KREBS chapters – 9,10,11,16. Appendix III POPULATION – a group of organisms of the same

1. POPULATION DYNAMICS KREBS chapters – 9,10,11,16. Appendix III POPULATION – a group of organisms of the same species occupying a particular space at a particular time CHARACTERISTICS – Density Birth rate (Natality) Death rate (Mortality) Immigration Emigration Age distribution Sex ratio

2. POPULATION DYNAMICS Density: Numbers / unit area Birth rate (Natality): numbers of offspring / unit time Can vary from once in a life time = SEMELPAROUS to many times = ITEROPAROUS

3. POPULATION DYNAMICS Death rate (Mortality): Converse of mortality is SURVIVAL LONGEVITY = length of life SURVIVAL can be estimated by measuring relative abundance of two age groups provided (i) number entering first age group and (ii) survival are both constant

4. POPULATION DYNAMICS Immigration and Emigration are aspects of DISPERSAL SOURCE populations – births are greater than deaths and So export individuals = emigration SINK populations – births less than deaths so numbers are maintained only by importing individuals = immigration Dispersers link populations. METAPOPULATION = a collection of subpopulations

5. LIFE TABLES LIFE TABLE – is an age-specific summary of the birth and death rates operating on a cohort of individuals COHORT – a group of organisms born in the same time period

6. LIFE TABLES Age interval can be any unit e.g. year, month, week LIFE TABLE – e.g. song sparrow population Cohort is described by x = age nx = number of survivors at age x lx = proportion surviving from birth to start of age x dx = number dying during interval x to x+1 qx = age-specific mortality = proportion dying during age interval x to x=1

8. LIFE TABLES Age interval can be any unit e.g. year, month, week nx = number of survivors at age x lx = nx / n0 dx = nx – nx+1 qx = dx / nx

9. SURVIVORSHIP CURVES

10. AGE-SPECIFIC MORTALITY

11. FECUNDITY • after maturity • reproduction • continues through • life

12. U.S. WOMEN 1989 FECUNDITY Human females stop reproducing at about 45 yrs

14. COHORT LIFE TABLE – is the schedule of deaths of a group born at a given time and followed through life. TIME SPECIFIC LIFE TABLE – is a cross-section of all cohorts represented by the frequency of the different ages in a population at a given moment in time

15. Time specific Life table Cohort Life table Age Birth t1 t2 t3 t0 Time

16. TIME SPECIFIC and COHORT LIFE TABLES

17. STABLE AGE DISTRIBUTION – occurs when survivorship (lx) and age-specific births (bx) are constant in each cohort STATIONARY AGE DISTRIBUTION – a special case of stable age distribution in that the population is stationary because births and deaths are equal

18. STATIONARY AGE DISTRIBUTION -occurs when r = 0 and b = d

19. STABLE AGE DISTRIBUTION FROM LIFE TABLE Survivorship Reproduction

20. STABLE AGE DISTRIBUTION FROM LIFE TABLE Survivorship Reproduction

21. STABLE AGE DISTRIBUTION FROM LIFE TABLE Survivorship Reproduction

22. STABLE AGE DISTRIBUTION FROM LIFE TABLE Survivorship Reproduction

23. STABLE AGE DISTRIBUTION FROM LIFE TABLE Survivorship Reproduction

24. STABLE AGE DISTRIBUTION FROM LIFE TABLE Survivorship Reproduction

25. STABLE AGE DISTRIBUTION FROM LIFE TABLE TOTAL POPULATION

26. STABLE AGE DISTRIBUTION Survivorship Fecundity