Big Idea 3: Earth’s Systems Interact

The biosphere comprises earth's living things, which can be found in many parts of the geosphere, the hydrosphere, and the atmosphere. Humans are part of the biosphere. Human activities can have important impact on all four spheres. All earth processes are the result of energy flowing and mass cycling within and between earth's systems. Earth's energy comes from the sun. And from earth's interior. Here's the flow of energy. And the cycling of matter that produces chemical and physical changes in Earth's materials. And changes in living things. Carbon, in large amounts, constantly cycles within earth systems of rock. Water, air, living things, and what we call the fossil fuels of coal, oil, and natural gas. Earth exchanges mass and energy with the rest of the solar system. Earth gains energy and loses energy through incoming radiation from the sun, heat loss into space. And from gravitational forces from the sun, moon and planets. 

Earth gains mass from the impacts of meteorites. And comets. While it loses mass through the escape of gases into space. Earth's systems interact over a wide range of temporal and spatial scales. These scales can be microscopically small to global in size. They can last from billions of a second to billions of years. It's the interactions between earth's systems that have shaped earth history. They will also determine earth's future. Regions where organisms actively interact with each other and their environment are called ecosystems. It is ecosystems that supply food, fuel, oxygen, and nutrients needed to sustain life. Ecosystems also provide services such as climate regulation. 

The cycling and purification of water and the development and maintenance of soil all needed to maintain the biosphere. Ecosystems are considered to be the essential support units for life itself. Earth's systems are dynamic. They continually react to changing influences. Parts of earth systems seem stable, some change over very long periods of time, while other parts can change very quickly and have a major impact on living things in the biosphere. Changes in part of one system can cause new changes to that system, or to other systems, often in surprising and complex ways. Geoscientists describe some of these changes as feedbacks. This means that they can increase or decrease the original changes and be unpredictable and or irreversible. 

Geoscientist knowledge and understanding of how feedback's work within earth systems is still developing. Earth's climate is an example of how complex interactions among systems can result in relatively subtle and significant changes. By looking at the geologic record, geoscientists can see that interactions among tectonic events, solar inputs, ocean circulation, volcanic activity, vegetation, precipitation, and human activities can all cause big and sometimes rapid changes to global and regional temperature patterns and precipitation. And that's big idea three. Earth is a complex system of interacting rock, water, air, and life.