Lamarckian explanation for adaptation was
favoured. Proof of genetic material as causative force in
evolution resulted in the speedy shifting of neoLamarckians to Darwinism.
Genetic assimilation : After the establishment of
Biological or Synthetic Theory (Modern Synthesis) (19361950), Waddington 17,18 proposed the idea of genetic
assimilation as “a process by which a phenotypic character,
which initially is produced only in response to some
environmental influence, becomes, through a process of
selection, taken over by the genotype, so that it is found
even in the absence of the environmental influence which
had at first been necessary.” Waddington 18 further
VOL. 77, NOS. 5–6
pointed out that a combination of orthodox Darwinism and
orthodox embryology can give the results that look like
the inheritance of acquired characteristics and
environmentally-induced genetic assimilation can produce
rapid evolutionary change as well as speciation. Later, a
number of experiments approved the concept.
The combination of organic selection and orthoplasy
(direct phenotypic evolution) is now commonly referred to
as the “Baldwin effect.” Alternately, Waddington’s genetic
assimilation is a process whereby an environmentally
induced phenotype, or “acquired character,” becomes
canalized through selection acting upon the developmental
system. Genetic accommodation is a modern term used to
depict the process of heritable changes that occur in
response to a novel induction. Genetic accommodation is
a key component of the Baldwin effect, and genetic
assimilation is a type of genetic accommodation 19.
Somatic selection : Other explanations include
‘somatic inheritance of acquired character’ 20, 21 and
hormonally mediated inheritance 22. Steele and his
colleagues explained why homologous DNA sequences
from the VDJ gene regions of parent mice were found in
their germ cells and seemed to persist in the offspring for
a few generations. The mechanism involved the somatic
selection and clonal amplification of newly acquired
antibody gene sequences that were generated via somatic
hyper-mutation in B-cells. The mRNA products of these
somatically novel genes were captured by endogenous
retroviruses of B-cells and were then transported through
the blood stream where they could breach the soma-germ
barrier (Weismann barrier) and retrofect (reverse transcribe)
the newly acquired genes into the cells of the germ line.
Lamarck in Recent Perspective
Two aspects in Lamarckism are logical and noncontroversial i.e. evolution is vertical and is gradual. The
major problem in the theory is the process of inheritance.
The literal heading of the theory (second law) was
“inheritance of acquired character”. No doubt that the
establishment and subsequent inheritance of traits is of
utmost importance in organic evolution.
Modes of inheritance of phenotypes : Inheritance of
phenotypes follows various pathways. Maynard-Smith 23
categorized the existence of two inheritance systems,
classical DNA sequence dependent inheritance system and
Epigenetic Inheritance System (EIS). Jablonka24 and
Jablonka and Lamb 25 identified at least three different
kinds of EISs, which help in the origin of new individuality.
Misra et al. 26 listed nine types of inheritance systems,
203
which are categorized under four subsystems viz., genomic
DNA of sex cells, genomic RNA, extra nuclear DNA and
protein. They proposed that all types of inheritance are
interconnected with each other and form an inheritance
web. Recently, it is thought that evolution may show
chimeric history 27. This may happen as a result of
inheritance web.
In addition to genetic inheritance, involving the
duplication of genetic material and its segregation during
meiosis, there are other hereditary elements that pass into
the germ cells also. These include methylation patterns in
DNA and chromatin marks, both of which regulate the
activity of genes. These are considered “Lamarckian” in
the sense that they are responsive to environmental stimuli
and can differentially affect gene expression adaptively,
with phenotypic results that can persist for many
generations in certain organisms 25. Evolution of new level
of individuality, mainly evolutionary transition from
unicellularity to multicellularity, were assisted through EIS
where adaptive characters are acquired in one generation
and subsequently transmitted to next 24. Lachmann and
Jablonka 28 also argued in favour of the existence of
‘Lamarckian’ factor in evolution of heritable phenotypic
variation.
Transmission of information through sex cell DNA
follows Mendelian pathways under the screening of natural
selection, while information transfer through other routes
may escape Mendelian principle 26. It was argued by the
authors that Weismann barrier is not always applicable
and there are instances where such barrier is truly
breached. Evolution of sexuality has given way to the
proposition of Mendel’s law and the reliance on inheritance
of acquired character has pushed to background. Recent
studies on horizontal gene transfer entail that
microorganisms have the adequate capacity to actively alter
genomes in response to environmental stress or
opportunities. It is quite obvious that horizontal gene
transfer/exchange might be the dominant force in earlier
phase of evolution and was more Lamarckian in character,
and only the latter stages becoming more Darwinian 26, 29.
