 Some of Dawkins’ critics think that genes play too important a role in his notion of replication. Replication, so they argue, can occur at other levels of organization as well. Just as Dawkins extended the notion of the phenotype, these authors propose to make the notion of replicators more general as well—to extend the replicator so to speak. Dawkins introduced his Extended Phenotype conception for two reasons. First, he wanted to extend the notion of a “phenotypic trait”. The sort of nest that a bird builds or the song that it sings can count as phenotypic traits just as much as the shape of its bill. Second, as mentioned earlier, Dawkins wanted to break the hold that organisms have over how we conceptualize the living world. Traits do tend to come bundled into reasonably discrete entities; but, for making inferences about the evolutionary process, traits can be treated as separate and distinct. However, as he proceeded, Dawkins eventually decided that extending the phenotype was not enough. He had to bury it. All sorts of fascinating mechanisms to one side, what really matters in selection takes place at the level of replicators.