The Great Permian-Triassic Extinction

The greatest mass extinction of the last 500 million years or Phanerozoic Eon happened 250 million years ago, ending the Permian Period and beginning the Triassic Period. More than nine-tenths of all species disappeared, far exceeding the toll of the later, more familiar Cretaceous-Tertiary extinction. For many years not much was known about the Permian-Triassic (or P-Tr) extinction. But starting in the 1990s, modern studies have stirred the pot, and now the P-Tr is a field of ferment and controversy. Fossil Evidence of the Permian-Triassic Extinction The fossil record shows that many lines of life went extinct both before and at the P-Tr boundary, especially in the sea. Most notable were the trilobites, the graptolites, and the tabulate and rugose corals. Almost completely exterminated were the radiolarians, brachiopods, ammonoids, crinoids, ostracodes and conodonts. Floating species (plankton) and swimming species (nekton) suffered more extinctions than bottom-dwelling species (benthos). Species that had calcified shells (of calcium carbonate) were penalized; creatures with chitin shells or no shells did better. Among the calcified species, those with thinner shells and those with more ability to control their calcification tended to survive. On land, the insects had severe losses. A great peak in the abundance of fungus spores marks the P-Tr boundary, a sign of massive plant and animal death. Higher animals and land plants underwent significant extinctions, though not as devastating as in the marine setting. Among the four-legged animals (tetrapods), the ancestors of the dinosaurs came through the best. The Triassic Aftermath The world recovered very slowly after the extinction. A small number of species had large populations, rather like the handful of weed species that fill an empty lot. Fungus spores continued to be abundant. For millions of years, there were no reefs and no coal beds. Early Triassic rocks show completely undisturbed marine sediments—nothing was burrowing in the mud. Many marine species, including the dasyclad algae and calcareous sponges, disappeared from the record for millions of years, then reappeared looking just the same. Paleontologists call these Lazarus species (after the man Jesus revived from death). Presumably they lived on in sheltered places from which no rocks have been found. Among the shelly benthic species, the bivalves and gastropods became dominant, as they are today. But for 10 million years they were very small. The brachiopods, which had completely dominated the Permian seas, nearly vanished. On land the Triassic tetrapods were dominated by the mammal-like Lystrosaurus, which had been obscure during the Permian. Eventually the first dinosaurs arose, and the mammals and amphibians became small creatures. Lazarus species on land included the conifers and ginkgos. Geologic Evidence of the Permian-Triassic Extinction Many different geologic aspects of the extinction period have been documented recently: Salinity in the sea fell sharply during the Permian for the first time, changing oceanic physics to make deep water circulation more difficult.The atmosphere went from very high oxygen content (30%) to very low (15%) during the Permian.The evidence shows global warming AND glaciations near the P-Tr.Extreme erosion of the land suggests that ground cover disappeared.Dead organic matter from the land flooded the seas, pulling dissolved oxygen from the water and leaving it anoxic at all levels.A geomagnetic reversal occurred near the P-Tr.A series of great volcanic eruptions was building up a gigantic body of basalt called the Siberian Traps. Some researchers argue for a cosmic impact at P-Tr time, but the standard evidence of impacts is missing or disputed. The geologic evidence fits an impact explanation, but it does not demand one. Instead the blame seems to fall on volcanism, as it does for other mass extinctions. The Volcanic Scenario Consider the stressed biosphere late in the Permian: low oxygen levels restricted land life to low elevations. Ocean circulation was sluggish, raising the risk of anoxia. And the continents sat in a single mass (Pangea) with a reduced diversity of habitats. Then great eruptions begin in what is Siberia today, starting the largest of Earths large igneous provinces (LIPs). These eruptions release huge amounts of carbon dioxide (CO2) and sulfur gases (SOx). In the short term the SOx cools the Earth while in the longer term the CO2 warms it. The SOx also creates acid rain while CO2 entering the seawater makes it harder for calcified species to build shells. Other volcanic gases destroy the ozone layer. And finally, magma rising through coal beds releases methane, another greenhouse gas. (A novel hypothesis argues that the methane was instead produced by microbes that acquired a gene enabling them to eat organic matter in the seafloor.) With all of this happening to a vulnerable world, most life on Earth could not survive. Luckily it has never been quite this bad since then. But global warming poses some of the same threats today.

