In an answer to the post 要 to indicate "will [verb]" vs "need", it is argued that
要；yào；want to, need to, going to
is actually the short form of either
需要；xūyào；to need, to want
However, in another answer it is said:
We cannot use 要 in place of 需要 here:
为什么人类需要氧气才能生存? Why does mankind need oxygen to be able to survive?
Question: When can we use 要 to replace 需要? Is there a difference between 需要 and 要 in the sense of need to / want to?