Media
Wikimedia is a global movement whose mission is to bring free educational content to the world. Through various projects, chapters, and the support structure of the non-profit Wikimedia Foundation, Wikimedia strives to bring about a world in which every single human being can freely share in the sum of all knowledge. 1)
Wikipedia
Wikipedia is a project to build free encyclopedias in all languages of the world.
Wiktionary
Wiktionary is a project to create a multilingual free content dictionary in every language.
Wikiquote
Wikiquote is a repository of quotations taken from famous people, books, speeches, films or any intellectually interesting materials. Proverbs, mnemonics or slogans are also included in Wikiquote.
Wikibooks
Wikibooks aims to build a collection of free e-book resources, including textbooks, language courses, manuals, and annotated public domain books. It aims to help both (self-)instruction of students and teachers in high schools and universities.
Wikisource
Wikisource is a multilingual project to archive a collection of free and open content texts.
Wikispecies
Wikispecies is an open, wiki-based project to provide a central, more extensive species database for taxonomy. It covers living and fossil representatives of Animalia, Plantae, Fungi, Bacteria, Archaea, Protista and all other forms of life.
Wikinews
The Wikinews project was launched with the mission to report the news on a wide variety of subjects. Contributors from around the world write news articles collaboratively. Reports range from original reporting and interviews to summaries of news from external sources. All reports are required to be written from a neutral point of view.
- Florida frog skull survey shows spikes, say scientists (2020/03/26 10:15)
Thursday, March 26, 2020
In a new study released by the Florida Museum of Natural History on Monday, scientists report spiky skulls evolved at least 25 separate times in different kinds of frogs. The survey was reportedly to be published in Proceedings of the National Academy of Sciences.
Anotheca spinosa, one of the species studied, was found to have prominent spikes under its skin. (Image: Brian Gratwicke)Lead author Daniel Paluh, a Ph.D. candidate at the University of Florida, said, "Superficially, frogs may look similar, but when you look at their skulls, you see drastic differences [...] Some of the weirdest skulls are found in frogs that eat birds and mammals, use their heads as a shield, or in a few rare cases, are venomous. Their skulls show how strange and diverse frogs can be."
Some scientists had previously suggested smaller frogs would tend to develop spiky skulls, but that is not what this study reports. Here, researchers evaluated CT scans on 158 different species. They found frogs that had similar ecological niches — meaning they either acquired food in the same way or defended themselves from predators in the same way — tended to develop skulls with similar grooves, spikes, or specialized jaw joints regardless of whether they were ancestrally related to each other.
According to the study, skulls with spikes, grooves or ridges — called hyperossification — often accompanied frogs eating very large prey relative to their own body size. The strong, spacious skulls would allow the frogs to have very big mouths with which to catch birds, rodents, reptiles and other frogs. Spikes sometimes coincided with venomous frogs. The researchers speculated the spikes make it dangerous for predators to hit the frog's head, as the spikes would break venom sacs under the frog's skin.
Other bone formations included projections resembling fangs or lower teeth that different species of frogs use for catching prey and fighting. Very few frogs have true lower teeth.
One of the study's authors, herpetologist David Blackburn, told Discover Magazine the frequency of spiky skulls evolving in otherwise unrelated frogs suggested some deep pattern frogs fell into as circumstances arose: "Somehow, these frogs are turning on some ancient developmental machinery in their DNA."
Since 1973, when frogs skulls were last comprehensively surveyed, scientists have documented enough new species to double the number known to humans. Also, modern techniques exploit CT scans, of which Paluh and his team made liberal use. The research was part of the oVert project, funded by the National Science Foundation, meant to comprehensively CT-scan over 20,000 vertebrate specimens from United States museums.
