Download Limiting Factors

Background Information
What is a Limiting Factor?
 Limiting Factors are…
(two similar definitions)
 conditions of the
environment that
limit the growth of a
species.
 biotic and abiotic
factors that prevent the
continuous growth of a
population.
What is a Limiting Factor?
 Populations would continue to increase if
they had all of the resources they require in
unlimited amounts, but there are always
factors that limit their increase.
 Limiting factors control
population growth.
What is Carrying Capacity?
 Carrying capacity is
the number of
individuals of a species
that an ecosystem can
support.
What is Carrying Capacity?
 Because of these limiting factors, each
ecosystem has a finite capacity for growth
connected to its carrying capacity.
Population Growth Curves
Exponential Growth - J
Logistic Growth - S
Exponential Growth
 Occurs when there is unlimited resources
 Causes a population to increase in size rapidly
 J-shaped curve
 No limiting factors!
 Biotic potential = the estimated population size under
optimal environmental conditions
Logistic Growth
 Occurs when there are limited resources
 Causes a population to grow and then stabilize at carrying
capacity (k)
 S-shaped curve
 Limiting factors control population size (aka
environmental resistance)
Carrying Capacity & Limiting Factor Review
 In nature, populations of organisms rarely grow
uncontrolled. Each ecosystem has a carrying
capacity (or number or organisms it can
sustain/support).
 Remember, limiting factors are biotic and abiotic
factors that prevent the continuous growth of a
population.
 Because of limiting factors, the number of
organisms in a population is often well below
carrying capacity.