Unit 4 human population

% change equation

((y2 - y1) / y1)*100

Natural rate of increase/decrease equation

(Crude birth rate − Crude death rate) / 10

Annual % growth rate equation

(Present) - (Past) / (Past)

Figure 17-9 Ways to Reduce Infectious Disease

-Increase research on tropical diseases and vaccines -Reduce poverty and malnutrition -Improve drinking water quality -Reduce unnecessary use of antibiotics -Sharply reduce use of antibiotics on livestock -Immunize children against major viral diseases -Provide oral rehydration for diarrhea victims -Conduct global campaign to reduce HIV/AIDS

List five factors that have contributed to genetic resistance in bacteria to commonly used antibiotics.

-Over-prescription of antibiotics -Patients not finishing the entire antibiotic course -Overuse of antibiotics in livestock and fish farming -Poor infection control in health care settings -Poor hygiene and sanitation -Absence of new antibiotics being discovered

Figure 17-4 Deadliest Infectious Diseases

-World health organization has estimated that the worlds seven deadliest diseases killed 10 million people per year, most are poor in less-developed countries -Pneumonia and flu -HIV/AIDS -Diarrheal diseases -Tuberculosis -Hepatitis B -Malaria -Measles

Doubling Time (rule of 70) equation

70/(growth rate percentage)

noise pollution

Any unwanted, disturbing, or harmful sound that impairs or interferes with hearing, causes stress, hampers concentration and work efficiency, or causes accidents.

life expectancy

Average number of years a newborn infant can be expected to live.

urbanization

Creation or growth of urban areas, or cities, and their surrounding developed land. See degree of urbanization, urban area.

Describe the potential for urban indoor farming.

Crops on these farms could be fed nitrogen and other plant nutrients extracted from the animal wastes and perhaps from city sewage treatment plants. Electricity for heat and lighting could be provided by geothermal, solar, or wind energy, energy from composted plant and animal wastes, and fuel cells powered by hydrogen produced from such forms of renewable energy. Thus, an urban vertical farm would mimic nature by applying all three scientific principles of sustainability.

Why there are more boys than girls in some countries?

Cultural preference for boys

zoning

Designating parcels of land for particular types of use.

toxicity

Measure of the harmfulness of a substance.

What are the major disadvantages of urbanization?

Most Urban Areas Have Huge Ecological Footprints Urban populations occupy only about 3% of the earth's land area, but they consume about 75% of its resources and produce about 75% of the world's pollution and wastes. Because of this high input of food, water, and other resources, and the resulting high waste output (Figure 22-9), most of the world's cities have huge ecological footprints that extend far beyond their boundaries, and they are not self-sustaining systems Most Cities Lack Vegetation In urban areas, most trees, shrubs, grasses, and other plants are cleared to make way for buildings, roads, parking lots, and housing developments. Thus, most cities do not benefit from vegetation that would absorb air pollutants, give off oxygen, dampen urban noise, and provide shade, wildlife habitat, and aesthetic pleasure. Many Cities Have Water Problems As cities grow and their water demands increase, expensive reservoirs and canals must be built and deeper wells must be drilled. This can deprive rural and wild areas of surface water and deplete groundwater supplies. Flooding also tends to be greater in cities that are built on floodplains near rivers or along low-lying coastlines subject to natural flooding. In addition, covering land with buildings, asphalt, and concrete causes precipitation to run off quickly and overload storm drains. Urban development has often destroyed or degraded large areas of wetlands that have served as natural sponges to help absorb excess storm water. Many of the world's largest coastal cities (Figure 22-3) will face a new flooding threat at some time in this century as sea levels rise because of projected climate change due to a warmer atmosphere (see Chapter 19 opening photo). Projected climate change is also expected to melt some mountaintop glaciers, and cities that depend on this ice for their water supplies will face severe water shortages. Cities Tend to Concentrate Pollution and Health Problems Because of their high population densities and high rates of resource consumption, cities produce most of the world's air pollution, water pollution, and solid and hazardous wastes. Pollutant levels are generally higher because pollution is produced in a smaller area and cannot be dispersed and diluted as readily as pollution produced in rural areas can. The concentration of motor vehicles and industrial facilities in urban centers, with just over two-thirds of the world's emissions of from human-related sources, causes disruption of local and regional portions of the carbon cycle (see Figure 3-17). This concentration of urban air pollution also disrupts the nitrogen cycle (see Figure 3-18) because of large quantities of nitrogen oxide emissions, which play a key role in the formation of photochemical smog. Also, urban nitric acid and nitrate emissions are major components of acid deposition in urban areas and beyond (see Figure 18-12, and Figure 18-13). Nitrogen nutrients in urban runoff and discharges from urban sewage treatment plants can also disrupt the nitrogen cycle in nearby lakes and other bodies of water, and cause excessive eutrophication (see Figure 20-1, and Figure 20-8). In addition, high population densities in urban areas can promote the spread of infectious diseases, especially if drinking water and sewage systems are inadequate or not available. Cities Have Excessive Noise Most urban dwellers are subjected to noise pollution: any unwanted, disturbing, or harmful sound that damages, impairs, or interferes with hearing, causes stress, hampers concentration and work efficiency, or causes accidents. Noise levels are measured in decibel-A (dbA) sound pressure units that vary with different human activities

