Here's a random question for you: Is it unethical to needlessly torture an amoeba? How would you even know? I'm possibly torturing a few thousand bacteria, just by sitting on my couch.
If it's okay to cause needless harm to an amoeba, what about a lungworm? We know torturing dragon flies is not okay, so at which point between lungworms and dragon flies do you say "be nice to living things?"
These are the questions that kept me from getting into the really good schools.
While looking up the spelling for amoeba, I found this really cool link. It's a slideshow of deep sea amoeba who are the size of grapes. Single celled living critters, the size of grapes. Amazing.