Lecture Outlines - APES · © 2011 Pearson Education, Inc. Lecture Outlines Chapter 10 Environment:...

© 2011 Pearson Education, Inc.

Lecture Outlines

Chapter 10

Environment:The Science behind the

Stories

4th Edition

Withgott/Brennan


This lecture will help you understand:

• Challenges of feeding a growing human population

• The Green Revolution • Preserving crop diversity• Strategies of pest management• Pollination• Genetically modified food• Feedlot agriculture• Aquaculture• Sustainable agriculture


Transgenic maize in Southern Mexico

• Corn (maize) originated in Mexico 9,000 years ago

• In 2001, genes from genetically modified corn appeared in traditional maize

• These transgenes (genes from another species) came from U.S. corn

• Could contaminate native crops

• The agrobiotech industry questioned these findings


Today, we are producing more food per person

• Food production exceeds population growth• We produce food through technology

- Fossil fuels, irrigation, fertilizer, pesticides, cultivating more land, genetic engineering

• Today, soils are in decline and most arable land is already farmed

By 2050, we will have to feed 9 billion people


Undernutrition and food security

• 1 billion people do not have enough to eat• Undernutrition = people receive fewer calories than

their minimum requirements - Due to economics, politics, conflict, and

inefficiencies in distribution• Most undernourished live in developing nations

- But 36 million Americans are “food insecure”• Food security = guarantee of an adequate, safe,

nutritious, and reliable food supply


Food security

• Undernutrition decreased between 1970 and 1990• Higher food prices (2006–2008) and the economic

slump (2008–2009) increased the number and percent of hungry

15% of the world’s population is hungry


Overnutrition and malnutrition

• Overnutrition = receiving too many calories each day- Developed countries have abundant, cheap junk

food, and people lead sedentary lives- In the U.S., 25% of adults are obese- Worldwide, over 400 million people are obese

• Malnutrition = a shortage of nutrients the body needs- The diet lacks adequate vitamins and minerals - Can lead to diseases


Malnutrition can lead to diseases

• Kwashiorkor = diet lacks protein or essential amino acids- Occurs when children stop

breast-feeding- Bloated stomach, mental and

physical disabilities• Marasmus = protein deficiency

and insufficient calories - Wasting or shriveling of the

body


The Green Revolution increased yields

• Spread to the developing world in the 1940s - Wheat, rice, corn

• Depended on lots of:- Synthetic fertilizers - Chemical pesticides - Irrigation- Machinery

Norman Borlaug won the Nobel Peace Prize for his work


Consequences of the Green Revolution

• From 1900 to 2000, cultivated area increased 33%- While energy inputs increased 80 times

• Positive effects on the environment- Prevented some deforestation and land conversion- Preserved biodiversity and ecosystems

• Negative effects on natural resources - Pollution, erosion- Salinization, desertification


The Green Revolution • Intensified agriculture saved millions from starvation

- Turning India into a grain exporter• Rich farmers with lots of land benefited

- Poor farmers were driven off the land into cities

Today, yields are declining in some Green Revolution areas


Monocultures increase output, but at a cost• Monoculture = large expanses of a single crop

- More efficient, increases output- Devastates biodiversity- Susceptible to disease and pests

• Human diet is narrowed: 90% of our food comes from 15 crop and 8 livestock species

Armyworms easily destroy monocultures


Biofuels affect food supplies

• Biofuels = are derived from organic materials- Replace petroleum in engines

• Ethanol = a biofuel derived from corn- 2007 subsidies doubled production

• Food prices increased - Farmers sold corn for ethanol, not food- Farmers planted biofuels, not food crops- Riots erupted in many nations


Preserving crop diversity: insurance against failure• Preserving native variants protects against crop failure• Monocultures are vulnerable

- Wild relatives contain genes that can provide resistance to disease and pests

- But Mexico has lifted its ban on transgenic corn• We have lost a great deal of genetic diversity in crops

- U.S. crops have decreased 90% in diversity• Market forces discourage diversity in food’s appearance

- Food producers prefer uniform, standardized food


Seed banks are living museums• Seed banks = institutions that preserve seed types as

living museums of genetic diversity- Seeds are collected, stored, and periodically planted

The “doomsday seed vault” in Norway stores millions of seeds from around the world


We have thousands of pesticides• Pest = any organism that damages valuable crops • Weed = any plant that competes with crops• Pesticides = poisons that target pest organisms

