1. Population Ecology!

2. Populations Population: all individuals of 1 species in area
Population size : number of individuals
Population density : number per area
Population distribution : dispersal pattern

3. Distribution patterns
1) Clumped: most common,
a) group around resources
b) social behavior
c) lack of offspring dispersal
2) Uniform (or close enough)
a) territory division
3) Random – rare
a) uniform resources
b) ignore each other

4. Population Size Estimates
1) full count
2) Quadrats
3) Transects
4) Mark-recapture
m-r good for organisms
that move around a lot

5. Mark-recapture Based on assumption: % marked on day 2 same as
the % of the total population that is marked
Steps: day 1 capture organisms & mark them
day 2 capture organisms & see what
% are marked
calculation day 2 marked = day 1 marked
day 2 total total population

6. Population Growth Positive growth …….. birth & immigration
Negative growth …… death & emigration
Migration : periodic change w/ seasons
Net reproduction = births – deaths
Per capita = per individual
Doubling time: time for pop to double size

7. Rapid Population Growth
Exponential growth : population grows at a rate proportional to its size
a) ideal conditions allow max growth rate
Biotic potential : max growth rate for a population (under ideal conditions)

8. Logistic Population Growth
Exponential Growth slowed by
1) Density dependent limiting factors
predation, parasites, disease
limited resources, competition
2) Density independent limiting factors
weather, natural disasters, humans

10. Carrying capacity =
Max # individuals an area can support indefinitely (D)
Steady state
#2 on graph
Life history patterns: adaptations that influence survival, reproduction & population size

11. Life History Patterns r-selected
a) favor low pop density (d independent)
b) quick production of many small babies
c) high biotic potential so called r-selected
K-selected
a) favor high pop density (d dependent)
b) good competitors
c) low biotic potential & parental care

12. Life History Strategies

13. Different Life Histories =
Different Survivorship Curves
Type I : live long & prosper
(parental care)
k-selected
Type II : could die at any time…
good luck
Type III : high infant mortality
r-selected

15. Human Population growth
growth to 2 billion…………..123 years
Growth to 3 billion …………. 33 years
Growth to 4, 5, 6 ………….. 14, 13, 12

16. Fertility Rates and $$$$$$$
Total Fertility Rate (TFR) –
average # children born per woman
World wide TFR = 6.5
Replacement = 2.1
TFR in developed countries = at or below 2.1
TFR in developing countries = highest

17. Demographic Transition Model