Population Size

1.     CheckPoint: Population Size

 

         View the Ch. 7 Alien Invasion VLR located under the Week Four Materials section of your student Web page.

         Post a 200- to 300-word response to the following:

o    Explain the four factors that produce changes in population size.

o    Which factors affect population size in the video?

• What do you predict will happen to the nutria population after the land is depleted of the nutrias’ food resource(75)?

Four factors that produce changes in population size are listed as birth rate, death rate, immigration and emigration. Birth rate is indicated by the increase or decrease in the number of offspring during a given time period. Changes in death rate, is the increase or decrease of the number of deaths a species has during a given time period. Changes in immigration is the increase or decrease in the number of individual members of a certain species into a specific area over a given period of time. There is also changes in emigration, which is an increase or decrease in the number of individual members of a certain species out of a specific area over a given time period.

The factors that are previewed in the video that affected population size is the immigration of the nutria, the decrease of demand for nutria fur caused more nutria to survive. The environmental depletion of plants in the nutria’s habitat since most were release or escaped when demand decreased. The pest behavior includes destroying aquatic vegetation, irrigation systems, eroding river banks and displacing native animals. This destruction of the natural environment has created the need to eradicate the nutria.

Once the land is depleted of the nutria’s food resource, one of two things would happen. Either the nutria will adapt and move onto an alternate food source or they will die out. Given their ability to adapt to a new environment by being immigrated, I feel as though they would adapt and move onto an alternate food source. Given their natural food source is underwater plants, they may move on land and start feeding on land plants.