Our bodies need certain vitamins and minerals to stay healthy.
In large amounts, some important vitamins and minerals are needed.
These include sugars and fats.
Micronutrients are needed in smaller amounts.
Micronutrients include vitamins, iron, and minerals.
Hunger occurs when people are deprived of food.
When insufficient calories are taken in, hunger occurs.
Poor nutrition can be a result of an insufficient or poorly balanced diet.
Those who aren't getting enough resources is referred to as undernourished.
There is not enough quantity or quality of food to sustain proper health and growth.
According to the Food and Agriculture Organization, 795 million people on Earth are not getting enough to eat.
The majority of these people are living in developing countries, but 15 million are living in developed nations.
In the United States, 38 percent of adults are considered obese and 2.1 billion people are overweight.
The simplest explanation for hunger is poverty.
Many people don't have the money to buy food or the resources to produce it because our planet produces enough food.
Human communities are trapped in a cycle of poverty, resource degradation and high fertility.
Asia, Africa, and Latin America did not need to import grain from other countries in the first third of the twentieth century.
All of these countries are now having problems with hunger because of their increasing populations.
China, Thailand, and Indonesia are working hard to improve the quality of life for their citizens.
In China, the number of people without enough food and clothing has decreased from 250 million in 1978 to 23.65 million in 2006 as a result of reform and development in rural areas.
The Zero-Hunger Initiative for West Africa, the Asia-Pacific Zero Hunger Challenge, and the Hunger-Free Latin America and the Caribbean Initiative aim to eradicate hunger and achieve food security by 2030.
In his book Mass Starvation: The History and Future of Famine, Alex de Waal states that the majority of famines in modern times are the result of warfare against their own people.
In the United States, one of the richest countries in the world, there are lots of hungry people.
The number of hungry people in the United States is less than it was in 1996 when the World Food Summit was held.
The goal of cutting the number of Americans living in hunger from 30.4 million to 15.2 million by 2010 has not been met.
According to the United States Department of Agriculture, 40.0 million Americans were food-insecure last year.
The USDA uses data from the U.S. Department of Commerce and the U.S. Census Bureau.
A lot of food is wasted.
The "sell by" date can cause food to be thrown out when it's still good to eat.
Fruits and vegetables are thrown away if they are not perfect.
The dumpsters behind the delis and bagel stores are filled with bread at the end of the day, which could have gone to a shelter or food pantry.
The main reason is poverty.
Many neighborhoods in which the majority of the citizens are low-income are called food deserts.
It's difficult to get fresh, healthy food.
The residents rely on low-quality processed foods.
Poverty is caused by lack of education on healthy food choices.
The Personal Responsibility and Work Opportunity Reconciliation Act was passed after a call for welfare reform.
Proponents of the welfare reform believe that people who are able to work should be encouraged to find employment so that they don't rely on government assistance.
The act limited the number of people who qualified for food stamps and the duration that people could receive food stamps.
At the time, it was generally agreed that welfare reform was necessary, but now many families are reaching their deadline for public assistance.
It will be important for state and local groups to find ways to support the truly needy since the implementation of this act.
In the United States, there are a number of charitable agencies that provide food to those in need.
Feeding America makes use of food that would otherwise go to waste.
Feeding America distributes food from food processors and distributors to food banks.
45 million Americans are fed each year by the organization.
While social reform is a viable solution to the problem of hunger in the United States, often the only solution in developing countries is to enable communities to become self-sufficient in food procurement.
These communities need monetary resources that will allow them to purchase food supplies or resources that will allow them to produce their own food.
Many countries can't feed their citizens because they can't produce the food they need.
Providing monetary resources to people so they can purchase food is not a viable solution in these cases.
The policies of international trade are controlled by the WTO.
The strong nations of the world have more sway over the creation of policies by the WTO.
It is difficult for developing nations to enter the world market because of trade policies.
Many of the poor countries have corrupt governments that prevent the distribution of food aid to their own citizens.
Developing countries have a trade problem with developed nations.
National resources have been degraded in an effort to reduce the national debt.
The people in poverty have nothing to export except labor.
Companies in the United States and other developed nations are outsourcing jobs to developing countries.
Many Americans are appalled at the terrible conditions under which these overseas laborers work.
