lecture 6 2009

lecture 6 2009 - Populations Dynamics I African buffalo...

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Populations: Dynamics I African buffalo

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Individual Population Community A group of regularly interbreeding individuals (intra specific) A collection of co- occurring populations (inter specific)
What is Population Dynamics? The study of (numerical) change in a population Why study dynamics? 1)To understand why population growth is limited 2)To identify causes of population declines 3)To estimate the portion of a population that can be safely harvested 4)To identify causes of population outbreaks

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What determines population size? Birth rate (+) Death rate (-) Immigration rate (+) Emigration rate (-) “Closed population” = population where no immigration or emigration occurs

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What determines population size? Population change = Births (b) – Deaths (d) + Immigrants (i) – Emigrants (e)
Population change = Births (b) – Deaths (d) + Immigrants (i) – Emigrants (e) Population next year = pop this year + Births (b) – Deaths (d) + Immigrants (i) – Emigrants (e) Next year = 500 + 104 (b) – 41 (d) + 11 (i) – 20 (e) = 554

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For simplification: i) Population size is called N ii) A population size at a given period in time is called N t iii)A population size at the next time interval is called N t+1 where t usually refers to years
Population next year = pop this year + Births (b) – Deaths (d) + Immigrants (i) – Emigrants (e) N t+1 = N t + (b-d) + (i-e)

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N t+1 = N t + (b-d) + (i-e) So, the rate of growth from one year to the
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This document was uploaded on 07/22/2009.

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lecture 6 2009 - Populations Dynamics I African buffalo...

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