1. Populations & Ecology
Distribution: geographic and ecological range (i.e. North America) (i.e. desert) Often determined by presence or absence of suitable habitat
Does it include migration areas?
Yes!
Dispersion: spacing of individuals

2. Populations: individuals of same species at the same place and time
Demography: Study of populations

3. Clumped: in groups
Can be social, due to resources, safety

4. Uniform (spaced): minimum distance from one another not common in animals
seen in plants such as oaks, creosote and sages

5. Random: no pattern, spaced without regard to one another

7. Survivorship Curves

8. r vs. k selection life history strategies
k-selected
r-selected
Fewer offspring
Slow development
Long lived
Good competitors
Slow dispersers
Much parental care
Examples??
Trees
bears
Many small offspring
Rapid development
Short lived
Poor competitors
Fast dispersers
Little parental care
Examples??
Weeds
ants
r-selected = opportunistic
k-selected = equilibrium

9. Exponential Growth: increases by multiples
N = number
in population t = time
r = rate of increase

11. Population Growth Rates
Exponential growth -increases by multiples starts off slowly than rapid increase
J-shaped curve
Logistic growth –population slows than stops growing at carrying capacity (K)
S-shaped curve
Carrying capacity (K): the number of individuals the environment can support

13. Density: number of individuals per area
Density dependent factors:
Crowding causes these factors to have more of an influence on population regulation
i.e. food, water, shelter, predators, disease
Density-independent factors:
Crowding has no influence
i.e. earthquakes, temperature

14. Natural Populations all normally reach K

15. Natural Regulations Territory size mammals/birds resources defendable
Physiological impairment White-tailed deer: reabsorption of embryos with poor nutrition

16. Oscillations: predator/prey cycles

17. Kaibab Deer Story Kaibab plateau in the grand canyon
200 deer/200 acres
In early 1900’s – predator elimination program
Between : 781 mountain lions, 556 bobcats, 31 wolves, 5000 coyotes killed
By 1911: 500 deer/200 acres
Massive starvation due to severe overgrazing
By 1950 only 50 deer/200 acres due to environmental degradation

19. Human Population Growth: r or K selected?

20. Age-structure diagrams: show proportion of population
at each age group Which is stable? Unstable?

21. Types of overpopulation
People Overpopulation: too many people for the area LDCs=lesser developed countries
Consumption Overpopulation: a few people use most of the resources MDCs=more developed countries