Recently, Jablonka and Lamb 30 argued that heredity
transmit in four dimensions i.e. genetic inheritance, the
conventionally recognized mode of inheritance via
transmission of DNA; epigenetic inheritance, or
transmission of non-genetic information from parental cells
to daughter cells, as in the cytoplasm of an egg; behavioral
inheritance, or cultural transmission of learned traits; and
symbolic transmission of information by means of abstract
representation, especially language in humans. The authors
204
explained that the outcome of these modes of inheritance
is subjected to the approval of natural selection. Their
argument on evolution portray on four dimensions,
corresponding to the four dimensions of inheritance.
Evolutionary novelties and Evo Devo concept : One
question is yet to respond that ‘why is there so much
elaboration of somatic system’ if the somatic tissue has
no role in inheritance. In nature, somatic tissues face most
of the environmental hazards yet their role in inheritance
is under scrutiny. All mutations/changes either in the germ
cell or in the soma are the outcome of environmental stress
i.e. through energy involvement. Long ago it was argued
that all changes (mutational modifications) require
developmental clearance [internal selection of Whyte 31
and epigenetic subsystem of evolution by Waddington
32 ] before expression and subsequent attestation from the
nature (natural selection). The conception of embryonic
development as a highly integrated series of canalized
pathways owes much to Waddington’s development of
the concepts of canalization, chreods, epigenetics, and the
epigenotype. The integrated, heritable, epigenetic
organization of embryonic development is Waddington’s
lasting legacy to development33. Waddington demonstrated
that how organisms respond to environmental changes
with hidden genetic variations and integrated environmental
responsiveness culminating into heritable change in
response to selection, coupled development, environment,
and evolution 33.
Evolutionary process demands explanations of the
underlying mechanism of the emergence of evolutionary
novelties i.e. origin of entirely new morphological
structures, new physiological functions, behavioural
patterns, etc. Evolutionary novelties arise in organismal,
functional, and molecular levels in relation to ecological
shifts, stress, developmental pattern and other
environmental factors 34. West-Eberhard 35 has noted that
mutationally induced novelties would occur in only a family
of individuals; whereas environmentally induced novelties
would occur to a population. Moreover, the inducing
environment would most likely also be a selecting
environment. Thus, there would be selection immediately
for this trait, and the trait would be continuously induced.
It is argud that this type of evolution would indicate that
the phenotype is produced first and then would later be
“fixed” by the genotype 35. The author is of the opinion
that genetic assimilation of morphs originally produced
through developmental plasticity may result in the origin
of new species. The author contradicted the long standing
notion of mutational novelties have superior evolutionary
SCIENCE AND CULTURE, MAY-JUNE, 2011
potentialities and argued that environmentally initiated and
modulated novelties may have greater evolutionary
potentialities than mutionally induced phenotypes 36.
The concept of modern evolutionary developmental
biology (Evo Devo) is concerned with the studies on the
mechanisms responsible for major morphological changes
and origin of homology. Extreme environments are closely
associated with phenotypic evolution. Badyaev 37 approved
the importance of stress-induced variation in evolution.
He explained that ‘accumulation of phenotypically neutral
genetic variance by developmental systems and
phenotypic accommodation of stress-induced effects,
together with the inheritance of stress-induced
modifications; ensure the evolutionary persistence of
stress–response strategies that provide a link between
individual adaptability and evolutionary adaptation’ 37.
Molecular biology, gene, DNA, etc. was not known to
Lamarck. Still he felt the importance of environmental stress
and its responsiveness in the animal’s body, physiological
excitation, to the stimulation of growth that results into
gradual transformation of characters. Lamarck had the
distinct vision about the evolution, which ascertain
through chain of causations.
