Biology Today Third Edition Chapter 11 Plants to Feed the World Copyright © 2004 by Garland Science Eli Minkoff Pam Baker.

Biology TodayThird Edition

Chapter 11

Plants to Feed the World

Copyright © 2004 by Garland Science

Eli Minkoff • Pam Baker

Plants to Feed the World

A. PlantsUses (food, etc)nutrition (photosynthesis; know equation)

B. EconomicsPlants are producersAnimals (and others) are consumersFungi and bacteria are decomposersEnergy flows through the economyChemicals are recycled within the economy

e.g., the nitrogen cycle

Plants to Feed the World

C. Plant anatomyparts and functionsvascular tissuewater movement

(osmosis, transport, transpiration)

D. Increasing crop yieldFertilizer (benefits and dangers)Soil makeup and conservationWater distribution (hydroponics)Monocultures (benefits and dangers)Pests and controlling themFood pyramid and biomagnificationGMO’s advantages / disadvantages ?

(genetically modified organisms -= GMO)

Plants

Over 250,000 species 80,000 are edible by humans 30 major crops in the world 4 feed more than all

others wheatricecornpotatoes

Food

Plants

Food (Drinks, spices)FragrancesDyesPoisonsDecorationsBuilding materialMedicinesFuelPaper

Plant Nutrition

autotrophic

photosynthesis

(energy)

sunlight CO2 H2O glucose O2+ + +

Sun supplies all of our energyPlants capture and store energy

(autotrophic)

Energy flow

We eat plant material to get energy(heterotrophic)

producers

consumersprimary, secondary, …

Some organisms are absorptive heterotrophs

decomposers

Fig. 11-1

Fig. 11-2

Fig. 11-3

Fig. 11-4

Fig. 11-5

Chemicals cycle

Energy flow

usplants

C6H12O6 O2

H2OCO2

Chemicals cycle

Other chemical cycle tooe.g., nitrogen

amino acid, DNA, RNA

Chemicals cycle

Plants need nitrogen too

absorb nitrates and nitrites

nitrogen-fixationconvert N2 from air to NH3

nitrificationconvert NH3 to NO3-,NO2-

Fig. 11-6

Fig. 11-8

Plant Anatomy

Specialized plant parts:leavesrootsstemsflowers

photosynthesisabsorptiontransportreproduction

vascular tissue

xylemphloem

water and mineralsnutrients (sap)

Fig. 11-9

hypotonic

Fig. 11-10

Increasing crop yields

Fertilizeradds nutrients needed by plants to the soil

Animal waste (manure)CompostingChemical fertilizer

disease&

run-off

Fig. 11-13

What do plants need to grow ?

watersoil

Soil

Loose material

weathered rockorganic material

Soil types

parent rockclimategroundwateractivity of living organisms

topsoil

made slowly(1 inch/200-1000 years)

lost to erosion

“non-renewable”

don’t poison it or loose it

Plants to Feed the World

A. PlantsUses (food, etc)nutrition (photosynthesis; know equation)

B. EconomicsPlants are producersAnimals (and others) are consumersFungi and bacteria are decomposersEnergy flows through the economyChemicals are recycled within the economy

e.g., the nitrogen cycle

Plants to Feed the World

C. Plant anatomyparts and functionsvascular tissuewater movement

(osmosis, transport, transpiration)

D. Increasing crop yieldFertilizer (benefits and dangers)Soil makeup and conservationWater distribution (hydroponics)Monocultures (benefits and dangers)Pests and controlling themFood pyramid and biomagnificationGMO’s advantages / disadvantages ?

(genetically modified organisms -= GMO)

Water

90% lost to transpiration

plants need it:photosynthesistransportturgor pressure

Irrigation

supplying water to crops

expensive ?

Increasing crop yields

What do plants need to grow ?

water yessoil no

Hydroponics

growing crops without soil

expensiveconstructionmaintenance

monoculture

“inside”

controlled climateprotectedno tillingmore control Fig. 11-15

Monocultures

single species

rapid spread of disease

damage by pests

depletion of soil

Figure 11.16 (1)

Figure 11.16 (2)

Controlling pests

30% of many crops are destroyed

insects (adult and/or larvae)rodentsfungi

protect with pesticides

(kills pests)

Increasing crop yields

Controlling pests

ideal pesticide

kill only target pestno effect on non-targetsavoid devel. of resistance strainsbreakdown to harmless substances

ideal pesticide does not exist

Increasing crop yields

DDT

kills lots of insectssprayed on soldiers to kill liceused on crops to kill pests

(more food)sprayed on water to kill mosquitoes

(less disease)

Increasing crop yields

Controlling pests

DDT

expensivekills non-target speciesDDT-resistancepollute drinking waterbiomagnification

food pyramid

Controlling pests

Width shows biomass

p r o d u c e r smust be on bottom

they can’t pass on all their energy to next level

primary

consumer

secondary

consumer

Figure 11.17

Controlling pests

biomagnification

some chemicals get concentrated in tissues of the body

Figure 11.18

many pesticides interfere with the nervous system of the pest

Controlling pests

may damage our nervous system as well

Controlling pests

Integrated pest control

monitor pest levels

Increasing crop yields

Figure 11.19a

Controlling pests

Integrated pest control

monitor pest levels

pheremones

Increasing crop yields

Figure 11.19b

Controlling pests

Integrated pest control

monitor pest levels

pheremones

predator species

Increasing crop yields

Figure 11.19d

? safe

Figure 11.19d

exotic species

Controlling pests

Integrated pest control

monitor pest levels

pheremones

predator species

economic impact . . .

Increasing crop yields

cost/benefit

Increasing crop yields

Artificial selection

“These breeders chose individuals of the species that best exemplified the trait they desired. They allowed these individuals to mate, while preventing mating between individuals that did not have the desired trait.” BT3 pg. 397

Figure 11.20

Increasing crop yields

Green Revolution

Export better strains to poor countriesBetter yields…

… we are no better off

population growthsustainability

See quote page 398, BT3

Increasing crop yields

Genetic engineering (GMO’s)

transgenic plants

nutritional value(protein, starch)

pest resistanceherbicide resistanceshelf life

Increasing crop yields

Genetic engineering (GMO’s)

transgenic plants

molecular farmingtobaccohave plant make “products”

“blue genes”blue pigment gene into cottons plants

Increasing crop yields

Genetic engineering (GMO’s)

transgenic plants

risks biological ?concerns ethical ?