1. Food and Agriculture
Chapter 15

2. Bellringer

3. 15.1 Feeding the World

4. Section 1: Feeding the World Preview
Old and New Foods
Humans and Nutrition
World Food Problems
Sources of Nutrition
Unequal Distribution
Diets Around the World
Droughts and Famines
The Green Revolution
The Ecology of Food
Food Efficiency

5. Objectives
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

6. Famine
the widespread malnutrition and starvation in an area
due to a shortage of food, usually caused by a catastrophic event.

7. Modern agriculture practices
provide most of the world’s population with enough food to survive.
However, some of these practices can cause environmental damage that eventually makes growing food crops more difficult.

8. Humans and Nutrition
The human body uses food
as a source of energy and
as a source of materials for
building and
maintaining body tissues.

9. Calories
The amount of energy that is available in food is
One Calorie is equal to
1,000 calories or
one kilocalorie.

10. The three major nutrients needed
carbohydrates,
proteins, and
Lipids (fats , steroids)
In addition
smaller amounts of vitamins and minerals to remain healthy.

11. Humans and Nutrition (copy to notes)

12. Malnutrition A disorder of nutrition
results when a person does not consume enough of each of the nutrients that are needed by the human body.
Many forms of malnutrition depending on the diet
Example: Need 8 essential amino acids from proteins.
This is easily done if a variety of foods is eaten.
However, if the only sources of food is corn and rice, which contain protein, but lacks one of the essential amino acids.
Amino acid deficiency can result

13. Sources of Nutrition
Diet
the type and amount of food that a person eats.
A healthy diet
maintains a balance of the right amounts of nutrients, minerals, and vitamins.

14. Food
Grains
produced in the greatest amounts worldwide,
plants of the grass family whose seeds are rich in carbohydrates.
Besides eating grains, most people eat
fruits, vegetables, and smaller amounts of meats, nuts, and other foods that are rich in fats and proteins.

15. Sources of Nutrition

16. Diets Around the World
People worldwide generally
consume the same major nutrients and
eat the same basic kinds of food.
But, diets vary by region.
People in more developed countries
tend to eat more food and
a larger proportion of proteins and fats than people in less developed countries.

17. Diets Around the World

18. The Ecology of Food
As the human population grows,
farmland replaces forests and grasslands.
Feeding everyone while maintaining natural ecosystems becomes increasingly difficult.
Different kinds of agriculture have
different environmental impacts and
different levels of efficiency.

19. Food Efficiency
The efficiency of a given type of agriculture
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 efficiently produces a large amount of food
with little negative impact on the environment.

20. Food Efficiency
On average,
more energy, water, and land are used to produced a Calorie of food from animals than to produce a Calorie of food from plants.
Animals 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 10 percent of the energy from the plants gets stored in the animals.

21. Food Efficiency
Thus, a given area of land can usually produce more food for humans when it is used to grow plants than when it is used to raise animals.

22. The efficiency of raising plants for food is one reason why diets around the world are largely based on plants.
However, meat from animals generally provides more nutrients per gram than most food from plants.

23. Old and New Foods
Researchers hope to improve the efficiency of food production by studying plants and other organisms that have high yield.

24. Yield
is the amount of crops produced per unit area.
Researchers are interested in
organisms that
can thrive in various climates and
do not require large amounts of fertilizer, pesticides, or fresh water.
Some organisms have been a source of food for centuries, while other sources are just being discovered.

25. World Food Problems
Malnourishment occurs because
people simply do not get enough food.
More food is needed each year to feed the world’s growing population.
World food production
has been increasing for decades,
but now food production is not increasing as fast as the human population is increasing.

26. World Food Problems

27. Unequal Distribution
If all the food in the world today were divided equally among the human population,
no one would have quite enough food for good health.
But food is not divided equally,
malnutrition is largely the result of poverty.
Even in the US, many of the poor suffer
Wars and political strife
can also lead to malnutrition because they interrupt transportation systems.

28. Droughts and Famines
A drought
is a prolonged period during which rainfall is below average, and
crops grown without irrigation may produce low yields or fail entirely.
Is more likely to cause famine in places where most food is grown locally.

