  To see this, suppose that an organism O has a genetically encoded  disposition N to build a special kind of nest; suppose further that  being raised in this kind of nest causes O-type offspring to have  characteristic C; and suppose finally, that Os with C enjoy greater  reproductive success than those without. Then, assuming that there is variation in N in the population, natural selection can operate so as to increase the proportion of Os with N — and hence also those  with characteristic C — in the population. Down the track, Os  will have C not by virtue of acquiring a special, genetically-encoded disposition-for-C. Rather, they will have C because their parents  have the genetically-encoded disposition N, and Os whose parents have N ‘automatically’ develop C.