Transcript IV. Limiting Factors - Crestwood Local Schools

IV. Limiting Factors
A. What are they?
1. There are two rules of population
ecology
a. All populations are capable of
exponential growth
b. None do
2. Why is rule #2 there, because of
limiting factors
3. Any factor, besides carrying capacity,
that would cause a decrease of a
population is a limiting factor
4. Density dependent limiting factorsdepend on the population size
5. Density independent limiting factorsaffects same percentage regardless of
population size
6. Density dependent show an S shaped
curve
7. Density independent show boom and
bust curve
8. Examples
a. Food limitation
b. Predation
c. Disease
d. Parasites
e. Space
f. Water
g. Climate
h. Natural disaster
i. Human disturbances
9. How does this affect humans
a. Humans are growing
exponentially right now
b. What limiting factors could
cause the most problems for
humans
B. Biotic Potential
1. Biotic potential is an organisms ability to
produce offspring
a. Affected by gestation period and
litter size
2. K-selected species usually have low
biotic potential
a. Populations stabilize around carrying
capacity (K)
b. Lots of competition for survival
3. r-selected species focus on quantity not
quality
a. Have high biotic potential
b. r= rate of population increase
without limiting factors
c. Usually show great variation in
population size