BIO 373 1st Edition Lecture 13 Outline of Last Lecture I. Influences on Population Sizea. Weatherb. Intraspecific competitionc. Density dependent factorsII. Logistic Growtha. Carrying capacityb. Compare to exponential growthIII. Simple and complex population dynamicsa. Exponential and logistic growthb. Population fluctuationsOutline of Current Lecture I. Delayed Density DependenceII. Population Dynamicsa. Extinctioni. Factorsii. Spatial dynamicsb. MetapopulationCurrent LectureDelayed Density Dependence- when r(tau) is small—logistic growth- when r(tau is intermediate—exhibits oscillations- when r(tau) is large—stable limit cyclePopulation Dynamics- populations can go extincto just as all populations can grow exponentially- factors: chance eventso genetic factors genetic drift= chance of propensity of alleles to be lost- can lead to fixation of an alleleThese 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. inbreeding= less diversity, similar alleles, decreased genetic variation in small populationso demographic stoichaciticity—chance events affect survival and reporoduction of individual birth rate and death rate frequencies may be unequal P(extinction)= (d/b)^Noo Environmental stoicasticity Good years and bad years for population growth, hence r changes through time- Optimal vs. suboptimal conditions on intrinsic rate of growth- Fluctuations—effects are much greater in small populations Natural catastrophes- Spatial Dynamicso Can be patchy distributions as opposed to continuouso Patchiness is increased due to human impacto Metapopulation concept= we see population in habitats that are suitable Persistence—0 or 1 (not there or there) probability of persistence of a population Regional or landscape scale- Dp/dt= cp(1-p)-ep- E= extinction, p= proportion of habitat patches occupied, c= colonization of patches Know metapopulation assumptions Some patches go extinct while others get colonization or recolonized and grow again Immigration into empty patches can sustain metapopulationo Application of metapopulation concept Habitat fragmentation- As patches get smaller, and more isolated, colonization rate decreases and extinction rate increases- If e/c >1, metapopulation will go extinct- A critical habitat threshold exists to avoid
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