01:119:115 Lecture Notes - Lecture 26: Freshwater Ecosystem, Herbivore, Phosphorus Cycle
22 Apr 2016
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Document Summary
Ecosystem = all living organisms in a community + the abiotic factors they interact with. Range from a microcosm to a large area such as a lake or island. Energy flow is linear flows in one direction through the ecosystem. All materials vital to life are recycled. Ecologists study the transformations of energy and matter within ecosystems (fig 55. 4) First law of thermodynamics = energy cannot be created or destroyed, only transformed. Energy enters ecosystem as solar radiation producers trap ~1% of solar energy that reaches earth photosynthesis stored as chemical e. Cellular respiration breaks molecules energy (in atp) used to work. Second law of thermodynamics = every exchange of energy increases the entropy of the universe. In an ecosystem, energy conversions not completely efficient. Some energy always lost as heat escapes into space. Law of conservation of mass: matter cannot be created or destroyed. Chemical elements continually recycled within ecosystems.
