Capter 12
Passenger Pigeon Extinction
 Alexander Wilson, an ornithologist in the early 1800s, described a flock of passenger pigeons that he
estimated was 240
 miles long and 1 mile wide and consisted of over 2 million birds.
 The passenger pigeon became extinct in1934.
Passenger pigeons Extinction m Why???
 were used as fertilizer.
 were good to eat.
 were suffocated by burning grass or sulfur below their roosts.
 had feathers used to stuff pillows.
Biodiversity facts
1. elimination of exotic vegetation leads to an increase in biodiversity
2. introduction of exotic species leads to a decrease in biodiversity
Extinction rates
 If there are 100 million different species, the background rate of extinction is about 30____ species per
year.
 conservation biologists estimated that the rate of extinction was thousands times higher ____ than the
estimated natural background extinction rate.
 The current extinction crisis differs from previous mass extinctions in that he current crisis is caused by
the human species.
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Endanger
Mathematical models indicate that organisms most vulnerable to habitat loss may be the top
competitors.
Wilson estimates that a 1.8% per year loss of tropical forest results in roughly a 0.5%____ loss of
species.
In a 1998 survey, 70% of the biologists polled believed we are in the midst of a mass extinction and that
this loss of species will pose a major threat to human existence in the next century.
 An endangered species is any species that can soon become extinct in all or part of its range.
 The California condor and whooping crane are endangered species.
Why are animals Extinction Prone?
All of the following characteristics would make a species more prone to extinction
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 low population density.
 specialized niche.
 low reproductive rate.
 fixed migratory patterns.
The timber wolf is extinction prone because of its preying on livestock.
The grizzly bear and American alligator are threatened species.
The whooping crane is vulnerable to reproduction rate.
The blue whale is extinction prone for extinction because of its low
 low reproduction rate.
 specialized feeding habits.
 fixed migratory patterns.
How population size affects extinction rate
Small populations of species
 may be below the critical population density.
 are vulnerable to catastrophic events.
 may have a reduced evolutionary potential for survival.
 A population size dropping toward a critical population density increases the chances of a smaller gene
pool and inbreeding.
(The type of species that offers the best opportunity to apply the prevention principle is the indicator species.)
Mamman;s
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Overall, about 25%____ of all mammals are at risk of becoming extinct in the wild in the very near
future.
The highest percentage of mammals at risk of becoming extinct in the near future are apes and
monkeys.
The country with the highest number of mammal species threatened with extinction is Indonesia.
The Value of Species
Biologists claim that species have
ecological value.
economic value.
medical and scientific value.
intrinsic value.
 If you eat cashews, avocados, or bananas, you can thank a bat.
Bats are endangered for all of the following reasons \
they live in habitats vulnerable to destruction.
they have a slow reproduction rate.
people are fearful of them.
 Fruit-eating bats on many tropical islands are keystone species.
Economic services performed by wild species include
nitrogen-fixation.
production of medicines.
pollination of crops.
fuelwood and lumber.
The ecosystem service provided by wild species is
recycling nutrients and decomposition of organic wastes.
diversifying the gene pool.
moderating Earth's climate.
natural pest and disease control.
Plant Service
About 90%____ of today's food crops were domesticated from wild tropical plants.
Wild plant species have economic value as
fiber.
dyes.
oils.
medicines.
Human impact on extinction
People regard wildflowers as beautiful, and this is evidence that wildflowers have aesthetic importance.
A single male lion living to age seven in Kenya is worth $515,000 as a tourist attraction.
Underlying causes of extinction and reduction of wildlife populations include
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affluence.
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human population growth.
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governmental policies that undervalue ecological services.
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rising resource use.
1. The cause of endangerment and extinction of wild species with the longest delay is human population
growth.
2. The greatest threat to most species is reduction of habitats.
3. The greatest species terminator is habitat destruction of tropical forests.
4. Since Europeans first settled North America, 98%____ of the tall-grass prairies in the United States
have been destroyed.
Island
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Symphonia on Madagascar is particularly vulnerable to extinction because it is an island species.
http://rsbl.royalsocietypublishing.org/content/5/6/821.full
You are studying species diversity in the Caribbean islands. Which island would you expect to have the
most number of species? a large island near the mainland
Why Do we Have Parks????
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People who believe that wild species have an inherent right to exist generally believe that species have intrinsic
value.
According to biologist E. O. Wilson, most people feel a sense of affinity toward the natural world that he calls
biophilia.
National parks can be viewed as habitat islands surrounded by
logging.
industrial activity.
energy extraction.
agriculture.
Habitat islands
can create small populations vulnerable to inbreeding.
are often too small to support the minimum number of individuals required to sustain a
population.
may be national parks, protected areas, or freshwater lakes.
are more vulnerable to competition from nonnative and pest species.
Fragmentation
Fragmentation of tropical forests would be harmful to migrating songbirds.
Habitat fragmentation
can create barriers that limit the ability of species to find food and mates.
increases edge areas that make some species more vulnerable to predators.
may create habitats too small to support the minimum breeding population of some species.
may limit the ability of some species to disperse and colonize new areas.
Nonnative Species
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nonnative organisms account for the greatest annual economic loss? crop weeds
invasive species has had a major impact on native bird and reptile populations is the brown tree snake
nonnative species often results in unforeseen consequences. This experience indicates that when
introducing nonnative species, we would be well-advised to apply the precautionary principle.
 About 1/2____ of the species on the U.S. official list of endangered and threatened species are there in
part because of population declines caused by nonnative species.
Nonnative Species Japanese kudzu vine
Japanese kudzu vine offers all of the following
starch used in Asian beverages and herbal remedies.
control of soil erosion.
a source of tree-free paper.
herbal remedies for diseases.
