Transcript Ecology PPT - Dr Magrann

Ecology
The study of the interrelationships
of plants and animals with each
other and with their environment
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ECOLOGY
• An ECOSYSTEM is how the community
interacts with its physical environment.
• A COMMUNITY is all the populations of
plants and animals in a particular area, such
as a forest or a pond.
• A POPULATION is all of the members of the
same species that inhabit a particular area.
• The BIOSPHERE is a community and its
physical environment, including all of the
land, water, and air on the planet where
organisms live.
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Population or Community?
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Succession
• Succession on land begins on bare rock. With
time, the rock is subjected to weathering by wind
and rain, and then mosses start growing on it,
and as they die off, they create mulch, which
turns into soil.
• Then grasses come along and grow in the soil,
then comes the larger plants.
• Later, trees take root.
• Eventually the area reaches its climax.
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Succession
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Ecosystem
• An ecosystem has both nonliving and
living components.
• The nonliving components include
sunlight, inorganic nutrients, and weather
conditions.
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Sand, Magnified
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Habitat
• The habitat of an
organism is where it
can be found, such
as under a log or at
the bottom of the
pond.
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• The niche of an
organism is its
profession or role in the
community.
• A description of the niche
of a tree is that they take
in sunlight, carbon
dioxide, and water from
the environment, and
have many interactions
with other organisms,
such as woodpeckers.
• Woodpeckers feed on
grubs from a tree, which
also provides a habitat for
their chicks.
Niche
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Organization
•
Producers are organisms with the capability of making
their own food for themselves. On land, the main
producers are green plants, and in freshwater
ecosystems, the main producers are algae. Therefore,
all animal life depends, directly or indirectly, on green
plants, algae, or some producer for food, energy, and
oxygen. Producers supply oxygen to all the others.
Consumers are organisms that use pre-formed food.
•
–
–
–
•
Herbivores feed directly on plants
Carnivores feed only on animals
Omnivores feet on both plants and animals
Decomposers feed on dead material of plants and
animals
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Which group are
the producers?
Consumers?
Decomposers?
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Energy Flow and Chemical Cycling
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Energy Flow and Chemical Cycling
• Ecosystems are characterized by two
fundamental phenomena:
• Energy flow begins when producers (plants)
absorb solar energy. Energy flow occurs
because all the energy content of organic food is
eventually converted to heat, which dissipates in
the environment.
• Chemical cycling begins when producers take
in nutrients from the soil. Eventually, these
nutrients are returned to the soil.
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Energy Flow
• Since a plant uses about 55% of its fuel to
stay alive, only about 45% of the plant’s
energy is available to an herbivore that
eats the plant.
• When a carnivore eats the herbivore, only
a portion of that energy goes into the
carnivore.
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Energy Flow
• A certain amount of the food eaten by a
herbivore is never digested and is
eliminated as feces.
• The energy from the food that was
absorbed is used for respiration, and
thereafter becomes heat.
• Only the excess food can increase body
weight, and it is this weight that becomes
available to carnivores.
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Energy Flow
• The elimination of feces and the death of a
body is the food made available to
decomposers.
• All the solar energy that enters an
ecosystem eventually becomes heat.
• Ecosystems are dependent on a continual
supply of solar energy
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Laws of Thermodynamics
• Energy cannot be created or destroyed; it can
only be transformed.
• When energy is transformed from one form to
another, there is always a loss of some usable
energy as heat.
• Eventually, all the energy that entered the
system is dissipated. Since energy cannot be
created, all ecosystems require constant energy
input (usually from the sun).
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Food Web
• Now let’s take an actual example—a forest
in New Hampshire. In this forest, the
producers include sugar maple trees.
• A food web shows the complicated
feeding relationships that exist in
natural ecosystems, and how organisms
acquire their food.
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Food Web
• Caterpillars, mice, rabbits, and deer feed on the leaves.
• Birds and mice feed on fruits and nuts, plus they eat the
caterpillars.
• Other predators eat the birds and mice.
• The bacteria and fungi that live off the decayed material
are also food for earthworms and beetles.
• These worms are then eaten by lizards, which are in
turn, eaten by birds.
• It’s all connected in a web, called a food web.
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Food Web
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Trophic Levels
• A food chain is a diagram that links
organisms that feed upon one another.
• For example: leaves—caterpillars—
sparrows—hawks.
• Another example: algae → insect larvae
→ fish → humans.
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Trophic levels
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Trophic Levels
• A trophic level is all the organisms that feed at a
particular link in a food chain.