Sources[edit]
- Steph Panecasio. "Frogs have evolved extreme skulls with hidden fangs and horns" — CNet, March 24, 2020
- Leslie Nemo. "New 3D Images Reveal the Evolutionary Wonders Hidden in Frog Skulls" — Discover Magazine, March 24, 2020
- Florida Museum of Natural History. "Skulls gone wild: How and why some frogs evolved extreme heads" — Eurekalert.org, March 23, 2020
External links[edit]
Wikiversity
Wikiversity is a project dedicated to learning materials and learning communities, as well as research. Wikiversity is not limited to university (or tertiary) level materials, but is open to materials and communities of all learner levels. The way it can facilitate learning activities and communities is still being explored, but is centered around the model of 'learning by doing', or 'experiential learning'.
Wikivoyage
Wikivoyage aims to create the world's largest free, complete and up-to-date world-wide travel guide.
Wikimedia Commons
Wikimedia Commons provide a central repository for free photographs, diagrams, maps, videos, animations, music, sounds, spoken texts, and other free media. It is a multilingual project with contributors speaking dozens of languages, that serves as a central repository for all Wikimedia projects.
- Wikimedia Commons picture of the day for March 28 (2020/03/28 02:00)
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A window in the Ellis Island Immigrant Hospital in New York City, USA, closed since 1930. The French artist JR created murals on hospital grounds from photographs of patients taken in the early 1900s. - Wikimedia Commons picture of the day for March 27 (2020/03/27 02:00)
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The east side of the Paul-Löbe-Haus in Berlin-Mitte, facing the river Spree, during the blue hour. On the left the Reichstag building can be seen. The Paul Löbe building was built according to plans of architect Stephan Braunfels. - Wikimedia Commons picture of the day for March 26 (2020/03/26 02:00)
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Sheathed woodtuft (Kuehneromyces mutabilis) on a beech tree in the grove area of Bamberg - Wikimedia Commons picture of the day for March 25 (2020/03/25 02:00)
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Scanned image of thin section from Siilinjärvi apatite ore in cross polarised transmitted light. Actual sector size about 37 × 20 mm. - Wikimedia Commons picture of the day for March 24 (2020/03/24 02:00)
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Exemplar of Lilac-breasted roller (Coracias caudatus), Kruger National Park, South Africa. - Wikimedia Commons picture of the day for March 23 (2020/03/23 02:00)
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Sunrise over Lake Wanaka from Boundary Creek, Otago, New Zealand - Wikimedia Commons picture of the day for March 22 (2020/03/22 02:00)
Picture of the day 
World Water Day is an annual event celebrated on March 22. The day focuses attention on the importance of fresh water and advocates for the sustainable management of freshwater resources. This day was first formally proposed in Agenda 21 of the 1992 United Nations Conference on Environment and Development in Rio de Janeiro. In 1993, the first World Water Day was designated by the United Nations General Assembly and since, each year focuses on a different issue. This image shows the Blautopf pond in Blaubeuren, Baden-Württemberg, Germany. - Wikimedia Commons picture of the day for March 21 (2020/03/21 02:00)
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Ferris wheel at the funfair Send in Münster, North Rhine-Westphalia, Germany
Wikipedia: Münster • North Rhine-Westphalia - Wikimedia Commons picture of the day for March 20 (2020/03/20 02:00)
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The Lenbachhaus is a major art museum in Munich's Kunstareal. A new wing, designed by Foster and Partners, was opened 2013. - Wikimedia Commons picture of the day for March 19 (2020/03/19 02:00)
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Wikidata
Wikidata aims to create a free knowledge base about the world that can be read and edited by humans and machines alike. The data available in Wikidata is licensed under the Creative Commons CC0 License to allow third-party users to freely reuse the data available, unlike other Wikimedia projects.
MediaWiki
The MediaWiki open source community maintains several software projects.
Meta-Wiki
Meta-Wiki is a project used as a central hub for various coordination and organization tasks, such as discussions affecting multiple wikis or planning upcoming events.
Wikimedia Incubator
The Wikimedia Incubator is a wiki used for developing new wikis.
Wikimedia Labs
Wikimedia Labs 2) is a project aimed to help volunteers get involved in Wikimedia operations and software development, and to make it easier for system administrators and developers to try out improvements to Wikimedia infrastructure, including MediaWiki.