Nonnative Species (The water hyacinth)
The water hyacinth
 is native to Central and South America.
 entered Florida via transplanting from an exhibit.
 has rapidly displaced native species.
 clogs waterways.
Water hyacinths have been most effectively controlled by manatees, which are a threatened species.
Water hyacinths can
 absorb toxic chemicals in sewage treatment lagoons.
 be fermented to form biogas fuel.
 be used as a mineral and protein supplement in cattle feed.
 The rapid doubling of a water hyacinth population(nonnative) in nutrient-rich waters with no
predators is an example of a positive feedback loop.
Accidental/Legal (Pets) / Illegal import of species
All of the following are organisms imported into the United States that cause damage
 sea lamprey.
 Japanese beetle.
 house sparrow.
 kudzu.
Illegal
Illegal hunting for profit is called poaching.
Illegal wildlife trafficking is the world's second ____ largest form of black-market commerce.
responsible for the strong decline in elephant populations?
legal ivory trade
habitat loss
poaching
low reproductive rate
As a result of the ban on elephant ivory sales, killing of bull walruses and hippos has increased. Which of the following
principles best describes this event? We can never do just one thing.
Nuisance species
All of the following species eare threatened or endangered because they are a nuisance to some humans.
 coyotes
 prairie dogs
 elephants
 wolves
1. Carolina parakeet was exterminated because it fed on fruit crops.
2. Prairie dogs have almost been driven to extinction by poison.
3. black-footed ferrets is almost extinct because its prime source of food has been killed by poison ( they
eat prairie dogs)Primary causes of mortality include habitat loss, human-introduced diseases, and
indirect poisoning from prairie dog control
Legal
Importing exotic birds for households may
 be hazardous to the owners' health.
 result in the decline of tourist income from exporting countries.
 result in a 90% animal death rate.
 endanger or threaten bird species.
The pet trade has depleted populations of
 birds.
 mammals.
 tropical fish.
 reptiles.
Some exotic plant species that may bring $5,000 to $15,000 to collectors are most likely orchids or cacti.
Even with the best management, wildlife reserves may be depleted in a few decades because of climatic change brought
about by projected global warming.
Laws Protecting Species
CITES is a(n) treaty controlling the international trade in endangered species.
CITES is limited by
 violators receiving only small fines.
 spotty enforcement.
 member countries exempting themselves from protecting some species.
 much of the illegal trade in wildlife going on in countries that have not signed the
treaty.
Lacey Act.-Transporting of live or dead wild animals across U.S. state borders without a federal permit is prohibited y the
The Endangered Species Act of 1973 allows the use of endangered species for approved scientific purposes or
 is one of the world's toughest environmental laws.
 if the use enhances the survival of the species.
 authorizes identification of endangered species solely on a biological basis.
 requires all commercial shipments of wildlife enter or leave the U.S. through one of
nine designated ports.
Animals listed as endangered or threatened cannot be ____ in the United States.
 injured
 hunted
 Collected or killed
DDT can harm wildlife by
 making them more vulnerable to diseases.
 making them more vulnerable to parasites and predators.
 killing them directly.
 decreasing reproductive rates.
Bird species likely to show the harmful effects of biological magnification from DDT.
Why?
 falcon
 cardinal
 pelican
 sparrow hawk
 owl
Bioinformatics includes
 providing means for communicating biological information, such as the Internet.
 building computer databases to organize and store useful biological information.
 providing computer tools to find, visualize, and analyze biological information.
 Species 2000 is an international project whose goals include providing information
on all of the following
 species distribution.
 global biodiversity.
 introduced species.
 exotic species.
Identification and delisting of species
Identification and listing of endangered species is done by the Fish and Wildlife Service.
Over the last quarter century, the number of species found exclusively on the U.S. list increased about ten times.
All of the following are candidates for delisting from the endangered and threatened species list
 gray wolf.
 bald eagle.
 peregrine falcon.
 American alligator.
Wild life refuge
All of the following would strengthen the Endangered Species Act
giving private landowners tax breaks for helping protect endangered ecosystems.
surveying the species and ecosystems we have.
locating and protecting the most endangered species.
giving private landowners financial incentives and technical help for helping protect
endangered species.
When wildlife experts must judge which species to save, they choose a species because it is
 has the best chance for survival.
 has the most ecological value to the ecosystem.
 is potentially useful for agriculture or medicine.
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The group of animals most protected by wildlife refuges are migratory waterfowl.
Wildlife refuges have been instrumental in helping all of the following species recover
key deer.
trumpeter swan.
brown pelican.
American alligator.
Wildlife managers have to make plans based on all of the following principles
 ecological succession.
 food and habitat requirements for each species.
 number of potential hunters.
 wildlife population dynamics.
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Weedy pioneer species are found primarily in early-successional stages.
Wilderness species would be expected to flourish best in mature, relatively undisturbed habitats.
Moderate-size, old-growth forest refuges are required by late-successional species.
Partially open areas with plenty of edge habitat are required by mid-successional species.
Waterfowl management includes
developing ponds.
protecting existing habitats.
building artificial nesting sites.
regulating hunting.
Flyways are migration routes.
Wild life Programs
Seed gene banks are refrigerated environments with low humidity.
A drawback of gene banks, arboreta, and botanical gardens is that
 there is not enough funding to provide storage of all endangered species.
 there is too little storage capacity.
 seeds in storage do not evolve and therefore become less fit for reintroduction into a
changed environment.
 some plant seeds do not store well.
Egg pulling refers to collecting eggs from the wild and hatching them in zoos or research centers.
Captive breeding programs in zoos require the captive population to number between 100 and 500.
Most wildlife management in the United States is keyed to management of population sizes and habitats to favor game
species.