Module 6 Enviro.

What is the data about the size and composition of a population which is gathered in a survey called?

a census

As the human population increases, which problem is technology least likely to be able to solve?

a lack of space in which to live

This shift from harvesting wild food sources to producing food through the techniques of farming and herding is known as what?

agriculture revolution

Which of the following was an important characteristic of the earliest permanent human settlements?

gathered food was stored

Earth is a closed system with respect to which of the following factors?

matter

The physical laws that govern Earth's systems involve which of the following?

matter and energy

Climate is primarily determined by the interaction of the air and what other factor?

oceans

Farming caused changes in the way the people lived their lives. What was one change described in the module?

people divided work among members of society

What makes it difficult to control human population growth?

personal and cultural views

Which of the factors did NOT control early human populations?

pollution

In a particular city in one year, the birth rate is 25 per 1,000 people. The death rate is 10 per 1,000 people. What is the city's annual population growth?

1.5%

A major period of population growth occurred around how many years ago?

10,000

Scientists estimate that the first modern humans evolved on Earth approximately how many years ago?

100,000

An arithmetic progression involves the addition of the same quantity to each number. Which might represent the arithmetic growth of agricultural production?

2, 4, 6

When did the human population begin to grow at a faster rate than at any other time in history?

300 years ago

In geometric progression, the ratio of each number to the preceding one is the same. Which is an example of a geometric progression?

4, 12, 36

What was the population of the United States around 1900?

80 million

Agriculture

A major period of population growth occurred around 10,000 years ago when people began to cultivate crops and domesticate animals. This shift from harvesting wild food sources to producing food through the techniques of farming and herding is known as the agricultural revolution. As agriculture spread and dominated other means of obtaining food, nomadic hunter-gatherer societies were gradually replaced by small farming communities, each with its own social structure. Farming provided an increased and steady food supply, which led to an increase in Earth's human population. In addition, social structure caused a general rise in the standard of living, which reduced mortality rates and increased life expectancy. It is estimated that 9,000 years ago there may have been between 5 and 10 million people on Earth.

Industry

Another major period of population growth has occurred during the past 300 years. This period of history, marked by the industrial revolution, has included a number of events that favor population growth. Technological advancements have improved food production and distribution, reduced the length of the workday, and provided people with safer work environments. In addition to the greater availability of goods and materials, there have been major technological advances that have improved the quality of health care and medicine.

Famine

Famine can also devastate human populations. The Irish Potato Famine of the 1840s resulted in the death of more than one million people. At this time, the potato was the main food staple in Ireland. A disease called potato blight destroyed the potato crop, resulting in severe starvation. Famine in China from 1876-1879 was responsible for more than 9 million deaths.

6.1

History of the Human Population 1

When measuring the growth rate of a specific population, births and deaths are not the only factors to be considered.

Immigration and emigration can also affect the size of a population. Immigration is the movement of individuals into an area, while emigration is the movement out of an area. When determining the size of the human population in a specific area such as a city or nation, the factors of immigration and emigration must be considered. When studying the size of the entire population of Earth, however, these factors do not apply. Humans cannot leave the planet, nor can newcomers arrive from elsewhere.

Growth and Changing Needs Review

In this section, we have learned the following: As the human population increases in size, the need for resources also increases. The percent growth rate of the human population can be determined by subtracting the number of deaths per year per 100 people from the number of births per year per 100 people. Immigration and emigration can affect the growth rate of the population. Demographic studies help planners to anticipate the future needs of a society.

Challenges of Overpopulation Review

In this section, we have learned the following: Efforts to reduce the growth rate of the human population are difficult to implement. Social and religious beliefs about family size and birth control vary from culture to culture. Technological advances that increase the carrying capacity of Earth by increasing available resources are often followed by spurts in population growth.

Look at the graph showing populations of different age ranges in Mexico.

Mexico has a small population of elderly people

6.3 NOTES

Notes on 6.3

6.1 QUIZ

QUIZ Notes

6.2 QUIZ

QUIZ Notes

6.3 QUIZ

QUIZ Notes

Challenges of Overpopulation

Rapid population growth directly affects the global ecosystem. An increase in population places a greater demand on the space needed to sustain large numbers of people. Population growth also places a greater demand on resources, such as minerals, fuels, and food. As humans take up more space on the surface of Earth, there is less land available for the planet's other inhabitants. When this happens, it becomes difficult to convince people to give up the land and other resources they need to survive for the sake of saving wildlife. However, all life on Earth is interconnected. Overpopulation and increased use of resources and energy in any country can affect other countries. Countries with growing populations may rely on the resources of other nations. Pollution from one country may affect a neighboring country.

