Lightlessness used in a sentence

Lightlessness in a sentence as a noun

There's an ecological niche for flightless rails; going from flightworthy to flightless is presumably an easy step; I expect there'd be pronounced morphological changes associated with adaptation to flightlessness. If the progenitor hasn't changed much, the landlubber adaptations could make the two parallel descendants much more similar to each other than to their parents.