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Chapter # 10 – Population Growth (pg. 204 – 221).

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Presentation on theme: "Chapter # 10 – Population Growth (pg. 204 – 221)."— Presentation transcript:

1 Chapter # 10 – Population Growth (pg. 204 – 221)

2 Statistical Results – Biased Coin-flipping Tuesdays LabThursdays Lab 2 0.05, 1,4 = 18.06 Reject Null Hypothesis (Statistically Significant) (P < 0.05) 2 0.05, 1,4 = 0.86 Accept Null Hypothesis (No Difference) (P > 0.05) 2 0.05, 2,8 = 7.28 Reject Null Hypothesis (Statistically Significant) (P < 0.05)

3 Chapter # 10 – Population Growth (pg. 204 – 221) 10.1Population Growth Reflects the Difference Between Birth and Death. 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. 10.3Different Life Tables Reflect Different Approaches to Defining Cohorts and Age Structure. 10.4Life Tables Provide Data for Mortality and Survivorship Curves.

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5 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. Life Tables provide an age-specific account of mortality. The construction of a life table begins with a cohort - a group of individuals born in the same period of time.

6 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. x n x. 0530 1159 2 80 3 48 4 21 5

7 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. x n x. 0-1530 1-2159 2-3 80 3-4 48 4-5 21 5-6 5 Gray Squirrels (Sciurus carolinensis)

8 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. x n x l x. 0-15301.00 1-21590.30 2-3 800.15 3-4 480.09 4-5 210.04 5-6 50.01 l x = the probability at birth of surviving to any given age. 159/530

9 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. x n x d x. 0-1530371 1-2159 79 2-3 80 32 3-4 48 27 4-5 21 16 5-6 5 5 d x = an estimate of age-specific mortality. This is the number of individuals that died during any given time interval. 159 - 80 530 - 159

10 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. x n x d x q x. 0-15303710.70 1-2159 790.50 2-3 80 320.40 3-4 48 270.55 4-5 21 160.75 5-6 5 51.00 q x = an estimate of age-specific mortality. 371/530 79/159

11 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival.

12 Chapter # 10 – Population Growth (pg. 204 – 221) Locations Falls City Cemetery Fircrest (Monmouth Cemetery Crystal Lake Cemetery (Corvallis) Females Born Before 1900 Born After 1900 Males Born Before 1900 Born After 1900

13 Age Class f (x) d (x) l (x) q (x) Age Class f (x) d (x) l (x) q (x) 1121Y10001222 2161331 3161432 4261519 5241623 6201718 729188 826190 921200 10 210 1119 220 Total X ZW0.0

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16 Chapter # 10 – Population Growth (pg. 204 – 221) 10.3Different Life Tables Reflect Different Approaches to Defining Cohorts and Age Structure. Dynamic Life Table – Following the fate (cohort) of a group of individuals born at a given time (year). Time-specific Life Table – One sample period assumes: constant birth and death rates each cohort sample according to actual population proportions.

17 Chapter # 10 – Population Growth (pg. 204 – 221) 10.4Life Tables Provide Data for Mortality and Survivorship Curves.

18 Gray Squirrel (Sciurus carolinensis) Years and Months Stonecrop (Sedum smallii)

19 Chapter # 10 – Population Growth (pg. 204 – 221) 10.4Life Tables Provide Data for Mortality and Survivorship Curves.

20 Chapter # 10 – Population Growth (pg. 204 – 221) 10.4Life Tables Provide Data for Mortality and Survivorship Curves. Type I – when individuals live out their physiological life span followed by heavy mortality at the end (convex). ex. - large mammals and humans

21 Chapter # 10 – Population Growth (pg. 204 – 221) 10.4Life Tables Provide Data for Mortality and Survivorship Curves. Type II – when survivorship rates do not vary with age (straight line). ex. – adult birds (some waterfowl and migratory songbirds, small mammals and reptiles.

22 Chapter # 10 – Population Growth (pg. 204 – 221) 10.4Life Tables Provide Data for Mortality and Survivorship Curves. Type I – when mortality rates are extremely high early in life (concave). ex. – fish, invertebrates, plants (annual and perennial).

23 Chapter # 10 – Population Growth (pg. 204 – 221) 10.6Birthrate and Survivorship Determine Net Reproductive Rate (R 0 ). Fecundity – the potential reproductive capacity of an organism or population. Net Reproductive Rate (R 0 ) – the average number of females that will be left (progeny) during a lifetime by a newborn female. If (R 0 ) is < 1.0, the population is decreasing. If (R 0 ) is = 1.0, the replacement. If (R 0 ) is > 1.0, the population is increasing.

24 Chapter # 10 – Population Growth (pg. 204 – 221) 10.7Age-Specific Mortality and Birthrates Can Be Used to Project Population Change.

25 Chapter # 10 – Population Growth (pg. 204 – 221) 10.7Age-Specific Mortality and Birthrates Can Be Used to Project Population Change. From such a projection table (life table) you can calculate the age distribution (stable or stationary) for each age class or cohort in the population and to project population growth ( λ - lambda ).

26 Chapter # 10 – Population Growth (pg. 204 – 221) 10.8Stochastic Processes Can Influence Population Dynamics. Stochasticity – variation in a population from random effects within a season or time period (t). Demographic Stochasticity – variation in population growth/declining rates from random effects among individuals in survival and reproduction within a season or time period (t). Environmental Stochasticity – variation in population growth/declining rates from random effects arising from environmental factors or the occurrence of natural disasters such as fire, flood, and drought within a season or time period (t).

27 Chapter # 10 – Population Growth (pg. 204 – 221) 10.9A Variety of Fators Can Lead to Population Extinction. 1.Resource Shortage 2.Restoration/Reintroduction 3.Potential new competitors, predators, etc. (Human-assisted)

28 Chapter # 10 – Population Growth (pg. 204 – 221) 10.10Small Populations are Susceptible to Extinction. 1.Stochastic Effects. 2.Wide Dispersal/Small Populations may have trouble locating mates. 3.Allee Effect – a decline in reproduction or survival at low densities. 4.Genetic Drift – random change in gene frequency. 5.Inbreeding.


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