3. - the end of an organism, normally a species.
- occurs when the last member of the species
dies.
- If over an extended period of time the birth
rate of a species is less than the death
rate, then extinction will eventually occur.
- a natural phenomenon predicted by Darwin in
his theory of evolution. A species goes extinct
if it is not able to adapt to changes in its
environment, or compete effectively with
other organisms.
i-introduction
4. - new varieties of organisms arise and thrive when
they are able to find and exploit an
ecological niche and species become extinct
when they are no longer able to survive in
changing conditions or against superior
competition.
i-introduction
5. - are periodic rises in the extinction rate
above the background level.
- are events which are not caused by changes
in habitat or competition but catastrophes.
1. The late Ordovician
2. Late Devonian
3. End Permian
4. Late Triassic
5. The Cretaceous Tertiary
i-introduction
6. Occurred about 439 million years ago
due to a drop in sea levels as glaciers
formed followed by rising sea levels as
glaciers melted. During this extinction 25
percent of marine families and 60 percent
of marine genera (the classification above
species) were lost.
i-introduction
7. Took place somewhere around 364 million years
ago. To this day its cause is unknown. However, evidence
supporting the Devonian mass extinction suggesting that
warm water marine species were the most severely
affected in this extinction event, has led many
paleontologists to believe that an episode of global
cooling, similar to the event which that may have
resulted in the Ordovician-Silurian mass extinction, may
have led to the Devonian extinction. Thus this theory
suggests that the extinction of the Devonian was
triggered by another glaciation event on Gondwana,
which is evidenced by glacial deposits of this age in
northern Brazil.
i-introduction
8. Happened about 251 million years ago and was
Earths worst mass extinction. 95 percent of all species, 53
percent of marine families, 84 percent of marine genera,
and an estimated 70 percent of land species such as plants,
insects and vertebrate animals were killed during this
catastrophe. Direct evidence for this period has not been
found but many scientists believe a comet or asteroid
impact led to this extinction. Others think that volcanic
eruption, coating large stretches of land with lava from the
Siberian Traps, which are centered around the Siberian City
of Tura, and related loss of oxygen in the seas were the
cause of this mass extinction. Still other scientists suspect
that the impact of the comet or asteroid triggered the
volcanism.
i-introduction
9. Taking place roughly 199 million to 214
million years ago, was most likely caused by
massive floods of lava erupting from the central
Atlantic magmatic province triggering the breakup
of Pangaea and the opening of the Atlantic Ocean.
The volcanism may have led to deadly global
warming. Rocks from the eruptions now are found
in the eastern United States, eastern Brazil, North
Africa and Spain. 22 percent of marine families, 52
percent of marine genera, and an unknown
percentage of vertebrate deaths were the result.
i-introduction
10. Occurred about 65 million years ago and is
thought to have been aggravated, if not caused, by
impacts of several-mile-wide asteroid that created
the Chicxulub crater now hidden on the Yucatan
Peninsula and beneath the Gulf of Mexico. Yet, some
scientists believe that this mass extinction was
caused by gradual climate change or flood-like
volcanic eruptions of basalt lava from the Deccan
Traps in west-central India. During this extinction, 16
percent of marine families, 47 percent of marine
genera, and 18 percent of land vertebrate
families including the dinosaurs.
i-introduction
12. Climatic Heating and Cooling
Climate Change is caused by a number of
things. The effect that climate has on extinction is
very big. The biodiverse Earth can't keep up with the
rapid changes in temperature and climate. The
species are not used to severe weather conditions
and long seasons, or a changing chemical make-up of
their surroundings. As more species die, it is only
making it more difficult for the survivors to find
food. The warmer climates we are used to present-
day are perfect for diseases and epidemics to thrive.
ii-discussion
13. Changes in Sea Levels or Currents
The changes in sea levels and currents is a
result, in part, of the melting freshwater. The
denser, saltier water sinks and forms the currents
that marine life depends on. Ocean floor spreading
and rising also affects sea level. A small rise in the
ocean floor can displace a lot of water onto land
that is already occupied. The gases from the
volcanic activity can also be absorbed by the water,
thus changing the chemical composition, making it
unsuitable for some life.
ii-discussion
14. Asteroids/Cosmic Radiation
Asteroids hit the earth with extreme force.
The reverberations can be felt around the world.
The impact site is completely destroyed. Cosmic
Radiation is radiation being emitted from outer
space and the Sun. It is hypothesized that being
exposed to too much cosmic radiation can mutate
genes, which can potentially weaken a species'
genepool in the future. Since the radiation comes
from space and the Sun, it is extremely difficult to
avoid the radiation. A supernova remnant is one
source of cosmic radiation.
ii-discussion
15. Acid Rain
Acid rain forms when sulfur dioxide and/or
nitrogen oxides are put out into the atmosphere.
