Both the earth's motions have a huge impact on the earth. Just like rotation, the revolution also has a huge impact on the phenomenons observed on the earth. One revolution demarks the completion of one whole year. The time period of the sun is 365.25 days and hence, every 4 years this quarter-day adds up and causes a leap year. Revolution of the earth around the sun is also the reason behind the change of season. The earth's orbit is an ellipse and the sun is at one of the focus. Hence when the earth is away from the sun, i.e. closer to the other focus, it is winter season on earth whereas when the earth is near the sun, the earth experiences summer.