age structure

Percentage of the population (or number of people of each sex) at each age level in a population.

risk

Probability that something undesirable will result from deliberate or accidental exposure to a hazard. See risk analysis, risk assessment, risk management.

Figure 17-15 Reduce Exposure to Endocrine Disruptors

Relays a list of actions that can be taken to reduce exposure to endocrine disruptors

Describe the eco-city model and how it applies the principles of sustainability.

cities are people-oriented, not car-oriented, and their residents are able to walk, bike, or use low-polluting mass transit for most of their travel. - solar hot-water heaters on rooftops, and micro-wind turbines, as well as from geothermal heating and cooling systems - buildings, vehicles, and appliances are all energy efficient - reuse, recycle, and compost 60-80% of their municipal solid waste.

What factors could hinder some less-developed countries from making this transition?

o Rapid population growth. o Extreme poverty. o Increasing environmental gradation.

What are environmental refugees and how quickly are their numbers growing?

people who have been forced to leave their traditional habitat, temporarily or permanently, because of a marked environmental disruption. #s are increasing

Describe Influenza

A respiratory illness caused by a virus. Flu is highly contagious and is normally spread by the coughs and sneezes of an infected person. Although unpleasant, flu is rarely life-threatening.

response

Amount of health damage caused by exposure to a certain dose of a harmful substance or form of radiation. See dose, dose-response curve, median lethal dose.

carcinogens

Chemicals, ionizing radiation, and viruses that cause or promote the development of cancer. See cancer. Compare mutagen, teratogen.

What are the world's three most populous countries?

China, India, and the US

Figure 17-12 Mercury Pollution

Demonstrates a number of ways to prevent and control mercury pollution

Distinguish between an epidemic and a pandemic of an infectious disease.

Endemic: a disease that exists permanently in a particular region or population. Pandemic: When an epidemic spreads throughout the world.

total fertility rate (TFR)

Estimate of the average number of children who will be born alive to a woman during her lifetime if she passes through all her childbearing years (ages 15-44) conforming to age-specific fertility rates of a given year. More simply, it is an estimate of the average number of children that women in a given population will have during their childbearing years.

Figure 17-19 Home Toxins

Gives examples of unexpected places where toxins could be lurking in the average home

Figure 22-16 Bicycle Trade-offs

Gives the advantages and disadvantages of relying on bicycles for transportation

risk analysis

Identifying hazards, evaluating the nature and severity of risks associated with the hazards (risk assessment), ranking risks (comparative risk analysis), using this and other information to determine options and make decisions about reducing or eliminating risks (risk management), and communicating information about risks to decision makers and the public (risk communication).

Population change equation

(births + immigration) - (deaths + emigration)

land-use planning

Planning to determine the best present and future uses of each parcel of land.

Summarize concerns about exposure to bisphenol A (BPA) and the controversy over what to do about exposure to this chemical.

