Theoretically, this process can go on indefinitely, effectively rendering the jellyfish biologically immortal,[3][6] although in practice individuals can still die. In nature, most Turritopsis dohrnii are likely to succumb to predation or disease in the medusa stage without reverting to the polyp form.[7] --WP
Same family, different genera. American bison are genus Bison, while the African buffalo like the infamous Cape Buffalo or the Mediterranean buffalo that the fancy mozzarella comes from are each separate genera. Not sure how many types there are, but those were the ones I checked.
I feel there are absolutely ethical ways to harvest animals. Proper game management can improve herds more efficiently than just letting them do their own thing, and people like Temple Grandin have looked at even making industrial farming more humane.
I was raised hunting deer, and still do (though I've been reconsidering it a lot the last few years) and I've met some that really care, and others that feel like those on the train cars.