ENVR101 Lecture Notes - Lecture 2: Sap, Carbon Cycle, Chemical Energy
28 Sep 2016
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Document Summary
A network of relationships among components that interact with and influence one another. Receives inputs of energy, matter, or information; processes these inputs; and produces outputs. Ex: if we get hot, we sweat; this cools down the body. Most systems in nature involve negative feedback loops that allow them to maintain homeostasis. Ex: in a cool climate, sunlight reflects off the white surface. As climate warms, sunlight is absorbed where dark surfaces are exposed. Light absorption speeds warming, exposing more dark surfaces. Runaway cycles of positive feedback are rare in nature but are common in natural systems altered by humans. All material in the universe that has mass and occupies space. Chemistry is the study of types of matter and their interactions. Matter can be transformed from one type of substance into others, but it cannot be destroyed or created. Because the amount of matter stays constant, it is recycled in nutrient cycles and ecosystems.
