Caption: Tardigrade (water bear) (Echiniscus sp.). Tardigrada is an obscure phyla of invertebrates located between the nematodes (roundworms) and the arthropods (crustacea, insects, and ticks). Tardigrades are microscopic aquatic animals that need water to live. Without water they shrivel into a cask stage and survive long periods of desiccation in a stage called cryptobiosis. Tardigrades are found in marine, freshwater, and semi-aquatic terrestrial habitats. Mosses, lichens, leaf litter, soil, and even the grains of sand on a beach are examples of such habitats. They are small, 0.2-0.5 mm in length, with 5 body segments and 4 pairs of legs. They breathe through their cuticle and have a hemocoel for circulation. Water bears feed on the fluids of plant and animal cells. They have stylets which allow them to pierce plant or animal cells. Cryptobiosis is of great interest in the study of cryogenics and tardigrades have been subjected to laboratory experiments which have verified their ability to survive.
Magnification*: x100
Type: SEM
Copyright 2004 Dennis Kunkel Microscopy, Inc.
Keywords: 24032H,03.01.04,anhydrobiosis,anoxybiosis,aquatic bears,aquatic organism,cryobiosis,cryptobiosis,crytobiotic,drought-resistant,Echiniscus,fresh water,marine,misc. invertebrates,salt water,Tardigrada,tardigrade,tardigrades,trehalose sugar,water bear,SEM,extreme environment,extremophile,extremophiles,extremophilic