Informative Speech - 793 Words

A List of Informative Speech Topics: Pick Only Awesome Ideas! Just when you thing youre way past through the question How to write an essay?, another one comes. Thats the thing students desperately Google like What is a informative speech? – and, believe experts, this is something youll definitely need some professional help in. Informative speaking is a speech on completely new issue. Tell your audience something they have never known! Now that you know the answer to the question â€Å"What is informative speaking?†, it’s time to check a great informative essay topics list – check the modern concerns and issues to deal with! A List of Informative Speech Topics: Healthcare and Medicine. First of all, check the informative†¦show more content†¦A List of Informative Speech Topics: in the Rhythm of Waltz. Among the most popular informative speaking topics, the ones concerning music must be really exciting. So why don’t you try some of these ideas: Musical Instruments and Character Peculiarities: The Melancholic Prefer Violins; The Role of Music in Society: A Means to Spur Creativity or Calm People Down? Music Therapy and Its effects: Another Panacea for the Humankind; Music as a Mixture of Art and Industry: the XXI Century Pop Culture; Musical Theater as the Most Unforgettable Experience: Something You Never Knew about It; The Most Notable Person in the Music History: Changing the World in a Moment; The Tendencies in the Music genres Development: XXI Century; Musical Expression: Definition and the Modern Interpretation. A List of Informative Speech Topics: What Makes Your Mouth Water In case you’re looking for the essay topics and ideas concerning nutrition, there’s a plenty of wonderful speeches for you to choose: The Most Exotic Food Ever: A Snapshoot of the World Culture; Food Additives, Their Effects and Threats: Be Careful What You Eat; Food Chains: the Mechanisms, the Efficiency and the Revenues; Providing Food Security: Learning What Meals Consist of; Food Habits in Different Countries: Learning the Peculiarities of Etiquette; Food and Nutrition: The Differences and the Similarities between the Two; Food ResourcesShow MoreRelatedInformative Speech Essay855 Words   |  4 Pagestype of speech would the speaker choose. Well chapter 13 contents the creative process for informative speaking. What informative speaking is how to choose a focused informative topic, how to conduct a research and informative outline? The chapter also contains how to organize the body, introduction, and conclusion of the informative speech. Lastly chapter 13 contents explain how to prepare to present the speech and evaluate and informative speech. In order to make a well informative speech the speakerRead MoreInformative Speech912 Words   |  4 Pagesï » ¿Informative Speech: The Causes of Homelessness Subject and Purpose 1. This informative speech on â€Å"The Cause of Homelessness â€Å"is very Inform able and worth listening to, because in today’s economy it could be you or me. Some seem to think homelessness is choice. I find this speech relevant to the world I live in today, due to the high unemployment rate, declining job market, and the economic hardships that families are enduring. This topic is not a broad one, but yet can be spokeRead MoreInformative Speech1497 Words   |  6 Pagesï » ¿ORGC 201 Informative Speech Assignment Create a 5-6 minute presentation using PowerPoint visuals. 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In order to better understand this issue of pay between men and women look at your wife’s or husband’s pay and you’ll see theRead Moreinformative speech1255 Words   |  6 Pagesï » ¿ Title: Information Speech Outline â€Å"The Evolution of Animation† Subject Code: USEL 23 - Speech Communication Prepared For: Datin Minda Hassan Prepared By: Nur Rabiatul Adawiyah Bt Mohd Nor Kamarudin (1411170007) Class: Oregon Program: ADFP Summer 2014 Preparation Outline Informative Speech â€Å"The Evolution of Animation – From 2D Animation to 3D Animation† General Purpose: To inform Specific Purpose: To inform my audience the evolution of animation. CentralRead MoreInformative Speech1145 Words   |  5 Pagesï » ¿Cheyenne Duran Comm 20 Kelly Glass October 23, 2013 Informative Speech Outline Topic: Gun Control Organizational pattern: Topical Specific purpose: To inform my audience about the controversial subject gun control. 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Wto Case Free Essays

