Boat isn't adapted for a scientist (8)
I believe the answer is:
botanist
'scientist' is the definition.
(I know that botanist is a type of biologist)
'boat isn't adapted' is the wordplay.
'adapted' indicates anagramming the letters.
'boat'+'isnt'='boatisnt'
'boatisnt' is an anagram of 'BOTANIST'.
'for a' acts as a link.
(Other definitions for botanist that I've seen before include "Expert in plant biology" , "Banks" , "Student of plants" , "Plant studier" , "Someone studying plants" .)