Evolution of the Present Day Atmosphere and Hydrosphere
The evolution of the present-day atmosphere and hydrosphere can be divided into several stages based on geological and biological events that shaped these systems over billions of years.

Formation of the Atmosphere and Hydrosphere
- The early Earth lacked an atmosphere and hydrosphere, with gases and water vapor gradually accumulating from volcanic outgassing and cometary impacts.
- The cooling of the Earth's surface led to the condensation of water vapor, forming the first oceans.

Development of the Atmosphere
- The primitive atmosphere primarily consisted of carbon dioxide, water vapor, and nitrogen.
- The evolution of photosynthetic organisms like cyanobacteria started the process of oxygenation, leading to the development of an oxygen-rich atmosphere.

Impact of Biological Processes
- The rise of oxygen-producing organisms significantly altered the composition of the atmosphere and hydrosphere.
- The formation of ozone in the atmosphere provided protection from harmful ultraviolet radiation, allowing for the colonization of land by plants and animals.

Modern Atmosphere and Hydrosphere
- Today, the atmosphere is composed mainly of nitrogen (78%) and oxygen (21%), with trace amounts of other gases.
- The hydrosphere encompasses all the water on Earth, including oceans, rivers, lakes, and groundwater, essential for supporting life and regulating climate.
In conclusion, the evolution of the present-day atmosphere and hydrosphere is a complex process influenced by geological, chemical, and biological interactions over billions of years. These systems continue to interact and evolve, shaping the conditions necessary for life on Earth.