The Earth science field began in the 20th century, but humans have been grappling with the nature of the planet on which they live since the dawn of their imagination. Although Earth science is typically seen as an "umbrella" term for a number of sciences, the 20th century ushered in the development of such fields as geochemistry, biogeochemistry, marine geology, and paleoceanography, forever changing and enhancing the study of Earth science.