The chemicals get absorbed by water droplets in
the clouds, and eventually fall to the earth as acid
precipitation. Acid rain increases the acidity of the
soil which affects plant life. It can also disturb
rivers and lakes to a possibly lethal level.
ii-discussion
16. Disease/Epidemic
Each species has defense mechanisms like
immunities and the ability to fight disease. With
the changing climate and landscape certain species
are losing their ability to fend off disease. They
are becoming more susceptible to disease and
epidemics, which can lead to their eventual
extinction.
ii-discussion
17. Spread of Invasive Species
Invasive species invade foreign territory.
They use resources that the other species depend
on. Once competition gets too great, the survival of
the fittest plan will begin, and one of the species,
usually the natural one, will die off.
ii-discussion
18. Top Human Causes of Extinction
• Increased human population
• Destruction/Fragmentation of Habitat
• Pollution
• Climate Change/Global Warming
ii-discussion
19. Habitat Degradation
Habitat loss and degradation affect 86% of all
threatened birds, 86% of mammals and 88% of threatened
amphibians.
Climate Change and Global Warming
John W. Williams from UW-Madison suggests that
changes in regions such as the Peruvian Andes, portions of the
Himalayas and southern Australia could have a profound
impact on indigenous plants and animals. Williams and his
research partners used computer models to estimate how
various parts of the world would be affected by regional
changes consistent with the IPCC's climate models. Their
findings indicated that “By the end of the 21st century, large
portions of the Earth’s surface may experience climates not
found at present and some 2th century climates may
disappear.”
ii-discussion
21. Forests in the tropics are cleared to make room
for farms. But tropical forest soil is very poor, and so
farmers have to keep moving on and destroying more and
more forests to grow their crops.
International companies also cut down forests for
their timber, or to make room for other plantations, in
which most native animals and plants cannot survive.
Each year, 1% of the world's tropical forest is
destroyed. This doesn't seem like much but it all adds
up, and is not good news for native plant and animal
species.
Although natural habitats are often completely
destroyed, they can also be broken up into lots of
isolated patches.
These patches may be separated by roads, fields
or human habitation, and may become too small to
support the species that depend on them. This process of
habitat fragmentation is the main reason for the decline
of many animals and plants.
ii-discussion
22. People use a lot of different crops and
domesticated animals for farming, and a lot more
animals and plants (like mice, rats, cockroaches and
weeds) live and thrive around us even if we don't
want them to!
As people have spread around the world, they
have taken many of these species with them, either
deliberately or accidentally.
But introduced species often have a very
harmful effect on native species.
Some people still transport animals from one
country to another, smuggling exotic species for an
illegal trade. This isn't good, as history tells us that
animals can only be introduced to a new habitat after
extensive scientific study has shown that these
introductions can only benefit the environment and
not damage native species.
ii-discussion
23. An obvious example of pollution is an
oil spill. This happens when oil is released
accidentally into the sea from a tanker,
pipeline or refinery. The spill forms a thin
layer of oil, called a slick, poisoning sea life,
and damaging the fur and feathers of seabirds
and mammals.
Car exhaust fumes are an obvious
form of air pollution. Production in factories
and other industry can have very serious
effects on the environment by releasing
molecules like Sulphur dioxide or nitrogen
oxide into our atmosphere. These molecules
can dissolve in water droplets in clouds to
form acid rain, which damages forests and
kills fish and other water animals.
ii-discussion
24. The growth of the human population is
the biggest threat to natural environments today.
One hundred years ago, there were one
billion people in the world. Now there are over six
billion!
Quite simply, there isn't enough room for
natural environments to coexist with all these
people, and the land they need to provide them
with food and shelter.
ii-discussion
25. People wanted whale oil and
whale meat, elephant ivory, and rhino and
tiger trophies. Although all of these
animals are now protected by law from
excess hunting, illegal poaching still
continues.
Other species are overharvested -
they are used faster than they can be
replaced - which is likely to lead to
decline and extinction.
ii-discussion
28. The golden toad is not the
only species to disappear
in the past 40 years, but it
might just be the
brightest. This fluorescent
amphibian was found in
the high-altitude ridges of
Costa Rica, but thanks to
pollution, global warming
and fungal skin infections,
the species became
extinct in 1989.
1. Golden Toad
(1989)
PLACE: Costa Rica
iii-summary
29. One of several
subspecies of leopard, the
Zanzibar leopard made its home
on the Zanzibar archipelago of
Tanzania. It's still unclear
whether this large cat is
technically extinct — there are
occasional unconfirmed sightings.
