Chapter 15 Section 1- Feeding the World

Identify the major causes of malnutrition. Compare the environmental costs of producing different types of food. Explain how food distribution problems and drought can lead to famine. Explain the importance of the green revolution.

Feeding the World ____________________________ is the widespread malnutrition and starvation in an

area due to a shortage of food, usually caused by a catastrophic event. Modern agriculture practices provide most of the world’s population with enough food to

survive. However, some of these practices can cause

_____________________________________________ that eventually makes growing food crops more difficult.

Humans and NutritionThe human body uses food both as a source of ____________________________ and as a source of ______________________ for building and maintaining body tissues.

The amount of energy that is available in food is expressed in ______________________________.

The major nutrients we get from food are _________________________________, ________________________________, and _______________________________. Our bodies need smaller amounts of _______________________________ and _____________________________ to remain healthy.

_________________________________________is a disorder of nutrition that results when a person does not consume enough of each of the nutrients that are needed by the human body.

There are many forms of malnutrition. For example, humans need to get 8 _______________________________ ______________________________________ from proteins. This is easily done if a variety of foods is eaten. However, in some parts of the world, the only sources of food may be corn and rice, which contain protein, but lacks one of the essential amino acids. ________________________________________________

can result from such a limited diet

Sources of Nutrition _________________________is the type and amount of food that a person eats. A

healthy diet is one that maintains a balance of the right amounts of nutrients, minerals, and vitamins.

The foods produced in the greatest amounts worldwide are _____________________________, plants of the grass family whose seeds are rich in ____________________________________________.

Besides eating grains, most people eat fruits, vegetables, and smaller amounts of meats, nuts, and other foods that are rich in _____________________________ and _____________________________.

Diets Around the World People worldwide generally consume the same major nutrients and eat the same

_______________________ __________________________________________. But, diets vary by region. People in more developed countries tend to ______________________________ food

and a _______________________ ____________________________________ of proteins and fats than people in less developed countries.

The Ecology of Food As the human population grows,

______________________________________________________________________________.

Feeding everyone while maintaining natural ecosystems becomes increasingly difficult. Different kinds of agriculture have different

_______________________________________________________ and different ________________________________________________________________.

Food Efficiency The ________________________________ of a given type of agriculture is a measure of the

quantity of food produced on a given area of land with limited inputs of energy and resources.

An ideal food crop is one that _______________________________________________________________________________ ________________________________________________________________________.

• On average, more energy, water, and land are used to produced a Calorie of food ________________________________ than to produce a Calorie of food _________________________.

• _____________________________ that are raised for human use are usually fed plant matter, but because less energy is available at each level on a food chain, only about _________ __________________________________from the plants gets stored in the animals.

• Thus, a given area of land can usually produce more food for humans when it is used ______________________________________________ than when it is used to _______________________ _________________________.

• The efficiency of raising plants for food is one reason why diets around the world are ___________________________________________________________________.

• However, meat from animals generally provides _________________________________________ per gram than most food from plants.

Old and New Foods• Researchers hope to improve ______________________________________________________________

by studying plants and other organisms that have high yield.• ______________________________ is the amount of crops produced per unit area.• Researchers are interested in organisms that can thrive in various climates and that

do not require large amounts of ____________________________, ___________________________ or _________________________________________. Some organisms have been a source of food for centuries, while other sources are just being ______________________________.

World Food Problems• Some people become malnourished because they _______________________________________

_________________________________________. • More food is needed each year to feed the world’s _________________________ population.• World food production has been increasing for decades, but now food production is

________________________________________________________________________________________________.

Unequal Distribution• If all the food in the world today were divided equally among the human population,

__________________________ would have quite enough food for good health.• But food is not divided equally, and malnutrition is largely the result of

______________________. Even in the United States, many poor people suffer from ___________________________________________.

• ____________________ and _______________________________________ can also lead to malnutrition because they interrupt transportation systems.

Droughts and Famines• A ____________________________ is a prolonged period during which rainfall is below

average, and crops grown without ____________________________________ may produce low yields or fail entirely.

• A drought is more likely to cause famine in places where _______________________________ __________________________.

