Physiological Adaptation of Fish to Its Environment

All organisms around the world are sparsely distributed depending on the environment that best suited to their modes of survival. Organisms undergo adaptation – an evolutionary process where they became well-suited to a particular. The process of adaptation happens through the natural selection, whereby nature selects those organisms that suit a certain habitat and sustain them for successive generation and ones that do not perish, hence the theme of survival for the fittest. The surviving species pass the same favorable features to their generation for their further survival after a progressive reproduction.

Water bodies have a diversity of conditions that enable fishes to adapt to their survival. The physiological adaptation of these animals varies to a particular habitat, and it relates to how their metabolism works to counter the changing environment. Fish metabolic activities seek to regulate their body functions in any opportune change of their environment and adapt to it. To control the body temperature, fishes undergo physiological thermoregulation. The physiological and metabolic activities regulate the body temperature and maintain it by means of countercurrent exchange system. The countercurrent exchange system is one where the hot blood in the blood vessels, as a result of muscular activities, passes along and gives up some heat to the blood in the adjacent blood vessels, which is flowing to the other parts of the body. This way fishes are able to keep warm. Fish also have the survival tactics in areas where water temperatures are on the point of freezing all the year round – like in the Antarctica region. In order to overcome the darkness due to the ice over the water surface, fish have a specialized sensory system called mechanosensory lateral line, which enables them to sense the motion of other animal in their environment and allows them to feed.

However, some fish subspecies normally live in the freshwater and in seawater depending on the environmental opportunities that affects their chances to survive (WhyEvolutionIsTrue, 2012). Freshwater fish have a mechanism, which makes possible them to concentrate salt within their bodies in the environment of salt deficiency; consequently, marine fish have the capability to excrete excess salt in the hypertonic environment.

The latter as well has chloride cell in their gills, which produce enzyme called gill Na+/K+ATPase that enables them to ride their plasma of excess salt build up when they drink seawater. The enzyme is applied to pump sodium out of their gills using the energy generated from the muscle. Freshwater fish have a physiological mechanism that allows them to concentrate salt and compensate their sanity environment. They achieve the balance of the body and that of the surrounding by producing very dilute, copious urine to rid them of the excess water in their body while taking ions through their gills (“Fish in Their Environments: Habitats & Adaptation,” 2010). Their adaptation favors their capability to adjust to the changing environment. The swordfish has a modified eye muscle with a concentration of mitochondrion cells. The mitochondrion organelles perform the duty of breaking down of food to obtain energy for normal eye movement and to provide heat for blood going to the brain. The physiological system of fish also operates within a fluid environment despite the change its environment. Osmoregulation in fish aims to get a stable balance of uptake and loss of water and solutes through their excretory organs. Marine fish, for example, bony fishes, are hypo-osmotic to seawater; respond to loosing water in their bodies by osmosis and gain salt by diffusion and from the food they eat. They also take up chloride ions through their skin and gills to balance osmotic condition of their environment.

In conclusion, fish, like all other animals, have their mode of adaptation to survive in their habitat regarding the circumstances that occur. They will continue to reproduce passing those adaptations to their next generation.