Jean Baptiste Lamarck was one of the first people to propose a theory of evolution to the public. Although his ideas were not widely accepted they paved the way for others to do work in that field.   Even before his work on evolution he did extensive work with invertebrates.  His work on invertebrates inevitably led him to his theory of evolution. This theory was not accepted at his time and has since been proven wrong.  The way he was raised and the institutions he attended gave him the opportunity to perform his work.

BACKGROUND

     Jean Baptiste Lamarck was born in the village of Bazentin-le-Petit in northern France on August 1,1744.  He was born into a military family as the youngest of eleven children.  Around 1756 Lamarck joined a Jesuit seminary at Amiens, but left to join the French military after his fathers death in 1761.  He remained in the army until illness forced him to leave in 1768.  Not too long after leaving the army Lamarck started to study medicine and plants. (Waggoner 2)  Lamarck took many excursions with Jean-Jacques Rousseau which led him to an interest in plants rather than medicine. (Weber 49)  Ten years later he gained attention and notoriety from his book Flore Francaise, about the plants of France.  He had the help of well known botanist Buffon on this book, which helped with his credibility.  From this book he was given the position of assistant botanist at the royal botanical garden, the Jardin des Plantes.  This position was not well paid and Lamarck was forced to live in poverty. (Clifford 1)  But in 1793 the Jardin des Plantes was reorganized to become the National Museum of Natural History.  This museum was run by twelve professors in twelve different scientific fields.  Lamarck was appointed to the professorship of the natural history of insects and worms.  Lamarck later gave these organisms the term invertebrates.   (Waggoner 1-2)

WORK WITH INVERTEBRATES
      Lamarck knew nothing about the subject of invertebrates at this time in his life.  Not many scientists did know anything about invertebrates.  Some even included snakes and crocodiles in this classification.  The name invertebrate did not even exist at this time, Lamarck coined the phrase after he had done his research.  But he set out to find out as much information as possible and to classify it in an orderly way.  The museum had many specimens at this time but they were poorly organized and classified.  Lamarck started by studying Linnaeus’s system of classification.  This classification only had two classes of invertebrates, insects and worms, but Lamarck expanded that to ten.  He was the first to separate the insects into Crustacea, Arachnida, and Annelida.  Lamarck organized his ten classes from the least complex to the most complex.  He said that this was how they had evolved.  Later he expanded his classification system to include all organisms that were known at the time.  He published this classification in 1809 in his book Zoological Philosophy.  Lamarck started with the most complex animal, mammals, and worked down all the way to polyps. (Lynch 1) He was convinced that structural complexity was the critical feature for determining the "natural order" of nature's productions. (Burkhardt 120)  He developed the classification system far beyond what it had been in the past. Lamarck studied both living and fossil invertebrates and wrote about his discoveries in his book Natural History of Invertebrate Animals.  Throughout his studies he was the first to notice the difference between invertebrates and vertebrates was the presence of a bony spinal column.  His theory and classification system set the standard of invertebrate taxonomy.  These classification divisions and subdivisions are still used in some ways today.  From these studies Lamarck noticed that some animals differed by vary small amounts.  He began to postulate new ideas of how the relationship between animals and how these animals transmutated into new species.  It was this work with invertebrates that led Lamarck to his theory of evolution and transmutation.

EVOLUTIONARY THEORY

    When the word evolution is mentioned, the first name to come to mind is Charles Darwin.  Many credit Darwin with the first theory of evolution.  In actuality Lamarck had proposed his theory of evolution over a half century before Darwin.  Lamarck’s theory, or Lamarckism as it is known now, has three major components; constant progression, spontaneous generation, and the theory of acquired traits.  Within these components are sub components such as the specialization of organs that are explained by one or more of the major components.  Before he came up with his theory it was believed by many that all species had been created at once and for ever.  After doing research on fossils and invertebrates he thought this theory was false.  He believed that species had evolved gradually over time by natural processes which it was the business of science to reveal. (Jordanova 7)  Lamarck looked at evolution as a process of increasing complexity and "perfection" not driven by chance. (Waggoner 4)

CONSTANT PROGRESSION

    The first major component to his theory was the idea of constant progression.  This means that every generation adapts its organs and body to become more advanced than the previous generation.  The specialization of organs was a big part of this constant progression.  This specialization of organs has six main points.  These points state that organic entities are the products of nature and take place over eons of time, only the simplest bodies are made immediately, the environment in which an organism originates causes the gradual development of organs and is the cause of diversity, growth is inherent in all parts of the organism, changes in conditions cause the modification of the organism over time, and all living bodies have undergone changes in their “organization” and “parts” therefore species are not fixed but are in a constant state of flux. (Hart 1)  At first Lamarck thought of evolution as a progression from least to most complex in a straight line.  But after further observation he revised his theory.  He discovered what he thought was two different paths of evolution, one for bodies with radial symmetry and the other for bodies with bilateral symmetry. Lamarck subdivided the bilateral bodies even further throughout his life.  He then traced the evolution form mollusks to fish to reptiles to amphibians and finally to mammals.  He noticed that the evolution was more like a tree with different subdivisions coming off like branches of a tree.  He still had the linear progression from least complex to more complex but then had special adaptations of specific lineages as lateral deviations or branches from the main sequence. (Gould 3)  Humans were at the top of his theory of evolution.  (Lynch 1)  Lamarck believed that for an organism to be more advanced it had to pass through all other stages of prehistory.  This means that every organism, even the most advanced, was originally a single celled organism but has evolved to become what it is over many years.

