Transcript Plants for Building Materials & Conservation of Forests.

How do you use plants?
Since plants are so familiar, we may
overlook how vital they are to human
life:
How you use plants:
• Food (& farming)
• Medicines
• Fossil Fuels & Fuels
• Building materials & conservation
• Aesthetics (ITS PRETTY- The light & dark side of
Landscaping plants)
Plants as Food
Plus: Controversial topics:
-Sustainable farming
-Are Genetically
modified plants safe?
-Can GM foods make
the food supply
healthier & solve
world hunger?
-Should food be used
to make ethanol?
Image: http://www.aboutwomans.com/wp-content/uploads/2007/12/11297.jpg
Agriculture & Farming
Beginnings of Agriculture
• 12-14,000 years ago, humans were nomad hunter
gatherers.
• Cultivating crops & raising animals allowed
humans to settle & became the foundation for
cities & civilizations.
• Some early crops grown successfully: Corn,
wheat & rice- still are primary food
sources for people.
6 crops provide 80% of human
caloric intake:
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Wheat
Rice
Corn
Potatoes
Manioc (cassava)
Sweet potatoes
http://en.wikipedia.org/wiki/Cassava
Much of Remaining 20% of human
food comes from:
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Bananas
Beans
Soybeans
Sorghum
Barley
Coconuts
Sugarcane
Sugarbeets
Problems with Farming
Tilling the soil:
• traditional way of farming
• turning over the top layer of
soil
• loosen soil for new seeds
• keep down weeds.
• Easier to apply chemicals
• Aids in decomposition &
enriches soil
Problems:
• Erosion
• Release of carbon
• Applying large quantities of
antibiotics & chemicals
No- Till
A newer idea which
advocates say will “save
the planet”
Along with crop rotation,
will keep down:
-Erosion
-Carbon release into
atmosphere
-Use less fertilizer,
pesticide & herbicide
Sustainable
Farming
• “Sustainability rests on the principle that we must
meet the needs of the present without compromising
the ability of future generations to meet their own
needs.”
http://www.sarep.ucdavis.edu/Concept.htm
• Sustainable farming practices may also include a
movement away from large, industrial farms to
smaller, local, organic food production.
Genetically Modified Food
What is Genetically Modified Food?
Genetic engineering: manipulating genes
• When a gene for a protein or other substance
from one species is inserted into the genome of
a different species.
• Now the organism produces substances that it
never had the capacity to do before.
All living things have the same
genetic building blocks
DNA- deoxyribonucleic acid
has 4 nitrogenous bases which make
up the “alphabet” for the genetic
code.
SO- the same sequence of DNA
codes for an enzyme, protein or other
molecule no matter which organism
it is in.
That is the basis for Gene technology
First GM food- A tomato
• The first commercially grown genetically
modified food crop, Flavr
Savr tomato, was made
by adding a gene that prevented it from rotting on the shelf.
• 1994- Approved by FDA –decided it was safe, was not a
health hazard, & did not need special labeling. Calgene
was allowed to release it into the market.
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Welcomed by consumers who purchased the fruit at two to five
times the price of standard tomatoes.
• Company was bought by Monsanto in 1995.
Fishy Strawberries
Scientists took a gene from the North
Atlantic Flounder that produces an
antifreeze & inserted it in a plasmid of a
bacterium
The bacterium infected the strawberry
& the flounder antifreeze gene entered the
strawberry’s DNA
The new GM
strawberry cells are
cloned & grown into new plants that
have strawberries which make a protein that
keeps the fruit from frost damage.
www.usbornequicklinks.com
Genetically Engineered Bt Corn
• soil bacterium Bacillus thuringiensis (Bt)
is a natural pesticide.
• Scientists isolated the blueprint (gene) for
a protein within the bacteria's DNA which
kills insects.
• Bt gene combined with DNA of corn.
• The makeup & heredity of the corn was
changed. The Bt protein that kills insects
is now made by the corn plant.
• Some studies show Monarch butterflies
are killed by the corn.
• Concerns that this may cause some
species to become extinct.
http://www3.iptv.org/exploreMore/ge/main.cfm
GM foods
• Could increase nutritional value
• Increase aesthetics (prettier food)
• Fight world hunger
• As the human population increases, science
may need to find ways to increase
production of food- much like it did after
WWII with new techniques such as
machinery & antibiotic use.
GM foods- Golden Rice
Golden Rice is part of the solution
to world hunger & malnutrition.
