01:119:115 Lecture Notes - Lecture 26: Radiant Energy, Herbivore, Autotroph
18 Oct 2016
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Levels of biological organization: the biosphere, ecosystems, communities, population, organisms, organs and organ systems, tissues, cells, organelles, molecules. Ecosystem: all living organisms in a community + the abiotic factors they interact with. Range from microcosm (little world), to a large area such as a lake or island. E(cid:272)osyste(cid:373)"s dy(cid:374)a(cid:373)i(cid:272)s i(cid:374)(cid:448)ol(cid:448)e t(cid:449)o (cid:373)ai(cid:374) pro(cid:272)esses: energy flow is linear flows in a one-way direction through an ecosystem, all materials vital to life are recycled. Ecologists study the transformations of energy and matter within ecosystems. Figure 55. 4: energy flow: conservation of energy, first law of thermodynamics: energy cannot be created or destroyed, only transformed. Energy enters ecosystem as a solar radiation produces trap ~ 1% of solar energy which reaches earth photosynthesis stored as chemical energy. Cellular respiration breaks molecules energy (in form of atp) used to do work. Second law of thermodynamics: every exchange of energy increases entropy of the universe. In an ecosystem energy conversions are not completely efficient.
