Earth's Crust: The Earth's crust has cooled considerably over the years. In fact, the Earth's crust is cooling all the time. Earlier, the Earth was actually a hot and liquid ball rotating around itself and revolving around the Sun. Gradually it cooled and the outermost surface solidified and turned into the rocky crust as we know it today.
Earth's Atmosphere: The Earth's atmosphere has changed greatly over time, mostly due to biological activity. Plants performed photosynthesis to release Oxygen in the environment. They also absorbed Carbon Dioxide from the atmosphere during the process. Other organisms respired to release Carbon Dioxide into the atmosphere. These processes changed the composition greatly. Carbon Dioxide, which was not present in the atmosphere at the time of formation of the Earth, now occupies 0.03% of the air. Nowadays, the concentration of Carbon Dioxide is increasing in the atmosphere due to large scale pollution.
In conclusion, Earth's crust cooled and Earth's atmosphere changed greatly.