Science could become religious study if the origin of evolution is dropped (8)
I believe the answer is:
ethology
'science' is the definition.
(ethology is a kind of science)
'the origin of evolution is dropped' is the wordplay.
'origin' suggests taking the first letters (I've seen 'origins' mean this).
'evolution' is an anagram indicator.
'is dropped' becomes 'logy' (I can't explain this - if you can you should give a lot more credence to this answer).
The first letter of 'of' is 'o'.
'the'+'o'='theo'
'theo' is an anagram of 'etho'.
'etho'+'logy'='ETHOLOGY'
'could become religious study if' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for ethology that I've seen before include "Behavioural science" , "Scientific study of character formation or animal behaviour, like theology" .)