Tasks: 1) Review the articles and explain what is the core of the dispute * The core of the dispute are economic relations between countries and its companies, which stand in WTO. In these situations each country tries to defend its rights and win, so WTO’s primary task is to solve the arising problems guided with one of the main principles – non-discrimination. The rule requires that a WTO member must apply the same conditions on all trade with other WTO members, i. We will write a custom essay sample on Wto Case or any similar topic only for you Order Now . a WTO member has to grant the most favorable conditions under which it allows trade in a certain product type to all other WTO members. So in the case of China – USA dispute WTO uses this principle and forces China to open the market for U. S. movies, music and books. China regulated US movies and music so far in order to protect their domestic entertainment market. But WTO ruled that China has to open to foreign entertainment materials according to globalization. ) Find and present at least three another disputes which are at the agenda of the Dispute Settlement Body of WTO. * DISPUTE DS450: China — Certain Measures Affecting the Automobile and Automobile-Parts Industries * The United States requested consultations with China concerning certain measures providing subsidies in the form of grants, loans, forgone government revenue, the provision of goods and services, and other incentives contingent upon export performance to automobile and automobile-parts enterprise s in China. DISPUTE DS455: Indonesia — Importation of horticultural products, animals and animal products * The United States requested consultations with Indonesia concerning certain measures it imposes on the importation of horticultural products, animals and animal products. * DISPUTE DS456: India — Certain Measures Relating to Solar Cells and Solar Modules * The United States requested consultations with India concerning certain measures of India relating to domestic content requirements under the Jawaharial Nehru National Solar Mission (â€Å"NSM†) for solar cells and solar modules. ) Explain the term â€Å"dumping prices† * Dumping price is name for the practice of selling a product in a foreign country for less than the price in the domestic country, or the cost of making the product. Such a low prices may constitute a competition problem; e. g. when a company, which is dominating in a market, â€Å"dumps† their price, and the price drops so far that the company sells at a loss in order to eliminate a competitor. * Dumping in CZE: Radim Jancura commented a situation about Regio Jet. They have lost about 50mil. Kc in 2012 and he accused CD of dumping prices. Commentator was surprised to hear that from Jancura, who provided tickets for 1Kc from Prague to Liberec in the beginning. And Jancura explained: â€Å"It’s not dumping prices when it’s small beginning company, because it can’t destroy the competition. But when the company owns more than 30% of the market, than it’s dumping†¦ † 4) Which other commodities are object of protectionist measures? * As we come closer to a free trade, the protectionist measures become weaker. You can read also Thin Film Solar Cell Nevertheless, there are commodities, which can be a good example of protectionism. The EU imposes substantial tariff rates on many agricultural markets in order to increase the income of European farmers through increasing prices. The most significant examples are meat, dairy products, vegetables, cereals, sugar and agricultural products. There was a 20-years â€Å"banana war†, which consisted in great tariffs on banana imports from Latin America. Exporters had to pay â‚ ¬176 per ton of bananas. But then 10 Latin American countries signed a â€Å"historic† agreement to end the â€Å"banana wars† and banana prices are expected to fall by 11%. Argentina has increased imports duties on 100 products, including over a dozen agricultural goods. Tariffs on the import of milk powder increased to 9% after there was a threat of falling incomes to Argentinian farmers. Apart from commodities mentioned above, we think it can be also all types of commodities which are somehow important for the domestic economy (eg. because of domestic jobs, certain key industries, etc. ——————————————– [ 1 ]. WTO | dispute settlement – the disputes – DS450. World Trade Organization [online].  © 2013 [cit. 2013-03-05]. Dostupne z: http://www. wto. org/english/tratop_e/dispu_e/cases_e/ds450_e. htm [ 2 ]. WTO | dispute settlement – the disputes – DS455. World Tra de Organization [online].  © 2013 [cit. 2013-03-05]. Dostupne z: http://www. wto. org/english/tratop_e/dispu_e/cases_e/ds455_e. htm [ 3 ]. WTO | dispute settlement – the disputes – DS456. World Trade Organization [online].  © 2013 [cit. 013-03-05]. Dostupne z: http://www. wto. org/english/tratop_e/dispu_e/cases_e/ds456_e. htm [ 4 ]. Dumping (pricing policy). In: Wikipedia: the free encyclopedia [online]. San Francisco (CA): Wikimedia Foundation, 2001- [cit. 2013-03-05]. Dostupne z: http://en. wikipedia. org/wiki/Dumping_(pricing_policy) [ 5 ]. Examples and Types of Protectionism – Economics Blog. Economics Help – Simplifying Economics [online].  © 2013 [cit. 2013-03-05]. Dostupne z: http://www. economicshelp. org/blog/6911/alevel/examples-of-protectionism/ How to cite Wto Case, Papers