Research indicates that the BPA in plastics can leach into water or food when the plastic is heated to high temperatures, microwaved, or exposed to acidic liquids. A 2009 Harvard University Medical School study found that there was a 66% increase in BPA levels in the urine of participants who drank from polycarbonate bottles regularly for just 1 week. According to lead researcher Karin Michels, the study confirmed that certain containers can release BPA into the liquids stored inside them, even when they are not heated.

toxic chemical

See poison, carcinogen, hazardous chemical, mutagen, teratogen.

toxicology

Study of the adverse effects of chemicals on health.

Summarize the debate over whether and how long the human population can keep growing.

The different view points about the growth of human population are... • There are too many people, due to overpopulation or overconsumption. Slowing human population growth should be an important priority. • Advances in technology have allowed us to temporarily overcome environmental limits and increase the earth's carrying capacity for our species. • A growing population means more workers, consumers, and creative people. There is no need to slow the world's population growth. • Since we are currently failing to meet the basic needs for the people living today, we will be unable to meet the needs of a larger population. • If we do not sharply lower birth rates, then death rates may increase because of declining health and environmental conditions as well as increasing social disruption in some areas. • Resource use and degradation of normally renewable resources may intensify as more consumers increase their ecological footprints in more-developed countries and in rapidly developing countries.

Describe HIV/AIDS

The third largest viral killer is the hepatitis B virus (HBV), which damages the liver and kills about 1 million people each year, according to the WHO. Like HIV, it is transmitted by unsafe sex, sharing of needles by drug users, infected mothers who pass the virus to their offspring before or during birth, and exposure to infected blood.

cluster development

a design technique or zoning strategy that involves grouping houses on smaller lots in one area of a development while preserving the remaining land on the site for recreation, common open space, or protection of environmentally sensitive areas.

emergent disease

a new disease or one that has been absent for at least 20 years

What are three factors that affect the level of harm caused by a chemical?

genetic, environment, habits

birth rate

the number of births in a population in a certain amount of time

What are the five key goals of new urbanism?

*Walkable and bike-friendly neighborhoods *Mixed-use and diversity *Quality urban design *Environmental sustainability *Smart transportation

What are six indicators that scientists study to assess a community's level of sustainability?

*growing as much of its own food as possible *generating all or most of its own carbon-neutral energy *generating all or most of its own carbon-neutral energy *recycling pollutants and wastes as resources within industrial ecosystems or as biodegradable wastes, and returning extracted resources such as water and minerals to the ecosystem. *doing all of the above in order to become carbon-negative as quickly as possible

Figure 6-4 Altering Nature to Meet Our Needs

8 ways humans have altered nature to meet our needs: 1. Reducing biodiversity 2. Increasing use of the net primary productivity 3. Increasing genetic resistance in pest species and disease causing bacteria 4. Eliminating many natural predators 5. Introducing harmful species into natural communities 6. Using some renewable resources faster than they can be replenished 7. Disrupting natural chemical cycling and energy flow 8. Relying mostly on polluting and climate-changing fossil fuels

Explain how the reduction of poverty and empowerment of women can help countries to slow their population growth.

A number of studies show that women tend to have fewer children if they are educated, have the ability to control their own fertility, earn an income of their own, and live in societies that do not suppress their rights. Although women make up roughly half of the world's population, in most societies they have fewer rights and educational and economic opportunities than men have.

dose

Amount of a potentially harmful substance an individual ingests, inhales, or absorbs through the skin. Compare response. See dose-response curve, median lethal dose.

Distinguish among bacteria, viruses, and parasites, and give examples of diseases that each can cause.

An infectious disease is a disease caused by a pathogen such as a bacterium, virus, or parasite invading the body and multiplying in its cells and tissues. Bacteria are singe-cell organisms that are found everywhere and that can multiply very rapidly on their own. Most bacteria are harmless or beneficial but some cause diseases such as tuberculosis and strep throat. Viruses are smaller than bacteria and work by invading a cell and taking over its genetic machinery to copy themselves and then spreading throughout a body. They cause diseases such as flu and acquired immune deficiency syndrome (AIDS). Parasites, organisms that live on or inside other organisms and feed on them, can also cause serious infectious diseases, including malaria. A transmissible disease (also called a contagious or communicable disease) is an infectious disease that can be transmitted from one person to another. Some are bacterial diseases such as tuberculosis and gonorrhea. Others are viral diseases such as the common cold, flu, and AIDS. A nontransmissible disease is caused by something other than a living organism and does not spread from one person to another. Such diseases include cardiovascular (heart and blood vessel) diseases, most cancers, asthma, and diabetes.

