From Environmental Technology

HW7 page 190

1.What are some of the factoors that have contributed to the hudge increase in the incidece of AIDS in sub-Saharan Africa?

• Women have little acess to prevention information or effective treatments for AIDS and most of them die because they cannot afford the high costs of potent antivirial drugs.

6.What is environmental resistance?

• Organisms cannot reproduce indefinately at their intrinsic rates of increase because the environment sets limits called environmental resistance. Which includes unfavorable environmental conditions as the limited availabilty of food, water, shelter, and other essential resources[resulting in increased compitition] and this limits imposed by disease and predation.

10.Explain how human diseases such as the Black Death, tuberculosis, and AIDS is related to high population densities found in urban environments. Are such diseases density-dependent or density-independent?

• Because of high population densities the people in the environment encounter one or another more frequently than low density populations, therefore the chance of spreading human diseases happen more rapidly.
• These diseases are density-dependent factors.

11.What is zero population growth? When do population experts think that the human population will have zero population growth?

• Zero population growth is when the birth rate is equal to the death rate.
• It is projected that humans will have zero population growth toward the end of the 21st century.