The competition between poor communities to get contracts with companies overseas is fierce because of continued poverty.
The majority of humans live in small communities and large urban centers.
Humans have lived in large centralized communities since the development of ancient civilizations.
Rome is in Italy and Athens is in Greece.
The world's urban centers have grown as quickly as they have.
Before the Civil War, only 15 percent of the population lived in a city.
Around 50 percent of the total population of the United States was encompassed by that number around the time of World War I, and today it is around 75 percent.
Almost half of the world's population lives in an urban area.
In the United States, this is partly due to the fact that our aging population has largely moved into the cities to have greater access to health services, employment opportunities, and cultural activities.
Satellite communities, or suburbs, are also considered when considering those who live in urban areas.
Lower oil prices have made it easier for people to commute to and from their jobs in cars, which has led to more people moving out of city centers.
The people who live in the suburbs occupy more space than the people who live in the city.
People who live in the suburbs have their own land space, which they don't need to share with others.
The term urban sprawl refers to the emigration of people out of the city into the suburbs.
Urban sprawl takes over a lot of land in the United States.
It is difficult to determine where the Denver metro area ends and the city of Boulder begins when you travel between the two cities.
Distribution of water to all citizens becomes more difficult when urban areas grow too large.
More people means more water use.
Water shortages have led to the implementation of restrictions on water usage.
What to do with all of the waste that's been created is one of the problems that comes from the increase in the population of cities.
When you think about it, most human activities create waste when you go to your local coffee shop.
There is a lot of garbage.
There are abandoned factories in urban areas.
These are called brownfields.
There is a chance that the soil and water are contaminated.
While many people find the suburbs pleasant places to live, ecologists and city planners have recently come to realize that this urban sprawl may reduce quality of life for all urban dwellers.
Policy-makers and citizens in metro areas are concerned about transportation.
If people were encouraged to use mass transit or participate in carpools, they would be less likely to use personal vehicles.
Reducing the number of cars on the road makes for less congestion on the roads.
Electric bikes, motor scooters, and bicycles are some of the "green" modes of transportation.
When there are enough people who will pay to use subway systems, they are cost-effective, even though they are extremely expensive to develop.
Both large and small cities have city buses.
Fleets of buses are less expensive than subways to create and maintain, and they decrease congestion by accommodating more people per vehicle.
Many cities have buses that are hybrid.
Rapid-rail or light rail systems are more common in Japan and Western Europe than in the United States, but as of recently they're being considered as an option for cities that don't have subways.
Rapid rail systems work by magnetic levitation; suspended above a track, a train moves along as a result of strong attractive and repulsive magnetic forces.
In order for cities to be sustainable, planners and developers need to build and manage cities to work with and within their natural settings.
Some cities in the United States and elsewhere in the world are setting examples of progressive thinking in the field of ecology.
The city of Boulder, Colorado, has been recognized for its green policies.
Cyclists can move freely from one area of the community to another on the bicycle paths.
People can commute to work without using their cars and create more emissions by using buses in and out of Denver.
The city provides parking areas for people who drive to work.
The city's strong recycling programs help reduce the amount of material added to landfills.
The city has open spaces that can be used for recreation.
These areas are leased to local ranchers.
Curitiba, Brazil, and Portland, Oregon have been held up as models for city planning.
There is an excellent mass transit system in Curitiba.
The city provides a variety of services to its citizens.
In the 70s, the state of Oregon became determined to head off urban sprawl, and the city of Portland established restrictive growth policies for urban areas that were adopted statewide.
The city encouraged developers to invest in established neighborhoods.
Metro is a regional body that deals with land use, city planning, and the development of natural areas.
Metro began to encourage neighborhood self-sufficiency in order to keep the number of people who need to commute for food or other supplies to a minimum.
As a result of urban sprawl, it will be important for city planners to deal with new problems in the future.
Providing green spaces, transportation alternatives, and planning for the supply of water are all new challenges for those involved in building cities.
Since 1960, urban populations have risen by 20%.
The global urban population is expected to grow by 1.84 percent per year until 2020.
We've made it sound like the cities of the world are doing well with the boom in population, but this is not the case.
Some megacities have grown to over 10 million people.
The increase in the population size of major cities has negative effects in less developed countries.
A lack of housing for the growing population is one of the worst effects.
