7KH 8QLYHUVLW\ RI &KLFDJR )URP )LQH6FDOH )RUDJLQJ WR +RPH 5DQJHV $ 6HPLYDULDQFH $SSURDFK WR ,GHQWLI\LQJ 0RYHPHQW 0RGHV DFURVV 6SDWLRWHPSRUDO 6FDOHV $XWKRUV &KULV + )OHPLQJ -XVWLQ 0 &DODEUHVH 7KRPDV 0XHOOHU .LUN $ 2OVRQ 3HWHU /HLPJUXEHU DQG :LOOLDP ) )DJDQ 6RXUFH 7KH $PHULFDQ 1DWXUDOLVW 1RW DYDLODEOH S ( 3XEOLVKHG E\ 7KH 8QLYHUVLW\ RI &KLFDJR 3UHVV IRU 7KH $PHULFDQ 6RFLHW\ RI 1DWXUDOLVWV 6WDEOH 85/ http://www.jstor.org/stable/10.1086/675504 . $FFHVVHG Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . The University of Chicago Press, The American Society of Naturalists, The University of Chicago are collaborating with JSTOR to digitize, preserve and extend access to The American Naturalist. http://www.jstor.org This content downloaded from 129.2.19.102 on Tue, 18 Mar 2014 14:51:23 PM All use subject to JSTOR Terms and Conditions