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e x t i n c t i o n

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- 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.

extinction

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More than 99% of all species,

amounting to over five billion species that

ever lived on Earth are estimated to be

extinct.

speciation- 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.

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Mass extinction- 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.

Big 51. The late Ordovician 2. Late Devonian 3. End Permian4. Late Triassic 5. The Cretaceous Tertiaryi-introduction

The Ordovician-Silurian extinction

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.

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Late Devonian extinction

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

Permian-Triassic extinction

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

End Triassic extinction

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.

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Cretaceous-Tertiary extinction

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. 

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II- di s cus s i o n

Natural causes of extinction

Climatic Heating and CoolingClimate 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

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

Asteroids/Cosmic RadiationAsteroids 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.

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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.

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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.

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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.

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human causes of extinction

Top Human Causes of Extinction• Increased human population• Destruction/Fragmentation of Habitat• Pollution• Climate Change/Global Warming

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Habitat DegradationHabitat loss and degradation affect 86% of all

threatened birds, 86% of mammals and 88% of threatened amphibians.

Climate Change and Global WarmingJohn 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.”

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What does “hippo” means???

H- habitat destructionI - invasive speciesP - pollutionP - populationO - overharvesting & overhuntingii-discussion

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

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.

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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.

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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.

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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.

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III- s u mm

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11 Extinct Animals We've Lost in Our Lifetime

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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 Ricaiii-summary

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: Tanzaniaiii-summary

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

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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

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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

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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)

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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

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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: Indonesiaiii-summary

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)

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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)

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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: Netherlandsiii-summary

List of extinct animals of the Philippines

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IV- so l ut i ons

Facing Extinction: Nine Steps to Save Biodiversity

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Landscape1. Biodiversity Parks2. Ecologically Reclaimed and Restored Habitats

Community3. The Fabric of Local Communities4. Diversity in Human Landscapes5. Legislation

Economy6. Ecological Economics7. Endowment: Biodiversity Trusts

Education and Science8. Bio literacy9. Toward Zero Extinction

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1. Biodiversity ParksThe 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.

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2. Ecologically Reclaimed and Restored Habitats

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

3. The Fabric of Local Communities

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

4. Diversity in Human Landscapes

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.

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5. LegislationPresent 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

6. Ecological EconomicsIn 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.

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7. Endowment: Biodiversity Trusts

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.

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8. Bio literacyAs 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

9. Toward Zero Extinction

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.

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THANK YOU