Five Precepts - did Buddha really preach them?

The five precepts are (from wikipedia) 1. I undertake the training rule to abstain from killing. 2. I undertake the training rule to abstain from taking what is not given. 3. I undertake the training rule to avoid sensual misconduct. 4. I undertake the training rule to abstain from false speech. 5. I undertake the training rule to abstain from fermented drink that causes heedlessness. I am very new to Buddhism, but from what I'm understanding right now, Buddha's teachings are very simple. The first 4 rules make sense. They are all forms of practicing detachment. But the 5th... it's too human. Too specific. I just don't see Buddha teaching it to his disciples. It's the same as with Ānantarika-karma, where the last crime is creating a schism in the sangha (the community of Buddhist monks and nuns). It's too specific and so Buddhist oriented. Once again, I just don't see Buddha teaching it. The question is, did Buddha teach the five precepts?