Edited with the trial version of Foxit Advanced PDF Editor To remove this notice visit www foxitsoftware com shopping BIOL 1543 1st Edition Lecture 19 Outline of Last Lecture I THE SCIENTIFIC STUDY OF BEHAVIOR II LEARNING III Mating behaviors IV SOCIAL BEHAVIOR AND SOCIOBIOLOGY V FORAGING BEHAVIORS VI POPULATION ECOLOGY VII Survivorship Curves Outline of Current Lecture I COMMUNITY ECOLOGY II PREDATION III PREDATION MIMICRY IV PREDATION COMMUNITY DIVERSITY V HERBIVORY VI TROPHIC STRUCTURE VII ECOSYSTEM ECOLOGY VIII CHEMICAL CYCLING CARBON AND WATER Current Lecture I COMMUNITY ECOLOGY a A community includes all the organisms more than one species inhabiting a particular area 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 i A biological community is an assemblage of all the populations of organisms living close enough together for potential interaction b Communities are characterized by i Species diversity ii Dominant species iii Response to disturbance iv Trophic structure feeding relationships c Competition may occur when a shared resource is limited i Interspecific competition occurs between two species if they both require the same limited resource ii A species niche includes its total use of biotic and abiotic resources iii The competitive exclusion principle states that two species cannot coexist in a community if their niches are identical 1 either one species will manifest dominance over the other or one species will change its niche to survive II PREDATION a Predation leads to diverse adaptations in both predator and prey i Predation is an interaction between species in which one species the predator kills and eats another the prey ii The adaptations of both predators and prey tend to be refined through natural selection iii Some prey gain protection through camouflage or chemical defenses III PREDATION MIMICRY a Some prey gain protection through mimicry a copycat adaptation in which one species mimics the appearance of another i Two types of mimicry 1 Batesian when a defenseless species mimics another species that has a defense 2 M llerian one unpalatable species mimicking another unpalatable species you wouldn t want to mess with either one b aposematic when a species has coloration or structures present that indicate a special means of defense i like the stripe on the back of a skunk IV PREDATION COMMUNITY DIVERSITY a A keystone predator keystone species may maintain community diversity by reducing the numbers of the strongest competitors i a species that exerts strong control on a community because of its niche b Removal of a keystone predator from a community can cause major changes in community dynamics V HERBIVORY a Herbivores and the plants they eat have various adaptations i Herbivores are animals that have adaptations for eating plants or algae ii Many plants produce toxic chemicals to protect against herbivores iii Some herbivore plant interactions illustrate coevolution or reciprocal evolutionary adaptations an evolutionary arms race 1 coevolution species 1 makes an adaptation species 2 will develop an adaptation to deal with the first adaptation then species 1 has another adaptation to deal with that adaptation Plant becomes toxic to caterpillars so that it doesn t get eaten Eggs Caterpillars adapt so that they can eat the plant without dying getting sick Plant then adapts to look like a butterfly has already lain eggs on it the sugar deposits so that butterflies seeing the sugar deposits eggs don t lay anymore eggs on the plant Sugar deposits VI TROPHIC STRUCTURE a Every community has a trophic structure feeding structure a pattern of feeding relationships consisting of several different levels b Trophic structures can be represented by food chains the stepwise flow of energy and nutrients from plants producers to herbivores primary consumers to carnivores secondary and higher level consumers c Detritivores animal scavengers fungi and prokaryotes decompose waste matter and recycle nutrients in ecosystems i fungi prokaryotes scavengers VII ECOSYSTEM ECOLOGY a Ecosystem ecology emphasizes energy flow and chemical cycling i closed system except for light energy sunlight in and heat out b An ecosystem includes a community and the abiotic factors with which it interacts VIII CHEMICAL CYCLING CARBON AND WATER a Solar heat drives the global water cycle precipitation evaporation and transpiration water given off by plants b Carbon is taken from the atmosphere by photosynthesis and used to make organic molecules then returned to the atmosphere by cellular respiration