Activity 4: Biology to Go
1. Birth and immigration increase a population and death and emigration
decrease a population.
2. If the death rate were greater than the birthrate over an extended period
of time, a population would become extinct.
3. An open ecosystem is one in which all four factors: birthrate, death rate, immigration, and emigration are operating. Students can provide an example
of any natural ecosystem like one operating in a forest. A closed ecosystem
is one in which only birthrate and death rate are operating. The island of reindeer was a closed ecosystem.
4. Annual rate of growth
= (20 – 5) 3 100)
= 5 3 1
= 300 %
5. Births: 60 divided by 8 = 7.5 or about 8 births every minute
Deaths: 60 divided by 13 = 4.6 or about 5 deaths every minute
Immigrants: 60 divided by 22 = 2.7 or 3 migrants every minute
8 births + 3 immigrants = 11 persons every minute
11–5 deaths = a net gain of 6 persons every minute
60 seconds divided by 6 = 1 person every 10 seconds. |