elsewhere that the fundamental biological meaning of gregariousness is that it allows of an indefinite enlargement of the unit upon which the undifferentiated influence of natural selection is allowed to act, so that the individual merged in the larger unit is shielded from the immediate effects of natural selection and is exposed directly only to the special form of selection which obtains within the new unit.
There seems little doubt that this sheltering of the individual allows him to vary and to undergo modifications with a freedom which would have been dangerous to him as an isolated being, but is safe under the new conditions and valuable to the new unit of which he now is a part.
In essence the significance of the passage from the solitary to the gregarious seems to be closely similar to that of the passage from the unicellular to the multicellular organism—an enlargement of the unit exposed to natural selection, a shielding of the individual cell from that pressure, an endowment of it with freedom to vary and specialize in safety.
Nature