• If a drought occurs, there may be _______________________________ to plant crops the following year. The effects of a drought can continue _______________________________.

• People in a given area can usually survive one crop failure. They may have ___________ _______________________________from previous seasons, or they may have systems for __________________________________________________ from elsewhere.

• But several years of drought ________________________________________________________ for any area of the world.

• For example, after a long drought, the soil may be _______________________________________ the production of food crops.

The Green Revolution

• Worldwide, between _______________ and _______________, increases in crop yields resulted from the use of __________________________________________________________ and ________________________________________________________________________________________.

• These changes were called the ____________________________________. Since the 1950s, the green revolution has changed the lives of millions of people.

• However, the green revolution also had some ____________________________ effects.• For example, most new varieties of grain produce ________________________________ only

if they receive _____________________________________, _______________________________, and ____________________. In addition, the machinery, irrigation, and chemicals required by new crop varieties can ________________________________________________ if they are not used properly.

• As a result of the ___________________________ of fertilizers and pesticides, yields from green revolution crops are __________________________. The grain production in the U.S. has decreased since 1990, partly because the amount of _______________________________ _________________________________ has decreased.

• In addition, the green revolution had a negative impact on _____________________________ __________________________, or farmers who grow only enough food for local use.

• Before the green revolution, subsistence farmers worked ______________ of the world’s farms.

• But they ________________________________________ the equipment, water, ad chemicals needed to grow new crop varieties.

•

Chapter 15 Section 2: Crops and Soil• Distinguish between traditional and modern agricultural techniques.• Describe fertile soil.• Describe the need for soil conservation.• Explain the benefits and environmental impacts of pesticide use.• Explain what is involved in integrated pest management.• Explain how genetic engineering is used in agriculture.

Crops and Soil• ____________________________________ is farmland that can be used to grow crops.• The Earth has only a _______________________________________________ of arable land.• But, as the human population continues to _______________________, the amount of

arable land per person _______________________________.

Agriculture: Traditional• The basic processes of farming include

• ____________________________• ____________________________• ____________________________ &• _____________________________

• Traditionally, ____________________ are pushed by the farmers or pulled by livestock. Plowing helps crops grow by ____________________________________________________________ _______________________________________________________________________________. Organic fertilizers, such as manure, are used to _________________________. While fields are __________________________________ by water flowing through ditches.

• These traditional techniques have been used since the earliest days of _____________________.

Agriculture: Modern• In most ________________________________countries, the basic processes of farming are

now carried out using modern agricultural methods.• ____________________________ powered by __________________________________________ is now

used to plow the soil and harvest crops. Synthetic _____________________________________ ____________________ have replaced manure and plant wastes to fertilize soil.

• A variety of overhead sprinklers and drip systems may be used for irrigation. And synthetic ______________________________________________________________________________.

Fertile Soil: The Living Earth• Soil that can support the growth of healthy plants is called _______________________soil.• _________________________________ is the surface layer of the soil, which is usually

_________________________ in organic matter than the subsoil is.• Fertile topsoil is composed of :

• ______________________________________

• ______________________________________• ______________________________________• ______________________________________• ______________________________________ such as __________________________________________

• Several layers of soil lie under the topsoil. The bottom layer is __________________________, which is the solid rock from which most soil originally forms.

• Most soil forms when rock is broken down into smaller and smaller fragments by ____________________, ___________________________, and _________________________________________. ________________________________________________ happens when the minerals in rock react chemically with substances to form new materials. Temperature changes and moisture can also cause rock to ____________________________________________________.

• It can take _____________________________________________________________ years for these geological processes to form a _____________________________________________________ of soil.

• Other processes also help to produce fertile topsoil. For example, the rock particles supply __________________________________________________ to the soil.

• Fungi and bacteria live in the soil, and they _____________________________ dead plants as well as organic debris and __________________________________________________ to the soil.

• Earthworms, insects, and other small animals help plants grow by ____________________ _______________ the soil and allowing air and water into it.

Soil Erosion: A Global Problem• ____________________________ is a process in which the materials of the Earth’s surface

are loosened, dissolved, or worn away and transported from one place to another by a natural agent, such as wind, water, ice, or gravity.

