Title: How do you use plants?
1How do you use plants?
2Since 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)
3Plants 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/uploa
ds/2007/12/11297.jpg
4Agriculture Farming
5Beginnings 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.
66 crops provide 80 of human caloric intake
- Wheat
- Rice
- Corn
- Potatoes
- Manioc (cassava)
- Sweet potatoes
http//en.wikipedia.org/wiki/Cassava
7Much of Remaining 20 of human food comes from
- Bananas
- Beans
- Soybeans
- Sorghum
- Barley
- Coconuts
- Sugarcane
- Sugarbeets
8Problems with Farming
- 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
- 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
9Sustainable 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.
10Genetically Modified Food
11What 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.
12All 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
13First 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. - Welcomed by consumers who purchased the fruit at
two to five times the price of standard tomatoes.
- Company was bought by Monsanto in 1995.
14Fishy 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 strawberrys 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
15Genetically 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
16GM 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.
17GM 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 (ß-carotene), is inserted into rice
genome.
www.goldenrice.org/
18So does everyone agree that GM foods are
wonderful?
- No- there are many questions protests about GM
crops. - Bioethics-
- is 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
19Protesters 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
20Summary GM foods
- Developing Nations
- 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 its safety.
- Developed Nations
- GM foods used to
- Make food look nicer
- increase shelf life
- fight pests
- Increase profits
- Questions remain about its safety.
21Why 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.
22Spices
23Spices
More ways you use plants
- Used to preserve enhance foods
- Freshen rooms
- Cosmetics
- Medicine
- Read black pepper- Savior of rotting meat (page 7
textbook)
24Some common spices
- Allspice-
- Caribbean cuisine
- weak antibiotic
- deodorant
- Anise-
- 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_spi
ces
25Some 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) -preservatio
n of certain foods. -insect repellent
26Some 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
27More 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
28Vanilla
- 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.
29Plants for Beverages
30Fermented 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.
31Sassafras 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
pre-1960 variety
32More 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.jp
g
33Wine 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
34Wine 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 wine-producing regions of the world.
35Medicinal Plants
36Plants 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
37Medically Important Plants
- Willow bark - used for headaches pain-
- we now know it has salicylic acid
- Or Asprin
Willow tree
38Plants have always been associated with healing
- Since ancient times, people have noticed that
plants can alleviate symptoms of many medical
conditions. - During the 1500s, Herbals- books which list
use for plants were written. - 1700s-modern chemistry used plant extracts
containing alkaloids other compounds for
healing. - Example Ephedrine is a powerful antihistamine
derivied from shrub Ephedra.
39Plants 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.
40Anti- 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.
41What 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 350500 million clinical malaria
episodes occur annually, resulting suffering in
a million deaths.
42The 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
43Other 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)
44Medically Important Plant Compounds
- In your textbook-
- 1. 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)
45Addictive plants
- Sometimes, plants take advantage of our
dependence on them create addictive chemicals
that make us chemically dependent. - For example
- cane plants create sugar
- coffee and tea plants create caffeine
- tobacco plants create nicotine
- coca plants create cocaine
- poppy plants create opium.
46We 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
47Plants for Fuel
48Plants 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.
49Photosynthesis fuels in the environment- Its 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.
50Fossil 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
51Fossil 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
52Wood 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
53Peat 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/Con
nemara/Landscapes/peat-farmer-1.jpg
54Ethanol
- 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.
55Ethanol 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
56Ethanol 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.
57Plants for Building Materials Conservation of
Forests.
58In 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
59Wood
- 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
60Wood is still a primary building product
- Frames for houses other buildings
- Decking,
- Furniture
61Forest Conservation
- Conservation was not a term most people used
before the late 1800s. - 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.
62Conservationist- 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. - His writings and philosophy strongly influenced
the formation of the modern environmental
movement.
www.johnmuir.org/
Show video Yosemite park
63Creating National Parks
- In 1903 President Theodore Roosevelt accompanied
Muir on a visit to Yosemite.
http//en.wikipedia.org/wiki/John_Muir
64Muir 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
65Conservation 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.
66Sustainable 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.
67Sustainable 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.
68Urban 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/
69Temperate 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.
70Tropical 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
Earths surface. - Today it is about 6 and more is lost daily.
71Tropical rain forests has several distinct layers
of foliage, each with its own vegetation and
wildlife.
72Tropical Rain Forest
- Threats
- 1. Logging- for lumber
- 2. Burning -to clear for farming, residences
- What you can do Recycle, Join a conservation
group - Dont buy wood like Mahogany, Teak
- Support products like nuts, fruit, rubber
- Don't buy products made from endangered animals
73Plants for Aesthetics
74Beautiful Gardens
Controversial Topic Are Non-Native invasive
species controllable?
www.glenwhangardens.co.uk/the_gardens.htm
75Invasive non-native plants in PA
Images information for the following slides
from http//www.invasivespeciesinfo.gov/plants/ma
in.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
- Tree of Heaven
- Kudzu
- Mile a minute weed
- (There are lots more)
Show video invasive species
76Tree-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
77Kudzu
- 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
78Mile-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
79Plants as Enemies
- Contact Dermatitis/ Allergic reactions
- Poison Ivy, oak, sumac, stinging nettle, giant
hogweed - Asthmatic reactions to tree flower pollen
80Poison 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
81Stinging 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
82Giant 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/E
dMat/PhytoSlides/16to20/default.asp
83Pollen 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?art
iclekey20277
84Ending Part I- (with some extra info)
85Plants dominate the land many bodies of water
Part I Plants
- 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.
86Advantages of life on land
Part I Plants
- Increased sunlight for photosynthesis
- Increased CO2 levels
- Access to inorganic molecules in soil
- Susceptible to drying out
Disadvantages of life on land