A proposition : A compile version of Lamarck’s vision
with modern propositions on evolution can be explained
as follows (Fig. 2). A phenotype (P1) in initial environment
(E1) may exhibit phenotypic change (P2) in different
environmental stress (E2). The continued environmental
stress may induce genome/gene duplication where internal
environment of the body could select one trait out of four
options available (as an outcome of genome/gene
duplication), may be after n number of generations. The
nature of internal selection is likely to be based on
epigenetic interaction among the parts of the developing
organism, i.e. in compliance to epigenotype, which is the
relationship between genotype and phenotype. This is
somewhat internal tinkering that explains relationship
between variability and evolvability. Variability is defined
as the tendency to vary, and the variability of a system
describes its ability to generate selectable variation.
Therefore, evolvability depends directly on variability and
evolvability is the capacity of a system to evolve in
response to selection 38 . The authors characterized
epigenetics as a collection of physical interaction(s)
between the products of developmental processes that
alters their final form 38. Evolution progresses due to the
Figure 2. A proposed version of evolutionary process compiling idea of Lamarck and modern concepts. Phenotype P1 expresses in
environment E1. If the population was shifted to an altered environment E2, a new phenotype P2 may result in response to new altered
environmental stress. If the organisms were returned back to their original environment E1, within few generations, the phenotype will
exhibit the old phenotype P1 . Continuous strong environmental stress for n number of generations may induce gene duplication event.
If gene duplication takes place, the development pathway has more options to select and approve one of the phenotypes arising out of
the gene duplication event. This is some sort of ‘internal tinkering’. The internally selected genotype will be fixed for the phenotype
P2 even after the stress is withdrawn. However, after n number of generation phenotype P2 will remain unaltered if the organisms were
returned back to E1.
E1 =Environment 1; E2= Environment 2; P 1 = Phenotype 1; P 2 = Phenotype 2
VOL. 77, NOS. 5–6
205
instability of the inherent structure present within the
biological system and interaction with the environment.
Thus the topology of evolutionary structure is helical
corresponding to the fundamental form of the nature 39.
Origin of more than one genotype (due to gene
duplication) is the foundation of instability of the inherent
structure of the organism and its interaction with the
environment is the outcome of the evolution.
Origin of new trait starts with following events:
biochemical → physiological → anatomical. It is to be
remembered that Lamarck envisaged about the chain of
causations from needs to efforts, to physiological
excitations, to the stimulation of growth and eventually to
the production of structures. The genotype of the trait
originated due to gene duplication could be retained in
the population either by subfunctionalization or
neofunctionalization of the altered genotype (Fig. 2). The
phenotype would continue to express even if the stress is
withdrawn. This phenomenon may be explained as ‘genetic
assimilation’ for altered phenotype or ‘genetic
accommodation’ for novel phenotype. Both are possible if
genome duplication takes place. The altered phenotype
explains microevolution and the novel phenotype is the
example of macroevolution. Role of whole genome
duplication in evolution was also explained 40.
J. B. Lamarck never visualized the idea of biological
diversity (horizontal diversity), which was nicely explained
by Charles Darwin 41. However, Lamarck’s argument for
microevolutionary change was based on transmutation of
species in accordance with the environmental set up. He
showed the different lines of origin of various major groups
of animals; still he failed to conceive the idea of
macroevolution that is, origin of higher categories. He had
the concept of origin of new traits and extinction. Darwin
filled the gap by explaining that origin of divergence is
always associated with both retention of traits and
extinction (i.e. both horizontal and vertical evolution) 41.
Further studies on Lamarck’s paradigm will certainly throw
new insight in the evolutionary mechanisms hitherto not
explained.
Acknowledgement
The author is thankful to Dr. Madhumita Manna,
Head of the Department of Zoology, and to the Principal,
Bethune college, Kolkata for their help. The author wishes
to thank Kankadeb Mishra, Department of Genetics and
Pathology, Uppsala University, Sweden for his help in
preparing the manuscript.
S
206
References
1.
E. Mayr, The Growth of Biological Thought: Diversity,
Evolution, and Inheritance (1982) (Harvard Univ. Pr.,
Cambridge).
2.
J. B. Lamarck, Philosophie zoologique, ou exposition des
considérations relative à ¾historie naturelle des animaux.
(1809) Paris. (English translation by Elliot, H. Macmillan,
London).
3.
R. W., Jr. Burkhardt, The Spirit of System :Lamarck and
Evolutionary Biology. (1977) (Cambridge University Press,
cambridge).
4.
J. B. Lamarck, Bull. Sci. de la France et de la Belgique,
Paris. (1907)
5.
