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Population. By: Jesse Garza & Z ach Gardner. Biodiversity. http://www.globalissues.org/issue/169/biodiversity. Scales of biodiversity : ecosystem diversity, species diversity, and genetic diversity What creates biodiversity?
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Population By: Jesse Garza & Zach Gardner
Biodiversity http://www.globalissues.org/issue/169/biodiversity • Scales of biodiversity: • ecosystem diversity, species diversity, and genetic diversity • What creates biodiversity? • mutations, evolution., artificial selection, natural selection, gene flow, and speciation
Species richness and Species evenness • species richness- is the number of species in a given area • Species evenness- determines if a species dominates an ecosystem or each species has a similar abundance.
Human population • Crude birth rate (CBR)-Number of births in a year • Crude death rate (CDR)-Number of deaths in a year • Growth Rate-Percent change of population • Doubling time-How long it takes to double a population • Total Fertility Rate (TFR)-Estimate average # of kids each woman in the population will bear. • Replacement-level fertility-The TFR required to offset the average number of deaths • Life expectance-How long infants live • Infant Mortality-Under 1 year old • Child Mortality-Under 5 years old • Age structure diagram-How members are distributed across age ranges • Net Migration Rate-The difference between immigration and emigration. http://www.prb.org/Educators/TeachersGuides/HumanPopulation.aspx
Population ecology • Overshoot: when a population becomes larger than the carrying capacity. • Die-off: results after an overshoot, because there are not enough resources to support the population. • K-selected: high survival rates but as they get older begin to die out. • r-selected: have a lot of offspring but very few make it to adulthood. So there quick decline http://www.youtube.com/user/EducatorVids2?v=S-tBXpxrRvU&feature=pyv
Growth models Exponential Logistic survivorship
Disturbances • Disturbances that can harm an ecosystem • Hurricanes • Ice storms • Volcanoes • Forest fires • Agriculture • Deforestation • Air pollution • surface mining
5 questions to Help Review • what causes biodiversity in an ecosystem? • Are all disturbances bad to an ecosystem? • what is the difference between K selected and R selected in a growth model? • What are the scales of biodiversity? • What is the difference between species richness and species eveness?