Over two thirds of the earth's surface is covered by water, and adaptation to the aquatic habitats dominated the first 150 to 200 million years of vertebrate development. More than half the living ...vertebrates are aquatic. Fish have evolved to colonise almost every type of aquatic habitat, and today they are a hugely diverse group of about 25,000 species. Evolution of this great diversity has resulted in fascinatingly different designs for special modes of life as well as solutions to the problems common to them all. Comparisons help to reveal the biological and physiological compromises fish have to make to satisfy the often conflicting demands on their lives. Today fish are found in almost every imaginable watery habitat, which include the shallows and depths of the oceans, coastal waters and estuaries, rivers, streams, lakes, ponds, and ephemeral water bodies. Many species inhabit freezing waters in polar regions whilst others thrive in ponds fed by thermal springs. Some have abandoned the water and become air breathers. Tunas in the open oceans swim rapidly and outperform their prey. How do they generate the forces required for high-speed swimming? Study of these fish shows that they have large masses of warmed red muscle, and that the required amounts of oxygen are delivered by unusually efficient respiratory and circulatory systems. Some freshwater carp are able to survive the long periods of very low oxygen levels that periodically occur in some ponds and lakes. How is their metabolism switched from aerobic to anaerobic pathways? The challenges of living in a particular environment are in part met by adaptations of body form and physiological function. Yet there are wider and equally important questions, such as why are these species successful in their particular environments? Answers to such questions may be found in the study of behaviour, in the dynamics of populations, in the ecology of the species and in evolutionary theory.
Bakterije se na različite načine prilagođavaju promjenama uvjeta okoline. U ovom su kratkom preglednom radu opisane različite strategije prilagodbe crveno pigmentirane bakterije Vibrio ruber, nedavno ...izolirane iz priobalja, na čimbenike stresa (tj. salinitet, viskoznost, UV svjetlost, mitomicin C, pristupačnost hranjiva i temperaturu). Bakterija Vibrio ruber se koristi različitim strategijama adaptacije kako bi se oduprla okolišnom stresu. Ovisno o koncentraciji soli, bakterija Vibrio ruber mijenja svoj lipidni sastav, te svojstva lipidne faze. Membrana se bakterije Vibrio ruber razlikuje od ostalih srodnih vrsta bakterije Vibrio po tome što ne sadržava hidroksi masne kiseline, ali zato ima izrazito velik udjel lizolipida. Nakupljanje anorganskih hranjivih tvari u bakteriji je selektivno i ovisi o uvjetima okoline. Bakterije se brzo prilagođavaju stresnim uvjetima i mijenjaju svoj proteinski sastav, metabolizam, tj. potrošnju ugljika i energije, te proizvodnju sekundarnih metabolita. Aktivnost glukoza-6-fosfat dehidrogenaze dobar je indikator stresa u Vibrio ruber. Bakterije mogu mijenjati viskozitet stanica kao odgovor na promjenu viskoziteta okoline. Imaju nekoliko virusnih elemenata u genomu koji se mogu inducirati mitomicinom C. Promjene u uvjetima okoline tijekom rasta bakterija bitno utječu na iskorištenje ugljika iz lizata mikrobnih stanica. Nedavno je otkrivena nova ekofiziološka funkcija sekundarnog metabolita prodigiozina, a to je da štiti stanicu od UV zračenja. Može se zaključiti da se u kratkom periodu istraživanja bakterije Vibrio ruber (kraćem od deset godina) dokazalo da se može upotrijebiti kao vrlo učinkovit model za ispitivanje ekofiziologije bakterija.