J. B. Lamarck, Historienaturelle des animaux sans vertebras.
7vols. Paris (1815-1822).
6.
L. J. Jordanova, Lamarck (1984) Oxford Publs. House,
Oxford.
7.
E. Mayr, One Long Argument. (1991). Harvard Univ. Pr.,
Cambridge.
8.
J. B. Lamarck, Recherches sur l’Organisation des Corps
Vivants. (1802b) Paris.
9.
J. B. Lamarck, Hydrogéologie. (1802a) L’Auteur, Paris.
10.
J. M. Baldwin, Am. Nat., 30: 441-451. (1896)
11.
J. M. Baldwin, Darwin and the Humanities. (1909) (Review
Publs, Baltimore).
12.
C. L. Morgan, Science, 4: 733-740. (1896).
13.
H. F. Osborn, Science, 4: 786-789. (1896).
14.
C. H. Waddington, Nature, 150: 563-565. (1942).
15.
A. S. Packard, Lamarck, The founder of Evolution: His
Life and His Work, (1901). Longmans, London.
16.
R. W., Jr. Burkhardt, Lamarckism in Britain and the United
States. In: Mayr, E. and Provine, W. (eds.). The
Evolutionary Synthesis. Harvard Univ. Pr., Cambridge. pp.
343-352. (1980).
17.
C. H. Waddington, Evolution, 7: 118-126. (1953).
18.
C. H. Waddington, Advances Genet., 10: 257-290. (1961).
19.
E. Crispo, Evolution, 61: 2469-2479. (2008).
20.
D. J. Steele, Somatic Selection and Adaptive Evolution:
On the Inheritance ofAcquired
Characters.
(1979).
Williams-Wallace, Toronto.
21.
Steele, E. J., Lindley, R. A. and Blanden, R. V. 1998.
Lamarck’s Signature: How Retrogenes Are Changing
Darwin’s Natural Selection Paradigm. Perseus Books.
22.
M. M. Clarke, P. Karpluk, and G. G. Jr. Bennett, Nature,
364: 712. (1993).
23.
J. Maynard Smith, J. theor. Biol., 143: 41-53. (1990).
24.
E. Jablonka, J. theor. Biol., 170: 301-309. (1994).
25.
E. Jablonka, and M. J. Lamb, Epigenetic inheritance system
and evolution. (1995). Oxford Univ. Pr., Oxford.
26.
K. K. Misra, A. K. Sarkar, and K. K. Chaki, Proc. zool.
Soc. Calcutta, 54: 38-48. (2001).
27.
W. F. Doolittle, and O. Zhaxybayeva, GenomeRes., 19:744756. (2009).
28.
M. Lachmann, and E. Jablonka, J. theor. Biol., 181: 1-9.
(1996).
SCIENCE AND CULTURE, MAY-JUNE, 2011
29.
M. Buchanan, Nature Reviews, 5: 531. (2009).
36.
30.
E. Jablonka, and M. J. Lamb, Evolution in Four
Dimensions, MIT Press, (2005). Cambridge, Massachusetts.
M. J. West-Eberhard, Proc. Natnl. Acad. Sci., 102: 65436549. (2005).
37.
A. V. Badyaev, Proc. R. Soc. B, 272: 877–886. (2005)
31.
L. L. Whyte, Internal Factors in Evolution. (1965).
Tavistock Publs., London.
38.
H. A. Jamniczky, J. C. Boughner, et al. Bioessays, 32:
553–558. (2010).
32.
C. H. Waddington, The Evolution of an Evolutionist. (1975).
Edinburgh Univ. Pr., Edinburgh.
39.
K. K. Misra, and P. Raychaudhuri, Sci. Cult., 69: 247-252.
(2003).
33.
B. K. Hall, Biological Theory, 3: 98-203. (2008).
40.
K. Mishra, and K. K. Misra, Curr. Sci., 94: 981-982. (2008).
34.
E. Nevo, Proc. zool. Soc., Calcutta, Haldane Comm. Vol.,
27-40. (1993).
41.
35.
M. J. West-Eberhard, Developmental Plasticity and
Evolution. (2003). Oxford Univ. Pr., Oxford.
C. Darwin, On the origin of species by means of natural
selection, or the preservation of favoured races in the
struggle for life. (1859). John Murray, London.
VOL. 77, NOS. 5–6
207