    He believed that changes in the environment cause changes in the needs of organisms living in that environment, which in turn causes changes in an organism's behavior.  A change in behavior would lead to greater or lesser use of a given organ.  The more an organism would use an organ the larger it would get.  If an organism did not use an organ it would cause that organ to shrink or disappear.  This is referred to as the “First Law” in Zoological Philosophy. (Waggoner 3)  Lamarck states,  “The frequent use of any organ, when confirmed by habit, increases the functions of that organ, leads to its development and endows it with a size and power that it does not possess in animals which exercise it less.” (Weber 60)  This is also known as specialization of organs.

SPONTANEOUS GENERATION

     For Lamarck's theory of constant progression to work there has to be a starting place.  This starting place came with the principle of spontaneous generation. The principle of spontaneous generation is the idea that living things originated directly from non living matter. Once the first single celled organisms advanced into more complex organisms there would have to be new protozoans to take the place of the ones that have advanced.  He believed that this was done by the creator. (Clifford 2)  Lamarck was sure that nature produced spontaneous generation everyday but we were unable to notice because of the extreme minuteness of the forms produced.  He stated that because the simplest forms inhabited the seas that it could be said that the animal kingdom could have only originated in marine waters.  Lamarck thought that nature performed spontaneous generation through the action of subtle fluids of a molecular or gelatinous nature.  Such things as heat and light traced the first outlines of organization and enabled such things as vapors to be absorbed into molecules, which were kept in motion by subtle fluids.  With the help of time and favorable conditions the molecule would be complicated and perfected. (Corsi 140-141)  This theory was later proved false by Louis Pasteur in 1864.  When it came to the creation of man he took the word of the Bible over even his own ideas. (Catholic Encyclopedia 2)

ACQUIRED CHARACTERISTICS

Acquired characteristics- modifications produced in an individual plant or animal as a result of mutilation, disease, use and disuse, or any distinctly environmental influence. (Encycolpedia.com)

    The most important part of Lamarckism was the idea that these altered traits could be passed on from generation to generation.  This was the mechanism of evolution for Lamarck.  Some theories did not contain a mechanism for the adaptations.  Lamarck's theory of acquired characteristics states that an animal would pass along physiological changes that it had encountered in its lifetime to its offspring.  These changes are a response to the animals survival needs.  One example that Lamarck used to satisfy this condition was the long necks of giraffes.  He said that giraffes used their necks to reach high leaves and developed elongated necks.  This elongated neck then will be transmitted to the next generation.  The organ will change and then become habit for that species. (Hart 1)  He believed that the environment played  the most important role in the adaptation of an organism.  Lamarck believed that all organisms had to conform or adapt to their environment in order to survive.  He believed that the environment of an organism would change the needs of that organism and make it adapt to the needs that it now exhibited.  Once the adaptation to the environment had occurred it was then made permanent from heredity.  They were made permanent by passing them on to the offspring of the next generation.  Acquired characteristics was the mechanism of how the specialization of organs took place.  Once the environment had changed and the organism has adapted its organs to satisfy the needs of the environment, that organ is passed on from generation to generation.  The result of acquired characteristics and the specialization of organs was the continuous, gradual change of all organisms, as they became adapted to their environments.  Darwin tried to refute the mechanism of Lamarck's inheritance but later he admitted the the heritable effects of use and disuse of organs might be important in evolution.  (Waggoner 3)  Geneticists have affirmed that inheritance is determined solely by the reproductive cells and is unaffected by somatic cells. (Encyclopedia.com)  This revolution disproved Lamarck's theory for good but did not come until far after the death of Lamarck.  Therefore his ideas were still not proven for sure to be true or false during his lifetime.

CRITICISMS OF LAMARCK

One major opponent of Lamarck was Georges Cuvier.  He was a fellow colleague of Lamarcks at the Natural History Museum.  Cuvier presented the eulogy for Lamarck after his death.  Cuvier did not give Lamarck any credit for his work in taxonomy or anatomy but decided just to criticize his theory of evolution and how it was unrealistic.  Cuvier stated "These evolutionary principles once admitted, it will easily be perceived that nothing is wanting but time and circumstances to enable a monad or a polypus gradually and indifferently to transform themselves into a frog, a stork, or an elephant....A system established on such foundations may amuse the imagination of a poet; a metaphysician may derive from it an entirely new series of systems; but it cannot for a moment bear the examination of anyone who has dissected a hand...or even a feather." (Gould 2)  The criticism of Lamarck was based on two main points.  The first was the idea that Lamarck's work was derived from fanciful speculation and divorced from real scientific progress.  The next point was that of the relation of the mind and the body.  Cuvier accused Lamarck of misconstructing the relationship to such an extent that he attributed to animals a will and consciousness found only in human beings. (Jordanova 101-102)  These were the main reasons why many did not accept Lamarck's theory.

