Big Idea I: The Earth is a system of systems

The Earth is composed of many systems, which cycle and interact in both space and time. It is also part of a multitude of systems, nested in larger systems like the solar system and the universe. Systems are composed of an untold number of interacting parts that follow simple rules, but they can and do evolve. For example: 

• Outlining the geologic history of any region demonstrates the concept of the Earth as a system of systems. Plate tectonics drives the formation of mountains. Subsequent weathering and erosion of the uplifted mountains leads to the formation of deltas in the adjacent shallow seas. And with uplifted continents, shorelines change and the distribution of marine communities are altered.
• The planet's systems are intimately connected: the forces of one system affect other systems nested within it. Systems that drive plate tectonics are obviously linked to and influence much smaller systems. The intense heat and pressure resulting from collisions can lead to the metamorphism of existing strata, or it can melt existing rocks to later form igneous rocks.
• As glaciers extended down from the north, they cut into river valleys in the central portion of New York. This glacial system shaped the landscape, carving the rivers into lakes and, after the glaciers' retreat, leading to the formation of deeply cut gorges. Had the glaciers never advanced so far south, the erosional forces that led to the formation of the gorges would have never been initiated.