crude death rate

Annual number of deaths per 1,000 people in the population of a geographic area at the midpoint of a given year. Compare crude birth rate.

crude birth rate

Annual number of live births per 1,000 people in the population of a geographic area at the midpoint of a given year. Compare crude death rate.

replacement-level fertility

Average number of children a couple must bear to replace themselves. The average for a country or the world usually is slightly higher than two children per couple (2.1 in the United States and 2.5 in some developing countries) mostly because some children die before reaching their reproductive years. See also total fertility rate.

mutagens

Chemical or form of radiation that causes inheritable changes (mutations) in the DNA molecules in genes. See carcinogen, mutation, teratogen.

teratogens

Chemical, ionizing agent, or virus that causes birth defects. Compare carcinogen, mutagen.

Summarize China's efforts to control its population growth.

China's goal has been to sharply reduce population growth by promoting one-child families. The government provides contraceptives, sterilizations, and abortions for married couples. In addition, married couples pledging to have no more than one child receive a number of benefits, including better housing, more food, free health care, salary bonuses, and preferential job opportunities for their child. Couples who break their pledge lose such benefits. Since 1980, China has undergone rapid industrialization and economic growth. According to the Earth Policy Institute, between 1990 and 2010, this reduced the number of people living in extreme poverty by almost 500 million. It also helped at least 300 million Chinese—a number almost equal to the entire U.S. population—to become middle-class consumers. Over time, China's rapidly growing middle class will consume more resources per person, expanding China's ecological footprint (see Figure 1-11) within its own borders and in other parts of the world that provide it with resources. This will put a strain on China's and the earth's natural capital unless China steers a course toward more environmentally sustainable economic development.

infectious disease

Disease caused when a pathogen such as a bacterium, virus, or parasite invades the body and multiplies in its cells and tissues. Examples are flu, HIV, malaria, tuberculosis, and measles. See transmissible disease. Compare nontransmissible disease.

transmissible disease

Disease that is caused by living organisms (such as bacteria, viruses, and parasitic worms) and can spread from one person to another by air, water, food, or body fluids (or in some cases by insects or other organisms). Compare nontransmissible disease.

nontransmissible disease

Disease that is not caused by living organisms and does not spread from one person to another. Examples include most cancers, diabetes, cardiovascular disease, and malnutrition. Compare transmissible disease.

Summarize concerns over exposure to phosphates.

Exposure of laboratory animals to high doses of various phthalates has caused birth defects and liver cancer, kidney and liver damage, premature breast development, immune system suppression, and abnormal sexual development in these animals

Summarize the three major population growth trends recognized by demographers.

First of all, in recent decades, the rate of population growth has slowed (Figure 6-2), but the world's population is still growing (Figure 6-1) at a rate of about 1.2%. This may not seem like much but in 2012 this growth added about 84 million people to the population—an average of more than 230,000 people each day, or almost 3 more people every second. Second, demographers recognize that, geographically, human population growth is unevenly distributed and this pattern is expected to continue (Figure 6-3). About 2% of the 84 million new arrivals on the planet in 2012 were added to the world's more-developed countries, where population is growing exponentially at about 0.1% a year. The other 98% were added to the world's middle- and low-income, less-developed countries, where the population is growing exponentially, 14 times faster at about 1.4% a year, on average. A third important trend in human population growth is the movement of people from rural areas to cities. More than half of the world's people now live in urban areas, or cities (see chapter-opening photo) and their surrounding suburbs. The great majority of these urban dwellers live in less-developed countries where resources for dealing with rapidly growing populations are limited.

Describe the three phases of urban growth in the United States.