- Insecticides = kill insects- Herbicides = kill plants- Fungicides = kill fungi

• 400 million kg (900 million lb) of pesticides are applied in the U.S. each year- 75% of this is applied to agricultural land

• $32 billion/year is spent on pesticides worldwide


Pests evolve resistance to pesticides

• Some individuals are genetically immune to a pesticide- They pass these genes to their offspring

• Pesticides stop being effective - Pesticide treadmill = chemists increase chemical

toxicity to compete with resistant pests• Pesticides also kill nontarget organisms

- Including predators and parasites of pests- Pest populations become harder to control


Pesticide resistance

• Over 556 insect species are resistant to 300 pesticides- Weeds and plant diseases have evolved resistance

to pesticides


Biological control (biocontrol)

• Biological control = uses a pest’s predators to control the pest- Reduces pest populations

without chemicals- Reduces chemical use

• Cactus moths control prickly pear

• Bacillus thuringiensis (Bt)= soil bacteria that kills many pests


Biocontrol agents may become pests

• It is risky to introduce an organism from a foreign ecosystem into a new ecological context- The effects of an introduced species are unpredictable

• The agent may have “nontarget” effects on the environment and surrounding economies- Cactus moths are eating rare Florida cacti

• Removing a biocontrol agent is harder than halting pesticide use- Biocontrol use must be carefully planned and

regulated


Integrated Pest Management (IPM)

• Techniques to suppress pests:- Biocontrol- Chemicals, if necessary- Population monitoring - Habitat alteration- Crop rotation and

transgenic crops- Alternative tillage methods- Mechanical pest removal

IPM in Indonesia increased rice yields 13% and saved $179 million/yr in phased-out subsidies


We depend on insects to pollinate crops

• Not all insects are pests; some are absolutely vital- 800 crop species rely on insect pollinators

• Pollination = male plant sex cells fertilize female sex cells- By wind or animals

• Pollinators include:- Hummingbirds- Bats- Insects (bees, wasps, etc.)

Flowers are evolutionary adaptations to attract pollinators


Conservation of pollinators is vital

• Populations of pollinators (e.g., bees) have plummeted• Colony collapse disorder = entire beehives have

vanished- Unknown causes—Insecticides? Parasites? Stress?

• Reducing or eliminating pesticide use and planting flowering plants will help preserve bees

Bees pollinate over 100 crops and contribute $15 billion in services/year


Genetically modified organisms

• Genetic engineering =laboratory manipulation of genetic material- Add, delete, modify DNA

• Genetically modified (GM) organisms = organisms that have been genetically engineered by …

• Recombinant DNA = DNA created from multiple organisms


Biotechnology is impacting our lives

• Biotechnology = the application of biological science to create products derived from organisms

• Transgenic organism = an organism that contains DNA from another species - Transgenes = the genes that have moved between

organisms• Biotechnology has created medicines, cleaned up

pollution, and dissolved blood clots


Some genetically modified foods


Genetic engineering versus agricultural breeding• Traditional breeding = changes organisms through

selective breeding of the same or similar species- Works with organisms in the field- Genes come together on their own- Uses the process of selection

• Genetic engineering = mixes genes of different species- Works with genetic material in the lab- Directly creates novel combinations of genes- Resembles the process of mutation


Biotechnology is changing our world

• GM foods are a big business• Most GM crops are herbicide

and pesticide resistant- Large-scale farmers grow

crops more efficiently- Most U.S. corn, soybeans,

cotton, and canola are genetically modified

Globally, 14 million farmers grew GM foods on 134 million ha


What are the impacts of GM crops?

• As GM crops expanded, scientists, citizens, and policymakers became concerned- Impacts on human health

• Concerns over escaping transgenes - They could harm nontarget organisms- Pests could evolve resistance- They could ruin the integrity of native ancestral

races and interbreed with closely related wild plants


Genetic engineering has benefits and risks

• Environmental benefits of genetic engineering:- Reduced use of chemical insecticides- Increased no-till farming- Decreased irrigation, deforestation, land conversion

• Negatives of genetic engineering:- Increased herbicide use affects health and habitats- Some GM fields support less biodiversity

• Precautionary principle = don’t undertake a new action until the effects of that action are understood


The GM debate involves ethics• People don’t like “tinkering” with the food supply• With increasing use, people are forced to use GM

products, or go to special effort to avoid them• Multinational corporations threaten the small farmer• Research is funded by corporations that profit if GM

foods are approved for use• GM crops have not eradicated hunger

- GM crops do not focus on increased nutrition, drought tolerance, etc.

