 The term replicator, originally introduced in the 1970s but since modified by philosophers in the 1980s, is used to refer to any entity of which copies are made (Dawkins 1976, 1982a,b; Hull 1980; Brandon 1982). Replicators were originally described using two orthogonal distinctions. A “germ-line” replicator, as distinct from a “dead-end” replicator, is “the potential ancestor of an indefinitely long line of descendant replicators” (Dawkins 1982a: 46). For instance, DNA in a chicken’s egg is a germ-line replicator, whereas that in a chicken’s wing is a dead-end replicator. Note that DNA are, but chickens are not, replicators, since the latter do not replicate themselves as wholes. An “active” replicator is “a replicator that has some causal influence on its own probability of being propagated,” whereas a “passive” replicator is never transcribed and has no phenotypic expression whatsoever (Dawkins 1982a: 47). There is special interest in active germ-line replicators, “since adaptations ‘for’ their preservation are expected to fill the world and to characterize living organisms” (Dawkins 1982a: 47).