Cause of extinction:
Locals believed the leopards were
kept by witches, and aggressively
hunted them. The animals were
seen as evil predators that must
be exterminated — and even
the government was in on the
campaign.
In the mid-'90s there
was a short-lived conservation
effort but it was deemed too
little, too late.
2. Zanzibar Leopard (1996)
PLACE: Tanzania
iii-summary
30. A native of Maui,
Hawaii, the Po'ouli, or Black-
faced Honeycreeper, was only
discovered in the 1970s. The
birds inhabited the
southwestern slope of Haleakala
volcano. But the population
declined rapidly, and by 1997
there were only three known
Po'ouli left. Efforts to mate the
remaining birds failed and the
species was formally declared
extinct seven years later.
Cause of extinction: Habitat
loss, along with disease,
predators and a decline in its
food source — native tree snails
— are all seen as reasons for the
bird's demise.
3. Po'ouli (2004)
PLACE: Southwestern slope of
Haleakala
iii-summary
31. The stunning Madeiran
Large White butterfly was found
in the valleys of the Laurisilva
forests on Portugal's Madeira
Islands. The butterfly's closest
relative, the Large White, is
common across Europe, Africa
and Asia.
Cause of extinction: Loss of
habitat due to construction as
well as pollution from
agricultural fertilizers are two
major causes of the species'
decline.
4. Madeiran Large White
(2007)
PLACE: Portugal
iii-summary
32. The Tecopa pupfish, a
native of the hot springs of the
Mojave Desert, has the
distinction of being the first
animal declared extinct under
the provisions of the
Endangered Species Act of 1973.
The pupfish's decline was
precipitated when its natural
habitat was encroached upon by
developers.
Cause of extinction:
Destruction of natural
habitat.
5. Tecopa Pupfish (1982)
PLACE: Mojave Desert
iii-summary
33. The last Pyrenean
ibex died in 2000. However,
a cloned ibex, created from
skin samples taken from the
last Pyrenean ibex, was
birthed in 2009. It died
shortly after birth from lung
complications.
Cause of extinction:
Hunting of the ibex
had caused the animal's
numbers to seriously dwindle
and conservationists blame
the Spanish government for
failing to act in time to save
it.
6. Pyrenean Ibex (2000)
iii-summary
34. The majestic West
African black rhino was
declared extinct in 2006, after
conservationists failed to find
any in their last remaining
habitat in Cameroon. The West
African black rhino was one of
four subspecies of rhinoceros.
Cause of extinction: Poachers
hunted the rhino for its horn,
which is believed by some in
Yemen and China to possess
aphrodisiacal powers.
7. West African Black
Rhinoceros (2006)
PLACE: Africa
iii-summary
35. Similar in appearance
to the Sumatran tiger, the Javan
tiger was native to the
Indonesian island of Java. In the
1800s they were so common
they were considered pests by
island natives, but as the island
was developed their population
dwindled. By the 1950s, only 20
tigers remained.
Cause of extinction: Loss of
habitat and agricultural
development led to severe
population decline.
Conservation efforts in the
1940s and '50s were
unsuccessful due to a lack of
adequate land and planning.
8. Javan Tiger (1979)
PLACE: Indonesia
iii-summary
36. Spix's Macaw, also
called the Little Blue Macaw,
was known for its beautiful
blue feathers. While some
still exist in captivity, these
tiny blue birds are extinct in
the wild.
Cause of extinction:
Habitat destruction
and illegal trapping and trade
contributed to the macaw's
dwindling numbers.
9. Spix's Macaw (2004)
iii-summary
37. Native to Round Island,
a tiny island off the coast of
Mauritius, the Round Island
Burrowing Boa preferred to live
on the topsoil layers of volcanic
slopes. It was once found on
several other islands around
Mauritius, but its population
had dwindled by the 1940s, and
it could only be found on Round
Island after 1949. It was last
seen in 1975.
Cause of extinction:
The introduction of
non-native species of rabbits
and goats to the island
destroyed vegetation and upset
the boa's habitat.
10. Round Island
Burrowing Boa (1975)
iii-summary
38. This Dutch butterfly —
a subspecies of the Alcon Blue
— was found mainly in the
grasslands of The Netherlands.
While closely related species
(pictured here) still exist in
parts of Europe and Asia, the
last Dutch Alcon Blue was seen
in the wild in 1979.
Cause of extinction:
Increases in farming
and building had a negative
impact on the Alcon Blue's
habitat and caused it to lose
its main food source.
