Biology and Philosophy 19: 327–352, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. Extended Phenotypes and Extended Organisms J. SCOTT TURNER Department of Environmental & Forest Biology, SUNY College of Environmental Science & Forestry, 1 Forestry Place, Syracuse, New York 13210, USA; E-mail:
[email protected] Received 7 October 2003; accepted in revised form 8 October 2003 Abstract. Phenotype, whether conventional or extended, is defined as a reflection of an underlying genotype. Adaptation and the natural selection that follows from it depends upon a progressively harmonious fit between phenotype and environment. There is in Richard Dawkins’ notion of the extended phenotype a paradox that seems to undercut conventional views of adaptation, natural selection and adaptation. In a nutshell, if the phenotype includes an organism’s environment, how then can the organism adapt to itself? The paradox is resolvable through a physiological, as opposed to a genetic, theory of natural selection and adaptation. Oh! let us never, never doubt What nobody is sure about!1 Introduction The twentieth century was not, for biologists at least, a doubt-filled century. In one of the most thorough-going intellectual revolutions in history, biologists, along with like-minded allies in chemistry and physics, revealed, among other things: the material basis of heredity; how heritable information is encoded; how genes are replicated; how this information is translated into functional machines; where genetic variation comes from; how genes behave in popula- tions, and how fidelity of genetic replication can be reconciled with genetic variation and natural selection. Like Sherman’s triumphant march through Georgia, the new biology was a juggernaut that swept everything before it, leaving the inhabitants stranded in a landscape that was transformed beyond all recognition.