The exploration of the cycles of earth and the tree of life. Continents collide and coalesce, then rift apart only eventually to collide again.
Ice sheets form, advance, retreat, melt, then form again.
And yet, however different, these patterns are inseparable. The metabolic activity of living organisms modifies the chemistry of Earth processes. The presence of land plants influences erosion and deposition. The movement of continents separates and combines populations of creatures, shaping the tree of evolution. Virtually every aspect of modern Earth environments and life is determined by this complex interaction.