Darwin, Then and Now

Posts Tagged ‘Lamarckian’

Charles Darwin attempted to avoid the use of the term “vestiges” largely because the term had been associated with the “erroneous” Larmarckian concept of “use and disuse” that was only “veritable rubbish.”

Jean-Baptiste Lamarck (1744 – 1829) was a member of the French Academy of Sciences and was appointed to the Chair of Botany in 1788. When the Muséum national d’Histoire naturelle was founded in 1793, Lamarck was appointed professor of zoology. In 1801, he published Système des animaux sans vertèbres, a major work on the classifications and coined the term invertebrates. Lamarck is thought to be the first use the term biology in its modern sense. Lamarck continued his work as a premier authority on invertebrate zoology.

Darwin did credit “Lamarck as the first man whose conclusions on the subject excited much attention.… In these works he up holds the doctrine that all species, including man, are descended from other species.”

Lamarck’s theory of evolution, which he referred to as “transformism,” was based on the idea that individuals develop new traits during their own lifetimes by “use and disuse” and transmit them to the next generation. Larmack writes – “Progress in complexity of organization exhibits anomalies here and there in the general series of animals, due to the influence of environment and of acquired habits.”

The giraffe served as Lamarck’s classic example of evolution through “use,” acquiring longer necks in successive generations in competition to reach the ever-scarcer leaves higher in the trees. In illustrating Lamarck’s views on adaptation, Darwin wrote, “To this latter agency he seems to attribute all the beautiful adaptations in nature; such as the long neck of the giraffe for browsing on the branches of trees.”

For Darwin, however, this explanation was simply not scientific – “Lamarck, who believed in an innate and inevitable tendency towards perfection in all organic beings, seems to have felt this difficulty so strongly that he was led to suppose that new and simple forms are continually being produced by spontaneous generation. Science has not as yet proved the truth of this belief.”

One of the most eminent pre-Darwinists was Charles Darwin’s own grandfather, Erasmus Darwin (1731–1802). Erasmus discussed his ideas at length in a two-volume work, Zoonomia, published in 1794. Erasmus wrote that “all … have risen from one living filament.”

Erasmus’ book was widely popular in Western Europe- even translated into German, French, and Italian. Erasmus envisioned that the driving force behind species modification was a result of “lust, hunger, and danger.” In line with Greek philosophy, Erasmus envisioned changes by “continuing to improve its own inherent activity.”

Actually how these “improvements” developed was completely unknown to Lamarck and Erasmus—evolution was a philosophy, not a science. The unknown cause of “improvements” is what drove Darwin to discover the underlying laws of nature—scientifically. Writing in the preface of The Origin of Species, Darwin suggests how Erasmus’s work, although “erroneous,” may have influenced Lamarck: “It is curious how largely my grandfather, Dr. Erasmus Darwin, anticipated the views and erroneous grounds of opinion of Lamarck in his Zoonomia.”

For Lamarck, new characteristics are acquired through the process of “use and disuse.” Darwin’s grandfather, Erasmus Darwin, was a Lamarckian evolutionist. Charles Darwin, however, in pursuit of a “scientific theory” of evolution, initially opposed Lamarckian evolution, only granting the theory marginal support.

In a letter written to J. D. Hooker in 1844, Darwin wrote, “Heaven forefend me from Lamarck nonsense of a ‘tendency to progression.’ … But the conclusions I am led to are not widely diff erent from his, though the means of change are wholly so.” “With respect to books on this subject,” Darwin continues, “I do not know any systematic ones, except Lamarck’s, which is veritable rubbish.”

Although attempting to distance himself from Lamarck’s concepts of “use and disuse” and “vestages,” Darwin distain for “use and disuse” eventually waned as causes for the origin of variation required for the actions of natural selection remained Darwin’s largest unsumountable enigma.

Since then, the term, “vestiges” has once again gained prominence over “rudiments,” as has Larmarckian concepts of evolution. The question remains, however, are structures classified as “vestiges” evidence of evolution? Specifically, have vestiges seemingly lost all or most of their original function in a species through evolution?

To address answers to these questions, we will be examining the most popular example of vestiges—the mammalian appendix in the up-coming posts.