• In the forest, trees, plants, and grasses are the
first trophic level, the caterpillars as well as the
mice and rabbits are the second trophic level,
the sparrows as well as the robins and finches
are the third trophic level, and so forth.
Therefore, in the following food chain, what
organism is at the second trophic level?
• grass → rabbits → snakes → hawks.
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What animals
are at the
fourth trophic
level?
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In this
food web,
what
trophic
level are
hawks?
Herring?
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Ecological Pyramids
• These trophic levels can be drawn in the
form of a pyramid, just like a nutrition food
pyramid.
• For example, in the following food
chain, hawks are at the top of the
ecological pyramid:
• Weeds – insects – mice –hawks.
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Ecological Pyramids
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Ecological Pyramids
• The problem is that some organisms fit
into more than one trophic level, such as
mice.
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Food
Chain vs.
Trophic
level
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The Water Cycle
• EVAPORATION is when water changes
from a liquid into a gas and is removed
from plant leaves on a warm day.
• PRECIPITATION is when water falls from
the sky in the form of rain, snow, hail or
sleet.
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Water Cycle
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The Water Cycle
• Fresh water is distilled from salt water as
the sun’s rays cause fresh water to
evaporate from seawater, and the salts
are left behind.
• Vaporized fresh water rises into the
atmosphere, cools, and falls as rain over
the oceans and the land.
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The Water Cycle
• Water evaporates from land, but since
land lies above sea level, gravity
eventually returns all fresh water to the
sea.
• In the meantime, water is contained within
standing waters (lakes and ponds), flowing
water (streams and rivers), and
groundwater.
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The Water Cycle
• When rain falls, some of the water sinks
into the ground and saturates the earth to
a certain level, called the water table.
• About ¾ of the planet is covered in water
but only about 1% is drinkable.
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The Phosphorus Cycle
• On land, the weathering of rocks makes
phosphate, which goes into the soil and is
taken up by plants.
• Some phosphate runs into the oceans for
algae to use.
• Phosphorus does not enter the
atmosphere; therefore, the phosphorus
cycle is called a sedimentary cycle.
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The Phosphorus Cycle
• Plants use phosphate to make ATP and
DNA.
• Animals that eat plants incorporate some
of the phosphate into teeth, bones, and
shells that take many years to decompose,
but when they do, it becomes available to
plants again.
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Phosphate Cycle
The Phosphorus Cycle
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Humans Alter Transfer Rates
• Humans impact the phosphorus cycle by mining
phosphate ores, making fertilizers, and using laundry
detergent. Animal wastes, detergents, and fertilizers add
excess phosphate to nearby waters.
• When there is too much phosphate in the water, too
much algae can grow. Then, when algae grow in
excess, a condition called an algal bloom occurs.
• Any large algal bloom has the potential to result in fish
and shellfish kills by depleting the water of
oxygen. Furthermore, as these large blooms die and
sink to the bottom, they commonly release chemicals
that can produce a foul odor and musty taste.
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FISH DEATHS
FROM ALGAE
BLOOMS
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The Nitrogen Cycle
• Nitrogen is an abundant element in the atmosphere as a
gas (78% of the atmosphere). However, nitrogen
deficiency in plants is a problem. Why?
• Plants cannot make use of nitrogen gas. They
depend on various types of bacteria that live in
nodules on their roots which are able to take the
nitrogen gas from the atmosphere and turn it into the
type of nitrogen that the plant can use (nitrates,
ammonia, and urea) to make amino acids and DNA.
• Humans cause an excess of nitrogen by using it in
fertilizers which run off into water bodies.
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Nitrate Cycle
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The Carbon Cycle
• Animals that inhale oxygen will exhale carbon
dioxide.
• Plants, on the other hand, will take in carbon
dioxide and give off oxygen.
• Animals are dependent on plants, not only to
produce food and energy, but also for a supply
of oxygen.
• However, since plants can make their own food
and get their own carbon dioxide, they can
function independently of the animal world.
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Carbon Cycle
The Carbon Cycle
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The Carbon Cycle
• In the carbon cycle, plants take up
carbon dioxide from the air, and convert it
into food by photosynthesis.
• The plant is then eaten by animals, and
when the animal exhales, some of that
carbon dioxide is returned to the
atmosphere.
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Reservoirs Hold Carbon
• Living and dead organisms are one of the
reservoirs for the carbon cycle.
• The world’s trees contain 800 billion tons
of carbon, and dead animals and plants in
the soil contain an additional 2,000 billion
tons of carbon.
