Posts Tagged ‘rudimentary’

Charles Darwin uses “vestiges” five times in The Origin of Species. Vestiges, since then has become synonomous with evolution. The emenent evolutionist, Douglas Futuyma, Professor of Ecology and Evolutionary Biology at the University of Michigan, notes that vestigial structures make no sense without evolution. The first question is—what are vestiges?

 In this first in a series on vestiges, we will discover how structures labeled as vestiges play an important role as evidence for the theory of evolutionary. Since the most popular example of a vestige structure is the human appendix, the human appendix will be the focus structure examined in this series.

By the time The Origin of Species was published in 1859, vestiges had already been a hot topic popularized by Robert Chambers’ following the publication of the Vestiges of the Natural History of Creation in 1844. The work brought together various ideas of stellar evolution and progressive transmutation of species. The book was a best-seller and is now seen as causing a shift in public opinion that paved the way for the general acceptance of evolution.

While agreeing with the general concept of evolution, Darwin took exception to the concept that evolution occurred by sudden changes in nature. Darwin wrote – “The author apparently believes that organisation progresses by sudden leaps, but that the effects produced by the conditions of life are gradual.”

Perhaps for these differences with Robert Chambers, Darwin even avoided defining the term “vestiges” in the The Origin of Species. In the Glossary, however, Darwin does define a related term: “RUDIMENTARY.—Very imperfectly developed.” In The Origin of Species, the term “rudimentary” appears 101 times.

Darwin envisions rudimentary structures to be the result of two different dynamics: 1) as structures “imperfectly developed”—emerging, and 2) as structures in disuse undergoing loss of function—elimination. Darwin writes – “Rudimentary organs will speak infallibly with respect to the nature of long-lost structures”—a Lamarckian disuse concept. Darwin explains that rudimentary structures exist because “natural selection… had no power to check deviations in their structure.”

Today however, only the elimination due to disuse concept is thought to be in operation. WIKIPEDIA.org states: “Vestigiality describes homologous characters of organisms that have seemingly lost all or most of their original function in a species through evolution. Answers.com defines vestige structures, as “A rudimentary or degenerate, usually nonfunctioning, structure that is the remnant of an organ or part that was fully developed or functioning in a preceding generation or an earlier stage of development.”

The next question is – how well does the human appendix fit the vestige structure criteria? Next week we will examine the existence of the appendix throughout the animal kingdom.