Biol 201 3-25-2011

Biol 201 3-25-2011 - rainfall, no offspring, while...

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Geometric Growth model Assumptions: Generations don’t overlap: Each individuals go through the same life cycle at the same time and then die. They are synchronized in age. Each individual female produces lambda new individual females Lambda is constant Non-Overlapping: One generation live and then they reproduce and die. In this model, you have Cohorts of individuals that are the same ages. Bacterial Splitting: An example for non-overlapping model. The way to predict the population of bacteria at time is N t = lambda t N 0 Lambda>1 N Lambda =1 Lambda<1 Time Lambda=1 log(N) Exponential growth model : overlapping generations, r-population growth is constant. dN/dt= Rn, the change in population is the growth constant by the population. N t = N 0 e rt r>0 N r=0 Why do populations not grow exponentially? There are density dependent and independent factors that change the population. Abiotic factors: The precipitation had a significant effect on the reproduction. With no
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Unformatted text preview: rainfall, no offspring, while significant rainfall= high reproduction. Weather is density independent factor. • Some biotic factors that are density independent: beech crop index vs juveline survival. Biotic and Abiotic: Red squirrels in UConn • Temperature affects seed production, the seed production affects the juvenile survivorship • In mast years, squirrels produce 2 litters. This increase is due to the increase in food, not weather. Demographic variability (Dtochasticity): population analog of genetic drift. seed 0.5 flowering adult age lx mx 1 1 0.5 3 R =1.5, because 0*1+3*1.5 The smaller the population, the higher the variation from the exponential growth model Density dependent factor graph= has a decrease in population. Self-Thinning:...
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This note was uploaded on 10/13/2011 for the course BIOL 201 taught by Professor Mitchell during the Spring '07 term at UNC.

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Biol 201 3-25-2011 - rainfall, no offspring, while...

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