The Earth has only one moon. The existence of a moon orbiting the Earth is responsible for several phenomena on Earth that affect life, including the generation of tides on a daily basis.
Although small by comparison to other moons in the solar system, Earth's moon is the largest moon in comparison to its planet among the eight planets of the solar system. The presence of the moon causes the tides, and many organisms rely on the tides to live.
The moon also affects life on Earth by stabilizing the Earth's tilt angle. The tilt angle, which is 23.5 degrees, is essential to maintaining life on Earth because it is the cause of the changing of seasons. If the moon were not present, large bodies such as the sun and Jupiter would affect the tilt angle and cause instability on Earth.