People are homeless, become "squatters," or make their homes in areas with no water, electricity, or stable housing.
Some of the reasons people in less developed countries are moving to cities are similar to the reasons people in developed countries are moving to cities.
War, religious or cultural persecution, or the degradation of their environment are some of the reasons why these people leave the country.
The ecological footprint is a concept that you should be familiar with.
An ecological footprint is a description of the environmental impact of a population.
It is defined as the amount of Earth's surface that is necessary to provide the needs of a particular population or individual.
Americans have one of the largest ecological footprints.
About 2.5 acres is 10,000 square meters.
The ecological footprint of Indonesia is only 1.1 hectares per capita.
A lot of affluent people have a higher ecological footprint than other people.
A mathematical model can be used to describe the impact humans have on the environment.
I is the total impact, P is population size, A is affluence, and T is level of technology.
It's a good idea to know that this formula exists and that the variables of a population's size, affluence, and level of technology all influence its environmental impact, even if you won't be asked to use it to calculate the impact of populations on the exam.
Over the past 500 million years, there have been five major extinction events, during which a significant percentage of all life on Earth, life in the oceans included, was wiped out.
The asteroid impact 65 million years ago near the present-day Yucatan Peninsula eliminated the dinosaurs and other large reptiles, leaving niches that were quickly filled by mammals through radiative adaptation.
Through evolutionary forces of natural selection, a species rapidly diversifies into new species to take advantage of newly freed up resources.
There is a lesson to be learned from this information that life on Earth is very adaptive.
Humans are stressing the planet and may cause it to be uninhabitable for our species.
Life will continue.
Humans impact Earth through their interaction with animals.
The extinction of many species has been caused by human activities.
The status of plant and animal species is evaluated by the International Union for Conservation of Nature.
If a species is under a high risk of extinction, if it is likely to become extinct, and if no action is taken, it is vulnerable.
Any species assigned to one of the three categorizations is considered a threatened species.
The Red List of Threatened Species is updated regularly.
There were over 10,000 threatened species in 2000.
This number has grown over the course of the year.
There have been extinctions in Earth's history.
The background extinction rate is a natural rate of extinction.
Knowledgeable scientists estimate that the current extinction rate is between 50 and 500 times higher than in the past.
The tropics are home to isolated small populations that are especially vulnerable to both natural and human-caused changes to their environments, so the rates of extinction there are high.
The species that are most vulnerable have several factors in common: they need large ranges of habitat to survive, have low reproductive rates, have specialized feeding habits, and have low population numbers.
Humans play a major role in the extinction of species because of our destruction of habitats.
Slash-and-burn farming is one of the destructive practices that people use because of poverty and rapid population growth.
When we build roads or cities, habitats are lost or fragmented, which may prevent the free movement of a species to find mates or escape danger, or it may reduce the area a species has for all the activities of its life cycle below a critical threshold.
Adding pollutants to the environment causes habitat degradation.
Invasive species and direct hunting are some of the factors that can contribute to extinction.
The term "biodiversity hot spot" was created by Dr. Norman Myers to describe a region that has lost 70% of its natural habitat due to threats.
There are things we can do.
Reducing the demand that destroys habitats is achieved by living sustainable and conserving resources.
It is against the law to trade in specific organisms.
We can help organisms on a species-by-species basis.
Zoos and other institutions have captive breeding programs in which species are bred under human control until their populations are high enough to be reintroduced into the wild.
Large tracts of land can be set aside and protected from human activity to conserve habitats.
In protected habitats, organisms can find their niches and survive.
National parks and animal sanctuaries are examples of protected habitats.
Many United States laws have been passed to reduce the rate of extinctions.
The human factors that can cause extinction are listed in the acronym HIPPCO.
You're ready for the key terms review and the following drills.
As you go through them, remember to use our techniques.
You can spout these terms in your sleep if you know them backwards and forwards.
You can download a PDF of Chapter 6 Drill.
Four suggested answers or completions are followed by each of the questions or incomplete statements.
Pick the one that is the best.
Chapter 13 has answers and explanations.
The population has a growth rate.
Limits on the growth of populations and their consumption of resources are imposed by a habitat's carrying capacity.
There are two examples of how carrying capacity can affect a population.
There are two examples of how nature slows down the consumption of natural resources by a population.