1. Population Dynamics
Chapter 6

2. Fiddle Facts – A Study in Population Ecology

3. Exponential Growth and Doubling Times
# of individuals added to a population at beginning of exponential growth is relatively small.
Numbers increase quickly as the population grows.
J curve = exponential
growth

4. Biotic Potential and Carrying Capacity
Biotic Potential - Maximum reproductive rate of an organism.
Carrying Capacity –
Maximum # of
individuals of any
species that can be
indefinitely supported
in a given area.

5. Boom and Bust Cycles
Overshoot (Boom) - Population exceeds carrying capacity of its environment.
Dieback (Bust) - Negative growth curve.
Severity of dieback generally related to the extent of overshoot.

6. Growth to a Stable Population
Logistic Growth - Growth rates regulated by internal and external factors.
Growth rate slows as population approaches carrying capacity.
S curve = Carrying capacity
Environmental Resistance
Any environmental factor
that reduces population
growth.

7. r-Adapted Species (Generalists)
Short life
Rapid growth
Early maturity
Many small offspring
Little parental care
Little investment in individual offspring.
Adapted to unstable environment.
Pioneers, colonizers
Niche generalists
Prey
Regulated mainly by extrinsic factors.
Low trophic level

8. K-Adapted Species (Specialists)
Long life
Slower growth
Late maturity
Fewer large offspring
High parental care and protection.
High investment in individual offspring.
Adapted to stable environment.
Later stages of succession.
Niche specialists
Predators
Regulated mainly by intrinsic factors.
High trophic level

9. Survivorship Curves
Four general patterns:
Full physiological life span = a
Probability of death unrelated to age = b
Mortality peaks both early and late in life = c
Mortality peaks early in life = d

10. Survivorship Curves

11. FACTORS THAT REGULATE POPULATION GROWTH
Intrinsic factors - Operate within or between individual organisms in the same species.
Extrinsic factors - Imposed from outside the population.
Biotic factors - Caused by living organisms.
Abiotic factors - Caused by non-living environmental components.