Question

A number of different, unrelated species of Arctic fishes have evolved an adaptation to avoid freezing in frigid, winter waters. These different species all use the same glycoprotein that they circulate through their blood to prevent ice crystals from forming in their bloodstream. What is the adaptation of freeze resistance in these fishes is an example of? What evolutionary process?

Answer 1

Arctic region is the place where the ground is frozen through out the year with very scarce vegetation.Glaciers,snow fiels and frozen rivers are the most interesting features of Arctic area.Majority of the flora and founa of ths region is adapted to survive at such extreme condition The temperature of Arctic ocean can reach upto 2 degree celsius and water temperature can go below 1 degree celsius but still animals and aqautic organisms thrive at such extreme condition.

Arctic fishes are well adapted to the extreme cold weather.From the period of ice age the fishes are struggling to adapt themself to tavorable for the cold climate w hich was not favorable condition for survival as they haven't faced such climate.Some of the Fish species could adapt to the ice but not all thespecies could survive thus many of the gene was not transformed to the next generation ,which is a very good example of natural selection.As the adaptable species reproduce and passed on their gene to next genetration,mutation in the genetic level took place which suppprted the fishes the fishes to pull on their life at Arctic region.Antifreez ability of the fishes are one of the significant adaptability boosting mechanism in which the cold blooded fishes can lower their body metabolism as the temperature dip to its lowest level.Eg;fishes like Arctic char,arctic cisko.

Antifreez characteristics in various species of fishes rae due to the presence of a antifreez protein called Antifreez glycoprotein(AFGP).It was found that the protein has arise from activated non coding sequence.This protein circulate through their blood serum and assist in lowering the freezing temperature compared to the temperaure they are surrounded with in Ocean.It is believed that the AFGP is derived from the pancreatic trypsinogen gene and production of AFGP was assumed to be used for the antifreezing of digestive juices at the primitive period and then the process expanded to the blood stream through liver metabolism process.There are four types of AFGP gene,I,II,III,1V,AFGP II is found in most of the fish species.Hence we can say that the gene is evolved by divergence and duplication of a particular gene million yers ago.