In real practical engineering terms, it would be pretty difficult to set up a room so that a true line of equilibria existed. The line is in practice likely to 'collapse to a point'. Russell Lande's argument too, about a line of equilibria in sexual selection, rests upon assumptions that may well not be true in nature. It assumes, for instance, that there will be a steady supply of new mutations. It assumes that the act of choosing, by a female, is entirely cost-free. If this assumption is violated, as it well may be, the 'line' of equilibria collapses into a single point of equilibrium. But in any case, so far we have only discussed the case where the choice discrepancy becomes smaller as the successive generations of selection go by. Under other conditions the choice discrepancy may become larger.
