Desolate nature's in evolution (9)
I believe the answer is:
saturnine
'desolate' is the definition.
'nature's in evolution' is the wordplay.
'evolution' indicates anagramming the letters.
'natures'+'in'='naturesin'
'naturesin' anagrammed gives 'SATURNINE'.
(Other definitions for saturnine that I've seen before include "A rust nine chnage to be grave and gloomy" , "dour" , "dismal" , "offering little amusement" , "Morose looking" .)