Age structure: The numbers or percentages of males and females in
young, middle and older age groups in that population
Pre-reproduction: ages 0-14 consisting of individuals normally too
young to have children.
Reproductive: ages 15-44 consisting of those normally able to have
children.
Post-reproductive: Ages 45 and older consisting of individuals normally
too old to have.
Demographic momentum: A country with a large percentage of its people younger
than age 15 will experience rapid population growth unless death rates rise sharply.
Between 2015-2050 the number of American ages 65 and older is projected to grow from
48 million. This process has been called the graying of America.
The graying of the world's population is due largely to declining birth rates and medical
advances that have extended life spans.
If population decline is gradual its harmful effects usually can managed.
One of the importance of chukdren as a part of the labor force especially in less-developed countries.
Urbanization also plays a role. People living in urban areas usually have better access to family
plannong services and tend to have fewer children than do those living in the rural areas in
less-developed countires.
Educational and employment opportunities available for women Total fertility rates tend to be low when women
have access to education and paid employment outside the home.
Average age at marriage also plays a role. Women normally have fewer children when their average
age at maariage is 25 or older.
Availabilty of reliable birth control methods
that allows women to control the number and spacing of their children.
Religious belief, tradition cultural norms play a role in some countries these factors favor large families,
because of opposition to abortion and some forms of birth control.
Population experts identity three major trends related to urban populations.
We learned a lot about Human Population,Urbanization and Environmental Hazards and its impact on human health. I learned that the 3 major factors
to our population growth is the emergence of early and modern agriculture which increased our food production. Second is the expansion of humans across the planet
and finally the decrease of the death rates with improvements to sanitation. We learned about the trends relating to the increase of population in urban areas.
That urban areas will continue to grow and that urban areas are increasing in size and scope. Poverty is increasing in urbanized areas because of the growth of its
population especially in less developed countries.
Another fascinating topic was the increase of antibiotic resistant bacteria and there will come a time that our
antibiotic will not work. The number one contributor to our problem is the increased use of antibiotics in our livestock, “80% of all antibiotics used in the US and 50%
of those used worldwide are added to the feed of healthy livestock.” and with 80% of our livestock being dosed with antibiotics “22% of antibiotic-resistant illness in humans
is linked to food, especially meat from livestock treated with antibiotics.” and this trend is only increasing.
The most dangerous thing that many people do each day is to drive
or ride in a car yet many people are not afraid of it, there are five factors that cause people to be less risky. Number 1 is fear, 2 is control of individuals over a given situation,
3 people have fear of things that they cannot control, 4 is optimism bias which is people applying risk to others but not themselves and finally risky things are highly pleasurable and give
people instant gratification. Example a lot of people are afraid of flying even though it is safer than driving a car.