Document Type

Letter to the Editor

Publication Date



Argues against an article published in 'BioScience' magazine in which Timothy Shanahan says that evolution is progressive and directional and embodies improvement.Discussion of regressive and progressive evolution and the accompanying multiplication or loss of phenotypic characteristics; Illustrations related to the blindness and loss of pigmentation in troglobitic, or deep-sea cave organisms; Response from Shanahan.

Publisher Statement

Copyright 2001 American Institute of Biological Sciences.

Available on publisher's site at

Recommended Citation

Shanahan, Timothy. "Evolution Is Opportunistic, Not Directional - Response." Bioscience 51 (2001): 6-6.

Included in

Philosophy Commons