When the Earth was young (30 million years) and was a bunch of molten lava, gigantic cosmic body hitting the ground, capturing part of her hot mantle and ricocheted back into space. Thus was formed the Moon .
A billion years ago the moon ceased to be geologically active. But this does not mean that the satellite earth does not perform important functions.
Tides and the height of the ocean
Perhaps the most obvious sign of the lack of the moon will be changes in the tides. If the moon did not affect our oceans, the tides would be three times more powerful. Sun, of course, also affect the tidal change, but it does not have as powerful a force as the moon. The moon also affects the height of the ocean; the gravitational pull of the moon causes a "swelling" of water around the middle of the earth. In other words, the less water at the poles than at the equator. If there was no moon, a bulge of water have disappeared, heading for a shallow poles.
The Earth's rotation
Daily Moon slows the Earth's rotation on a tiny amount of time. Section "microseconds per year" for 365 days, you get this amount of time. If we had no moon, which slows down the rotation of the planet, we would "tighten" up to six hours of the day. While this may sound funny, keep in mind that the six-hour day can lead to all sorts of consequences. Firstly, would strengthen the winds and storms. Secondly, it is likely to have influenced the development of life on our planet. Due to the presence of a few short hours of daylight and darkness, who knows what would have evolved beyond the plants and animals.
The Earth's axis
And yet the moon affects the earth's axis, helping us to maintain a graceful slope of 23 degrees, thanks to which we have quite a good climate and living conditions. Without the Moon, we would have risked align or rolls onto its side. When upright (almost zero slope) we will see the sun just a few minutes - as Uranus, with its 97-degree slope - or we could give 42 years of continuous sunlight, followed by '42 darkness.
So without the moon, Earth would be a completely different planet.