First, people migrated from rural areas to large central cities. In 2012, about 71% of Americans lived in urban areas with at least 50,000 people, and about 54% lived in 51 urban areas with 1 million or more residents (Figure 22-5). Second, many people migrated from large central cities to smaller cities and suburbs. Currently, about half of urban Americans live in the suburbs (Figure 22-2, center photo), nearly a third in central cities, and the rest mostly in rural housing developments beyond suburbs. Third, many people migrated from the North and East to the South and West. Between 1980 and 2009, about 80% of the U.S. population growth occurred in the South and West, especially in states such as Nevada, Colorado, and Florida. This migration slowed in 2010 and 2011.

What are five factors that can cause people to misjudge risks?

Five factors can cause people to see a technology or a product as being more or less risky than experts judge it to be. First is fear. Research going back three decades shows that fear causes people to overestimate risks and to worry more about unusual risks than they do about common, everyday risks. Studies show that people tend to overestimate numbers of deaths caused by tornadoes, floods, fires, homicides, cancer, and terrorist attacks, and to underestimate numbers of deaths from flu, diabetes, asthma, heart attack, stroke, and automobile accidents. The second factor in our estimation of risk is the degree of control we have in a given situation. Most of us have a greater fear of things over which we do not have personal control. For example, some individuals feel safer driving their own car for long distances than traveling the same distance on a plane. But look at the numbers. The risk of dying in a car accident in the United States while using a seatbelt is 1 in 6,070, whereas the risk of dying in a U.S. commercial airliner crash is about 1 in 9 million. The third factor is whether a risk is catastrophic, not chronic. We usually are more frightened by news of catastrophic accidents such as a plane crash than we are of a cause of death such as smoking, which has a much higher death toll spread out over time. Fourth, some people suffer from optimism bias, the belief that risks that apply to other people do not apply to them. While people get upset when they see others driving erratically while talking on a cell phone or text messaging, they may believe that talking on the cell phone or texting does not impair their own driving ability. A fifth factor is that many of the risky things we do are highly pleasurable and give instant gratification, while the potential harm from such activities comes later. Examples are smoking cigarettes, eating lots of ice cream, and getting a tan.

smart growth

Form of urban planning that recognizes that urban growth will occur but uses zoning laws and other tools to prevent sprawl, direct growth to certain areas, protect ecologically sensitive and important lands and waterways, and develop urban areas that are more environmentally sustainable and more enjoyable places to live.

Figure 22-17 Buses Trade-offs

Gives the advantages and disadvantages of relying on buses for transportation

Figure 22-18 Mass Transit Rail Trade-offs

Gives the advantages and disadvantages of relying on mass transit rail for transportation

Figure 22-20 Rapid Rail Trade-offs

Gives the advantages and disadvantages of relying on rapid rail for transportation

urban sprawl

Growth of low-density development on the edges of cities and towns. See smart growth.

pathogen

Living organism that can cause disease in another organism. Examples include bacteria, viruses, and parasites.

demographic transition

Hypothesis that countries, as they become industrialized, have declines in death rates followed by declines in birth rates.

population change

Increase or decrease in the size of a population. It is equal to (Births + Immigration) − (Deaths + Emigration).

Summarize India's efforts to control its population growth.

India is undergoing rapid economic growth, which is expected to accelerate. This not only will help many people in India, but it will also put more pressure on the country's and the earth's natural capital. On the other hand, economic growth may help India to slow its population growth by accelerating its demographic transition.

Figure 17-3 Pathways of Infectious Disease

Infectious Diseases can enter the body through: -Pets -Livestock -Wild Animals -Insects -Food -Water -Air

Figure 22-8 Undesirable Impacts of Urban Sprawl

Land and Biodiversity Land and Biodiversity Condor 36/ Shutterstock.com. Water Water spirit of america/ Shutterstock.com. Energy, Air, and Climate Energy, Air, and Climate ssuaphotos/ Shutterstock.com. Economic Effects Economic Effects ronfromyork, 2009/Used under license from Shutterstock.com. Loss of cropland Loss and fragmentation of forests, grasslands, wetlands, and wildlife habitat Increased use and pollution of surface water and groundwater Increased runoff and flooding Increased energy use and waste Increased emissions of carbon dioxide and other air pollutants Decline of downtown business districts More unemployment in central cities

Describe Malaria

Malaria is caused by a parasite that is spread by the bites of certain mosquito species. It infects and destroys red blood cells, causing intense fever, chills, drenching sweats, severe abdominal pain, vomiting, headaches, and increased susceptibility to other diseases.