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Reservoirs Hold Carbon
• Some of these remains are subjected to
physical processes that transform them
into coal, oil, and natural gas.
• We call these materials the fossil fuels.
• Most of the fossil fuels were formed about
300 million years ago, when an
exceptionally large amount of organic
matter was buried before decomposing.
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GREENHOUSE EFFECT
• This is when gases trap heat in the lower
atmosphere.
• These gases (such as CO2) are mainly a
result of humans burning fossil fuels and
forests.
• Because of burning fossil fuels and wood, an
excess of carbon is released into the air.
• The typical method of clearing a rain forest is to
burn it down, thus creating even more carbon
dioxide in the atmosphere, and requiring more
plants to absorb it for us.
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GREENHOUSE EFFECT
• So, when we burn down forests, we are causing
two kinds of damage: we increase the carbon
dioxide in the air, while decreasing the main
reservoir that takes up excess carbon dioxide.
• In addition, this excess carbon dioxide (and
other gases) in the atmosphere cause more
global warming.
• These gases allow the sun’s rays to pass
through, but they absorb and reradiate heat
back to the earth, the phenomenon called the
greenhouse effect.
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GREENHOUSE EFFECT
• One consequence of global warming
impacting the climate is that there will
be more rain along the coasts and
dryer conditions inland.
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Rain along the coasts; dry inland
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What can you do?
• If everyone in America replaced one light bulb
with an Energy Star compact Fluorescent light
bulb, it would reduce greenhouse gasses
equivalent to getting 2 million cars off the road.
• If one in every ten houses in America used
Energy Star appliances, it would have a benefit
equivalent to planting 1.7 million acres of new
trees.
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Walmart Goes Green
• http://spiritualityhealth.com/articles/tenlessons-wal-mart-going-green
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Ten Lessons from Wal-Mart
Going Green
•
•
•
apply to anyone, five aimed specifically at businesses.
Carbon = energy = money. Carbon comes from using energy. Energy costs
money, which means cutting carbon saves the planet and saves you
money. So do what Wal-Mart does: use energy-efficient lighting. Plant
shade trees near your house or business. Insulate your attic and, if you
have a flat roof, paint it white. Clean the filters in your refrigerator, heater,
and AC. Small businesses that followed Wal-Mart’s advice have had their
energy bills drop 20 to 60 percent by taking just those steps.
Waste = Money. If Wal-Mart stores in California can cut their waste by 81
percent, anything’s possible. So cut out the disposable water bottles, and
use the tap and a glass. Make your own coffee instead of using all those
disposable latte cups. Consider bulk foods (they’re cheaper) and products
with a longer shelf life, such as organic milk, because a shocking third of our
food ends up spoiled and in the trash. Compost. Recycle. Donate. Wal-Mart
does all of this — and makes a cool $100 million a year from stuff it used to
pay to have hauled to the landfill.
•
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Ten Lessons from Wal-Mart
Going Green
•
•
•
Make sustainability about health. Let’s be honest: we all say we want to be
greener, but when it comes to voting with our time and our wallets, not so
much. So when Wal-Mart wants to sell green, it emphasizes how
sustainable choices are often healthy choices: organic baby food and
clothes, for instance, are pesticide-free and therefore healthier for babies.
And that does influence consumer behavior.
Start with quick wins. Wal-Mart caught sustainability fever by reducing the
packaging on a single toy — and finding it simultaneously saved a forest
and $2.5 million. What can a smaller business or household do? Switching
out light bulbs will garner visible savings, as will washing in cold water. Or
plant a vegetable garden nurtured with your own compost — the single
most sustainable thing anyone can do.
Listen to the kids. Wal-Mart is adopting sustainable business practices for
two reasons: The fi rst is because, right now, sustainability boosts profi ts.
The second has to do with the customers of tomorrow — our kids. Today’s
Wal-Mart shoppers are not particularly motivated to buy green. But their
kids are.
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Ten Lessons from Wal-Mart
Going Green
•
•
•
•
For Businesses: Sustainability starts at the top. no matter the size of the
company, CEOs have to make sustainability their priority — and make their
direct reports do the same. No one else can.
Everything is fair game. For a top-down sustainability mandate to succeed,
it must “infect” thinking throughout a business. it can’t be the job of a
separate sustainability team but rather the consideration of every
department and line worker, from buyers to truck drivers to warehouse
foremen.
