What is the relationship between the atmosphere, life, and the earth's surface?

The atmosphere supports life, and life affects the composition of the atmosphere.

Animals like insects, birds, dinosaurs, and humans rely on the oxygen in the atmosphere to fuel our biological functions and, in turn, we release carbon dioxide.  Plants and some single-celled organisms use sunlight to break down carbon dioxide and release oxygen back into the air. This cycle needs to be in balance or disaster can occur—one of the greatest extinction events in Earth's...

The atmosphere supports life, and life affects the composition of the atmosphere.

Animals like insects, birds, dinosaurs, and humans rely on the oxygen in the atmosphere to fuel our biological functions and, in turn, we release carbon dioxide.  Plants and some single-celled organisms use sunlight to break down carbon dioxide and release oxygen back into the air. This cycle needs to be in balance or disaster can occur—one of the greatest extinction events in Earth's prehistory occurred about 2.3 billion years ago when an explosion of photosynthesizing organisms flooded the atmosphere with poisonous levels of O2.

The atmosphere is also responsible for maintaining livable conditions on the Earth's surface. 

The Ozone Layer is a shield of ozone (O3) in the upper reaches of the atmosphere. Ozone deflects many types of harmful radiation from the sun. This radiation is potentially harmful to most types of life; without ozone, much of the Earth's surface would be scorched clean. 

The entire atmosphere is also responsible for maintaining consistent temperature across the planet. You may think it gets warm during the day and chilly during the night, but the range is minuscule compared to other celestial bodies. For example, the Moon, which lacks any atmosphere at all, reaches 100 degrees Celsius in the sun, but dips to negative 150 degrees in the shade!