The ideas above seem great intros: "Here in science class we will do our best to explain to you how science has reasoned that humans came to be on this planet and I apologies if this offends any ideas you or your parents may hold which disagree with this, I'm simply here to pass on to you the most up to date learning on the subject, I'd feel I was failing you, as potential future scientists, if I didn't represent the most recent science to you......"

Also: " Over the centuries of human population the Earth over, humanity has searched for answers to reasons as to why we are here. Could we have some suggestions as to what these have been and are today in many parts of the Earth?......."(Myth storm follows) then go onto the comment above.

Alternative intro: How all species came to be on this planet; request different Earth centric views; discuss the science centric view; discuss the evidence in favour of each idea enabling each human brain to make a selection. ( A kinda pays your memes and takes your choice approach)