Race to the top, not the bottom: Keeping the company at the point where
emissions, waste, toxins, and sprawl are legal is a race to the bottom. New
thinking about the environment perceives it as an opportunity to use
sustainability for competitive advantage, a tool to make a business leaner,
cleaner, and less wasteful, beyond anything that regulations require — a
race to the top.
Don’t wait for the market, lead it: Wal-Mart decided to get out in front of
consumer demand on sustainability and found that it served the bottom line
anyway — it pays to be green. But today’s sustainability efforts mean the
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company will be ready when consumer demand does catch up.
Global Warming
• One concern is that the world’s overall
temperature, called the global climate will
continue to warm at a rate ten times faster
than any time in the past.
• There is more carbon dioxide in the air
from the burning of fossil fuels and the
burning and clearing of forests to make
way for farmland and pasture.
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Global Warming
• The oceans are currently absorbing about
one half of the carbon dioxide emitted, or
else the increase would he much higher
than this stated amount.
• In addition, methane gas is being given off
by oil wells, rice paddies, and all sorts of
organisms including domesticated cows,
and this also contributes to global
warming.
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Global Warming
• These gases are known as greenhouse gases
because just like the panes of a greenhouse
they allow the sun’s radiation to pass through
but hinder the escape of heat.
• Actually, water is also a greenhouse gas
because clouds do the same thing.
• If the earth’s temperature rises due to the
greenhouse effect, more water will evaporate,
forming more clouds, compounding the problem.
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Global Warming
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Predicted Consequences
• Global warming will bring about climate
changes, glaciers would melt, and sea levels will
rise, evaporation will increase, and most likely
there will be more rain along the coasts and
dryer conditions inland.
• There will be more droughts inland, which will
reduce crop yields and also cause trees to die
off.
• Billions will have to be spent to keep coastal
cities, like New York, Boston, and Miami from
disappearing into the sea.
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Global Warming
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Acid Rain
• Pure water has a pH of 7 but the small
amount of carbon dioxide in the
atmosphere combines with water to
produce a weak acid.
• Therefore, we get rain with an acid pH.
• In addition, coal and oil that is burned will
release sulfur dioxide into the air.
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Acid Rain
• The oil well fires started during the Persian
Gulf War released much sulfur dioxide into
the atmosphere.
• Automobile exhaust puts nitrogen oxides
in the air.
• Both sulfur dioxide and nitrogen oxides are
converted to acids when they combine
with water vapor in the atmosphere.
• That gives the rain an even more acid pH.
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Acid Rain
• When the soil absorbs this rain, it
becomes acidic too, and it causes forests
to die, and the waters cannot support
normal fish populations.
• The acid rain also corrodes marble, metal,
and stonework, an effect that is noticeable
in cities.
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Ozone layer
• Ozone is a naturally occurring substance that is
supposed to stay up high in our atmosphere and
absorbs the harmful ultraviolet radiation that
tries to enter our planet.
• However, we are now getting ozone forming
down lower where we breathe.
• The air pollutants from fossil fuels react with one
another in the presence of sunlight to produce
ozone.
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Ozone
• Breathing ozone affects the respiratory and
nervous systems, resulting in respiratory
distress, headache, and exhaustion.
• These symptoms are particularly apt to appear
in young people; therefore, in Los Angeles,
where ozone levels are often high,
schoolchildren must remain inside the school
building.
• Ozone also damages plants.
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Carbon Monoxide
• Carbon monoxide from car exhaust blocks
the hemoglobin in our blood from carrying
oxygen.
• Breathing large quantities of automobile
exhaust can even result in death because
of this effect.
• Carbon monoxide is released into the air
from the burning of tropical forests.
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Ozone Depletion
• Normally, warm air near the ground
escapes into the atmosphere. However
smog keeps cold air at ground level
beneath a layer of warm air above.
• This is particularly true of Los Angeles,
and that’s why it’s called the “air pollution
capital” of the United States.
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Ozone Depletion
• When the ozone in the upper part of our
atmosphere becomes depleted, UV radiation
impairs crop and tree growth and also kills
plankton (microscopic plant and animal life) that
sustain oceanic life.
• Without an adequate ozone shield, food sources
and health are threatened.
• UV radiation also causes mutations that can
lead to skin cancer, cataracts, and affect our
immune system.
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Soil Erosion
• Wind and rain carry away about 25 billion tons of
topsoil yearly, worldwide.
• If this rate of loss continues, the earth will lose
practically all of its topsoil by the middle of the
next century.
