9-3 how do humans accelerate species extinction?
DESCRIPTION
There are four underlying causes of species extinction that result for human activities…. Population _____________ _______________ resource use _____________________ natural capital _________________ growth Rising Undervaluing PovertyTRANSCRIPT
9-3 How do Humans Accelerate Species Extinction?
Concept 9-3The greatest threats to any species are (in order) loss
or degradation of its habitat, harmful invasive species, human
population growth, pollution, climate change, and overexploitation.
There are four underlying causes of species extinction that result
for human activities.
Population _____________ _______________ resource use
_____________________ natural capital _________________ growth
Rising Undervaluing Poverty Natural Capital Degradation
Causes of Depletion and Extinction of Wild Species Underlying
Causes Population growth Rising resource use Undervaluing natural
capital Poverty Direct Causes Figure 9.9: This figure illustrates
both the underlying and direct causes of depletion and extinction
of wild species resulting from human activities (Concept 9-3) (see
Figure 1-9, p. 13). The biggest cause is habitat loss, degradation,
and fragmentation. This is followed by the deliberate or accidental
introduction of harmful invasive (nonnative) species into
ecosystems. Question: What are two direct causes that are
specifically related to each of the underlying causes? Habitat loss
Pollution Commercial hunting and poaching Climate change Habitat
degradation and fragmentation Overfishing Sale of exotic pets and
decorative plants Introduction of nonnative species Predator and
pest control Fig. 9-9, p. 198 Loss of Habitat Is the Single
Greatest Threat to Species: Remember HIPPCO
Biodiversity researchers summarize the most important direct causes
of extinction using the acronym _____________________ Habitat
destruction, degradation, and fragmentation Invasive (nonnative)
species Population and resource use growth Pollution Climate change
Overexploitation HIPPCO According to researchers, the greatest
threat to wild species is ________________ loss, degradation, and
fragmentation Ex:Polar bears are losing the ice beneath their feet
Habitat fragmentation occurs when large, intact areas of habitat
are ________________ into smaller, isolated patches or
________________________ Divisions may be caused by roads, logging
operations, crop fields, and urban development habitat divided
habitat islands Habitat Fragmentation
Habitat fragmentation can Decrease tree ____________ in forests
Block migration __________________ _________________ populations
Create _________________ to colonization Inhibits finding
___________ and _____________ Isolated populations may be more
vulnerable to ___________________ ___________________ species
____________________ ____________________ events (storms, fires)
cover routes Divide barriers food mates predators Competitor
Disease Catastrophic Asian or Indian Elephant
Indian Tiger Range 100 years ago Range today Black Rhino Range in
1700 Range today African Elephant Probable range 1600 Range today
Asian or Indian Elephant Former range Range today Stepped Art Fig.
9-10, p. 199 Some Deliberately Introduced Species Can Disrupt
Ecosystems
Most species introductions are beneficial Food Shelter Medicine
Aesthetic enjoyment Pest control But nonnative species may have
_____ __________________ predators, competitors, parasites, or
pathogens that would help to control their numbers in their
original habitats no natural Deliberately Introduced Species
Purple loosestrife European starling African honeybee (Killer bee)
Nutria Salt cedar (Tamarisk) Figure 9.11: These are some of the
more than 7,100 harmful invasive (nonnative) species that have been
deliberately or accidentally introduced into the United States.
Marine toad (Giant toad) Water hyacinth Japanese beetle Hydrilla
European wild boar (Feral pig) Fig. 9-11a, p. 200 Accidentally
Introduced Species
Sea lamprey (attached to lake trout) Argentina fire ant Brown tree
snake Eurasian ruffe Common pigeon (Rock dove) Figure 9.11: These
are some of the more than 7,100 harmful invasive (nonnative)
species that have been deliberately or accidentally introduced into
the United States. Formosan termite Zebra mussel Asian long-horned
beetle Asian tiger mosquito Gypsy moth larvae Fig. 9-11b, p. 200
Case Study: The Kudzu Vine
Sounds like CUD-zoo Deliberately imported from Japan in the 1930s
to help prevent ______________ in the southeastern U.S. The vine
that ate the South grows rapidly and is difficult to
kill._______________ anything in its path erosion engulfs Kudzu
Taking Over an Abandoned House in Mississippi, U.S.
