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.
Forensic limnology water conducting tissues, which affects their dispersion throughout ecosystems. These microscopic organisms mainly inhabit freshwater environments because of their inability to survive with the cleaning agents present in domestic water sources. Diatoms are identifiable based on each species unique silica cell walls and vary depending on their environment. Because they have determinant properties diatoms create flora profiles for scientists. When these microscopic algae die, their frustules (silica cell walls) becomes a part of the water sediment. The presence of the frustules enables scientists to compare the cell walls of the deceased organisms with the living diatoms to determine characteristics of