Well the Moon is in a locked gravitational tug around the world, making the world slightly wobble on it's axis. Thus all ocean tides around the world create high and low tides. Which has a dramatic effect on the worlds weather.
Because if we had no moon, the worlds weather would be considerably 更多 violent as wind would possibly rival that on Neptune. So the Moon plays a vital role in slowing the Earth spin on it's axis.
Thus calming things down enough for complex life to survive the harsh elements that surrounds them.