Tachytely

tachytely

[¦tak·ə¦tel·ē]
(evolution)
Evolution at a rapid rate resulting in differential selection and fixation of new types.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Tachytely

 

a very rapid rate of evolution over a relatively short period of time, characteristic of certain groups of organisms; the term was coined by G. G. Simpson in 1944. The formation of a new family, for example, of mammals, requires tens of millions of years on the average, but for some groups—those exhibiting tachytely—the process has been completed within a few million years. Abrupt and frequent changes in the environment are assumed to be the most important factors responsible for tachytely. Tachytelic groups later quickly become bradytelic or horotelic, or they become extinct.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.