The GM industry is driven by market considerations driven by financial interests of corporations


GMO producers are suing farmers

• Monsanto has launched 112 lawsuits against 372 farmers, winning an average $385,000 per case - Monsanto sued Percy Schmeiser of Canada for

using its GM seeds without paying for them- Schmeiser said the seeds blew onto his field from

adjacent fields- The courts sided with Monsanto, saying that

Schmeiser had violated Monsanto’s patent

Corporations go to great lengths to protect their GM investments


The future of GM foods

• Europeans demand that GM foods are labeled• U.S. consumers have mostly accepted GM crops

- They don’t realize most food contains GM products• The U.S. sued the European Union before the World

Trade Organization for hindering free trade• The Cartagena Protocol on Biosafety lays out

guidelines for open information about exported crops- The U.S. has not joined

• Brazil, India, and China approve GM crops


Consumption of animal products is growing

• As wealth and commerce increase, so does meat, milk, and egg consumption

• Since 1950, global meat production has increased fivefold and per capita meat consumption has doubled

Domestic animals raised for food increased from 7.2 billion in 1961 to 24.9 billion in 2008


Our food choices are also energy choices

• Eating meat is far less energy efficient than eating crops

• 90% of energy is lost from one trophic level to the next

• Eating lower on the food chain feeds more people

• Some animals convert grain into meat more efficiently than others


Environmental ramifications of eating meat

• Land and water are needed to raise food for livestock

• Producing eggs and chicken meat requires the least space and water- Producing beef

requires the most


Resources needed for livestock production

When we choose what to eat, we choose how we use resources


Feedlot agriculture• Feedlots (factory farms) =

also called Concentrated Animal Feeding Operations (CAFOs)

• Huge warehouses or pens deliver food to animals living at extremely high densities- Over half of the world’s

pork and most of its poultry

U.S. farms house hundreds of thousands of debeaked chickens in crowded cages


High consumption leads to feedlot agriculture

• Traditional agriculture keeps livestock on grasslands• Feedlot animals are fed grain grown on cropland

- One-third of the world’s cropland is fed to livestock• Feedlot agriculture allows economic efficiency

- Greater production of food- Unavoidable in countries with high meat

consumption, like the U.S. • Reduced grazing impacts on the land

- Manure can be applied to fields as fertilizer


Livestock agriculture pollutes water and air

• Feedlots produce huge amounts of manure and urine- Causing eutrophication- Waterborne pathogens sicken people

• Crowded, dirty housing causes outbreaks in disease- Heavy use of antibiotics, hormones, heavy metals- Chemicals are transferred to people- Microbes evolve resistance to antibiotics

• Air pollution: odors, ammonia (acid rain)- More greenhouse gases (CO2, methane, nitrous

oxides) than automobile emissions


We raise fish on “fish farms”

• World fish populations are plummeting- Technology and

increased demand• Aquaculture = raising

aquatic organisms in a controlled environment- Species are raised in

open-water pens or land-based ponds


Aquaculture is growing rapidly

• Over 220 freshwater and marine species are grown

• The fastest-growing type of food production- Provides ¾ of the

world’s fish, ½ of the shellfish

- Most widespread in Asia


The benefits and drawbacks of aquaculture• Benefits:

- A reliable protein source- Can be sustainable - Reduces pressure on

overharvested wild fish- Energy efficient

• Drawbacks:- Diseases require

expensive antibiotics- Lots of waste- Uses grain- Escaped GM fish

introduce disease or outcompete wild fish


Sustainable agriculture

• Industrial agriculture may seem necessary- But less-intensive agricultural methods are better

• Sustainable agriculture = does not deplete soil, pollute water, or decrease genetic diversity

• Low-input agriculture = uses smaller amounts of pesticide, fertilizers, growth hormones, water, and fossil fuels than industrial agriculture

• Organic agriculture = uses no synthetic fertilizers, insecticides, fungicides, or herbicides- Relies on biological approaches (e.g., composting

and biocontrol)


Organic approaches reduce inputs and pollution

• Organic Food Production Act (1990) establishes national standards for organic products- The USDA issued criteria in 2000 by

which food could be labeled organic• Some states pass even stricter guidelines

for labeling- California, Washington, Texas

• Nearly 500 organizations offer certification services


The benefits of organic farming

• Farmers have lower input costs, enhanced income, reduced chemical pollution, and soil degradation- They practice stewardship to the land- Obstacles include risks and costs of switching to

new methods• Consumers are concerned about pesticide’s health risks

- They want to improve environmental quality- Obstacles include the higher price of organics


Organic agriculture is booming• Organic farmers can’t keep

up with demand- U.S. consumers pay

$22.9 billion/year• Production is increasing

- 1.8 million ha in the U.S.


