Simple Eye in Invertebrates Head of Polistes with two compound eyes and three ocelli A simple eye (sometimes called a pigment pit[1][2]) refers to a type of eye form or optical arrangement that contains a single lens. A "simple eye" is so called in distinction from a multi-lensed "compound eye", and is not necessarily at all simple in the usual sense of the word. The eyes of humans and large animals, and camera lenses are classed as "simple" because in both cases a single lens collects and focuses light onto the retina or film. The structure of an animal's eye is determined by the environment in which it lives, and the behavioural tasks it must fulfill to survive. Ocelli or eye spots[edit] "Ocellation" redirects here. Many snails and slugs (gastropod mollusks) also have ocelli, either at the tips or at the bases of the tentacles. Simple eyes in arthropods[edit] Spider eyes[edit] This jumping spider's main ocelli (center pair) are very acute. Dorsal ocelli[edit] Stemmata[edit] Genetic controls[edit] See also[edit]
Les sons créateurs de formes géométriques Alain Boudet Dr en Sciences Physiques, Thérapeute psycho-corporel, Enseignant Résumé: Lorsqu'une plaque sur laquelle on a déposé du sable ou un liquide est soumise à une vibration ou à un son, le sable ou le liquide s'arrangent en d'extraordinaires figures géométriques. Ces figures sont segmentées en cellules symétriques d'autant plus fines et complexes que la fréquence vibratoire est élevée. Les sons peuvent-ils se manifester par des formes? Commençons en contemplant ces quelques images. La première image représente un film d'eau déposé sur une membrane ronde en latex soumise à une vibration de 19 Hertz, éclairé par une lampe installée au-dessus. La deuxième image représente une grosse goutte d'eau déposée sur une surface plate soumise à une vibration de quelques dizaines de Hertz, éclairée par une lampe installée au-dessus. La troisième image représente une plaque ovale en acier, de longueur 23 cm, sur laquelle on a déposé du sable fin et qui vibre à 12'301 Hertz. Le tube de Kundt
Argentine Ants Use Chemical Warefare Trevor Sorrells A native winter ant in the act of trying to apply a drop of the whitish toxin it can secrete from its abdomen onto an Argentine ant. The angle of the photograph distorts the relative sizes of the two species, which are roughly the same size. Argentine ants are taking over the world – or at least the nice temperate parts. They've spread into Mediterranean and subtropical climates across the globe in sugar shipments from Argentina, and no native ant species has been known to withstand their onslaught – until now. The winter ants – named for their unusual ability to function in cold weather, rather than grind to a halt like most insects – manufacture a poison in a gland in their abdomen that they dispense when under extreme duress. "This is the first well-documented case where a native species is successfully resisting the Argentine ant," said Deborah M. "I did not believe it at first," she said. Argentine ant invasion Courtesy of Leah Kuritzky An ant 'massacre' L.A. Stumble
Jubilothèque — A propos Corpus Science collection This digital library project was initiated and implemented by the Bibliothèque Interuniversitaire Scientifique Jussieu as part of the four-year 2005-2008 contract of the University Pierre et Marie Curie, with the financial support of the Sous-Direction des Bibliothèques et de l'Information Scientifique. Additional funding given by the Direction de la Technologie enabled a substantial addition to the number of digitized books. Since 2009, the BUPMC is associated with the National Library of France and is consequently granted by the BnF for digitization projects. The projet includes mainly printed monographs in french language, a few offprints and manuscripts, ranging from the end of the XVIIIth century to the beginning of the XXth century. In 2013 the digital library numbers over 380 000 digitized pages. The selection of the corpus followed several criteria : This selection would not have been possible without the support and implication of the scientific community.
Egyptian Giant Solpugids (Camel Spider) Camel spiders became an Internet sensation during the Iraq war of 2003, when rumors of their bloodthirsty nature began to circulate online. Many tales were accompanied with photos purporting to show spiders half the size of a human. For many years, Middle Eastern rumors have painted camel spiders as large, venomous predators, as fast as a running human, with a voracious appetite for large mammals. The myths are untrue. The camel spider's history of misinformation begins with a misidentification. Camel spiders, also called wind scorpions and Egyptian giant solpugids (SAHL-pyoo-jids), are only about 6 inches (15 centimeters) long. Camel spiders are not deadly to humans (though their bite is painful), but they are vicious predators that can visit death upon insects, rodents, lizards, and small birds.