• This is compounded by increased use of
fertilizers, pesticides, and fossil fuel energy.
• One solution is for farmers to use different
cropping methods to control soil erosion.
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Desertification
• Desertification the transformation of
land to desert conditions because of
overgrazing and over-farming.
• It is particularly a problem along the edge
of the Sahara Desert in Africa, but occurs
in the US as well.
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Desertification
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Deforestation
• Removal of forests impacts the amount of
carbon dioxide in the atmosphere, the
amount of fresh water available, and the
retention of soil.
• Yet, a huge number of trees have been turned
into paper and wood products.
• The animals that live in these forests have been
displaced.
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Deforestation
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Recovery
of a
forest
after a
fire
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Nitrate Levels After Deforestation
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Deforestation
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Deforestation
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Habitat loss
• Habitat loss is of most concern in tropical
rain forests and coral reefs.
• Tropical rain forests are home to more wildlife
than temperate forests.
• For example, temperate forests across the entire
United States contain about 400 tree species
compared to 750 types of trees in the rain
forests.
• There are about twice as many fish, frogs, and
birds in a rain forest.
• A million species of plants and animals are in
danger of disappearing within 20 years as a
result of deforestation.
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Habitat loss
• Many of these life-forms have never been
studied, and yet they may be useful sources of
food or medicines.
• Logging occurs because people prefer furniture
made from tropical woods.
• In Brazil, the government does not require
citizens to own any land they clear in the
Amazon forest.
• Once the cleared land is incapable of sustaining
crops, the farmers move on to another part of
the rain forest.
• In the meantime, cattle ranchers move in and
keep the area deforested.
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Extinction
• Hunting causes a lot of problems.
Animals are being hunted on land and
water for both pleasure and profit.
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Habitat Destruction
• Another major cause of extinction is
habitat destruction outright or by
fragmentation into small pieces that
cannot support the same species richness
as before.
• By the year 2020, very little undisturbed
rain forest will exist outside of National
parks and other relatively small protected
areas.
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Introduction of New Species
• The accidental or purposeful introduction of
new species into an ecosystem can cause the
extinction of another species.
• The brown tree snake somehow slipped into
Guam from the Pacific islands in the late 1940s.
• Since then, it has wiped out 9 of 11 native bird
species, leaving the forests eerily quiet.
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Introduction of Species
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Pollution
• Pollution like pesticides has caused a
decrease in predatory birds and
amphibians.
• The loss of entire species will most likely
be detrimental to humans since they
depend on them for raw materials, food,
medicines, and other things.
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Natural Medicines
• Great benefits can come from unlikely species.
• The Gila monster has deadly saliva, but it is useful at
regulating insulin levels in diabetics.
• The vampire bat has substances in its salivary glands
that prevent clotting, and are found to break up clots in
stroke victims.
• The scorpion’s venom can seek out and destroy brain
tumors.
• The puffer fish has poisonous spines but are effective in
easing the pain of heroine withdrawal and cancer.
• The saliva of the leech can reduce the risk of blood clots
during surgeries.
• The poisonous frog has deadly skin secretions, but is
effective as a pain killer without being addictive.
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Coral Reefs
• Like a tropical forest, coral reefs are most
likely sources of new medicines yet to be
discovered.
• If we lose one species, we may be losing an
important, life-saving medicine.
• Not only that, a reef serves as a storm barrier
that protects the shoreline and provides a safe
harbor for ships.
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Coral Reefs
• Reefs around the globe are being destroyed.
• Tons of soil from deforested tracts of land brings
nutrients that stimulate the growth of all kinds of
algae.
• This has contributed to population explosion of
starfish that are devouring Australia’s Great
Barrier Reef.
• Reefs are also being damaged by pollutants that
seep into the sea.
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Coral Reefs
• About 90 % of the coral reefs of the Philippines
are dead or deteriorating due to over-fishing.
• The methods are sinister, including the use of
dynamite to kill the fish, making it easier to
scoop them up, and use of cyanide to stun the
fish to capture them alive.
• The seaweed overgrows and kills the coral.
• It is estimated that we may lose 60% of all coral
reefs in the next 50 years.
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Coral Reefs
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Coral Reefs
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Oil Drilling in the Arctic:
Discussion
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The Harm Done by Acid Rain:
Discussion
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Ecology Videos
•
•
•
•
•
How Ecosystems Work 3 mins
Climax Communities 3 mins
Competition, Predation, and Symbiosis 3 mins
Exploring Oceans 7 mins
Water Cycle 3 mins
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