Sherree L. Kassuba
The human population is forever growing and growing. “It took millions of years to get the first billion humans on earth by 1850. Then it took 80 years to add another billion by 1930, and only 30 years more to add a third billion by 1961. But it took only 16 years to add the fourth billion by 1976. We may add the next billion in the 14 years between 1976 and 1990. One billion is about the number of people in China and Russia today or four times the present population of the United States.”
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That is a lot of people in such a short amount of time. We have to remember that those numbers that just kept multiplying are not just from birth alone, but from the decline in older people dying. People are living for longer periods of time because of better food, housing, and medical improvements. The death rate among children was once much higher than it is today. Science and medicine have reduced the death rate by controlling diseases and epidemics. Vaccinations, antibiotics, and insecticides are used throughout the world to prevent and cure diseases. There are more and more children living until they are old enough to reproduce. As more people reproduce, more children are born and population size keeps increasing.
How do people find out all these numbers? Population specialists or people known as demographers do the work. They use the crude birth rate and crude death rate to determine population size. How they find out the numbers is by taking the numbers of births or deaths per 1000 persons in the population at the mid-year of any given year. Then the demographers divide the total number of births or deaths per year by the total population at midyear and multiply the results by 1,000. Here are two good examples of the birth and death rates.
”Average U.S. Population Growth in 1977
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9,078
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babies were born each day
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5,200
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persons died each day
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3,878
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people were added each day
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+ 1,100
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legal immigrants
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4,978
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new Americans each day, or 34,845 per week
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or
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18 million per year (without counting illegal immigration of about 1 million per year)”
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“Average World Population Growth in 1978
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334,000
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babies born each day
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140,000
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people died each day
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194,000
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people were added each day
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or
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1.4 million people per week
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or
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71 million people per year”
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They are called “crude” simply because they do not allow for differences in the structure of populations. They are the most readily available figures, and although they are often quite useful, comparison of crude rates may be misleading. An example of this was in the late 60’s when there was the highly publicized drop in the birth rate in the United States, which some people and publications misinterpreted as heralding the end of the U.S. population explosion. This could, of course, have been caused by a decrease in the number of women in the childbearing years rather than by a change in the desired family size of individual women.
Many other factors influence birth rates in addition to the number of women in their childbearing years. Severe economic conditions, epidemics, and wars may cause declines. The growth of the women’s liberation movement in the United States since 1965 may well have become an important influence on birth rates. Young women are expressing more interest in careers and equal opportunities and less interest in being a homemaker than they did in earlier years. Many women are very honest about their personal lack of interest in having children, an attitude which would have been virtually unthinkable 15 to 20 years ago.
Concerning death rates, most human populations show rather high age-specific death rates in the age from birth up to one year and considerably lower rates in the next nine years. Infants are more likely to die than children. After the age of ten there is generally a slow rise in death rates until around 45 or 50, and then a rapid rise. Sometimes the students really can’t comprehend how many people there really are on the planet, or how much a million or billion people really are. “But let us just say the class decided to take one second out to say “hello” to each additional person added during one year. If the class worked around the clock we would need 2 1/2 years to say hello to them and during that time of greeting 178 million more persons would have arrived on this earth, putting the class back 6 1/2 years saying all those “hellos”.
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