• In the U.S., ______________________________ of the original topsoil has been lost to erosion in the past 200 years.

• Without topsoil, crops cannot be grown. Yet, _____________________________________________ ______________________________________________________________________________________________.

Land Degradation

• ____________________________________________ happens when human activity or natural processes _____________________________________________ so that it can no longer support the local ecosystem. In areas with dry climates, desertification can occur.

• __________________________________________ is the process by which human activities or climatic changes make arid or semiarid areas more desert-like.

• This process is causing some of our __________________________________ to disappear.

• For example, in the past, people who lived in the drier part of the _______________ ___________________________________ grazed animals, while people in the wetter part of the region planted crops.The grazing animals were moved from place to place to find fresh grass. The cropland was planted for only a few years, and then allowed to lie fallow, or to remain unplanted, for several years.

• These methods allowed the land to ______________________________________________ the people in the Sahel.

• But the population in the region has _______________________, and the land is being farmed, grazed, and deforested faster than it can ________________________________. Crops are planted too frequently and fallow periods are being shortened or eliminated completely.

• As a result, the soil is losing _________________________________________________________. Because of overgrazing, the land has fewer plants to _____________________________ in place.

• So, large areas have become ___________________ and can no longer produce food.

Soil Conservation• There are many ways of ___________________________ and _________________________________

topsoil and ______________________________________ erosion. • Soil usually erodes downhill, and many soil conservation methods are designed to

prevent ________________________________erosion. • For example, soil-retaining ___________________________ can be build across a hillside. On

gentler slopes, _______________________________________, which consists of plowing across the slope of a hill instead of up and down the slope, can be used.

• An even more effective method of plowing is ____________________________________________ across the hillside instead of plowing the entire slope.

• These strips catch soil and water that run down the hill.• Still, many areas of land that have hills are not suited to farming, but may be better

used as __________________________________________________.• In ___________________________________________, a crop is harvested without turning the soil

over, as in traditional farming.• Later, the seeds of the next crop are planted among the remains of the previous

crop. __________________________________________________________________________________________. • Although this method saves time and reduces soil erosion, it is not suited for all

crops. Other disadvantages include soil that is ___________________________________________ and lower crop yields over time.

Enriching the Soil• Soil was traditionally fertilized by adding organic matter that would decompose,

_________________________________ to the soil and improving the soil ____________________.• However, _______________________________________________ that contain nitrogen,

phosphorous, and potassium have changed farming methods. Without them, world food production would be less than half of what it is today.

• If erosion occurs in areas fertilized with inorganic materials, ___________________________ __________________________________________

• A modern method of enhancing the soil is to use both organic and inorganic materials by _____________________ and ___________________________________________ to the soil.

• ______________________________ is a mixture of decomposing organic matter, such as manure and rotting plants, that is used as fertilizer and soil conditioner.

• Many cities and industries now compost yard and crop wastes. This compost is then sold to farmers and gardeners, and the process __________________________________________.

Salinization• The accumulation of salts in the soil is known as ____________________________________.• Salinization is a major problem in places that have low rainfall and naturally salty

soil.• When water ________________________________ from irrigated land, ________________________

are left behind.• Salinization can be slowed if _____________________________________________________ are lined

to prevent water from seeping into the soil, or if the soil is watered heavily to wash out salts.

Pest Control• Worldwide, pests destroy about ________________ of the world’s potential food harvest.• A _______________________ is any organism that occurs where it is not wanted or that

occurs in large enough numbers to cause economic damage.• Humans try to control populations of many types of pests, including

• _______________________________• _______________________________• _______________________________• _______________________________

Pesticides• Many farmers rely on pesticides to produce their crops.• A __________________________________ is a poison used to destroy pests, such as insects,

rodents, or weeds; examples include insecticides, rodenticides, and herbicides.• Pesticides, however, can also harm beneficial plants and insects, wildlife, and even

people.

Pesticide Resistance• Over time, spraying large amounts of pesticide to get rid of pests usually makes the

pest problem _________________________.• Pest populations may evolve ____________________________________, the ability to survive

exposure to a particular pesticide.• More than _______________________ species of insects have developed resistance to

pesticides since the 1940s.