Charles Lyell was also an opponent of Lamarck.  Lyell's ideas were similar to those of Cuvier.  He stated that Lamarck did not provide convincing empirical support for transformism.  Lyell also added that Lamarck's work with fossils was also weak, because he was unable to prove a historical progression of species.  Lyell did not believe that fossil record provided any evidence for biological progression. (Burkhardt 211)  Another thing that Lyell disagreed with was the thought that man must be seen as an integral part of nature's history.  Lyell thought that this stepped over the boundary that separated the natural and social worlds.  Lyells thinking depended on strong definition of immutable species, on successive creations, and on the separation of man from the rest of nature.  This is why Lyell was so opposed to the relationship between man and animals.  Lyell later was converted to an evolutionary position and thought he had done an injustice to Lamarck, but Lamarck's ideas were so widely criticized that he did not recant his statements. (Jordanova 103-105)

One of the few people who was an advocate of Lamarck was Geoffroy Saint- Hilaire.  He was the professor of birds and mammals at the Natural History Museum at the time. (Burkhardt 202)  Throughout his life he became increasingly convinced of Lamarckian doctrines.  This was one reason that he and Cuvier were constantly struggling.  Geoffroy thought that all living things were "formed according to a single plan, basically identical in its principles, which nature has varied in countless ways in all its ancillary parts." (Corsi 231)  Through his work he came to believe in organic mutability and gave him reason to praise Lamarck.  In his work on the anatomy of crocodiles he  suggested the possibility that they had come from antediluvian creatures, Teleosaurus and Stenosaurus.  He said the differences were "great enough to have been arranged according to our rules in the class of generic distinctions."  He cited Lamarcks ideas of environment changing the organization of living things.  Geoffroy believed that changes in temperature and the composition of the atmosphere directly impacted living things.  These changes had more effect on the embryos than they do on the adults of an organism.  Even though he accepted the idea of environment affecting living things he did not touch on the mechanism that actually creates the changes in the organism.  (Burkhardt 207)

    The majority of people at the time did not believe Lamarck's theory.  Now many of his ideas have been proved false and nearly no one believes his theory.  Even though his theory was and is not accepted it paved the way for many theories that people believe now.  Without Lamarck's theory Darwin's theory of evolution may have never been postulated.

OTHER INTERESTING FACTS ABOUT LAMARCK

Coined term invertebrate from the work he did with them.
Coined term biology in 1802 for the discipline that is now known as.
Lamarck died blind and in poverty.

SOURCES FOR THIS ARTICLE

    This article is a brief summary of the life and ideas of Jean-Baptiste Lamarck.  For more information about this subject here are some good sources to look at.  They provide much more detail than is explained here and also introduce some ideas that are not discussed in the above article.

Burkhardt, Richard W.  The Spirit of System: Lamarck and Evolutionary Biology.
    Harvard University Press.  Cambridge, Mass.  1977.

Catholic Encyclopedia: Chevalier de Lamarck.  http://www.newadvent.org/cathen/08753c.htm

Clifford, D.  "Jean- Baptiste Lamarck – Biography."
    www.clarehall.cam.ac.uk/userpages/djhc2/biogs/lamarck_2.htm.  10/13/2001.
    Pg. 1-2.

Corsi, Pietro.  The Age of Lamarck: Evolutionary Theories in France (1790-1830).
    University of California Press.  Berkeley.  1988.

Encyclopedia.com.  http://encyclopedia.com/articles/07169.html. 10/21/2001.

Gould, Stephen Jay.  "A division of worms."  Natural History.  Feb. 1999 vol. 108.  New
    York. Pg. 18-22

Hart, Thomas E.  "Lamarck and his Theory of Evolution."
    www.65.107.211.206/science/lamarck1.html.  10/13/2001.  Pg. 1.

Hutchinson Family Enyclopedia.          http://ebooks.whsmithonline.co.uk/htmldata/ency.asp?mainpage=HTTP://EBOOKS.WHSMITHONLINE.CO.UK/ENCYCLOPEDIA/98/M0007898.HTM

Jordanova, L.J.  Lamarck.  Oxford University Press.  Oxford.  1984.

Waggoner, Ben.  "Jean-Baptiste Lamarck (1744-1829)."
    www.ucmp.berkeley,edu/history/lamarck.html.  10/13/2001.
    Pg. 1-4.

Weber, A. S.  19th Century Science Anthology.  Broadview Press.  Peterborough,
    Ontario, Canada.  2000.  Pg. 49-65.