Assignment: Tracking Energy
Smart businesses do careful accounting of their daily profits and expenses. In a similar way, we can track the amount of energy moving through trophic levels of a biological system to determine its overall productivity. There are many energy "transactions" to keep track of and account for when trying to calculate productivity. Producers capture light energy and convert it into chemical energy, stored in macromolecules such as glucose, which have mass. To measure the energy in biological systems, the potential energy of these molecules must be measured indirectly as "biomass." A consumer eats producers, and this biomass is either stored as chemical energy, used as kinetic energy for movement, converted to cellular energy to power cell processes and growth, or energy is lost as heat. According to the second law of thermodynamics, when light energy is converted to chemical energy in photosynthesis or transferred from a producer to its consumer, some energy will always be lost as heat during each transfer.
Tracking Energy Reflection Questions
I. Describe one way you could keep track of energy use and transfer in a biological system.
II. Identify the possible inputs and outputs of mass and energy between the sun and a producer.
III. Draw a simple diagram showing the inputs and outputs you identified in question II.