background preloader


Tardigrades (also known as waterbears or moss piglets)[2][3][4] are water-dwelling, segmented micro-animals, with eight legs.[2] They were first described by the German pastor Johann August Ephraim Goeze in 1773. The name Tardigrada (meaning "slow stepper") was given three years later by the Italian biologist Lazzaro Spallanzani.[5] Since 1778, over 1,150 tardigrade species have been identified. Tardigrades are classified as extremophiles, organisms that can thrive in a physically or geochemically extreme condition that would be detrimental to most life on Earth.[6][7][3] For example, tardigrades can withstand temperatures from just above absolute zero to well above the boiling point of water, pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space. Tardigrades form the phylum Tardigrada, part of the superphylum Ecdysozoa. Description[edit]

Related:  Animal PhylaSpace

Dicyemida Dicyemida, or Rhombozoa, is a phylum of tiny parasites that live in the renal appendages of cephalopods. Although the name "Dicyemida" precedes "Rhombozoa" in usage, and is preferred by most contemporary authors, "Rhombozoa" still enjoys much popular support. Taxonomy[edit] Classification is controversial.[1] Traditionally, dicyemids have been grouped with the Orthonectida in the Mesozoa; however, molecular phylogenies indicate that dicyemids may be more closely related to the roundworms.[2] The phylum is not divided in classes, but contains three families, Conocyemidae, Dicyemidae, and Kantharellidae.[3] Molecular evidence suggests that this phylum are derived from the Lophotrochozoa.[4][5]

Astrophysics: Fire in the hole! Andy Potts In March 2012, Joseph Polchinski began to contemplate suicide — at least in mathematical form. A string theorist at the Kavli Institute for Theoretical Physics in Santa Barbara, California, Polchinski was pondering what would happen to an astronaut who dived into a black hole. Obviously, he would die.

Flatworm In traditional zoology texts, Platyhelminthes are divided into Turbellaria, which are mostly nonparasitic animals such as planarians, and three entirely parasitic groups: Cestoda, Trematoda and Monogenea; however, since the turbellarians have since been proven not to be monophyletic, this classification is now deprecated. Free-living flatworms are mostly predators, and live in water or in shaded, humid terrestrial environments such as leaf litter. Cestodes (tapeworms) and trematodes (flukes) have complex life-cycles, with mature stages that live as parasites in the digestive systems of fish or land vertebrates, and intermediate stages that infest secondary hosts. The eggs of trematodes are excreted from their main hosts, whereas adult cestodes generate vast numbers of hermaphroditic, segment-like proglottids which detach when mature, are excreted, and then release eggs. Over half of all known flatworm species are parasitic, and some do enormous harm to humans and their livestock.

Plutonium tests offer hope for dark space missions - space - 15 March 2013 The future is looking brighter for missions to the solar system's dark corners. Plutonium needed to power the spacecraft that cannot rely on solar power has been created in the US for the first time in 25 years – albeit in small quantities. Some destinations, such as the outer solar system or the polar regions of Mars, receive too little sunlight for ambitious missions to use solar panels there. Onychophora The two extant families of velvet worms are Peripatidae and Peripatopsidae. They show a peculiar distribution, with the peripatids being predominantly equatorial and tropical, while the peripatopsids are all found in what used to be Gondwana.[5] Formerly considered part of Tracheata,[6] velvet worms are now considered close relatives of the Arthropoda and Tardigrada, with which they form the taxon Panarthropoda. This makes them of palaeontological interest, as they can help reconstruct the ancestral arthropod. Anatomy[edit]

The Spacecoach Equation My view is that the spacecoach, the subject of renewed discussion below by Brian McConnell and a design he and Alex Tolley have created, is the most innovative and downright practical idea for getting crews and large payloads to the planets that I’ve yet encountered. It’s low-cost and uses ordinary consumables as propellant, dramatically revising mission planning. Brian and Alex have continued refining the concept, as explained below in Brian’s essay on a modified version of the rocket equation. Have a look and you’ll see that planning long duration missions or missions with larger crews becomes a much more workable proposition because more consumables translate into more propellant. Could the spacecoach be our ticket to building a space-based infrastructure, with unmistakable implications for even deeper space? by Brian S McConnell

Nemertea Nemertea is a phylum of invertebrate animals also known as "ribbon worms" or "proboscis worms".[3] Alternative names for the phylum have included Nemertini, Nemertinea and Rhynchocoela.[2] Although most are less than 20 centimetres (7.9 in) long, one specimen has been estimated at 54 metres (177 ft), which would make it the longest animal ever found.[4] Most are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many have patterns of yellow, orange, red and green coloration. In most species the sexes are separate, but all the freshwater species are hermaphroditic.

Nematomorpha Description and biology[edit] Nematomorphs possess an external cuticle without cilia. Internally, they have only longitudinal muscle and a non-functional gut, with no excretory, respiratory or circulatory systems. Nematode Habitats[edit] Nematodes have successfully adapted to nearly every ecosystem from marine to fresh water, to soils, and from the polar regions to the tropics, as well as the highest to the lowest of elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual and species counts, and are found in locations as diverse as mountains, deserts and oceanic trenches. They are found in every part of the earth's lithosphere.[5] They represent, for example, 90% of all life forms on the ocean floor.[6] Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on earth, their diversity of life cycles, and their presence at various trophic levels point at an important role in many ecosystems.[7] Their many parasitic forms include pathogens in most plants and animals (including humans).[8] Some nematodes can undergo cryptobiosis. Anatomy[edit]

Mollusca A striking feature of molluscs is the use of the same organ for multiple functions. For example, the heart and nephridia ("kidneys") are important parts of the reproductive system, as well as the circulatory and excretory systems; in bivalves, the gills both "breathe" and produce a water current in the mantle cavity, which is important for excretion and reproduction. Good evidence exists for the appearance of gastropods, cephalopods and bivalves in the Cambrian period 541 to 485.4 million years ago.

Limnognathia L. maerski has very complicated jaws, with fifteen separate elements. The parts of the jaw structure are connected by ligaments and muscles. The jaw parts are very small, ranging from 4 μm to 14 μm. The animal can extend part of its jaw structure outside of its mouth while eating. It also extends much of its jaw structure outside of its mouth when it is regurgitating items that are indigestible.