What are hormonally active agents (HAAs), what risks do they pose, and how can we reduce these risks?

Molecules of certain pesticides and other synthetic chemicals such as bisphenol A (BPA; Science Focus 17.3) have shapes similar to those of natural hormones. This allows them to attach to molecules of natural hormones and to disrupt the endocrine systems in humans and in some other animals (Concept 17-3). These molecules are called hormonally active agents (HAAs) or endocrine-disrupting chemicals (EDCs).

What are the major advantages and disadvantages of motor vehicles?

Motor vehicles provide mobility and offer a convenient and comfortable way to get from one place to another. For many people, they are symbols of power, sex appeal, social status, and success. Also, much of the world's economy is built on producing motor vehicles and supplying fuel, roads, services, and repairs for them. Despite their important benefits, motor vehicles have many harmful effects on people and the environment. Globally, automobile accidents kill about 1.3 million people a year—an average of nearly 3,600 deaths per day—and injure another 50 million people. They also kill about 50 million wild animals and family pets every year. In the United States, motor vehicle accidents killed 36,200 people in 2012 and injured another 2.2 million, at least 300,000 of them severely. Car accidents have killed more Americans than have all the wars in the country's history. Motor vehicles are the world's largest source of outdoor air pollution, which causes 30,000-60,000 premature deaths per year in the United States, according to the Environmental Protection Agency. They are also the fastest-growing source of climate-changing emissions. Motor vehicles have helped to create urban sprawl and the car commuter culture. At least a third of the world's urban land and half of that in the United States is devoted to roads, parking lots, gasoline stations, and other automobile-related uses. This prompted urban expert Lewis Mumford to suggest that the U.S. national flower should be the concrete cloverleaf

migration

Movement of people into and out of specific geographic areas. Compare emigration and immigration.

fertility rate

Number of children born to an average woman in a population during her lifetime. Compare replacement-level fertility.

infant mortality rate

Number of children born to an average woman in a population during her lifetime. Compare replacement-level fertility.

Describe West Nile virus

One virus that has become prevalent fairly recently is the West Nile virus, which is transmitted to humans by the bite of a common mosquito that gets infected when it feeds on birds that carry the virus. Since 1992 when this virus emerged in the United States, it has spread from coast to coast. According to the CDC, between 1999 and 2012, the West Nile virus caused severe illnesses in nearly 26,000 people and killed more than 1,100 people. Such illnesses include viral encephalitis, an acute infection of the brain and spinal cord, and viral meningitis, an infection in the membranes that cover the brain and spinal cord. In 2012, West Nile virus outbreaks occurred in Europe, Africa, and the United States. The U.S. outbreak was the worst ever recorded. Scientists have not determined the causes for these outbreaks, but some suspect that a long stretch of warm, dry weather in 2012 was a factor. The Culex mosquito that carries the virus reproduces and matures faster in such weather.

Figure 22-15 Transportation Priorities

Shows a hierarchy of transportation means in more-sustainable cities

List four ways to reduce dependence on motor vehicles.

One way to phase in such full-cost pricing, in keeping with one of the social science principles of sustainability (see Figure 1-5), would be to charge a tax or fee on gasoline to cover the estimated harmful costs of driving. Another way to reduce automobile use and urban congestion is to raise parking fees and charge tolls on roads, tunnels, and bridges leading into cities—especially during peak traffic times In Germany, Austria, Italy, Switzerland, and the Netherlands, more than 300 cities have car-sharing networks that provide short-term rental of cars. Portland, Oregon (Core Case Study), was the first U.S. city to develop a car-sharing system. These systems can reduce car ownership and also help to reduce congestion and air pollution. Network members reserve a car in advance or contact the network and are directed to the closest car. They are billed monthly for the time they use a car and the distance they travel. In Berlin, Germany, car sharing has cut car ownership by 75%. According to the Worldwatch Institute, car sharing in Europe has reduced the average driver's emissions by 40-50%. In the United States, car-sharing networks have sprouted on some college campuses and in several cities, and some large car-rental companies have begun renting cars by the hour.