29. Droughts and Famines
If a drought occurs,
there may be no seed to plant crops the following year.
The effects of a drought can continue for years.

30. People in a given area
can usually survive one crop failure.
They may have saved enough food from previous seasons, or they may have systems for importing food from elsewhere.

31. But several years of drought
cause severe problems for any area of the world.
For example,
after a long drought,
the soil may be less able to support the production of food crops.

32. The Green Revolution
Worldwide, between 1950 and 1970,
increases in crop yields resulted from
the use of new crop varieties and
the application of modern agriculture techniques.
Since the 1950s, the green revolution
has changed the lives of millions of people.
However, also had some negative effects.

33. For example,
Most new varieties of grain
produce large yields only if they receive large amounts of water, fertilizer, and pesticides.
In addition, the machinery, irrigation, and chemicals required by new crop varieties can degrade the soil if they are not used properly.

34. As a result of the overuse of fertilizers & pesticides,
yields from green revolution crops are falling.
The grain production in the U.S. has decreased since 1990,
partly because the amount of water used for irrigation has decreased.

35. In addition, The Green Revolution
a negative impact on subsistence farmers, or farmers who grow only enough food for local use.
Before the green revolution,
subsistence farmers worked most of the world’s farms.
But they could not afford the equipment, water, and chemicals needed to grow new crop varieties.

36. Known
Unknown
Solution
Math Practice

37. Quick Check 15.1

38. Bellringer

39. Section 2: Crops and Soil Preview
Agriculture: Traditional/Modern
Fertile Soil: The Living Earth
Soil Erosion: A Global Problem
Land Degradation
Soil Conservation
Enriching the Soil
Salinization

40. Objectives
Distinguish between traditional and modern agricultural techniques.
Describe fertile soil.
Describe the need for soil conservation.

41. Crops and Soil

42. Arable land
is farmland
limited area of arable land.
Dilemma
As the human population increases,
the amount of arable land per person decreases.

43. Agriculture: Traditional
The basic processes of farming include plowing, fertilization, irrigation, and pest control.
Plows helps
mixing soil nutrients,
loosening soil particles, and
uprooting weeds.
Organic fertilizers, such as manure,
Fields are irrigated by ditches.

44. Agriculture: Modern
The basic processes of farming are now carried out using modern agricultural methods.
powered by fossil fuels
Synthetic chemical fertilizers have replaced manure and plant wastes
A variety of overhead sprinklers and drip systems may be used for irrigation.
Synthetic chemicals are used to kill pests.

45. Fertile Soil:
Supports the growth of healthy plants

46. 6 Basic Layers
Surface liter
Topsoil
Zone of leaching
Subsoil
Rock particles
Bedrock, which is the solid rock from which most soil originally forms.

47. Fertile Soil: The Living Earth

48. Topsoil
surface layer of the soil,
usually richer in organic matter
composed of
living organisms,
rock particles,
water,
air, and
organic matter, such as dead or decomposing organisms.

49. Soil
forms when rock is broken down into smaller and smaller fragments by
wind,
water, and
chemical weathering.
happens when the minerals in rock react chemically with substances to form new materials.
Temperature changes & moisture can cause rock to crack and break apart.
a few centimeters of soil can take hundreds or even thousands of years to form

50. Other processes affected topsoil
the rock particles supply mineral nutrients
Fungi and bacteria decompose dead plants as well as organic debris  nutrients
Earthworms, insects, and other small animals help by
breaking up the soil and
allowing air and water into it.

52. Soil Erosion: A Global Problem
a process in which materials of the Earth’s surface are
Loosened,
dissolved, or
worn away
In the U.S.,
About half of the original topsoil has been lost to erosion in the past 200 years.
Almost all farming methods increase the rate of soil erosion.
and transported from one place to another by a natural agent, such as wind, water, ice, or gravity.

53. Soil Erosion: A Global Problem

54. Land Degradation
Happens when human activity or natural processes damage the land
it can no longer support the local ecosystem.
In areas with dry climates, desertification can occur.
Desertification
A process by which human activities or climatic changes make arid or semiarid areas more desertlike.
is causing some of our arable land to disappear.

