They can all be followed by a pair of consecutive letters of the alphabet to form a six-letter word:
SCARAB THOUGH NAPALM SOLEMN TECHNO DOLLOP DIVERS DIVEST GALAXY
They are placed in order according to the letters that have been added.
Of the four words in the second list, one can also be followed by a pair of consecutive letters: PARA -> PARADE, and therefore belongs between SCAR and THOU in the list.
The other three could be followed by a pair of consecutive letters in reverse order: BECKON, CLEFTS, PASTED.