Unit A

Module 1 Introduction

 Energy Flow and the Cycling of Matter

Energy from the Sun is captured for use through photosynthesis. Matter is cycled through the biosphere.

How does energy enter the
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biosphere? If you feel the Sun on your face and see some leafy green things, that's usually the starting point. Energy in the biosphere exists in many different forms: radiant energy from the Sun, heat energy from burning hydrocarbons, and chemical energy stored in the bonds of chemical compounds. Although we can often feel the Sun's warmth, experience a suntan from the Sun's wavelengths, or use the heat from a fire to keep us warm, these forms of energy are not available for us to use. The energy that we use to run, jump, talk, and think comes from the energy stored in the chemical bonds of our food. The same is true for all other consumers in the biosphere. What do producers do for people and other consumers?

Photosynthesis and chemosynthesis are both processes that provide food for consumers.  Photosynthesis uses energy from the Sun and carbon dioxide in the air to make sugar and oxygen.  Chemosynthesis occurs deep in the ocean, in the absence of sunlight, and uses chemical compounds as energy rather than sunlight to produce organic matter.