BIO120 Population SimuText 1 Notes Population PDF

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Simutext Population Module Notes for BIO120 Course. Sections 1-5 included. Keywords: geometric growth, exponential growth, logistic growth, dispersal and metapopulation, and variability in population...

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Section 1: Geometric Growth ! • Example 1: Soybean crops and common water hemp (weed)!

• Example 2: Sockeye Salmon !

! Section 2: Exponential Growth ! • Example 1 Aphis glycines (the soybean aphid) is an exotic insect pest that feeds on soybeans !

explosion (locusts sweeping through the African savannah) may approach rmax for short periods of time ! ‣ Larger animals tend to have smaller rmax ! • Example 2 Water hyacinth = invasive species native to South America and introduced to southern US !

Section 3 Logistic Growth ! • Takes into account the limitation of resources and presence of predators ! • Examples aphids limited by the sugar soy beans produce, paramecium limited by resources, sheeps introduced to Tasmania ate most of the food and are limited by rainfall that helps grow the food back ! • K = carrying capacity, the population still fluctuates but not drastically ! • Example 1 Aphids !

! Section 4 Dispersal and Metapopulations ! • Example 1 Salamander !

away !

‣ Examples marbled salamander ! ‣ Granville fritillary butterfly in southwest Finland! ! Section 5 Variability in population ! • Environmental stochasticity is the random variability in resource availability, ecological community composition, predator pressure, and weather event. Causes fluctuation in a population’s growth rate (r)! • Demographic stochasticity causes variation in a population’s growth where there could be many births in a row or many deaths in a row leading to higher or lower population growth and unexpected extinction ! • Allee Effects is a phenomenon in ecology where there is a positive correlation between population size and the population growth rate; smaller populations have a lower birth rate an higher death rate !

• Deterministic Chaos is behaving that is unpredictable in the long term and appears to be random even though the underlying model is completely described and deterministic...