Increases in Growth Rate

Scientists estimate that the first modern humans evolved on Earth approximately 100,000 years ago. Scientists can only guess about population size and growth during the early stages of human history. However, there is some agreement that during this time, the population consisted of hunter-gatherers who lived in small families or tribal groups. When humans roamed the forests and plains as hunter-gatherers, populations grew slowly. Starvation, predation, and disease prevented people from living long lives—35 may have been considered very old. These conditions kept the infant mortality rate high as well. Between 10,000 and 20,000 years ago, some people began to establish permanent settlements. Evidence suggests that these people did not cultivate food, but they did store the food they gathered. Food storage reduced the threat of starvation and lowered the death rate, causing an increase in population size.

History of the Human Population

Some of the best-known ideas about population growth in the past two centuries were proposed by British economist Thomas Malthus. Writing in 1798, Malthus argued that population growth was not always desirable. Malthus pointed out that populations tend to increase geometrically (1, 2, 4, 8, 16 . . .) whereas the food supply tends to increase arithmetically (1, 2, 3, 4, 5 . . .). The human population, therefore, has the potential to increase at a much faster rate than the food supply. Malthus believed that the tendency of the human population to outgrow its resources would lead to such conditions as famine, war, and other human sufferings. To avoid such outcomes, Malthus advocated practices that would reduce the population growth rate, including late marriages and small families. These ideas have been widely discussed and debated ever since.

Health Care

The development of the germ theory of disease occurred at the height of the industrial revolution in the late 1800s. The germ theory of disease identified bacteria and other microorganisms as the agents responsible for many diseases. Before the development of the germ theory, people did not recognize the connection between health and hygiene. The germ theory resulted in improved hygiene, sterile surgery, better methods of waste disposal, and water treatment. These developments reduced the death rate, particularly among infants and children. The biomedical revolution of the twentieth century has also resulted in an increase in population growth. During this revolution, death rates continue to decrease as health and hygiene improve. The discovery of antibiotics and vaccines has wiped out or controlled many life-threatening diseases. In particular, infant mortality has decreased due to better prenatal care.

The doubling time of a population

The doubling time of a population indicates how long it will take, at the present rate of growth, before a particular population doubles its size. Doubling time can be used to illustrate the negative potential of uncontrolled population growth. For example, consider the need to double housing, food supplies, jobs, education, water, energy, and health facilities, just to maintain the present standard of living. Then consider the challenge of attempting to improve that standard of living in the same time period.

The plague

The plague may have killed more people than any other single disease. So devastating was the plague that within several years it claimed the lives of more than 25 percent of the adult population of Central Europe and Asia. The population of England was reduced by about 50 percent between 1348 and 1379. In addition to the plague, worldwide outbreaks of cholera, typhus, malaria, yellow fever, and smallpox claimed hundreds of thousands of lives. The more densely populated cities became, the more quickly diseases spread.

War

Wars have a destructive effect on human populations. Combat can claim many lives in a short time period. Other factors that reduce populations, such as disease, famine, and environmental destruction, can occur due to military activities. Cutting off food supplies is a common tactic among warring groups. Examples of wars that have taken enormous tolls on human life include the Thirty Years' War (1618-1648) when about one-third of the inhabitants of Germany and Bohemia were killed. Historically, many lives have also been lost in tribal and civil wars throughout Africa, India, China, South America, and the United States. World War I claimed an estimated 21.5 million lives, while an estimated 35-60 million people may have died as a result of World War II.

Which revolution of the twentieth century has also resulted in an increase in population growth?

biomedical revolution

All Earth systems are connected through which of the following?

biotic and abiotic interactions

Why does overpopulation put severe stress on the environment?

competition for resources is greater

The science of the changing vital statistics in a human population is called

demography.

Sweden has a higher percentage of which demographic group than the United States?

elderly people

Earth is an open system with respect to which of the following factors?

energy

Which cultures have a small impact on the environment because their population density is low?

hunter-gather

Which of following does NOT occur when energy from the sun reaches Earth?

it is absorbed by Earth's core

Strategies for living on Earth can be divided into three main categories. Which of the following is NOT one of the catagories?

religious

When calculating global population growth, what do you do with the death rate?

subtract it from the birth rate

Growth rates are determined by

subtracting the death rate (number of deaths per one thousand people) from the birth rate (number of births per one thousand people). For example, in recent years the birth rate in Egypt has averaged 29 births per year per 1,000 people. The death rate has averaged 8 deaths per year per 1,000 people. Thus, the population grew at a rate of 21 persons per year per 1,000 people, or 2.1 percent (2.1 persons per 100 people).

The most rapid population growth rate in history resulted from which of the following?

the Industrial Revolution

Which of the following is a characteristic of hunter-gatherer societies?

they are nomadic

Problems associated with a declining population size include which of the following?

weakened economic strength