BIO 105 1st Edition Lecture 2 Ecosystem an association of organisms and their physical environment Trophic Levels Producers plant autotrophs are closest to the energy input and are the FIRST TROPHIC LEVEL Q What is the typical energy transfer between trophic levels 20 Number of trophic levels in an ecosystem 4 5 levels o WHY not enough energy Biological Magnification A non degradable or slowly degradable substance becomes more and more concentrated in the tissues of organisms at higher trophic levels of a food web Ex We get concerned about high levels of mercury Biogeochemical Cycles Main reservoir for the nutrient is in the environment 3 Components 4 Cycles 4 Reservoirs Hydrologic Component 1 Water Cycle ocean main reservoir Atmospheric Component 2 Nitrogen Cycle atmosphere main reservoir o Nitrogen fixation fixing bacteria on plants and in ground convert nitrogen gas into ammonia 3 Carbon Cycle sediments and rocks main reservoir o Carbon is the major ingredient in all organic molecules o Atmospheric carbon is mainly carbon dioxide Sedimentary Component These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 4 Phosphorous Cycle earth s crust main reservoir only one without an atmospheric component most prevalent limiting factor in ecosystems Important 75 of earth covered by water 93 salt water 51 of U S water contaminated Green House Effect Greenhouse gases impede the escape of heat from Earth s surface excessive CO2 in upper atmosphere trapping heat and gases Animal Behaviors and The Environment Lecture 4 Innate Behavior behavior performed in same way by all individuals of a species Fixed Action Pattern stereotyped response ex wasp goes to circular shape Learning response that change with experience Imprinting Triggered by exposure to simple sign stimulus ex geese hatchlings treat the first moving object they see as their mother Sign Stimulus causes Starling Nest Decoration Starling line nest with wild carrot carrots protected nest and birds from mites mites takeover without wild carrot