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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 , 1,4 = Reject Null Hypothesis (Statistically Significant) (P < 0.05) , 1,4 = 0.86 Accept Null Hypothesis (No Difference) (P > 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

7 Chapter # 10 – Population Growth (pg. 204 – 221) 10.2Life Tables Provide a Schedule of Age- Specific Mortality and Survival. x n x 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 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 d x = an estimate of age-specific mortality. This is the number of individuals that died during any given time interval

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 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) 1121Y 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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