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Chapter 5
Populations
5-1
How Populations Grow
KWL
What
are three things you want
to know about population
growth?
What do you know about
population growth?
How Populations Grow
 Characteristics
of Populations
–Three important characteristics
of a population
geographic distribution
Density
growth rate
Geographic Distribution
Geographic Distribution
Geographic
distribution, or range, is
a term that describes
the area inhabited by a
population.
Population Density
 Population
density is the number of
individuals per unit area.
 The population of saguaro cactus in the
desert plant community has a low
density, whereas other plants in that
community have a relatively high
density.
Populations Growth
 Population
Growth
 Three factors can affect population size:
Birth Rate-number of births
Death Rate-the number of deaths
the number of individuals that enter or
leave the population.
* Simply put, a population will increase or
decrease in size depending on how many
individuals are added to it or removed from it
Immigration & Emmigration
 Immigration
the movement of individuals into an
area, is another factor that can cause a
population to grow.
 Emigration
the movement of individuals out of an
area, can cause a population to
decrease in size.
Word Origin
 Immigration
is formed from the Latin prefix
in-, meaning “in,” and migrare, meaning “to
move from one place to another.
 If the Latin prefix e- means “out,” then
which of the following means “migration
out”?
A.) emigration
B.) migration
C.) Immigration
Carrying Capacity
Carrying
Capacity
The number or the largest
number of individuals that a
given environment can support.