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© 2011 Pearson Education, Inc. Lecture Outlines Chapter 10 Environment: The Science behind the Stories 4th Edition Withgott/Brennan.

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Presentation on theme: "© 2011 Pearson Education, Inc. Lecture Outlines Chapter 10 Environment: The Science behind the Stories 4th Edition Withgott/Brennan."— Presentation transcript:

1 © 2011 Pearson Education, Inc. Lecture Outlines Chapter 10 Environment: The Science behind the Stories 4th Edition Withgott/Brennan

2 © 2011 Pearson Education, Inc. 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

3 © 2011 Pearson Education, Inc. 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

4 © 2011 Pearson Education, Inc. 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

5 © 2011 Pearson Education, Inc. 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

6 © 2011 Pearson Education, Inc. 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

7 © 2011 Pearson Education, Inc. 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

8 © 2011 Pearson Education, Inc. 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

9 © 2011 Pearson Education, Inc. 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

10 © 2011 Pearson Education, Inc. 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

11 © 2011 Pearson Education, Inc. 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

12 © 2011 Pearson Education, Inc. 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

13 © 2011 Pearson Education, Inc. Biofuels affect food supplies Biofuels = are derived from organic materials -Replace petroleum in engines Ethanol = a biofuel derived from corn subsidies doubled production Food prices increased -Farmers sold corn for ethanol, not food -Farmers planted biofuels, not food crops -Riots erupted in many nations

14 © 2011 Pearson Education, Inc. 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

15 © 2011 Pearson Education, Inc. 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

16 © 2011 Pearson Education, Inc. 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

17 © 2011 Pearson Education, Inc. 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

18 © 2011 Pearson Education, Inc. Pesticide resistance Over 556 insect species are resistant to 300 pesticides -Weeds and plant diseases have evolved resistance to pesticides

19 © 2011 Pearson Education, Inc. 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

20 © 2011 Pearson Education, Inc. 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

21 © 2011 Pearson Education, Inc. 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

22 © 2011 Pearson Education, Inc. 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

23 © 2011 Pearson Education, Inc. 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

24 © 2011 Pearson Education, Inc. 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

25 © 2011 Pearson Education, Inc. 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

26 © 2011 Pearson Education, Inc. Some genetically modified foods

27 © 2011 Pearson Education, Inc. 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

28 © 2011 Pearson Education, Inc. 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

29 © 2011 Pearson Education, Inc. 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

30 © 2011 Pearson Education, Inc. 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

31 © 2011 Pearson Education, Inc. 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

32 © 2011 Pearson Education, Inc. 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

33 © 2011 Pearson Education, Inc. 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

34 © 2011 Pearson Education, Inc. 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

35 © 2011 Pearson Education, Inc. 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

36 © 2011 Pearson Education, Inc. 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

37 © 2011 Pearson Education, Inc. Resources needed for livestock production When we choose what to eat, we choose how we use resources

38 © 2011 Pearson Education, Inc. 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

39 © 2011 Pearson Education, Inc. 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

40 © 2011 Pearson Education, Inc. 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 (CO 2, methane, nitrous oxides) than automobile emissions

41 © 2011 Pearson Education, Inc. 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

42 © 2011 Pearson Education, Inc. 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

43 © 2011 Pearson Education, Inc. 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

44 © 2011 Pearson Education, Inc. 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)

45 © 2011 Pearson Education, Inc. 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

46 © 2011 Pearson Education, Inc. 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

47 © 2011 Pearson Education, Inc. 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.

48 © 2011 Pearson Education, Inc. 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

49 © 2011 Pearson Education, Inc. 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

50 © 2011 Pearson Education, Inc. 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

51 © 2011 Pearson Education, Inc. 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

52 © 2011 Pearson Education, Inc. 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.

53 © 2011 Pearson Education, Inc. QUESTION: Review Which term describes the condition when a person receives fewer calories than he or she needs? a)Undernutrition b)Overnutrition c)Food security d)Malnutrition

54 © 2011 Pearson Education, Inc. 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.

55 © 2011 Pearson Education, Inc. 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.

56 © 2011 Pearson Education, Inc. 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.

57 © 2011 Pearson Education, Inc. 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.

58 © 2011 Pearson Education, Inc. 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.

59 © 2011 Pearson Education, Inc. 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.

60 © 2011 Pearson Education, Inc. 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.

61 © 2011 Pearson Education, Inc. 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 kg b)22 kg c)3 kg d)12 kg

62 © 2011 Pearson Education, Inc. QUESTION: Interpreting Graphs and Data What does this graph show about sales of organic food in the United States? a)Sales increased slowly b)Sales increased but not the dollar amounts c)Acreage has declined in the past years d)Sales, dollar amounts, and acreage increased


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