What are three ways to preserve open spaces around a city?

One way to preserve open space outside a city is to draw a boundary around the city and to prohibit urban development outside that boundary. This urban growth boundary approach is used in the U.S. states of Oregon, Washington, and Tennessee. In 1979, Portland, Oregon (Core Case Study), established a strict urban growth boundary, and it worked. Although Portland's population increased by 38% between 1980 and 2011, its urban area expanded by only 2%. Another approach is to surround a large city with a greenbelt—an open area reserved for recreation, sustainable forestry, or other nondestructive uses. In many cases, satellite towns have been built outside these greenbelts. The best of these are self-contained, not sprawling, and are linked to the central city by a public transport system that does minimal damage to the greenbelt. Many cities in western Europe and the Canadian cities of Toronto and Vancouver have used this approach. Greenbelts can provide vital ecosystem services such as absorption of and other air pollutants, which can make urban air more breathable and help to cut a city's contribution to climate change. A more traditional way to preserve large blocks of open space is to create municipal parks. Examples of large urban parks in the United States are Central Park in New York City (Figure 22-22); Golden Gate Park in San Francisco, California; and Grant Park in Chicago, Illinois. Portland, Oregon (Core Case Study), has 288 parks along with trails and natural areas distributed throughout the city that give its citizens easy access to nature and recreational opportunities. Currently, urban forests occupy about 26% of Portland, and the city has plans to increase this to at least 33%.

Figure 17-20 Greatest Threats to Human Health

Shows the annual death tole from various causes

What are PCBs and why are they a threat?

PCBs are a class of more than 200 chlorine-containing organic compounds that are very stable and nonflammable. They exist as oily liquids or solids but, under certain conditions, they can enter the air as a vapor. Between 1929 and 1977, PCBs were widely used as lubricants, hydraulic fluids, and insulators in electrical transformers and capacitors. They also became ingredients in a variety of products including paints, fire retardants in fabrics, preservatives, adhesives, and pesticides. The U.S. Congress banned the domestic production of PCBs in 1977 after research showed that they could cause liver cancer and other cancers in test animals. Studies also showed that pregnant women exposed to PCBs gave birth to underweight babies who eventually suffered permanent neurological damage, sharply lower-than-average IQs, and long-term growth problems.

What are some of the reasons why people live in cities?

People live in urban areas, or cities (Figure 22-2, top), suburbs that spread out around city centers (Figure 22-2, center), and rural areas or villages (Figure 22-2, bottom). Urbanization is the creation and growth of urban and suburban areas. It is measured as the percentage of the people in a country or in the world living in such areas. Urban growth is the rate of increase of urban populations.

dose response curve

Plot of data showing the effects of various doses of a toxic agent on a group of test organisms. See dose, median lethal dose, response.

Explain why the use of the precautionary principle and pollution prevention to deal with health threats from chemicals are controversial.

Pollution prevention is a strategy for implementing the precautionary principle (see Chapter 9). According to this principle, which can be applied to many other problems, when there is substantial preliminary evidence that an activity, technology, or chemical substance can harm humans or the environment, we should take precautionary measures to prevent or reduce such harm, rather than waiting for more conclusive scientific evidence

risk assessment

Process of gathering data and making assumptions to estimate short- and long-term harmful effects on human health or the environment from exposure to hazards associated with the use of a particular product or technology.

family planning

Providing information, clinical services, and contraceptives to help people choose the number and spacing of children they want to have.

urban growth

Rate of growth of an urban population. Compare degree of urbanization.

Figure 17-21 Effects of Poverty

Shows the percentage of the world's population without access to various basic resources

How has the global TFR changed since 1955?

Since 1955 the Crude birth rate (CBR) in developing countries has decreased, following an earlier similar pattern of the developed countries.

What is a neurotoxin and why is methylmercury an especially dangerous one?