-Biofortified rice may alleviate life-threatening
micronutrient deficiencies in developing
countries-(decrease starvation)
- Genetically modified- gene for
provitamin A (β-carotene), is inserted
into rice genome.
www.goldenrice.org/
So does everyone agree that
GM foods are wonderful?
• No- there are many questions &
protests about GM crops.
• Bioethicsis the study of
ethical issues related
to DNA technology.
A Greenpeace activist dressed
as a cow protests at the headquarters
of milk giant Murray Goulburn
in Melbourne. (AAP: Julian Smith
Protesters in India vs GM foods
• On 8 April 2008, farmers’ organizations and other civil society groups in India
protest the dangers of GM crops in general & Bt Brinjal in particular.
• Hazards reported to be deaths of livestock after animals grazed on Bt corn & Bt
cotton & also allergic reactions & some deaths in villagers.
http://www.i-sis.org.uk/gmProtestsIndia.php
Summary GM foods
Developed Nations: Developing Nations
GM foods used to:
*Make food look nicer
*increase shelf life
*fight pests
•Increase profits
•Questions remain
about its safety.
• A world hunger problem
exists (many causes)
GM seeds are used to
• increase nutritional
content & prevent loss of
crops to pests
• However, questions remain
about it’s safety.
Why GM foods are Controversial:
• Is the food safe to eat? (new chemicals)
• The risk of gene transfer to weeds.
• Crop biodiversity, worries about "gene
pollution" & ecology
• Concern about horizontal transfer of
genes from GM crops to other
organisms, such as bacteria.
Spices
More ways you use plants:
Spices
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Used to preserve & enhance foods
Freshen rooms
Cosmetics
Medicine
• Read black pepper- Savior of rotting meat
(page 7 textbook)
Some common spices:
• Allspice– Caribbean cuisine
– weak antibiotic
– deodorant
• Anise–
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sweet and very aromatic.
flavoring used in deserts
mild antiparasitic
its leaves can be used to treat
digestive problems, relieve
toothache, and it is used to treat
lice and scabies.
All of the following spices from: http://en.wikipedia.org/wiki/List_of_herbs_and_spices
Some common spices
Chives:
-condiment
-medicinal purposes
-insect repellant
Cinnamon:
-condiment & flavoring deserts, cereals,
candies, tea, hot cocoa and liqueurs.
-medicine (cure for colds. Diarrhea,
Diabetes, toothache, bad breath)
-preservation of certain foods.
-insect repellent
Some common spices
Garlic (Allium sativum )
-food, in many cultures
-medicine
* prevents heart disease including
atherosclerosis, high cholesterol, high
blood pressure, Cancer, diabetes,
-anti-bacterial activity
-Antibiotic activity- intestinal parasites
Also- Garlic has been reasonably
successfully used in AIDS patients to treat
cryptosporidium in an uncontrolled study
in China.
Garlic supplementation in rats along with
a high protein diet has been shown to
boost testosterone levels
**Spices/herb lab
More about garlic:
• Many cultures have used garlic for protection or
white magic, perhaps owing to its reputation as a
potent preventative medicine.
• Central European folk beliefs considered garlic a
powerful ward against demons, werewolves, and
vampires.
• The association of garlic to evil spirits may be based
on the antibacterial, antiparasitic value of garlic,
which could prevent infections that lead to delusions,
and other related mental illness symptoms.
• In Northeastern India, it is believed that garlic mixed
with water spread around the home will keep snakes
from entering
Vanilla
• There are three main commercial
preparations of natural vanilla for
use in cooking & baking:
– whole pod
– powder (ground pods)
– extract (in alcoholic solution)
• In old medicinal literature, vanilla
is described as an aphrodisiac and a
remedy for fevers.
• The cosmetics industry uses vanilla
to make perfume.
Plants for Beverages
Fermented Plants for : root beer,
beer & wine
• Beer - Hops
(Humulus) is a small
genus of flowering plants.
The female flowers,
commonly called hops, are
used as flavoring &
stabilizers during beer
brewing.
Sassafras tree
Root Beer
- also known as sarsaparilla, is a
carbonated beverage originally created from
sassafras. Originally made from Bark from the
roots of the sassafras tree.
-popularized in North America, comes in two forms:
alcoholic and soft drink.