Governments can support organic farming

• In 1993, the European Union adopted a policy supporting farmers financially during conversion to organic farming

• The U.S. offers no support so organic production lags- The 2008 Farm Bill gives $112 million over 5

years for organic agriculture- Many farmers can’t switch, because they can’t

afford the temporary loss of income- In the long run, organic farming is more profitable

than conventional farming


Locally supported agriculture is growing• Sustainable agriculture reduces fossil fuel use from

long-distance transport of products- Food is chemically treated for freshness and color

• Farmers’ markets = provide fresh, locally grown food

• Community-supported agriculture (CSA) - Consumers pay farmers

in advance- Consumers get fresh food- Farmers get a guaranteed

income


Sustainable agriculture mimics natural ecosystems• Ecosystems operate in cycles

- Stabilized by negative feedback loops• Small-scale Japanese farmers add ducks

to rice fields- Ducks eat weeds, insects, snails- Their waste is fertilizer- Their paddling oxygenates

the water- Fish and ferns provide food

and habitat


Conclusion

• Industrialized agriculture has relieved pressures on the land- But the environmental consequences are severe

• To support 9 billion humans, we must shift to sustainable agriculture- Biological pest control, organic agriculture- Pollinator protection, preservation of native crops- Aquaculture- Careful, responsible genetic modification of food


QUESTION: Review

Which statement is true?

a) We have become more sustainable in food production.

b) We can convert much more land to agricultural production.

c) Technology in the form of fossil fuels, pesticides and fertilizers has increased production.

d) Population growth has exceeded food production in recent decades.


QUESTION: Review

Which term describes the condition when a person receives fewer calories than he or she needs?

a) Undernutritionb) Overnutritionc) Food securityd) Malnutrition


QUESTION: Review

Which of the following is NOT correct about the Green Revolution?

a) It dramatically increased food production.b) It most benefits poor farmers.c) It uses large amounts of fertilizers and pesticides.d) It prevented starvation of millions of people.


QUESTION: Review

Which of the following is NOT a problem with using pesticides?

a) Many species can become resistant to pesticides.b) Offspring of resistant species are also resistant.c) Pesticides kill many non-target species.d) All are problems involved in using pesticides.


QUESTION: Review

Which statement about GM food production is NOT true?

a) It mixes genes from different organisms.b) It mimics natural selection.c) It involves working with genetic material in the lab.d) Producing GM foods is a big business.


QUESTION: Review

Which statement is NOT correct about factory farming?

a) It is far more energy efficient than eating grains.b) Some species convert grain into meat more

efficiently than other species.c) Much of the world’s grain is fed to livestock.d) More livestock can be produced in an area.


QUESTION: Review

Sustainable agriculture:

a) Uses concentrated animal feeding operations.b) Maximizes use of fertilizers and pesticides.c) Does not deplete soil or pollute water.d) Is currently not a feasible solution.


QUESTION: Weighing the Issues

The green revolution has increased crop yields, but only by increasing fertilizers, pesticides, irrigation and hybrid seed. Do you consider it a success?

a) Yes, because more people were fed, regardless of the price.

b) Yes, because industrialized countries can help through education and technology.

c) No, we will eventually pay the environmental costs of producing food in this way.

d) It does not matter, I can buy food whenever I want.


QUESTION: Weighing the Issues

Factory farming allows us to have lots of meat products. But the animals are often kept in undesirable, stressful the conditions. Should the quality of the animals’ lives be considered when we decide how to raise food?

a) Yes, the quality of an animal’s life is important, too.b) Yes, but only if it does not interfere with access to

meat.c) No, animals have no right to a quality of life.d) I don’t care, I’m not fond of cows or chickens.


QUESTION: Interpreting Graphs and Data

If a person eats 3 kg of meat per week, how many kg of grain are required if the meat came from a pig?

a) 60 kgb) 22 kgc) 3 kgd) 12 kg


QUESTION: Interpreting Graphs and DataWhat does this graph show about sales of organic food in the United States?

a) Sales increased slowlyb) Sales increased but

not the dollar amountsc) Acreage has declined

in the past yearsd) Sales, dollar amounts,

and acreage increased

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