August Weismann on Germ-Plasm Variation |
| |
Authors: | Rasmus G Winther |
| |
Institution: | (1) Department of History and Philosophy of Science, Indiana University, Goodbody Hall 130, 1011 East Third Street, Bloomington, IN, 47405-7005, U.S.A. |
| |
Abstract: | August Weismann is famous for having argued against the inheritance of acquired characters. However, an analysis of his work
indicates that Weismann always held that changes in external conditions, acting during development, were the necessary causes
of variation in the hereditary material. For much of his career he held that acquired germ-plasm variation was inherited. An irony, which is in tension with much of the standard twentieth-century history of biology, thus exists – Weismann
was not a Weismannian. I distinguish three claims regarding the germ-plasm: (1) its continuity,(2) its morphological sequestration,
and (3) its variational sequestration. With respect to changes in Weismann's views on the cause of variation, I divide his
career into four stages. For each stage I analyze his beliefs on the relative importance of changes in external conditions
and sexual reproduction as causes ofvariation in the hereditary material. Weismann believed, and Weismannism denies, that
variation, heredity, and development were deeply intertwined processes. This article is part of a larger project comparing
commitments regarding variation during the latter half of the nineteenth century.
This revised version was published online in July 2006 with corrections to the Cover Date. |
| |
Keywords: | August Weismann development evolutionary developmental biology externalism genetics germ-plasm heredity inheritance of acquired characters nineteenth century sexual reproduction variation |
本文献已被 PubMed SpringerLink 等数据库收录! |
|