Sassafras bark was banned by the FDA in
1960 because of its constituent chemical safrole,
which causes permanent liver damage & cancer. A
safrole-free variety is now used, with some
claiming that it has a weaker flavor than the pre1960 variety
More on the sassafras tree
• Dried root bark produces an essential oil of safrole
that was once used as a fragrance in perfumes and
soaps, food and for aromatherapy.
• Safrole is a precursor for the clandestine manufacture
of the drug ecstasy, and as such, its transport is
monitored internationally.
• The species are unusual
in having 3 distinct leaf
patterns on the same plant
http://www.uni-graz.at/~katzer/pictures/sass_08.jpg
Wine History
Wine was produced in many
ancient cultures.
The ancient Chinese made
wine from native wild "mountain
grapes”.
Early people in the middle
east made wine, but it became
strictly forbidden in Islam to
consume alcohol except for
medicinal purposes. Clay wine amphora or pots bake in the sun in Ica, Peru
http://www.lifeinitaly.com/wines/history.asp
Wine History
• Evidence of Wine production
has been found in Europe dating
back to at least 4000 BC.
– following the decline of Rome and therefore of widespread
wine production, the Christian Church supported wine made for
celebrating Catholic Mass.
– In medieval Europe, In places such as Germany, beer was
banned and considered pagan and barbaric
• Eventually, winemaking capability like England who enjoyed
wine varieties of Sherry, Port and Madeira.
• Records of winemaking & grape cultivation kept by
Christian monks of France & northern Italy helped various
regions match the best variety grape for their soil.
• By 1800, France would be recognized as the best of the wineproducing regions of the world.
Medicinal Plants
Plants as traditional medicine
• Early people used almost 3,000 different plants as
medicine.
• Black cohosh, a staple of Cherokee medicine, served many
purposes- from diuretic to a cure for rheumatic pains.
• Bloodroot provided the Cherokee with medicine to cure coughs
and lung inflamations.
American ginseng
Blood root
Medically Important Plants
• Willow bark - used for
headaches & pain• we now know it has
•
salicylic acid
Or “Asprin”
Willow tree
Plants have always been associated
with healing
• Since ancient times, people have noticed that plants can
alleviate symptoms of many medical conditions.
• During the 1500’s, “Herbals”- books which list use for
plants were written.
• 1700’s-modern chemistry used plant extracts containing
alkaloids & other compounds for healing.
• Example: Ephedrine is a powerful antihistamine
derivied from shrub Ephedra.
Plants in modern medicine
Taxus brevifolia (Pacific Yew)
Conifer - NorthAmerica
Produces anti-cancer
drug - TAXOL
Taxus brevifolia (Pacific Yew) foliage
A Chemotherapy drug
used in breast, ovarian and lung cancer treatment,
Taxus brevifolia was already becoming scarce when
its chemotherapeutic potential was realized.
Anti- malarial Drug
Cinchona Tree & Quinine
• Bark of cinchona trees produces several alkaloids.
• The alkaloid, quinine, acts as a
febrifuge -a medication that reduces fevers.
• Quinine was used in the battle against malaria since the
1630's.
• Of 38 species of cinchona, four species have economic
value for the production of quinine: C. calisaya, C.
legeriana, C. officianalis and C. succirubra.
What is Malaria?
• Malaria is caused by protozoan of the genus Plasmodium.
• Infection begins with a bite from an infected mosquito.
• The parasite travels from the mosquito to your liver, where the
parasite begins to reproduce.
• The parasite leaves the liver and travels to the bloodstream, where
it infects red blood cells. The parasite reproduces in the red blood
cells, which destroys the cells and releases more parasites into the
bloodstream.
• An estimated 350–500 million clinical malaria episodes occur
annually, resulting suffering & in a million deaths.
The most famous story behind the
discovery of Quinine
• In 1638 the Countess Ana of Chinchon.
contracted malaria in Peru.
• Given a powder that cured her of the fevers.
Impressed by this new cure she collected the
bark and gave it to others who needed it.
• (However, it is widely disputed that the
Countess was responsible for spreading the
bark, or that she even had malaria.)
• Nevertheless, Linnaeus named the genus
Cinchona in her honor.
Show video DDT/ malaria
Other examples of medicinal drugs
–Curare comes from a tropical vine, and is
used as an anesthetic and to relax muscles during
surgery.
– A person with lymphocytic leukemia has a 99%
chance that the disease will go into remission
because of the rosy periwinkle.
– More than 1,400 varieties of tropical plants
are thought to be potential cures for
cancer.
