We've discussed what the Earth would be like without us. How about without the moon?
The Moon has been a stabilizing factor for the axis of rotation of the Earth. If you look at Mars, for instance, that planet has wobbled quite dramatically on its axis over time due to the gravitational influence of all the other planets in the solar system. Because of this obliquity change, the ice that is now at the poles on Mars would sometimes drift to the equator. But the Earth’s moon has helped stabilize our planet so that its axis of rotation stays in the same direction. For this reason, we had much less climatic change than if the Earth had been alone. And this has changed the way life evolved on Earth, allowing for the emergence of more complex multi-cellular organisms compared to a planet where drastic climatic change would allow only small, robust organisms to survive.It strikes me as incredible that we are approaching the 40th anniversary of the first moon landing, and interest in being there is still meager. Perhaps the Chinese will pick up the lead, whilst we devote our energies to better garege door openers.
The Moon has influenced biology in other ways as well. For species living near the coast, the tide is an important factor. When you look at the shorelines, you can recognize different layers of organisms that have adapted to the salt water conditions based on the ebb and flow of the tide. [More]