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Abstract. Tardigrades are polyextremophilic small organisms capable to survive in a variety of extreme conditions. By reversibly suspending their metabolism (cryptobiosis - tun state) tardigrades can dry or freeze and, thus, survive the extreme conditions like very high or low pressure and temperatures, changes in salinity, lack of oxygen, lack of water, some noxious chemicals, boiling alcohol, even the vacuum of the outer space. Despite their peculiar morphology and amazing diversity of habitats, relatively little is known about these organisms. Tardigrades are considered some lesser known taxa. Studying tardigrades can teach us about the evolution of life on our planet, can help us understand what extremophilic evolution and adaptation means and they can show us what forms of life may develop on other planets.
Key Words: tardigrades, extremophiles, extreme environments, adaptation.
Rezumat. Tardigradele sunt mici organisme poliextremofile capabile să supravieţuiască într-o varietate de condiţii extreme. Suspendandu-şi reversibil metabolismul (criptobioză) tardigradele pot să se usuce sau să îngheţe şi, astfel, să supravieţuiască unor condiţii extreme precum presiuni şi temperaturi foarte scăzute sau crescute, variaţii de salinitate, lipsă de oxygen, lipsă de apă, unele chimicale toxice, alcool în fierbere, chiar şi vidul spaţiului extraterestru. În ciuda morfologiei lor deosebite şi a diversittii habitatelor lor, se cunosc relativ puţine aspecte se despre aceste organisme. Tardigradele sunt considerate a fi o categorie mai puţin cunoscută de organisme. Studiul tardigradelor ne poate invăţa despre evoluţia vieţii pe planeta noastră, ne poate ajuta să înţelegem ce reprezintă evoluţia şi adaptarea de tip extremofil şi ne poate arăta ce forme de viaţă se pot dezvolta pe alte planete.
Cuvinte cheie: tardigrade, extremofile, medii de viaţă extreme, adaptare.
Introduction. Unlike humans and most of the organisms on Earth, some creatures are more flexible in the habitats where they feel comfortable. Different from all living organism adapted to "normal" environments, there are organisms adapted to extreme, at the far edge of the normal conditions chosen in the course of evolution by most of the organisms living today.
Organisms which inhabit extreme environmental conditions are called extreme lovers or Extremophiles (from Latin extremus meaning "extreme" and Greek philiā (ф^а) meaning "love"), term first used in 1974 by R. D. MacElroy.
A more exact definition of this term defines an extremophile as an organism that...