© 2011 Pearson Education, Inc. The Race to Feed the World & Preserving Crop Diversity AP Environmental Science Mr. Grant Lesson 61

© 2011 Pearson Education, Inc. Objectives: Define the term food security. Explain the challenge of feeding a growing human population. Identify the goals, methods, and consequences of the “green revolution.” Describe approaches for preserving crop diversity. Categorize the strategies of pest management. TED - At TEDxTelAviv, Shimon Steinberg looks at the difference between pests and bugs -- and makes the case for using good bugs to fight bad bugs, avoiding chemicals in our quest for perfect produce.

© 2011 Pearson Education, Inc. Food Security: An adequate, reliable, and available food supply to all people at all times. Define the term food security.

© 2011 Pearson Education, Inc. Explain the challenge of feeding growing human population. Our food production has outpaced our population growth, yet 1 billion people still go hungry. Under-nutrition, over-nutrition, and malnutrition are all challenges. Growing crops for biofuels can result in food shortages.

© 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

© 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

© 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

© 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

© 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

© 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

© 2011 Pearson Education, Inc. Identify the goals, methods, and consequences of the “green revolution.” The green revolution aimed to increase agricultural enhanced productivity per unit area of land in developing nations. Scientists used selective breeding to develop crop strains that grew quickly, were more nutritious, or were resistant to disease or drought The expanded use of fossil fuels, chemical fertilizers and pesticides has increased pollution. The increased efficiency of production has fed more people while reducing the amount of natural land converted for farming.

© 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

© 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

© 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

© 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

© 2011 Pearson Education, Inc. Describe approaches for preserving crop diversity. Protecting diversity of naïve crop varieties provides insurance against failure of major crops. Seed banks preserve rare and local varieties of seed, acting as storehouses for genetic diversity.

© 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

© 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

© 2011 Pearson Education, Inc. Categorize the strategies of pest management. We kill “pests” and “weeds: with synthetic chemicals that can pollute the environment and pose health hazards. Pests can evolve resistance to chemical pesticides, forcing us to design more toxic poisons. We employ natural enemies of pests against them in the practice of biological control. Integrated pest management combines various techniques and minimizes the use of synthetic chemicals.

© 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

© 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

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

© 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

© 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

© 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

© 2011 Pearson Education, Inc. TED Video Shimon Steinberg's biotech lab researches ways to harness the natural benefits of insects on a massive scale. "My dream is to narrow the gap even more by finding more robust and reliable good bugs we can mass produce or conserve in the field, as well as create more public demand for natural pest control and increase awareness among growers." Shimon Steinberg: Natural pest control... using bugs! (15:24)