Human Health Concerns• Pesticides are designed to kill organisms, so they may also be __________________________

to humans.• ________________________________________ among children in areas where large amounts of

pesticides are used on crops are sometimes higher than the national average.• People who apply pesticides need to __________________________________________________ to

protect themselves from contact with these chemicals.

Pollution and Persistence• The problem of pesticides harming people and other organisms is especially serious

with pesticides that are persistent.• A pesticide is _____________________________________if it does not break down easily or

quickly in the environment.• Persistent pesticides do not break down into harmless chemicals, and they

_____________________________________________________________________.• Some pesticides have been ________________________ in the United States for decades but

can still be __________________________________ in the environment.

Biological Pest Control• ________________________________________________________ is the use of certain organisms by

humans to eliminate or control pests.• Every pest has enemies in the wild, and these enemies can sometimes be used to

control pest populations.• Biological pest control includes the use of

• ________________________________,• ________________________________• ________________________________• _________________________________________________

Integrated Pest Management• Integrated pest management is a modern method of controlling pests on crops.• The goal of integrated pest management is not to ________________________________________

but to _____________________________________________ to a level that causes minimal economic damage.

• Such programs can include _________________________________________________________________ ______________________________________________________________________________________________.

• __________________________________________ are the first methods used to control the pest. So, natural predators, pathogens, and parasites of the pest may be introduced.

• __________________________________________, such as vacuuming insects off the plants, can also be used.

• As a last resort, small amounts of ________________________________________ may be used. These insecticides are changed over time to reduce the ability of pests to evolve resistance.

Engineering a Better Crop• ______________________________________________ is a technology in which the genome of a

living cell is modified for medical or industrial use.• Scientists may use genetic engineering to ________________________________________________,

such as resistance to certain pests, from one organism to another.• Plants that result from genetic engineering are called

____________________________________ (GM) plants.

Implications of Genetic Engineering• In the United States, we now ___________________________________ genetically engineered

agricultural products everyday.• Many of these products, however, have not been ________________________________________

for their environmental impacts.• Some scientists warn that these products will cause problems _________________________.

Sustainable Agriculture• Farming that conserves natural resources and helps keep the land productive

indefinitely is called _____________________________________________________________.• Sustainable agriculture involves planting productive, pest-resistant crop varieties

that require _________________________, _________________________________, _____________________, and ___________________________.

Chapter 15 Section 3: Animals and Agriculture• Explain how overharvesting affects the supply of aquatic organisms used for food.• Describe the current role of aquaculture in providing seafood.• Describe the importance of livestock in providing food and other products.

Animals and Agriculture• Food from animals has been the basis of life for some human populations for

_______________________________• Our ancestors obtained animal protein by ___________________________________________.

Today, most people get animal protein from ____________________________________ species.• ____________________________________ describes organisms that have been bred and

managed for human use.

Food from Water• Because fish are an important food source for humans, the _____________________________

has become an important industry worldwide.• However, when too many fish are harvested over a long period of time,

________________________________________________can be damaged.

Overharvesting• _________________________________________ is the catching or removing from a population

more organisms than the population can replace.• Many governments are now trying to stop overharvesting. They have created _______

__________________________________, so that fish populations can recover.

Aquaculture• ____________________________________ is the raising of aquatic plants and animals for

human use or consumption.• Fish and other aquatic organisms provide up to ___________________ of the animal

protein consumed worldwide.• Aquaculture may be ________________________________ to the overharvesting of fish and

other organisms in the world’s oceans.• _________________________________ is not a new idea.• This practice probably began in ________________________________________ years ago.• Today, China leads the world in using aquaculture to produce _________________________.• There are a number of different methods of aquaculture. Among these are

• _______________________________• _______________________________

• Fish farms generally consist of many individual ponds that each contain fish at a specific stage of development. Fish ______________________________________________________ _____________________________________________________________________________________________.

