Transcript Biology Today Third Edition

Eli Minkoff • Pam Baker
Biology Today
Third Edition
Chapter 11
Plants to Feed the World
Copyright © 2004 by Garland Science
Plants to Feed the World
A.
Plants
Uses (food, etc)
nutrition (photosynthesis; know equation)
B.
Economics
Plants are producers
Animals (and others) are consumers
Fungi and bacteria are decomposers
Energy flows through the economy
Chemicals are recycled within the economy
e.g., the nitrogen cycle
Plants to Feed the World
C.
Plant anatomy
parts and functions
vascular tissue
water movement
(osmosis, transport, transpiration)
D.
Increasing crop yield
Fertilizer (benefits and dangers)
Soil makeup and conservation
Water distribution (hydroponics)
Monocultures (benefits and dangers)
Pests and controlling them
Food pyramid and biomagnification
GMO’s advantages / disadvantages ?
(genetically modified organisms -= GMO)
Plants
Food
Over 250,000 species
80,000 are edible by humans
30 major crops in the world
4 feed more than all others
wheat
rice
corn
potatoes
Plants
(Drinks, spices)
Food
Fragrances
Dyes
Poisons
Decorations
Building material
Medicines
Fuel
Paper
Plant Nutrition
autotrophic
photosynthesis
sunlight + CO2 + H2O
(energy)
glucose + O2
Energy flow
Sun supplies all of our energy
Plants capture and store energy
(autotrophic)
producers
We eat plant material to get energy
(heterotrophic)
consumers
primary, secondary, …
Some organisms are absorptive heterotrophs
decomposers
Fig. 11-1
Fig. 11-2
Fig. 11-3
Fig. 11-4
Fig. 11-5
Energy flow
Chemicals cycle
C6H12O6
O2
plants
us
H2O
CO2
Chemicals cycle
Other chemical cycle too
e.g., nitrogen
amino acid, DNA, RNA
Chemicals cycle
Plants need nitrogen too
absorb nitrates and nitrites
nitrogen-fixation
convert N2 from air to NH3
nitrification
convert NH3 to NO3-,NO2-
Fig. 11-6
Fig. 11-8
Plant Anatomy
Specialized plant parts:
leaves
photosynthesis
roots
absorption
stems
transport
flowers
reproduction
vascular tissue
water and minerals
xylem
phloem nutrients (sap)
Fig. 11-9
hypotonic
Fig. 11-10
Increasing crop yields
Fertilizer
adds nutrients needed
by plants to the soil
Animal waste (manure)
Composting
Chemical fertilizer
disease
&
run-off
Fig. 11-13
What do plants need to grow ?
water
soil
Soil
Loose material
weathered rock
organic material
Soil types
parent rock
climate
groundwater
activity of living organisms
topsoil
lost to erosion
made slowly
(1 inch/200-1000 years)
“non-renewable”
don’t poison it or loose it
Plants to Feed the World
A.
Plants
Uses (food, etc)
nutrition (photosynthesis; know equation)
B.
Economics
Plants are producers
Animals (and others) are consumers
Fungi and bacteria are decomposers
Energy flows through the economy
Chemicals are recycled within the economy
e.g., the nitrogen cycle
Plants to Feed the World
C.
Plant anatomy
parts and functions
vascular tissue
water movement
(osmosis, transport, transpiration)
D.
Increasing crop yield
Fertilizer (benefits and dangers)
Soil makeup and conservation
Water distribution (hydroponics)
Monocultures (benefits and dangers)
Pests and controlling them
Food pyramid and biomagnification
GMO’s advantages / disadvantages ?
(genetically modified organisms -= GMO)
Water
plants need it:
photosynthesis
transport
turgor pressure
90% lost to transpiration
Increasing crop yields
Irrigation
supplying water to crops
expensive ?
What do plants need to grow ?
water
soil
yes
no
Hydroponics
growing crops without soil
“inside”
controlled climate
protected
no tilling
more control
expensive
construction
maintenance
monoculture
Fig. 11-15
Monocultures
single species
rapid spread of disease
depletion of soil
damage by pests
Figure 11.16 (1)
Figure 11.16 (2)
Increasing crop yields
Controlling pests
insects (adult and/or larvae)
rodents
fungi
30% of many crops are destroyed
protect with pesticides
(kills pests)
Increasing crop yields
Controlling pests
ideal pesticide
kill only target pest
no effect on non-targets
avoid devel. of resistance strains
breakdown to harmless substances
ideal pesticide does not exist
Increasing crop yields
Controlling pests
DDT
kills lots of insects
sprayed on soldiers to kill lice
used on crops to kill pests
(more food)
sprayed on water to kill mosquitoes
(less disease)
Controlling pests
expensive
kills non-target species
DDT-resistance
pollute drinking water
biomagnification
food pyramid
DDT
Width shows biomass
secondary
consumer
primary
consumer
producers
must be on bottom
they can’t pass on all their energy to next level
Figure 11.17
Controlling pests
biomagnification
some chemicals get
concentrated in tissues of
the body
Figure 11.18
Controlling pests
many pesticides interfere with the
nervous system of the pest
may damage our nervous
system as well
Increasing crop yields
Controlling pests
Integrated pest control
monitor pest levels
Figure 11.19a
Increasing crop yields
Controlling pests
Integrated pest control
monitor pest levels
pheremones
Figure 11.19b
Increasing crop yields
Controlling pests
Integrated pest control
monitor pest levels
pheremones
predator species
Figure 11.19d
? safe
Figure 11.19d
exotic species
Increasing crop yields
Controlling pests
Integrated pest control
monitor pest levels
pheremones
predator species
economic impact . . .
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 countries
Better yields…
… we are no better off
population growth
sustainability
See quote page 398, BT3
Increasing crop yields
Genetic engineering (GMO’s)
transgenic plants
nutritional value
(protein, starch)
pest resistance
herbicide resistance
shelf life
Increasing crop yields
Genetic engineering (GMO’s)
transgenic plants
molecular farming
tobacco
have plant make “products”
“blue genes”
blue pigment gene into cottons plants
Increasing crop yields
Genetic engineering (GMO’s)
transgenic plants
risks
concerns
biological ?
ethical ?