Transcript How Do Humans Affect Ecosystems?

How Do Humans Affect
Ecosystems?
Humans Change Ecosystems
What are some ways humans change
ecosystems?
• Mining
• Farming
• Burn fossil fuels
• Pollution
• Burning coal
Humans Change Ecosystems
~Burning Coal ~ The Journey~
Burning coal releases sulfur dioxide, a gas that can
travel on the wind for many kilometers. It can mix with
water vapor in the air to form sulfuric acid. This acid
travels through the air and falls in precipitation on
forests and farmlands far from the original source. The
acid damages the leaves and stems of trees and other
plants. It can damage tree roots, making it harder for
trees to get nutrients. The trees weaken and are more
likely to die. Acid in precipitation has not only
damaged forests. It has also harmed water ecosystems,
killing fish in some lakes.
Humans Change Ecosystems
~Burning Oil ~ The Journey~
Burning oil doesn’t release as many gases as
coal does. However, many people depend on
oil shipped from faraway places, and
sometimes there are spills from tankers,
pipelines, and offshore wells. Those spills harm
ecosystems, too. Chemicals in the oil can kill
aquatic life. Lumps of oil often was up on shore
and spoil beaches.
Activity
Draw one of these Journeys as a comic strip
Burning coal releases sulfur dioxide,
a gas that can travel on the wind for
many kilometers. It can mix with
water vapor in the air to form sulfuric
acid. This acid travels through the air
and falls in precipitation on forests
and farmlands far from the original
source. The acid damages the leaves
and stems of trees and other plants.
It can damage tree roots, making it
harder for trees to get nutrients. The
trees weaken and are more likely to
die. Acid in precipitation has not only
damaged forests. It has also harmed
water ecosystems, killing fish in some
lakes.
Burning oil doesn’t release
as many gases as coal does.
However, many people
depend on oil shipped from
faraway places, and
sometimes there are spills
from tankers, pipelines, and
offshore wells. Those spills
harm ecosystems, too.
Chemicals in the oil can kill
aquatic life. Lumps of oil
often was up on shore and
spoil beaches.
Humans Change Ecosystems
Introduction of exotic plants and animals
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Exotic organisms is one that is not native to the ecosystem
Can be harmful because they have no natural
enemies in the new area.
Exotic animal population goes up and crowd
out native species
Humans Change Ecosystems
Most exotic species arrive by accident but some
are introduced on purpose.
~Plant Journey~
Kudzu, plant native to Japan and China, was
planted in the USA to stop soil erosion. It
spread out of control in many parts of the
country. Many native plants have died because
of competition from kudzu.
What are examples of other exotic
species introduced to the USA?
Africanized Honeybee – accidently released during breeding experiment
Asian Carp - brought into the United States from Asia to manage water quality and vegetation in
catfish.
Asian Longhorned Beetle - entered the United States in wood pallets holding pipe shipped from
China for a sewer project in the late 1980s
Brown Tree Snake – found recently in Hawaii. Undetermined how.
European Wild Boar - First brought to North America by Spanish explorers to be used as domestic
pigs.
Red Imported Fire Ant - Thought to have hitched a ride to the United States in ship ballast from
South America
Zebra Mussel - Catching a lift from Eastern Europe aboard freighters
http://www.pbs.org/wnet/nature/episodes/animals-behaving-worse/americas-least-wanted/911/
Florida Pythons
Accidentally or intentionally released pythons are inhabiting dry as well as
wet habitats, and feeding on or competing with native species. Giant
pythons are well-adapted for success in Florida, where the habitat is
similar to their Asian home. Although they are non-venomous, pythons
are among the largest snakes in the world, reaching up to twenty-six feet
long. Their size and power makes them one of the top predators in
Florida’s Everglades National Park, taking on even the alligators, and
posing a threat to many of the indigenous and endangered species.
Invasive Pythons in Florida
Humans Change Ecosystems
EXTINCTION
ENDANGERED SPECIES
Loss of an entire species.
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Can occur naturally but
introduction of species can
increase rates by 100 to 1000
times natural rate
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Most common cause of
extinction is habitat loss
one with so few individuals that
it could die out.
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Ex. Black rhinoceros, African
elephant, and Blue whale
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Species decreasing in number
but not yet endangered are
called threatened.
Ecosystems in Danger
~The Story~
People constantly change Earth’s surface to
meet their needs. They drain wetlands and cut
down forests to make room for homes, roads,
and shopping centers. They turn natural
grasslands into farms, and they fill in bays to
add more dry land to cities. But while these
changes might be useful for some people, they
harm or destroy ecosystems.
Ecosystems in Danger
Tropical rainforests
• Once covered 6 million sq miles of Earth
• Destroyed for farmland, fuel, exotic wood
• Scientists estimate about 50% tropical
rainforests have been destroyed.
Ecosystems in Danger
Grasslands
• Most disrupted ecosystem
• Plowed for farmland due to fertile soil
• 99% of tallgrass prairie is gone
• Species decrease in number or disappear
entirely.
Ecosystems in Danger
Wetlands
• Years ago most people thought wetlands were
useless
• People drained and filled them for farm land
and homes
• More than half of the original wetlands of the
USA are gone
• Many wetland species are now endangered
How can we help?
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Laws prevent pollution
Ecosystems protected by National Parks
Restoration programs
Protect baby animals from predators and
dangerous human interactions
Endangered Species Act (ESA)
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Several species have been saved from extinction