•  
  •  
 

Document Type

Research

Abstract

While we have come to recognize clearly the fact of extinction of animal types and their replacement by other forms of life there appears to have been less attention to the special factors concerned in such extinction, or, to put it differently we have been devoting our attention especially to the factors concerned in the production of new types, the variation and evolution of animals, rather than the factors of extinction. It is true that these may bear a close relationship and present mutual dependencies and possibly we might take them as necessary corollaries or consider factors of extinction as merely negative factors of evolution, but it seems to me worthwhile to attempt a distinct formulation of those factors especially concerned in the elimination of life forms even if for no other purpose than to emphasize those factors of progressive evolution against which they contrast.

Publication Date

1901

Journal Title

Proceedings of the Iowa Academy of Sciences

Volume

9

Issue

1

First Page

47

Last Page

52

Copyright

©1901 Iowa Academy of Science, Inc.

Language

en

File Format

application/pdf

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.