Figure 9.12: Kudzu has taken over this abandoned house in the U.S.
state of Mississippi. The vine, which can grow 5 centimeters (2
inches) per hour, was deliberately introduced into the United
States for erosion control. Digging it up and burning it do not
halt its spread. Grazing goats and repeated doses of herbicides can
destroy it, but goats and herbicides also destroy other plants, and
herbicides can contaminate water supplies. Scientists have found a
common fungus that can kill kudzu within a few hours, apparently
without harming other plants, but they need to investigate any
harmful side effects it may have. Fig. 9-12, p. 201 Case Study: The
Kudzu Vine
Could there be benefits of kudzu? Fiber for making _____________
(could end up saving trees) Kudzu starch powder reduces desire for
alcohol Edible, high levels of vitamins _____ and _____ Japan
actually maintains a kudzu farm in Alabama and ships the starch to
Japan paper A C Another deliberately introduced species that became
invasive was the African ___________________
Imported to Brazil as a cheap substitute for conventional escargot
When export prices for escargot fell, breeder dumped the imported
snails into the wild Devours many food ______________ Carries
parasites that cause ___________________ and other human diseases
land snail crops meningitis Some Accidentally Introduced Species
Can Also Disrupt Ecosystems
Argentina fire ant: 1930s Accidentally introduced in Alabama May
have been on ________________ of lumber or imported coffee Reduced
populations of native ants Painful stings can kill Pesticide
spraying in 1950s and 1960s worsened conditions .genetic
__________________ 2009: tiny parasitic flies may help control fire
ants shiploads resistance Fight Between a Python and
Alligator
Pythonssold as _______________. Accidentally introduced to the
Florida ____________________ pets Everglades Figure 9.13: This huge
python and an American alligator were in a life-or-death struggle
in the Florida Everglades. After a 10-hour battle the alligator
killed the snake by taking it underwater and drowning it. However,
in some struggles, these snakes kill and eat the alligatorstheir
only natural predator in the Everglades. Fig. 9-13, p. 202
Prevention Is the Best Way to Reduce Threats from Invasive
Species
Prevent them from becoming ________________ Learn the
characteristics of the species Set up research programs Try to find
natural ways to control them International treatiesban transfers
between countries Public education established What Can You Do?
Controlling Invasive Species
Figure 9.14: Individuals matter. Here is a list of some ways to
prevent or slow the spread of harmful invasive species. Questions:
Which two of these actions do you think are the most important?
Why? Which of these actions do you plan to take? Fig. 9-14, p. 203
Other Causes of Species Extinction (1)
Human population growth and overconsumption have greatly expanded
the human ecological ________________ which has eliminated,
degraded, and fragmented vast areas of wildlife habitat
Pollution________________ have killed honeybees (crop pollinators)
, many birds and fish Climate change - ______________ temperatures
and melting ice may drive to of all _______ animals and plants to
extinction footprint pesticides higher land Other Causes of Species
Extinction (2)
Toxins can be _____________ through a food chain Organisms at
_____________ trophic levels are exposed to ALL of the toxins
encountered by lower levels Bioaccumulation biomagnified higher
Case Study: Where Have All the Honeybees Gone?
Honeybees are responsible for pollinating______ of
insect-pollinated plants Helps to produce _______ of the human food
supply 2006 studies reported a______ drop in honeybee populations
Dying due to Pesticides? Parasites? Viruses, fungi, bacteria?
Microwave radiation cell phones? 80% 1/3 30% Case Study: Where Have
All the Honeybees Gone?
In 2008, the U.S. had a record loss of ______ of their commercial
honeybee colonies 1/3 of the deaths were due to colony
_____________ _______________ (CCD) in which most or all of the
adult worker bees mysteriously _______________ Suspected causes
Parasites Fungus , virus, bacteria Pesticides Poor nutrition and
stress caused by _____________ diets and ______________ around the
country 36% collapse disorder vanish artificial moving Review
Questions! What does HIPPCO stand for?
Why are nonnative species potentially harmful? The process of a
toxin, like DDT, moving and accumulating through food chains is
called Habitat loss Pollution Invasive species Climate change
Population growth Overexploitation They may have no natural
predators or other factors to limit their growth Biomagnification
or bioaccumulation