11. Dutch Alcon Blue
Butterfly (1979)
PLACE: Netherlands
iii-summary
48. Landscape
1. Biodiversity Parks
2. Ecologically Reclaimed and Restored Habitats
Community
3. The Fabric of Local Communities
4. Diversity in Human Landscapes
5. Legislation
Economy
6. Ecological Economics
7. Endowment: Biodiversity Trusts
Education and Science
8. Bio literacy
9. Toward Zero Extinction
iv-solutions
49. The task is not as insurmountable as it
might appear. By preserving and endowing just
25 biodiversity hotspots (less than two percent
of the earth’s land area) we could help protect
44% of vascular plant species and 35% of all
species of mammals, birds, reptiles and
amphibians for $500 million a year—less than
0.1% of the funds allocated to the United
States’ Troubled Asset Relief Program (TARP) to
bail out incompetent financial institutions.
iv-solutions
50. Humans need to play conservation offense as well as
defense. Beyond the immediate concern with the loss of a
particular population, species, or ecosystem, a focus on
long-term recovery and biological revival is also essential.
Scientific research can inform the restoration of local
habitats and help denaturalize entire ecosystems by uniting
scattered fragments.
EXAMPLE:
In Costa Rica, scientists, businesspeople, politicians,
and the local community helped regenerate 700 square
kilometers of a tropical forest system—an area assaulted by
ranching, hunting, logging, and fires for almost 400 years.
They purchased large tracts of land, stopped the farming
and fires, and let nature take back its original terrain.
iv-solutions
51. It is where local populations increase around
protected areas, a key challenge will be to
mitigate the inevitable impacts by weaving the
protected areas into the fabric of local
communities, thereby promoting traditions of
stewardship.
EXAMPLE:
In Peru, villagers are literally weaving palm
branches from Amazonian trees into baskets for
sale in overseas markets. The goal is to make
conservation productive, bettering the lives of
local weavers while shifting communities away
from large-scale consumption.
iv-solutions
52. Pick a square kilometer of land at random
and the odds are high that people live or work
on it and that they have quick access to many
others via road or stream. Chances are also
good that at nightfall you will see artificial light
emanating from that patch of land. Less than a
fifth of the world’s land surface has escaped the
direct touch of Homo sapiens. Humanity now
utilizes almost half of everything that grows on
the planet, consuming more than 40% of the
Earth’s net primary productivity.
iv-solutions
53. Present laws, commissions, and treaties, when fully
enforced, may be best able to handle the direct exploitation of
wildlife species. Treaties such as the Convention on International
Trade in Endangered Species and the International Whaling
Commission’s moratorium on commercial whaling have helped
lower trade in rare and declining species. Domestic laws, such as
the Endangered Species Act in the United States, are explicitly
designed to stop anthropogenic extinctions. The act has been
successful in reducing the extinction rate and recovering several
high profile species, such as the alligator, bald eagle, and gray
whale.
Legislation and economic disincentives should be
strengthened and enforced on local, national, and international
levels, with the latter designed especially to exert pressure on
noncompliant nations. Incentives, economic and otherwise, are
also essential. Payments for the ecosystem services provided by
habitat protection can be used to help fund communities near
conservation areas, thereby making biodiversity protection both
more appealing and profitable.
iv-solutions
54. In the seventeenth and eighteenth
centuries, economic relationships were seen as a
reflection of the natural world. The scholar and
philosopher David Hume regarded economic
processes as part of nature. His contemporary Carl
Linnaeus praised the “economy of nature” in a
treatise on self-regulation in animals and plants.
Thomas Malthus worked within the tradition of the
natural sciences. For these and other thinkers of
the Enlightenment, human reason was understood
as a derivative of natural instincts; nature was a
benevolent force in creating wealth.
iv-solutions
55. One innovative way to establish and
maintain protected areas is by creating
conservation trust funds. There is an urgent need
for such endowments, especially in the tropics,
where human numbers and consumption are
burgeoning and populations of many wildlife
species are in decline. In these developing
countries, money to maintain national parks is
often short. In many cases, expenditures are less
than five percent of those deemed necessary to
establish and maintain a viable reserve network.
iv-solutions
56. As a society, we need to establish an ecological
identity that helps foster a love of nature. Biologists
can convey the excitement of natural history and the
joy of scientific inquiry to students and the general
public. Social scientists can help make the connection
between wildlife conservation and human well-being.
Great places to start are in the home and in
elementary school. “See spot run” should be replaced
by “See the plant grow in the sun.” Many authors have
written convincingly on the need for environmental
literacy and outdoor education, to take students
directly into parks, farms, and shorelines. There is
evidence that students who receive such place-based
education typically outperform their peers.
iv-solutions
57. The goal needs to be made clear: to
reverse the current trend and add anthropogenic
extinction to the injustices—slavery, child labor,
apartheid, the Iron Curtain—found abhorrent by
civilized people. Achieving such a social and
ecological transformation will require ingenuity
and initiatives that are global in scope, yet
regional in implementation.
iv-solutions