22 Pesticides Farming

8/8/2019 22 Pesticides Farming

http://slidepdf.com/reader/full/22-pesticides-farming 1/48

This lesson will increase your knowledge of conceptscovered in the following TEKS for biology:

3.a ± Analyze, review, and critique scientific explanations, includinghypotheses and theories, as to their strengths and weaknesses using scientificevidence and information

3.c ± Evaluate impact of research on scientific thought, society, and the

environment3.f ± Research and describe the history of biology and contributions of scientists

4.b ± Investigate and identify cellular processes

6.d ± Compare genetic variations observed in plants and animals7.b ± Illustrate the results of natural selection in the speciation, diversity,

phylogeny, adaptation, behavior and extinction



This lesson will increase your knowledge of conceptscovered in the following TEKS for biology:

9.d ± Analyze the flow of matter and energy through different trophic levels and between organisms and the physical environment

11.b ± Investigate and identify how organisms respond to external stimulation

11.c ± Analyze the importance of nutrition, environmental conditions and physical exercise on health

11.d ± Summarize the role of microorganisms in maintaining and disruptingequilibrium including diseases in plants and animals and decay in an ecosystem

12.b ± Interpret interactions among organisms exhibiting predation, parasitism,commensalism, and mutualism

12.e ± Investigate and explain interactions in an ecosystem including foodchains, food webs, and food pyramids



Previous Lesson

Agricultural Systems andTransgenic Organisms



Q uestion: Manyof us take

agriculture for granted. Howhas it affected

human history?Photos courtesy of Texas Parks and Wildlife Department



Development of agricultural systems made

advanced civilization possible

10,000 BC

Photo courtesy of TexasDepartment of Transportation

Today



Q uestion: When did domesticationbegin and what was the first animaldomesticated?



Dates (BC) and Places of FirstEvidence for Domestication

from Diamond, J., Guns, Germs and Steel, Random House, 1997

Dog 10,000 BC SW. Asia,China, North America

Sheep 8,000 BC SW. AsiaGoat 8,000 BC SW. AsiaPig 8,000 BC China, SW. AsiaCow 6,000 BC SW. Asia, India, North AfricaHorse 4,000 BC UkraineDonkey 4,000 BC Egypt





Q uestion: Why is there a controversyover using grain to fatten cattle?

From: Time , November 8 , 1999



Many more peoplecould be fed by thegrain used to feed thecattle than can be fedby the cattlethemselves

This is becauseproductive energy isdiminished with eachtrophic level

Based on: Scientific American , September 1976



Q uestion: What is good and badabout genetically engineeredagricultural plants?



Genetically Engineered PlantsThe Good: Crops can be engineeredto have important components of

diet, contain medically importantproteins, and to be pest resistantThe Bad: Plants could contain

pesticides that would harm humansand wildlife, or proteins that couldcause allergies in humans. Geneticscould escape to traditional crops.



Today¶s LessonToday¶s Lesson

Pesticides andPesticides andOrganic FarmingOrganic Farming



Pests, DDT and biomagnificationDDT, eagles and falconsEndangered Species ActOrganic farming

Overview of Lesson



Domestic crops wereDomestic crops were

selected for maximumselected for maximumproductivity and had littleproductivity and had little

natural pest resistancenatural pest resistance



Blight hitspotatoes, 1845

Based on: P op ulati o n Re po rts , May 1992

Potato famine of Ireland was caused bygenetically uniform crops and lack of

pesticides to protect them



Pests attack andPests attack andeat our food cropseat our food crops

This problem isThis problem isdue, in part, to notdue, in part, to notselecting for pestselecting for pestresistance duringresistance duringdomesticationdomestication

Today¶s PestsToday¶s Pests

Based on: N ati o nal Ge o gra phic , February 1980



DDT was invented in theDDT was invented in the

1940¶s and viewed as:1940¶s and viewed as:-- miracle for farmersmiracle for farmers-- and safeand safe



³ The most discussed of the new insecticides is³ The most discussed of the new insecticides isdichlorodichloro- -diphenyldiphenyl- -trichloroethane, shortened totrichloroethane, shortened toDDT but also called Guesarol. This compound hasDDT but also called Guesarol. This compound hasremarkable power to kill insects, particularly bodyremarkable power to kill insects, particularly bodylicelice--the µcooties¶ of World War I. The prevalence of the µcooties¶ of World War I. The prevalence of typhus, carried by body lice, in the Mediterraneantyphus, carried by body lice, in the Mediterraneantheater of this war has emphasized its value.theater of this war has emphasized its value.DDT¶s effectiveness in war may well beDDT¶s effectiveness in war may well beovershadowed by its value in peace. Painstakingovershadowed by its value in peace. Painstakinginvestigations have shown it to be signallyinvestigations have shown it to be signallyeffective against many of the most destructiveeffective against many of the most destructiveinsects that feed upon crops.´insects that feed upon crops.´

Scientific AmericanScientific American , July 1944., July 1944.



