Freshwater crab Nature (IUCN); of the species for which data are available, 32% are threatened with extinction. For instance, all but one of Sri Lanka's 50 freshwater crab species are endemic to that country, and more than half are critically endangered. Freshwater crab There are around 1,300 species of freshwater crabs, distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas.
Osmotrophy Osmotrophy Osmotrophy is the uptake of dissolved organic compounds by osmosis for nutrition. Organisms that use osmotrophy are osmotrophs. Some mixotrophic microorganisms use osmotrophy to derive energy. The organisms that used osmotrophy are known to be an osmotrophs which are usually found in protists and fungi although exclusively osmotrophic feeding in contemporary ecosystems are restricted to microscopic bacteria thereby used the process of osmosis for the movement of food although some macroscopic animals like molluscs, sponges, corals, brachiopods and echinoderms used osmotrophic feeding as a supplemental food source. Osmotrophy is a means of gathering nutrients in microscopic organisms that relies