1. Review & Discussion Agricultural Systems and Transgenic Organisms

2. Question: Many of us take agriculture for granted. How has it affected human history? Photos courtesy of Texas Parks and Wildlife Department

3. Development of agricultural systems made advanced civilization possible 10,000 BC Photo courtesy of Texas Department of Transportation Today

4. Question: When did domestication begin and what was the first animal domesticated?

5. Dates (BC) and Places of First Evidence for Domestication from Diamond, J., Guns, Germs and Steel, Random House, 1997 Dog10,000 BCSW. Asia,China, North America Sheep8,000 BCSW. Asia Goat8,000BCSW. Asia Pig8,000BCChina, SW. Asia Cow6,000BCSW. Asia, India, North Africa Horse4,000BCUkraine Donkey4,000BCEgypt

6. From: Fort Worth Star-Telegram The dog was one of the first animals domesticated 10,000 years of domestication may explain why dogs are man’s best friend

7. Question: Why is there a controversy over using grain to fatten cattle? From: Time, November 8, 1999

8. Many more people could be fed by the grain used to feed the cattle than can be fed by the cattle themselves This is because productive energy is diminished with each trophic level Based on: Scientific American, September 1976

9. Question: What is good and bad about genetically engineered agricultural plants?

10. Genetically Engineered Plants The Good: Crops can be engineered to have important components of diet, contain medically important proteins, and to be pest resistant The Bad: Plants could contain pesticides that would harm humans and wildlife, or proteins that could cause allergies in humans. Genetics could escape to traditional crops.

11. Today’s Lesson Pesticides and Organic Farming

12. Pests, DDT and biomagnification DDT, eagles and falcons Endangered Species Act Organic farming Overview of Lesson

13. Domestic crops were selected for maximum productivity and had little natural pest resistance

14. Blight hits potatoes, 1845 Based on: Population Reports, May 1992 Potato famine of Ireland was caused by genetically uniform crops and lack of pesticides to protect them

15. Pests attack and eat our food crops This problem is due, in part, to not selecting for pest resistance during domestication Today’s Pests Based on: National Geographic, February 1980

16. DDT was invented in the 1940’s and viewed as: - miracle for farmers - and safe

17. “The most discussed of the new insecticides is dichloro-diphenyl-trichloroethane, shortened to DDT but also called Guesarol. This compound has remarkable power to kill insects, particularly body lice-the ‘cooties’ of World War I. The prevalence of typhus, carried by body lice, in the Mediterranean theater of this war has emphasized its value. DDT’s effectiveness in war may well be overshadowed by its value in peace. Painstaking investigations have shown it to be signally effective against many of the most destructive insects that feed upon crops.” Scientific American, July 1944.

18. Arial crop sprayers were used to spray tons of DDT on crops across the U.S. Photo courtesy of Texas Parks and Wildlife Department

19. Pests became resistant to DDT Based on: National Geographic

20. Pesticide Resistance In the beginning, most pests were sensitive to DDT but a few were resistant The resistant forms survived and reproduced In the end, most pests were resistant to DDT Based on: National Geographic, February 1980

21. Biomagnification The concentration of pesticides in higher levels of food chains

22. Most food chains consist of four trophic levels Based on: Mader, S., Inquiry Into Life, McGraw-Hill Trophic Levels

23. Energy Available to Consumers at Next Trophic Level Energy Lost by Respiration Energy Lost by Death and Decay Energy Lost by Excretion Energy Lost by Egestion of Feces Energy Ingested

24. DDT is concentrated as it moved up food chain This is because energy is lost (from respiration) as go up food chain but DDT is not Based on: Campbell et al, Biology: Concepts and Connections, Benjamin Cummings DDT in Food Chain

25. Pests, DDT and biomagnification DDT, eagles and falcons Endangered Species Act Organic foods Overview of Lesson

26. Bald Eagle Once was widelyOnce was widely distributed over U.S. distributed over U.S. As a top carnivore it feeds on fishAs a top carnivore it feeds on fish Swoops down and captures fish off the surface of the waterSwoops down and captures fish off the surface of the water Photo courtesy of Texas Parks and Wildlife Department