Biographie de Johannes Kepler : les polyèdres Johannes Kepler est un astronome allemand à qui nous devons beaucoup : Il a élucidé les mystères des orbites des planètes autour du Soleil, et en a sorti 3 lois qui sont aujourd'hui les fondements de la mécanique céleste. Grâce à lui, nous pouvons estimer avec une grande précision la distance, la taille, la vitesse des objets qui parcourent le système solaire. Il croyait également que les 6 planètes connues à l'époque étaient imbriquées dans les 5 solides parfaits de Platon, qu'on appelle polyèdres, et que la perfection de cette horloge était la preuve du génie de Dieu, notre créateur. Parcourez notre gamme de posters sur Johannes Kepler : Scolarité et études du jeune Kepler Astronome et physicien allemand, Johannes Kepler est né le 27 Décembre 1571 à Weil der Stadt, dans le Wurtemberg. Kepler vit chez ses grands-parents de 1574 à 1576, il part ensuite avec ses parents à Léonberg où il entre à l’école latine. Initié à l'héliocentrisme en cachette Sa vision de l'Univers Le tétraèdre Le cube
Six-Legged Giant Finds Secret Hideaway, Hides For 80 Years No, this isn't a make-believe place. It's real. They call it "Ball's Pyramid." It's what's left of an old volcano that emerged from the sea about 7 million years ago. A British naval officer named Ball was the first European to see it in 1788. It sits off Australia, in the South Pacific. What's more, for years this place had a secret. A satellite view of Ball's Pyramid in the Tasman Sea off the eastern coast of Australia. toggle caption Google Maps Here's the story: About 13 miles from this spindle of rock, there's a bigger island, called Lord Howe Island. On Lord Howe, there used to be an insect, famous for being big. Then one day in 1918, a supply ship, the S.S. Totally gone. There was a rumor, though. Some climbers scaling Ball's Pyramid in the 1960s said they'd seen a few stick insect corpses lying on the rocks that looked "recently dead." Climbing The Pyramid Where, they wondered, did that poop come from? They were alive and, to Nick Carlile's eye, enormous. That wasn't so easy.
Tinkerbella nana The family Mymaridae includes more than 1,400 species of diminutive insects called fairyflies. They are not flies at all, but tiny wasps that deposit their eggs inside the eggs of other insects. Most of these parasitoids are found in tropical latitudes and the southern hemisphere, where they attack unborn offspring of true bugs, beetles, flies, barkflies and dragonflies. The family includes the smallest of all known insects, Dicopomorpha echmepterygis, from Central America, whose males are a mere 139μm That is smaller than quite a few single-celled protists. The common name fairyfly was no doubt inspired by the small size, delicate form and wispy wings with long posterior fringes. A new species of fairyfly, Tinkerbella nana, has been described by John T Huber of Natural Resources Canada and John S Noyes of London's Natural History Museum. Huber and Noyes fill this gap with a fascinating discussion of the diverse factors that go into setting a limit on smallness for insects.
Whip Scorpion We've seen the elegant Scorpion with their often rather dainty pincers, now let's see their relatives, the chunky Whip Scorpions with their own brutal, barbarous claws. Whip Scorpions, also known oddly as Vinegaroons, are indeed arachnids with thick, hefty bodies. Most of them are 3 cm (1.2 in) long or a bit under, but the biggest ones can reach 8.5 cm (3.3 in). They have their 8 legs but, just like our very own Camel Spider, they only use 6 of them to walk. But check out those claws! With these they can grapple with small insect and millipede prey, though the bigger ones can also catch small vertebrates. Whatever the prey, the Whip Scorpion simply grabs it and crushes and mushes it in those formidable pincers. Like the Scorpion, the Whip Scorpion cares for her eggs and carries her young on her back. Young Whip Scorpions take about 3 years to reach adulthood, after which they have about 4 more years of life left in them.
Long exposure fireflies Ant mill An ant mill is an observed phenomenon in which a group of army ants separated from the main foraging party lose the pheromone track and begin to follow one another, forming a continuously rotating circle. The ants will eventually die of exhaustion. This has been reproduced in laboratories and the behaviour has also been produced in ant colony simulations.[1] This phenomenon is a side effect of the self-organizing structure of ant colonies. Each ant follows the ant in front of it, and this will work until something goes wrong and an ant mill forms.[2] An ant mill was first described by William Beebe in 1921 who observed a mill 1,200 feet (365 m) in circumference.[3] It took each ant 2.5 hours to make one revolution.[4] Similar phenomena have been noted in processionary caterpillars and fish.[5] See also[edit] References[edit] External links[edit]