If the moon were removed, there would still be tides (due to the sun), but they would be a good deal smaller. That the sun's contribution to the tides is significant is shown by the fact that tides are smaller at first & last quarter (when the sun is working against the moon) than at new & full moon (when the two are working together).

A *very* big favor that the moon does for the earth's inhabitants is that it stabilizes the inclination of the axis of rotation. I do not know what the mechanism for this effect is, but I have read & heard about it from reliable sources. I gather that the axis of Mars (whose moons are too tiny to be of any effect) nutates (wobbles) extravagantly & irregularly on times scales of thousands of years. The axis of the earth does slowly precess, but in such a way that its inclination is a steady 22.5 deg (I think it is) to the perpendicular to the plane of its orbit. Thus, the polar circles & the tropics stay put on the globe. Imagine what it would be like if, say, that angle doubled, to 45 deg. The polar circles would coincide with the tropics, and the temperate zones would disappear. In Ottawa, at the summer solstice, the sun would be overhead at noon and barely skim the horizon at midnight. At the winter solstice there would be no sunrise. Not many existing life forms could make it thru the summer *and* the winter during such a climatic episode.

Have you thanked your moon today?