– Also-See page 42, medically important
compounds
– (you will be doing a report on this eventually)
Medically Important
Plant Compounds
In your textbook1. page 10
–read about antibiotic plant chemicals.
2. Page 42
– Read about alkaloids produced by certain
plants & about using cell cultures to produce these
compounds.
• (You will be doing a research paper about some of
these drugs during chapter 2)
Addictive plants
• Sometimes, plants take advantage of our
dependence on them & create addictive
chemicals that make us chemically
dependent.
For example:
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cane plants create sugar
coffee and tea plants create caffeine
tobacco plants create nicotine
coca plants create cocaine
poppy plants create opium.
“We underestimate the plant
kingdom.”
• Plants are so ubiquitous and stationary that we
ignore them and take them for granted. We
assume that plants are passive and dumb.
• We call lazy people "couch potatoes" and dull
people "vegetables”.
• Note- Addictive plants undermine our potential
for life and enslave us.
http://www.organicmd.org/plantsandanimals.html
Plants for Fuel
Plants as Fuel
• Past photosynthesis provides the
fossil fuels needed to power industry,
engines & automobiles.
• We burn wood as fuel.
• We can burn peat
moss.
• We now ferment plants into ethanol.
Photosynthesis & fuels in the
environment- It’s a cycle
• Burning firewood, ethanol, or coal, oil & other fossil
fuels releases CO2 back to the atmosphere,
increasing "greenhouse gases" in the environment.
• Since photosynthesis converts carbon dioxide from
the air to carbohydrates- Plants act also as a “carbon
sink”.
• As photosynthesis consumes carbon dioxide
and releases oxygen, it helps counteract the
effect of combustion of fossil fuels.
Fossil Fuels
• Are plant - fossilized remains
• Fossil fuels are non-renewable resources because they
take millions of years to form, and reserves are being
depleted much faster than new ones are being formed.
• Concern about fossil fuel supplies is one of the causes of
regional and global conflicts.
• The production and use of fossil fuels raise environmental
concerns.
• A global movement toward renewable energy is under way to
help meet increased energy needs
Fossil Fuels
• It was estimated by the Energy Information
Administration that in 2005, 86% of primary
energy production in the world came from
burning fossil fuels
• The remaining non-fossil sources:
– hydroelectric 6.3%,
– nuclear 6.0%,
– and other (geothermal, solar, wind, and wood and
waste) 0.9 percent
Wood is Cellulose
• One of the carbohydrates resulting from
photosynthesis is cellulose, which makes up the
bulk of dry wood .
• Burning wood converts cellulose back to carbon
dioxide & releases the stored energy as heat.
• Burning fuel
– is basically the same oxidation process that occurs in
our bodies;
– it liberates the energy of "stored sunlight" &
returns carbon dioxide to the atmosphere
Peat Moss
• Sphagnum moss- a nonvascular plant, has been
used a s a source of fuel in places like Ireland,
North Eastern United States & Canada.
• Ireland uses peat for 20% of its fuel.
• It is higher in
kilocalories than
wood but less
than coal.
http://www.danheller.com/images/Europe/Ireland/Connemara/Landscapes/peat-farmer-1.jpg
Ethanol
• Ethanol (grain alcohol) produced from
sugars and starches by fermentation is a
major automobile fuel.
• It is added to gasoline in the United States
to help reduce emissions of harmful
pollutants.
• It can be made from any plant, most often
sugar cane (Brazil) or corn.
Ethanol Controversy
• Largest use of ethanol is as a motor fuel and fuel
additive.
• The United States fuel ethanol industry is based
largely on corn.
• It is disputed whether ethanol as an automotive fuel
results in a net energy gain or loss.
– As reported in "The Energy Balance of Corn Ethanol: for
ethanol made from corn in the U.S. is 1.34 (it yields 34%
more energy than it takes to produce it). Input energy
includes natural gas based fertilizers, farm equipment,
transformation from corn or other materials, and
transportation.
– However, other researchers report that production of
ethanol consumes more energy than it yields
Ethanol Controversy
• It has been estimated that "if every bushel of U.S. corn, wheat,
rice and soybean were used to produce ethanol, it would only
cover about 4% of U.S. energy needs on a net basis
• The USA government highly subsidizes ethanol production
(it pays the farmers to make it)
• Additionally- Using corn may increase the prices of food.
• Recent articles have blamed subsidized ethanol production for
the nearly 200% increase in milk prices since 2004.
• Using corm for ethanol is being blamed for an
increase in world hunger.