Arial crop sprayersArial crop sprayerswere used to spraywere used to spraytons of DDT ontons of DDT oncrops across thecrops across theU.S.U.S.

Photo courtesy of Texas Parks and Wildlife DepartmentPhoto courtesy of Texas Parks and Wildlife Department



Pests became resistant to DDTPests became resistant to DDT

Based on: N ati o nal Ge o gra phic



Pesticide ResistancePesticide Resistance

In the beginning, mostIn the beginning, mostpests were sensitive topests were sensitive toDDT but a few wereDDT but a few wereresistantresistant

The resistant formsThe resistant forms

survived and reproducedsurvived and reproduced

In the end, most pestsIn the end, most pestswere resistant to DDTwere resistant to DDT

Based on: N ati o nal Ge o gra phic , February 1980



BiomagnificationBiomagnification

The concentration of The concentration of pesticides in higher levels of pesticides in higher levels of

food chainsfood chains



Most food chains consist of four trophic levels

Based on: Mader, S., I nquiry I nt o Life , McGraw-Hill

Trophic Levels



Energy Availableto Consumers at

Next Trophic Level

Energy Lost byRespiration

Energy Lost byDeath and Decay

Energy Lost byExcretion

Energy Lost by

Egestion of Feces

Energy Ingested



DDT is concentrated asDDT is concentrated asit moved up food chainit moved up food chain

This is because energyThis is because energyis lost (from respiration)is lost (from respiration)as go up food chain butas go up food chain butDDT is notDDT is not

Based on: Campbell et al, B i o l o gy: C o nce p ts

and C o nnecti o ns , Benjamin Cummings

DDT in Food Chain



Pests, DDT and biomagnification

DDT, eagles and falconsEndangered Species ActOrganic foods

Overview of Lesson



Bald EagleBald Eagle

Once was widelyOnce was widelydistributed over U.S.distributed over U.S.

As a top carnivore itAs a top carnivore itfeeds on fishfeeds on fish

Swoops down andSwoops down andcaptures fish off thecaptures fish off thesurface of the water surface of the water

Photo courtesy of Texas Parks and WildlifePhoto courtesy of Texas Parks and WildlifeDepartmentDepartment



Scientists discovered that DDT wasScientists discovered that DDT wasconcentrated in the bald eagleconcentrated 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 DepartmentPhotos courtesy of Texas Parks and Wildlife Department



Scientists foundScientists foundthat the eagle eggsthat the eagle eggshad thin egg shellshad thin egg shellsand broke easilyand broke easily

Nests containedNests containedbroken, rotten eggsbroken, rotten eggs

The number of The number of

young producedyoung producedper breedingper breedingpair was reducedpair was reduced



Population of adultPopulation of adulteagles declined to 4,000eagles declined to 4,000

and the eagle was listedand the eagle was listedas ³ Endangered´as ³ Endangered´




The Environmental Protection Agency (EPA)The Environmental Protection Agency (EPA)banned DDT in 1972banned DDT in 1972




Eagle reproduction before and after DDT banEagle reproduction before and after DDT ban

Based on: Grier, J., Science, 1982



Eagle populations increased rapidly andEagle populations increased rapidly andthe eagle is now listed as ³ Threatened´the eagle is now listed as ³ Threatened´

From: Time , July 11, 1994



Peregrine FalconPeregrine Falcon Occurred naturallyOccurred naturallyover most of over most of

continental U.S.continental U.S.

Nests on cliffsNests on cliffs

Keen eyesightKeen eyesight(if human, could read(if human, could readnewspaper print at 110 yards)newspaper print at 110 yards)

Feeds on other birds,Feeds on other birds,knocking them out of knocking them out of the sky at 200 m.p.h.the sky at 200 m.p.h.




