The Earth supplies us with the materials and energy needed for our lives. Knowing as much as we can about the earth ---what it is like today and how it has evolved through geologic time, going back 4,500,000,000 years, that is 4.5 Billion years, is crucial to understanding how humans can build a sustainable life.

Geology (and so the study of layers of Earth) is useful in:
-predicting earthquakes, volcanic eruptions, landslides, and other natural disasters (and the damage they cause)
-finding mineral resources (oil, iron, titanium) -finding out how the environment has changed in the past (climate, sea level)
-finding out what living things existed at different times in the past, and how they survived or did not survive the changes in the environment that I mentioned.