Plants for Building Materials &
Conservation of Forests.
In Long-lived plants, stems become
strong, thick, useful woody trunks.
Controversial topics:
-Why would you want to make
sure that the wood products
you buy come from well
managed forests?
-What is conservation &
sustainable forest
management?
-Why should YOU care
About the tropical rain
Forest?
http://www.buildingconservation.com/articles/wood/wood.jpg
Wood
• Recall: What we call wood consists almost entirely
of dead cells- the cellulose is what is left of the plant
cell wall.
• Forests have been cut down for wood :
– agricultural clearing
– wood for fuel (most of the world still burns
wood, not fossil fuel, for heating & cooking)
– making paper (made from wood pulp)
– building products
Wood is still a primary building
product
• Frames for houses & other buildings
• Decking,
• Furniture
Forest Conservation
• “Conservation” was not a term most
people used before the late 1800’s.
• In the United States, however, between
about 1850 and 1920, a heightened
conservation consciousness first emerged as
a complex, broadly popular political and
cultural movement.
Conservationist- John Muir
• One of the first people who wanted to
conserve forest land was
John
Muir (1838-1914)
• His writings of his adventures in nature, and
wildlife, especially in the Sierra Nevada
Mountains of California, were read by millions
and are still popular today.
• His direct activism helped to save the Yosemite
Valley and other wilderness areas.
• The Sierra Club, which he founded, is now one of
the most important conservation organizations in
the United States.
www.johnmuir.org/
• His writings and philosophy strongly influenced
the formation of the modern environmental
Show video Yosemite park
movement.
Creating National Parks
• In 1903 President Theodore Roosevelt
accompanied Muir on a visit to Yosemite.
http://en.wikipedia.org/wiki/John_Muir
Muir Woods National Monument
• California Redwood trees -12 miles over the Golden
Gate Bridge from San Francisco.
• became a National Park in 1908
• Comprised of 295 acres of Redwood Forest
www.inetours.com/.../Muir_Woods.html
Conservation Biology
• (Read additional notes
• page 9 textbook
• on Theodore Roosevelt
& Gifford Pinchot)
President Theodore Roosevelt and Gifford Pinchot, Standing on Deck of Steamer
Mississippi, 1907.
Sustainable Forestry
• The Ministerial Conference on the Protection of Forests
in Europe (MCPFE), Defines sustainable forest
management as:
– “the stewardship and use of forests and forest
lands in a way, and at a rate, that maintains their
biodiversity, productivity, regeneration capacity,
vitality and their potential to fulfill, now and in
the future, relevant ecological, economic and
social functions, at local, national, and global
levels, and that does not cause damage to other
ecosystems.”
Sustainable Forestry
• In simpler terms, can be described as
– “the attainment of balance”
– balance between society's increasing
demands for forest products and
benefits,
– and the preservation of forest health
and diversity.
“Urban Forests – Trees Working
Where People Do”
• As our cities expand
and our population
moves to increasingly
urbanized areas,
American Forests
recognizes the
ecological value of
urban trees as an
important conservation
issue.
PLANT TREES NOW!!
http://www.americanforests.org/
Temperate Deciduous Forest
The forest biome where we live.
Deciduous -means shedding or falling off of
leaves
-Most intact in eastern North America
- In Europe, Most of the forest was cleared for agriculture, with
remnants surviving only in some royal hunting preserves.
In Asia
-China -intensive agriculture
- cleared for at least 4,000 years.
-Korea the forest is more intact
fall foliage is like New England's.
Tropical Rain Forests
• Why save the rain forest?
• All forests have both economic and ecological value,
but tropical forests are especially important in global
economy
• Has the most biodiversity & most species of any
Biome (Regions with distinctive climates and organisms)
• Tropical rainforests produce 40% of Earth's oxygen.
• Many of the medicines we use come from rainforest
plants
• Tropical Rain Forest used to cover about 20% of
Earth’s surface.
• Today it is about 6% and more is lost daily.
Tropical rain forests has several distinct
layers of foliage, each with its own
vegetation and wildlife.
Tropical Rain Forest
Threats:
1. Logging- for lumber
2. Burning -to clear for farming, residences
What you can do: Recycle,
Join a conservation
group
Don’t buy wood like Mahogany, Teak
Support products like nuts, fruit, rubber
Don't buy products made from endangered animals
Plants for Aesthetics
Beautiful Gardens
Controversial Topic:
Are Non-Native invasive species controllable?
www.glenwhangardens.co.uk/the_gardens.htm
Invasive non-native plants in PA
Images & information for the following slides from:
http://www.invasivespeciesinfo.gov/plants/main.shtml
Images: Invasive.org and Google
• What is a non-native invasive species?
