Definitions of "evolution"

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The word evolution has many usages.  Even when only biological evolution is meant, there are many various processes, any or all of which may be meant.  Clear communication (whether you are the writer / speaker or the reader / listener) requires awareness of and attention to these various meanings, to minimize ambiguity and patent misunderstanding.  In anti-evolutionist writings, the concept is considerably muddled by the addition of several extra concepts that have no place in scientific usage.

Note that Darwin used the word "evolved" only once in his Origin of Species, where it was the very last word of the text.  He did not even once use the word "evolution".  

Perhaps wisely, the authors of our textbook (Stearns & Hoekstra) do not even try to define evolution.


The Oxford English Dictionary (the standard reference for word usage in the English language) presents 12 different definitions for "evolution", including:

Note that several of these meanings include connotations of pre-existing plan or goal.

Also note that all but the last of these usages predate the modern application of the term to describe biological evolution.  

These prior meanings have served to contaminate and mislead popular understanding of the biological processes first presented by Darwin (who avoided the word "evolution", presumably in a futile attempt to avoid such misinterpretations).  As a result, popular understanding of evolution commonly includes elements of predestination, goal-directedness, or progress which have no place in conventional current scientific understanding of biological evolution.  

(More:  Essay by Stephen Jay Gould)


In reference to modern understanding of biological evolution, casual use of the word "evolution" can refer to any of a variety of patterns and processes, including:


Related to the various meanings of "evolution" are various stances, or "-isms", which reflect more-or-less extreme perspectives on what is important in evolution.


Anti-evolutionist writings often conflate these several meanings, especially the distinction between the many "factual" aspects of evolution (i.e., those patterns and processes which are known by more-or-less-direct observation) and the "theoretical" organization of associated concepts into an explanation of the interrelationships between observable pattern and observable process, as if criticisms relevant in one domain were directly applicable to another.  There is also commonly a presumption (or an explicit assertion) that evolution (as understood by the anti-evolutionist) must necessarily be random, purposeless, godless, associated with immorality, and false.

For examples of anti-evolutionist argument (pro and con) see the listings at Talk.Origins.

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SIUC / College of Science / Zoology / Faculty / David King / ZOOL 304
URL: http://www.science.siu.edu/zoology/king/304/evodef.htm
Last updated:  24 September 2003 / dgk