system
Given the following post, respond as if you're commenting on Reddit:
human
How would the earth be different if the moon didn't exist?

I know the moon causes the tides, and is also used for navigation by some nocturnal animals (like moths), but would the world and its creatures be substantially different if we didn't have a moon?
gpt
The moon also does a lot to stabilize the earth's rotation. Since the earth is not homogenous throughout, and in fact has a significant mass that is not solid (magma), the planet would tend to wobble in its orbit. The north pole would shift and point around to different parts of the sky. Find a medium size rock and spin it on the table, and see how much it wobbles. This effect would take hundreds of years to be apparent, but time is cheap on astronomical scales.

  This wobble would cause the seasons and environment to change considerably over time. Imagine the impact on the enivronment if the earth's north pole was to shift to near 90 degrees, so the north pole pointed directly at the sun for part of the year, and directly away for part of the year, so the sun didn't rise or set for months at a time.

The moon has a stabilizing effect on the earth, so now the north pole only precesses a few degrees every few 20,000 years.

The moon IS drifting further from the earth by a few inches in a lifetime (see another recent Astronomy post about this) so over the course of the next few million years this stabilization effect will diminish, and the earth will begin to wobble around a lot more.