Some natural and synthetic chemicals in the environment, called neurotoxins, can harm the human nervous system (brain, spinal cord, and peripheral nerves). Effects can include behavioral changes, learning disabilities and delays, attention deficit disorder, paralysis, and death. Examples of neurotoxins are PCBs, arsenic, lead, and certain pesticides. Methylmercury (Core Case Study) is an especially dangerous neurotoxin because it is so persistent in the environment and it can be biologically magnified in food chains and food webs

death rate

The number of deaths in a population in a certain amount of time

cultural carrying capacity

The limit on population growth that would allow most people in an area or the world to live in reasonable comfort and freedom without impairing the ability of the planet to sustain future generations. Compare carrying capacity.

List three major trends in global urban growth.

Three major trends in urban population dynamics are important for understanding the problems and challenges of urban growth: 1.The percentage of the global population living in urban areas has increased sharply, and this trend is projected to continue. Between 1850 and 2012, the percentage of the world's people living in urban areas increased from 2% to 52% (see chapter-opening photo) and is likely to reach 67% by 2050. Between 2012 and 2050, the world's urban population is projected to grow from 3.6 billion to 6.3 billion. The great majority of these 2.7 billion new urban dwellers will live in less-developed countries. 2.The numbers and sizes of urban areas are mushrooming. In 2012, about 48% of the world's people lived in nearly 850 urban areas with 500,000 or more people (see chapter-opening photo). Also, there were 26 megacities—cities with 10 million or more people—19 of them in less-developed countries (Figure 22-3). Nine of these urban areas are hypercities with more than 20 million people. The largest hypercity is Tokyo, Japan, with 37.1 million—more than the entire population of Canada. Some of the world's megacities and hypercities are merging into vast urban megaregions, each with more than 100 million people. The largest megaregion is the Hong Kong-Shenzhen-Guangzhou region in China with about 120 million people. 3.Poverty is becoming increasingly urbanized, mostly in less-developed countries. The United Nations estimates that at least 1 billion people (almost 3 times the current U.S. population) live in the slums and shantytowns that lie within or around most of the major cities of less-developed countries. This number may triple by 2050.

What are the major advantages of urbanization?

Urbanization has many benefits. From an economic standpoint, cities are centers of economic development, innovation, education, technological advances, social and cultural diversity, and jobs. Urban residents in many parts of the world tend to live longer than do rural residents and to have lower infant mortality and fertility rates. They also have better access to medical care, family planning, education, and social services than do their rural counterparts. Urban areas also have some environmental advantages. Recycling is more economically feasible because of the high concentrations of recyclable materials in urban areas. Concentrating people in cities can help to preserve biodiversity by reducing the stress on wildlife habitats. Multistory apartment and office buildings in central cities require less energy per person to heat and cool them than do single-family homes and smaller office buildings in suburbs. Also, central-city dwellers tend to drive less and rely more on mass transportation, walking, and bicycling. This helps to explain why New York City and many other large U.S. cities have some of the lowest per capita carbon dioxide emissions of all cities.

risk management

Use of risk assessment and other information to determine options and make decisions about reducing or eliminating risks. See risk, risk analysis, risk communication.

Describe Tuberculosis

is an infectious disease usually caused by the bacterium Mycobacterium tuberculosis (MTB). Tuberculosis generally affects the lungs, but can also affect other parts of the body.

Figure 6-14 Problems with Rapid Population Decline

threaten economic growth, labor shortages, less gov revenues, less entrepreneurship, less likelihood for new technology, pensions cut, increasing public deficits,

Give an example of a risk from each of the following: - Biological hazards - Chemical hazards - Physical hazards - Cultural hazards - Lifestyle choices

• Biological hazards from more than 1 ,400 pathogens that can infect humans. A pathogen is an organism that can cause disease in another organism. Examples are bacteria, viruses, parasites, protozoa, and fungi. • Chemical hazards from harmful chemicals in air, water, soil, food, and human-made products. (Core Case study) • Physical hazards such as fire, earthquakes, volcanic eruptions, floods, and storms. • Cultural hazards such as unsafe working conditions, unsafe highways, criminal assault, and poverty. • Lifestyle choices such as smoking, making poor food choices, drinking too much alcohol, and having unsafe sex.

List nine factors that can affect the birth rates and fertility rates.

•importance of children as part of the labor force •urbanization •cost of raising and educating children •educational & employment opportunities •infant mortality rate • average age at marriage • availability of reliable methods of birth control •religious beliefs, tradition, and cultural norms