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Populations. Demography Demography is the study of processes that influence population size - it is the way we study changes brought about by births,

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Presentation on theme: "Populations. Demography Demography is the study of processes that influence population size - it is the way we study changes brought about by births,"— Presentation transcript:

1 Populations

2 Demography

3 Demography is the study of processes that influence population size - it is the way we study changes brought about by births, deaths and dispersal For Northwest Montana, Greater Yellowstone, Central Idaho

4 The Fundamental Equation of Ecology – Harper 1977 Δ N = B – D + I – E Change in Number = Births – Deaths + Immigration - Emigration John L. Harper – 1925-2009

5 Rearrange Fundamental Equation Δ N = B – D + I – E N future = N now + B – D + I – E Often we assume that I = E, so no net dispersal

6 Common Field Grasshopper

7 Grasshopper – development and incomplete metamorphosis

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9 Red Deer – Stag, Hind, Fawn

10 Isle of Rhum, Scotland

11 Red deer fawn being tagged for study

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14 Arithmetic scaleLogarithmic scale

15 General types of survivorship curves

16 Human management of species may change survivorship curves A – fish mortality in typical population B – fish taken by fishing

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19 Population Pyramid For France Jan. 1, 1967

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21 Changes in population of Japan over time

22 Changes in population of Canada from 1971-2006

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