That which endures is not one or another association of living forms,
but the process of which the cosmos is the product, and of which these
are among the transitory expressions. And in the living world, one of
the most characteristic features of this cosmic process is the struggle
for existence, the competition of each with all, the result of which is
the selection, that is to say, the survival of those forms which, on the
whole, are best adapted to the conditions which at any period obtain;
and which are therefore, in that respect, and only in that respect, the
fittest. The acme reached by the cosmic process in the vegetation of
the downs is seen in the turf, with its weed and gorse. Under the
conditions, they have come out of the struggle victorious; and, by
surviving, have proved that they are the fittest to survive.