1

Population Size

Wendy Lile

SCI275

University of Phoenix

Due March 3, 2012

Sarah Hsu

2

Population SizeThe four factors that produce a change in population size are the growth rate, the death

rate, immigration, and emigration. The growth rate is the rate in which people are born and the

death rate is the rate in which people die. If the growth rate is higher than the death rate then the

population increases and if the death rate is higher than the growth rate the population decreases.

Immigration is when peoples from outside the country move in, therefore increasing the

population; emigration is when peoples from inside the country movie out, decreasing the

population.

The two factors that affect the population size in the video are immigration on the

animals and their growth rate. Immigration is a factor because these animals were brought into

our country for fir trading and when the market declined they were just left here and are now

taking over. Their growth rate is a factor because they breed like rabbits and the vegetation in

the area that they are in is diminishing and causing environmental problems and changes.

After the nutria population grows to a certain extent and the land that they are thriving on

disappears they will either move to another location or they will eventually die off because they

never really belonged there in the first place.