55. For example of Land Degradation
In the past, people who
lived in the drier part of the Sahel region in Africa grazed animals,
Lived in the wetter part planted crops. .

56. For example of Land Degradation
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 adequately support the people in the Sahel.

57. But the population in the region has grown
The land is being farmed, grazed, and deforested faster than it can regenerate.
Crops
are planted too frequently and
fallow periods are being shortened or eliminated completely.
As a result, the soil is losing fertility and productivity.

58. But the population in the region has grown
Because of overgrazing,
the land has fewer plants to hold the topsoil in place.
large areas
 desert and
can no longer produce food.

59. Many ways to Conserve Soil
Soil usually erodes downhill,
many techniques are designed to prevent downhill erosion.

60. Many ways to Conserve Soil
For example,
soil-retaining terraces can be build across a hillside.
On gentler slopes, contour plowing, which consists of plowing across the slope of a hill instead of up and down the slope, can be used.

61. Soil Conservation
An even more effective method of plowing is leaving strips of vegetation across the hillside instead of plowing the entire slope.
These strips catch soil and water that run down the hill.

62. No-till Farming
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.
The remains of the first crop hold the soil in place while the new crop develops.
saves time and reduces soil erosion,

63. No-till Farming
Disadvantages
not suited for all crops.
Not good for soil that is too densely packed

64. Enriching the Soil traditionally
Added organic matter would decompose, adding nutrients and improving the soil texture.
However, inorganic fertilizers containing
nitrogen,
phosphorous, &
potassium
Doubles food production
If erosion occurs in areas fertilized with inorganic materials, waterways may become polluted.

65. Enriching the Soil
Over the past 50 years, the use of such inorganic fertilizers has increased rapidly.

66. Enriching the Soil
A modern method
uses both organic and inorganic materials
adds compost and chemical fertilizers to the soil.
Compost
a mixture of decomposing organic matter, such as manure and rotting plants,
used as fertilizer and soil conditioner.

67. Many cities and industries
compost yard and crop wastes.,
sell or give away,
saving costly land fill space.

68. Salinization
The accumulation of salts in the soil
Major problem in places that have
low rainfall and
naturally salty soil.
When water evaporates from irrigated land, salts are left behind.

69. Picture Salinization

70. Salinization
can be slowed if irrigation canals are lined to prevent water from seeping into the soil, or
if the soil is watered heavily to wash out salts.

71. Quick Check 15.2 a

72. Section 2: Crops and Soil Preview, continued
Pest Control
Integrated Pest Management
Pesticides
Engineering a Better Crop
Pesticide Resistance
Human Health Concerns
Implications of Genetic Engineering
Pollution and Persistence
Sustainable Agriculture
Biological Pest Control

73. Objectives 15.2 a
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.

74. Pest Control
Worldwide,
pests destroy about one-third of the world’s potential food harvest.
A pest - any organism
That occurs where it is not wanted or
That occurs in large enough numbers to cause economic damage.
Many types: plants, fungi, insects, & microorganisms.

75. Pesticides
a poison used to destroy pests, such as
insects,
insecticides
rodents,
rodenticides
Weeds;
herbicides.
Pesticides, however, can also harm beneficial plants and insects, wildlife, and even people.

76. Pesticide Resistance
Over time, may make the pest problem worse.
May evolve resistance,
Fact:
More than 500 species of insects have developed resistance to pesticides since the 1940s.

77. Human Health Concerns
Pesticides
are designed to kill organisms,
may also be dangerous to humans.
Cancer rates 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 follow safety guidelines to protect themselves from contact with these chemicals.

78. Pollution and Persistence
A persistent pesticide
does not break down easily or quickly in the environment into harmless chemicals
Will accumulate in the water and soil.
Increases possibility of harming people and other organisms.
Some pesticides have been banned in the United States for decades but can still be detected in the environment.

79. Biological Pest Control
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
pathogens,
plant defenses,
chemicals from plants,
and the disrupting of insect breeding

80. Integrated Pest Management
a modern method of controlling pests
The goal
not to eliminate pest populations
but to reduce pest damage to a level that causes minimal economic damage.
Such programs can include a mix of
farming methods,
biological pest control, and
chemical pest control.

