Answer: clines

AnswerCrossword Clue
CLINESGradual changes, in biology.
CLINESBiological changes
CLINESPatsy and Eddie
clinesthe gradual change in certain characteristics exhibited by members of a series of adjacent populations of organisms of the same species
clines(in systemic linguistics) a scale of continuous gradation; continuum
clinesCLINE, changes of form within a species