Tardigrada

-
Tardigrade
Tardigrade, any of a group of tiny arthropod-like animals characterized by four pairs of stubby legs ending in large claws, a stout body, rounded back, and lumbering gait. They are also known as “water bears.” Tardigrades live worldwide in moist land habitats, along rocky shorelines, and on the bottoms of streams, lakes, and oceans. Their most striking feature is their ability to temporarily enter a nearly lifeless state known as anabiosis, which helps them survive environmental extremes. About 400 species of tardigrades are known and they range in length from 0.1 to 0.5 mm (0.004 to 0.02 in).

Tardigrades are most commonly found in association with the water film on mosses, liverworts, and lichens. Their densities may reach 2 million individuals per sq m (185,874 per sq ft) of moss. Some live in hot springs and a few live in a symbiotic relationship with or on the bodies of other animals. Tardigrades use a pair of oral stylets, or needle-like mouthparts, to pierce the walls of plant cells and feed on the liquid inside. Most species are plant eaters, but some are predators, feeding on tiny invertebrates and bacteria, and a few are detritivores, feeding on dead tissue and debris.

Scientific classification: Tardigrades make up the phylum Tardigrada. It is not clear to what other animals tardigrades are most closely related, but they are most similar to arthropods (insects, crustaceans, etc.), annelids (segmented worms), and gastrotrichs.

Comments

Post a Comment

Popular posts from this blog

The Animal Kingdom

-
Image
. Kingdom Animalia includes more than one million living species, grouped into more than 30 phyla. Vertebrates, members of the phylum Chordata, comprise only one percent of these organisms. Phylum Arthropoda is more successful in sheer numbers, total mass, and distribution than all other groups of animals combined. The remaining animal phyla are composed of mostly marine-dwelling organisms. THE MAJOR PHYLA : Acanthocephala (Spiny-Headed Worm) Annelida (Annelids) Arthropoda (Arthropods)-> subphyla: Chelicerata, Crustacea, and Unirama Brachiopoda (Lampshell) Chaetognatha (Arrowworm) Chordata (Chordates)-> subphyla: Cephalochordata, Tunicata , Vertebrata ( fishes , amphibians , reptiles , birds , and mammals ) Cnidaria (Cnidarians) Ctenophora (Comb Jellies) Cycliophora (Symbion) Echinodermata (Echinoderms)-> Subphyla: Pelmatozoa, Eleutherozoa Echiura (Spoonworm) Ectoprocta (Moss Animals) or Bryozoa Entoprocta (Entoprocts) Gastrotricha (Gastrotrich) Gnathostomulida ...
Read more

Cattle

-
Cattle, name for the ruminant mammals of the genus Bos, and particularly those of the domesticated species, Bos taurus and B. indica. The term oxen, broadly used, refers also to closely related animals, such as the buffalo and the bison. Narrowly used, ox refers to a mature castrated male used for draft purposes. In referring to domestic cattle a grown male is a bull, a grown female a cow, an infant a calf, and an animal between one and two years old a yearling. A female that has not given birth is a heifer; a castrated male is a steer. Most cattle have unbranched horns consisting of a horny layer surrounding a bone extension of the skull; these horns, unlike those of deer, are not shed. Some cattle are naturally hornless. Western, or European, domestic cattle (Bos taurus) are thought to be descended mainly from the aurochs, a large European wild ox domesticated during the Stone Age, extinct since 1627. A smaller species, the Celtic shorthorn, was the most important domestic ox of t...
Read more

Chimpanzee

-
Chimpanzee, an ape, genus Pan, of the equatorial forests of central and W Africa. The common chimpanzee, Pan troglodytes, lives N of the Congo River. Full-grown animals of this species are up to 5 ft (1.5 m) tall and weigh about 150 lb (68 kg); they have an arm spread of up to 9 ft (2.7 m) and are much stronger than humans. They are covered with long, black hair over most of the body and have naked faces ranging in color from nearly white to nearly black. The pygmy chimpanzee, P. paniscus, now usually called the bonobo, lives south of the Congo. It is a bit smaller and more slenderly built, with a black face. Chimpanzees spend much time on the ground, where they walk on all fours, using the soles of the feet and the knuckles of the hands; they can also stand on two legs and sometimes walk this way for short distances. They climb trees in pursuit of food and for nesting and can swing by their hands from branch to branch. Their diet consists largely of fruit and other plant matter, but ...
Read more