27. Scientists discovered that DDT wasScientists discovered that DDT was concentrated in the bald eagle concentrated in the bald eagle DDT affected the eagle’s ability to reproduceDDT affected the eagle’s ability to reproduce Photos courtesy of Texas Parks and Wildlife Department

28. Scientists found that the eagle eggs had thin egg shells and broke easily Nests contained broken, rotten eggs The number of young produced per breeding pair was reduced

29. Population of adult eagles declined to 4,000 and the eagle was listed as “Endangered” Photo courtesy of Texas Parks and Wildlife Department

30. The Environmental Protection Agency (EPA) banned DDT in 1972 Photo courtesy of Texas Parks and Wildlife Department

31. Eagle reproduction before and after DDT ban Based on: Grier, J., Science, 1982

32. Eagle populations increased rapidly and the eagle is now listed as “Threatened” From: Time, July 11, 1994

33. Peregrine Falcon Occurred naturallyOccurred naturally over most of continental U.S. over most of continental U.S. Nests on cliffsNests on cliffs Keen eyesightKeen eyesight (if human, could read newspaper print at 110 yards) Feeds on other birds, knocking them out of the sky at 200 m.p.h.Feeds on other birds, knocking them out of the sky at 200 m.p.h. Photo courtesy of Texas Parks and Wildlife Department

34. After DDT was introducedAfter DDT was introduced in 1940s, DDT weakened in 1940s, DDT weakened the birds’ egg shells, the birds’ egg shells, devastating the population devastating the population By early 1970s, the entireBy early 1970s, the entire U.S. population was down U.S. population was down to 12 breeding pairs to 12 breeding pairs Peregrines were declaredPeregrines were declared federally endangered and federally endangered and DDT banned DDT banned Peregrines were bred inPeregrines were bred in captivity and reintroduced captivity and reintroduced successfully in cities successfully in cities DDT & Peregrine Photos courtesy of Texas Parks and Wildlife Department

35. Pests, DDT and biomagnification DDT, eagles and falcons Endangered Species Act Organic foods Overview of Lesson

36. “In the United States at least 500 species and subspecies of plants and animals have become extinct since the 1500s.” Douglas Chadwick, H., National Geographic, March 1995

37. Endangered Species Act of 1973 The Secretary of the Interior determines whether a species is endangered or threatenedThe Secretary of the Interior determines whether a species is endangered or threatened The Secretary develops and implements recovery plans for the conservation of endangered speciesThe Secretary develops and implements recovery plans for the conservation of endangered species

38. Definitions - Endangered Species Act Endangered Species - Any species that is in danger of extinction throughout all or a significant portion of its rangeEndangered Species - Any species that is in danger of extinction throughout all or a significant portion of its range Threatened Species - Any species that is likely to become an endangered species within the foreseeable future Threatened Species - Any species that is likely to become an endangered species within the foreseeable future

39. OTHER COMEBACKS ESA is having some success 2009 Stats Animals 613 Plants 747 endangered species in the U.S. Gray whale (California population) Aleutian Canada goose American alligator Brown pelican Utah prairie dot Greenback cutthroat trout 1994 1985 1990 1987 1984 1978 date of change Species removed from endangered list or reclassified as threatened Based on: Time, July 11, 1994

40. Pests, DDT and biomagnification DDT, eagles and falcons Endangered Species Act Organic foods Overview of Lesson

41. Defining “Organic” Foods produced without hormones, antibiotics, herbicides, insecticides, chemical fertilizers, genetic modification or germ-killing radiation The USDA labels such foods “certified organic” From: Newsweek, Sept. 30, 2002

42. Availability of Organic Products Based on: Newsweek, Sept. 30, 2002

43. Unanswered Questions about Certified Organic Foods Are organic food safer than other foods? Do organic foods taste better? Are organic foods worth the extra costs? Are people eating organic diets healthier than people with conventional diets?

44. Can organic farming help the environment? Pesticides now kill 67 million American birds per year The Mississippi River dumps enough fertilizer into the Gulf of Mexico to maintain a 60 mile “dead zone” devoid of fish

45. Pesticides and Human Health India suffering from human health consequences of pesticide use InfertilityInfertility Cancer related deaths increasingCancer related deaths increasing Childhood cancersChildhood cancers Mental retardationMental retardation Research shows pesticides and fertilizers in the groundwater.