Islam solves this very simply: evil (as in people doing bad things) is an unavoidable consequence of free will; you couldn't have both a world with no evil and

Islam solves this very simply: evil (as in people doing bad things) is an unavoidable consequence of free will; you couldn't have both a world with no evil and a world with free will. Animals doing nasty stuff to each other is just nature, there's no good or evil about it, because animals don't have free will, they just follow their instincts. Calling the actions of a parasite evil just because it makes one feel icky has no basis in theology.