• Fish ranches _________________________________________________________________________________

_________________________________________________________________________________________________ • As with other methods of food production, however, aquaculture can cause

environmental damage if not _______________________________________________________.• Aquatic organisms can produce a large amount of _______________________, which can be

a source of ___________________________.• Because aquaculture requires so much water, the process ______________________________

local water supplies.• Despite these problems, aquaculture will continue to be an important source of

___________________________ for the human diet.

Livestock• ______________________________ is the term given to domesticated animals that are raised

to be used on a farm or ranch or to be sold for profit.• Populations of livestock have ________________________________________ in the last 40 years.• ________________________________________________ produce most of the meat that is

consumed in developed countries.• In __________________________________ countries, livestock not only provide leather, wool,

eggs, and meat, but also serve other functions.• Some livestock are used as ___________________________________ to pull carts and plows.• Other livestock provide manure as the main source of __________________________________

or as a ______________________for cooking.

Ruminants• _____________________________________ are cud-chewing mammals that have a three- or

four-chambered stomach.• __________________________, • __________________________, and • _________________________ are examples of ruminants.

• _______________ is the food that these animals regurgitate from the first chamber of their stomachs and chew again to aid digestion.

• When we eat the meat of ruminants, we are using them to ______________________________ ______________________________, such as grass stems and woody shrubs, into _______________ __________________________________—such as beef.

• Humans have created hundreds of ____________________________________________ that are suited to life in different climates.

• Worldwide meat production per person has ______________________________________________ since 1950.

Poultry• Since 1961, the population of chickens worldwide has _____________________________ to a

greater percentage than the population of ________________________________________________.

• Chickens are a type of __________________________, domesticated birds raised for meat and eggs.

• In more-developed countries, chickens and turkeys are usually raised in _________________________________________________

Chapter 15 Study Questions

1. What is a major cause of famine in the world today?

2. What is the main difference between fertile and infertile soil?

3. What is the eventual result of land degradation?

4. Which is an effect of soil erosion?

5. In what year did the total amount of grain production equal the average amount of grain per person?

6. What is the main reason that, while total grain production has increased each year, the amount of grain per person has been relatively steady?

7. If the trend that was in place from 1990–1995 continues through 2005, what will be the average amount of grain available per person?

Bees Help Feed the World

Bees pollinate more species of plants than any other animal. Today there are more than 20,000 species of bees around the world. The most familiar species is the European honeybee, Apis mellifera, which was imported to the United States in the 1600s. Beekeepers raise European honeybees to collect the honey they produce. The bees also benefit farmers by pollinating crop plants. Wild and beekeeper-raised honeybees pollinate more than 90 kinds of cultivated crops, which are worth $10 billion a year.

Decline in Honeybees

In the 1990s, the population of beekeeper-raised honeybees decreased by 25 percent in the United States. Many bees were killed by diseases or parasites. Pesticides used by farmers and home gardeners kill bees as well as pests. Honeybees continue to lose food sources as native plant habitat is replaced with buildings and parking lots.

Blue Orchard Bees

Farmers are turning to other species of bees to pollinate their crops. One such species is the blue orchard bee, Osmia lignaria, which is native to much of western North America. Blue orchard bees are more efficient pollinators than honeybees. Unlike honeybees, they will visit flowers under cloudy skies, in a light drizzle, and in colder weather. Also, blue orchard bees tend to move from tree to tree, while honeybees tend to stay in one tree. Therefore, blue orchard bees are better pollinators of trees that must be cross-pollinated, such as fruit trees. As a result, about 600 blue orchard bees can pollinate a 1 hectare (2.5 acre) apple orchard that it would take as many as 50,000 European honeybees to pollinate.

1. Which Species of bee is most familiar? ____________________________________________________2. Is it native to the U.S.? if not, where is it from? And when did it arrive here? _________

________________________________________________________________________________________________3. What are the two main reasons beekeepers raise bees? _________________________________

_________________________________________________________________________________________________4. Just how “busy” are the bees? ______________________________________________________________5. When did the bees start to decline? By how much? ______________________________________6. List 4 things leading to the decline of the bees. a. ____________________ b. ________________

c. _________________________d. __________________________________________________________________7. Which bee species may help replace the European honeybee? _________________________8. Is it native to the U.S.? If so, from where? _________________________________________________9. List differences between European honeybees and blue orchard bees

a. active weather _____________________________________________________________________________

b. tree movement ____________________________________________________________________________10. How successful are blue orchard bees compared to European Honeybees?