81. Integrated Pest Management
Biological methods
Natural predators, pathogens, and parasites of the pest may be introduced.
Cultivation controls,
such as vacuuming insects off the plants,
Small amounts of insecticides
Last resort,
These insecticides are changed over time to reduce the ability of pests to evolve resistance.

82. Engineering a Better Crop
Genetic engineering
a technology in which the genome of a living cell is modified for medical or industrial use.
Used to transfer desirable traits, such as resistance to certain pests, from one organism to another.
Plants that result from genetic engineering are called genetically modified (GM) plants.

83. Engineering a Better Crop

84. Implications of Genetic Engineering
In the United States, we now eat and use genetically engineered agricultural products everyday.
Many of these products,
have not been fully tested for their environmental impacts.
Some scientists warn that these products will cause problems in the future.

85. Sustainable Agriculture
Farming that conserves natural resources and helps keep the land productive indefinitely
Involves
planting productive,
pest-resistant crop varieties that require little energy,
pesticides,
fertilizer, and
water.

86. Quick Check 15.2

87. Section 3: Animals and Agriculture
Preview
Bellringer
Objectives
Animals and Agriculture
Food from Water
Overharvesting
Aquaculture
Livestock

88. Section 3: Animals and Agriculture
Preview
Ruminants
Poultry

89. Bellringer

90. Objectives
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.

91. Animals and Agriculture
Food from animals has been the basis of life for some human populations for centuries.
Our ancestors obtained animal protein by hunting and fishing. Today, most people get animal protein from domesticated species.
Domesticated describes organisms that have been bred and managed for human use.

92. Food from Water
Because fish are an important food source for humans, the harvesting of fish has become an important industry worldwide.
However, when too many fish are harvested over a long period of time, ecological systems can be damaged.

93. Food from Water
The North Atlantic cod fishery has collapsed because too many fish were harvested over time.

94. Overharvesting
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 no-fishing zones, so that fish populations can recover.

95. Aquaculture
Aquaculture is the raising of aquatic plants and animals for human use or consumption.
Fish and other aquatic organisms provide up to 20 percent of the animal protein consumed worldwide.
Aquaculture may be one solution to the overharvesting of fish and other organisms in the world’s oceans.

96. Aquaculture
Aquaculture is not a new idea.
This practice probably began in China about 4,000 years ago.
Today, China leads the world in using aquaculture to produce freshwater fish.

97. Aquaculture
There are a number of different methods of aquaculture. Among these are
Fish farming
Fish ranching
Fish farms generally consist of many individual ponds that each contain fish at a specific stage of development. Fish grow to maturity in the ponds and are then harvested.
Fish ranches raise fish to a certain age, release them to the ocean, and then harvest the adults when they return to their birthplace to breed.

98. Aquaculture
As with other methods of food production, however, aquaculture can cause environmental damage if not managed properly.
Aquatic organisms can produce a large amount of waste, which can be a source of pollution.
Because aquaculture requires so much water, the process can deplete local water supplies.
Despite these problems, aquaculture will continue to be an important source of protein for the human diet.

99. Livestock
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 changed dramatically in the last 40 years.
Large livestock operations produce most of the meat that is consumed in developed countries.

100. Livestock

101. Livestock
In developing countries, livestock not only provide leather, wool, eggs, and meat, but also serve other functions.
Some livestock are used as draft animals to pull carts and plows.
Other livestock provide manure as the main source of plant fertilizer or as a fuel for cooking.

102. Ruminants
Ruminants are cud-chewing mammals that have a three- or four-chambered stomach.
Cattle, sheep, and goats are examples of ruminants.
Cud 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 convert plant material, such as grass stems and woody shrubs, into food that we can digest—such as beef.

103. Ruminants
Humans have created hundreds of breeds of cattle that are suited to life in different climates.
Worldwide meat production per person has increased significantly since 1950.

104. Poultry
Since 1961, the population of chickens worldwide has increased to a greater percentage than the population of any other livestock.
Chickens are a type of poultry, domesticated birds raised for meat and eggs.
In more-developed countries, chickens and turkeys are usually raised in factory farms.

105. Graphic Organizer

106. Quick Check 15.3