– Invasive plants are introduced species that can thrive in
areas beyond their natural range of dispersal. These plants
are characteristically adaptable, aggressive, and have a
high reproductive capacity. Their vigor combined with a
lack of natural enemies often leads to outbreak
populations.
• Examples:
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Tree of Heaven
Kudzu
Mile a minute weed
(There are lots more)
Show video invasive species
Tree-of-Heaven
• Tree-of-Heaven
• Scientific name: Ailanthus altissima (Mill.) Swingle
• Common names: Tree-of-heaven, China-sumac,
varnishtree
• Native To: China
• Date of U.S. Introduction: Late 1700s
• Means of Introduction: Ornamental
• Impact: Crowds out native species; damages pavement
and building foundations in urban areas
Kudzu
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Scientific name: Pueraria montana
(Lour.) Merr. var. lobata (Willd.)
Maesen & S. M. Almeida
Common name: Kudzu
Native To: Asia
Date of U.S. Introduction: Late
1800s
Means of Introduction: Introduced
for erosion control
Impact: Crowds out native species
http://library.thinkquest.org/03oct/00946/pic_used/kudzu.gif
Mile-A-Minute Weed
Scientific name: Persicaria
perfoliata (L.) H. Gross (formerly
known as Polygonum perfoliatum
L. )
• Common name: Mile-A-Minute
weed, Chinese tearthumb
• Native To: Asia
• Date of U.S. Introduction: 1930s
• Means of Introduction: Introduced
accidentally as a contaminant of
ornamental stock
• Impact: Crowds out native species
Plants as Enemies
• Contact Dermatitis/ Allergic reactions:
– Poison Ivy, oak, sumac, stinging nettle, giant
hogweed
• Asthmatic reactions to tree & flower pollen
Poison Ivy.
• A classic presentation with
vesicles and blisters after
contact with the urushiol
oil in the plant.
• A line of vesicles (linear
lesions) caused by dragging
the resin over the surface of the
skin with a scratching finger is
a highly characteristic sign of
plant contact dermatitis.
www.lib.uiowa.edu/.../md/dermnet/poisonivy1.html
Stinging nettle (Urtica dioica)
• Flowering plant, native to Europe, Asia,
northern Africa, and North America
• The plants have stinging hairs whose
tips come off when touched, injecting
these irritants:
– acetylcholine
– histamine
– 5-HT
– formic acid
• common names: "7 minute stitch",
burn nettle, burn weed, and burn
hazel
http://en.wikipedia.org/wiki/Stinging_nettle
Giant Hogweed
(Heracleum mantegazzanium).
• Severe blistering reactions develop
from exposure to the sap.
• Native to Asia, is an invasive species
in the United States after being
introduced as a landscaping plant.
• Children should be kept away from
Giant Hogweed, and protective
clothing (including eye protection)
should be worn when handling it or
digging it.
http://www.lni.wa.gov/Safety/Research/Dermatitis/EdMat/PhytoSlides/16to20/default.asp
Pollen Allergy, What Is It?
• Each spring, summer, fall, tiny particles are
released from trees, weeds, and grasses.
• Their mission is to fertilize parts of other
plants, but many never reach their targets.
• Instead, they enter human noses & throats,
triggering a type of seasonal allergic rhinitis
called pollen allergy, hay fever or rose fever.
• Of all the things that can cause an allergy,
pollen is one of the most widespread.
• Short of staying indoors when the pollen count is high--and
even that may not help--there is no easy way to evade
windborne pollen.
http://www.medicinenet.com/script/main/art.asp?articlekey=20277
Ending Part I(with some extra info)
Part I Plants
Plants dominate the land & many
bodies of water
• Plant life existed in the oceans over 3 billion
years ago.
• No life existed on the land because of UV
radiation since there was no ozone layer.
• Approximately 475 million years ago,
enough oxygen had been produced so that
an ozone layer formed in the atmosphere.
• Small club shaped plants were the first to
live on the edges of land near water.
Part I Plants
Advantages of life on land
• Increased sunlight for photosynthesis
• Increased CO2 levels
• Access to inorganic molecules in soil
Disadvantages of life on land
• Susceptible to drying out