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Unformatted text preview: Population density: true density will never be known, must be based on samples- Sessile organisms (plants) Plots and Transects: usually employ nearest neighbor distance Density is inversely proportional to distance Ex. If the distance between neighbors is smaller, that means more organism is available, and density is higher.- Motile Organisms (animals): observation based on plots/transects okay if not too motile Base on the evidence of organisms. Ex. looking for rodent burrows Sessile stationary Five traps Trapping- mark-recapture method Trap (capture) individuals in a population now at time (time 1) Mark the trapped individual Release all the marked individuals back into the population After 1~2 days, trap (capture) individuals from the same population (time 2) Check for individual at time 2 that are recapture (marked individual already) Ex. Time 1- capture and mark 50 individuals, then release Time 2- capture 50 individuals, 5 of them are marked (5 recapture) 5/50 = 10% sample are marked Extrapolate to population: 10% of population is marked 50 trapped individual / 10% recapture rate = 500 estimated total population Equ: M/N = R/C M = # caught and marked at time N = the total # in population (the true deputy) R = the # recapture at time 2 C = the total # caught at time 2 Ex. 948 captured at time 1, 421 captured at time 2, and 167 at the time 2 were marked. The Ex....
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This note was uploaded on 05/29/2008 for the course BIO 325 taught by Professor Brandom during the Spring '08 term at Cal Poly Pomona.
- Spring '08