After DDT was introducedAfter DDT was introducedin 1940s, DDT weakenedin 1940s, DDT weakenedthe birds¶ egg shells,the birds¶ egg shells,devastating the populationdevastating the population

By early 1970s, the entireBy early 1970s, the entire

U.S. population was downU.S. population was downto 12 breeding pairsto 12 breeding pairs

Peregrines were declaredPeregrines were declaredfederally endangered andfederally endangered andDDT bannedDDT banned

Peregrines were bred inPeregrines were bred incaptivity and reintroducedcaptivity and reintroduced

successfully in citiessuccessfully in cities

DDT & PeregrineDDT & Peregrine

Photos courtesy of Texas Parks and Wildlife DepartmentPhotos courtesy of Texas Parks and Wildlife Department





³ In the United States at least 500³ In the United States at least 500species and subspecies of plantsspecies and subspecies of plantsand animals have become extinctand animals have become extinctsince the 1500s.´since the 1500s.´

Douglas Chadwick, H.,Douglas Chadwick, H., N ati o nal Ge o gra phic N ati o nal Ge o gra phic , March 1995, March 1995



Endangered Species Act of 1973Endangered Species Act of 1973The Secretary of the Interior The Secretary of the Interior determines whether a species isdetermines whether a species isendangered or threatenedendangered or threatened

The Secretary develops andThe Secretary develops andimplements recovery plans for theimplements recovery plans for theconservation of endangered speciesconservation of endangered species



DefinitionsDefinitions - - EndangeredEndangeredSpecies ActSpecies Act

Endangered SpeciesEndangered Species -- Any species that isAny species that is

in danger of extinction throughout all or ain danger of extinction throughout all or asignificant portion of its rangesignificant portion of its range

Threatened SpeciesThreatened Species -- Any species that isAny species that is

likely to become an endangered specieslikely to become an endangered specieswithin the foreseeable futurewithin the foreseeable future



OTHER COMEBACKSESA is havingsomesuccess

2009 StatsAnimals 613Plants 747

endangeredspecies in theU.S.

Gray whale(Calif orn ia popu lation)

Aleutian Canadagoose

American alligator

Brown pelicanUtah prairie dot

Greenback cutthroattrout

1994

1985

1990

1987

1984

1978

date of change

Species removed fromendangered list or reclassified as threatened

Based on: Time , July 11, 1994



Pests, DDT and biomagnification

DDT, eagles and falconsEndangered Species ActOrganic foods

Overview of Lesson



Defining ³ Organic´Defining ³ Organic´

Foods produced withoutFoods produced withouthormones, antibiotics,hormones, antibiotics,herbicides, insecticides,herbicides, insecticides,

chemical fertilizers,chemical fertilizers,genetic modification or genetic modification or germgerm- -killing radiationkilling radiation

The USDA labels suchThe USDA labels suchfoods ³ certified organic´foods ³ certified organic´

From:From: N ewsweek N ewsweek , Sept. 30, 2002, Sept. 30, 2002



Availability of Organic Products

Based on:Based on: N ewsweek N ewsweek , Sept. 30, 2002, Sept. 30, 2002



Unanswered Q uestions aboutUnanswered Q uestions about

Certified Organic FoodsCertified Organic Foods

Are organic food safer than other foods?Are organic food safer than other foods?

Do organic foods taste better?Do organic foods taste better?

Are organic foods worth the extra costs?Are organic foods worth the extra costs?

Are people eating organic diets healthier thanAre people eating organic diets healthier thanpeople with conventional diets?people with conventional diets?



Can organic farming helpCan organic farming help

the environment?the environment?

Pesticides now kill 67 million AmericanPesticides now kill 67 million American

birds per year birds per year

The Mississippi River dumps enoughThe Mississippi River dumps enoughfertilizer into the Gulf of Mexico to maintainfertilizer into the Gulf of Mexico to maintain

a 60 mile ³ dead zone´ devoid of fisha 60 mile ³ dead zone´ devoid of fish



Pesticides and Human HealthPesticides and Human Health

India suffering from human healthIndia suffering from human healthconsequences of pesticide useconsequences of pesticide use

InfertilityInfertilityCancer related deaths increasingCancer related deaths increasingChildhood cancersChildhood cancersMental retardationMental retardation

Research shows pesticides and fertilizersResearch shows pesticides and fertilizersin the groundwater.in the groundwater.



Next Lesson

The Water Cycle

Documents

22 Pesticides Farming