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Unformatted text preview: Patterns and Processes Ecology • The study of the distribution and abundance of organisms and the factors and interactions that determine distribution and abundance • i.e. where they are at, how many are there, and why? • The History of Ecology • roots lie in natural history, human demography, biometry, and applied problems of agriculture and medicine • Until 1960, ecology was not considered an important science • in last 40 years, it has become increasingly experimental and increasingly important as a guide to sound envi- ronmental science • Environment • Abiotic components - non-living chemical and physical factors • temperature, light, nutrients, water • Biotic components - living (biological) factors • other organisms, competition, predation • Interaction - abiotic and biotic components interact • organisms are affected by the environment but their presence/activities also change the environment • Ecological Scales • Levels of Biological Organization ( Ecology ) Introductory Biology II: EEMB 2 - Ecology EEMB 2 1 Ecologists Major Contributions Hunters and Gatherers Human Demography Aristotle Historia Animallum Herodotus and Plato Providental Ecology Graunt and Leeuwenhoek Population Growth Farr Farr’s Rule: relationship between the density of the population and death rate Buffon, Malthus, Quelet, and Verhulst Population Regulation Edward Forbes and H.C. Cowles Community regulation and succession Rober Ross Mathematical model of the spread of infectious disease (systems analysis) A.G. Tansley, F.E. Clements, and Charles Elton Some of the founders of modern ecology • Methods of Approach • Ecological evidence (a variety of sources) • observation and monitoring in the natural environment • Manipulative Feld experiment • Controlled, laboratory experiments • not very realistic - always test against a real system • Mathematical models • The criterion of comparison is the distribution and abundance of organisms in natural environments • The goal of ecology : To observe patterns, describe processes and use this information to predict, manage, and control • make sure processes/patterns are same as original conditions • If all things fail, use math to test predictions • Statistics and scientifc rigor • Application of statistics attach a level of conFdence to conclusions that are the results of investigations • Must be careful with statistics - proves nothing • Ecology relies on obtaining estimates from representative samples • P-values (probability level) • measure the strength of conclusions being drawn • Null Hypothesis • assume that there is no association between variables • SigniFcance Testing • If P is less than .05 (5%) then the results are described as statistically signiFcant • Probability is tested by signiFcance testing • by sheer chance, one gets results • 95% conFdence... As P increases, conFdence decreases • Summary • Ecological phenomena occurs at a variety of scales...
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- Winter '09
- Population Ecology, Balanus, Conversational French