1. Population Ecology

2.  A group of individuals of the same species occupying a given area  Can be described by demographics  Vital statistics such as size, density, distribution, and age structure

3.  Number of individuals in some specified area of habitat  Crude density information is more useful if combined with distribution data clumped nearly uniform random Fig. 45-2a, p.802

4.  Immigration adds individuals  Emigration subtracts individuals  Births add individuals  Deaths subtract individuals

5.  Interval in which number of births is balanced by number of deaths  Assume no change as a result of migration  Population size remains stable

6. G = rN  G is population growth per unit time  r is net reproduction per individual per unit time  N is population size

7.  Population size expands by ever increasing increments during successive intervals  The larger the population gets, the more individuals there are to reproduce Fig. 45-5a, p.804

8.  Maximum number of individuals that can be sustained in a particular habitat  Logistic growth occurs when population size is limited by carrying capacity

9.  As size of the population increases, rate of reproduction decreases  When the population reaches carrying capacity, population growth ceases

10. Fig. 45-8, p. 807 initial carrying capacity new carrying capacity Logistic Growth Graph

11.  Population may temporarily increase above carrying capacity  Overshoot is usually followed by a crash; dramatic increase in deaths Reindeer on St. Matthew’s Island Fig. 45-9, p.807

12. G = r max N (K-N/K)  G = population growth per unit time  r max = maximum population growth rate per unit time  N = number of individuals  K = carrying capacity

13.  A population’s growth depends on the resources of its environment  Deer introduced to Angel Island  Population outstripped resources

14.  Any essential resource that is in short supply  All limiting factors acting on a population dictate sustainable population size

15.  Logistic growth equation deals with density- dependent controls  Limiting factors become more intense as population size increases  Disease, competition, parasites, toxic effects of waste products

16.  Factors unaffected by population density  Natural disasters or climate changes affect large and small populations alike

17.  Patterns of timing of reproduction and survivorship  Vary among species  Summarized in survivorship curves and life tables

18. Graph of age-specific survivorship Figure 45.11 Page 809

19. Fig. 45-11a, p.809

20. Fig. 45-11b, p.809

21. Fig. 45-11c, p.809

22.  Over 6 billion people alive  About 2 billion live in poverty  Most resources are consumed by the relatively few people in developed countries

23.  Expanded into new habitats  Agriculture increased carrying capacity; use of fossil fuels aided increase  Hygiene and medicine lessened effects of density-dependent controls

24.  Exponential growth cannot continue forever  Breakthroughs in technology may further increase carrying capacity  Eventually, density-dependent factors will slow growth 39_18

25.  Divide population into age categories  Population’s reproductive base includes members of the reproductive and pre- reproductive age categories

26. Show age distribution of a population Rapid Growth Slow Growth Zero Growth Negative Growth

27. Fig. 45-17b, p.815

28.  Direct counts are most accurate but seldom feasible  Can sample an area, then extrapolate  Capture-recapture method is used for mobile species

29.  Capture, mark, and release individuals  Return later and capture second sample  Count the number of marked individuals and use this to estimate total population

30.  Marking has no effect on mortality  Marking has no effect on likelihood to being captured  There is no immigration or emigration between sampling times

31.  Maximum rate of increase per individual under ideal conditions  Varies between species  In nature, biotic potential is rarely reached