Marine Life Essay Examples

AND ADAPTATIONS

OF DIFFERENT ORGANISMS
ADAPTATIONS
Adaptation means developing features which will consequently help in adjusting to the natural environment of the organism. There are different life forms on the earth. Each organism has to undergo certain bodily changes to adapt themselves to the surroundings. These changes come through generations, thus called as evolution. The organisms thus evolve in order to fit themselves in the environment. They undergo modifications of their structures depending on the requirement of the nature. It is the adaptation that enables the organism to survive. If the organism is unable to evolve and adjust accordingly then it will have to face extinction. The failure to develop will result in loss of life.
The aquatic species form a totally different entity of organisms. They sustain the environment by multiple changes in their physical constitution. As the types of aquatic organisms are variable, so are the ranges of adaptations. Different types of aquatic organisms undergo different sets of changes to fit themselves in to the environment. In order to get accustomed to the aquatic environment the marine species undergo certain bodily changes that enable them to cope up with the aquatic conditions. The three species which have certain similar and some dissimilar adaptive features are the bony fish, cartilaginous fish and the toothed whale. Although they have varying features, but some commonality do make them one. The mechanism of maintaining the osmotic pressure and the salinity is more or less the same in all the three groups. However some has better features for detection of prey, like echolocation, which is not present in all the three types. Also certain respiratory features set apart one type from the other.
The bony fish for example, has a swim bladder which the cartilaginous fishes lack. The swim bladder is filled with air; it thus helps the fish to float on the water surface even when it is not swimming. In addition to this, the bony fishes have a fusiform body shape that decreases the water resistance, also the covering of the whole body with scales helps in further reduction of water resistance (Animalfacts.net, 2015). The cartilaginous fishes have a very sharp sense of hearing which helps them to locate prey from a farther distance. They can hear sounds of very low frequency. Also they have a membrane over their eyes called as tapetum. This membrane reflects back light into the eye. This helps in better vision even in the dark. With the help of ampullae of Lorenzini, which are special organs distributed over the head of the fishes, they can detect any change in the electrical signals from other organisms. They have spiracles on either side of their heads, near the eyes. These spiracles help in delivering oxygen to the gills without letting in much of much of mud or sand. This feature is especially useful when the fishes are resting near the land (Scienceclarified.com, 2015). The toothed whales on the other hand share similar features in terms of detection of the prey or any other nearby organism. For serving the purpose they have large ears, along with that they have a special feature called as echolocation. The position of the larynx in the toothed whale is such that it enables the organism to swallow and echolocate simultaneously (Reidenberg and Laitman, 1987). The toothed whales have blubber inside their layer of skin. Blubber is basically a layer of fat that helps in adjusting the toothed whale with the temperature (Whalefacts.org, 2015).
The bony fish excrete through their gills. The sea water is more salty than the internal fluid of the fishes. Thus due to pressure gradient the fishes lose large quantity of water through their gills to maintain osmolarity. Similarly in fresh water fishes the salinity is more inside the body of the fishes. Thus the fishes absorb water from the sea to maintain the water gradient (Wikipedia, 2015). However in the cartilaginous fishes the mode of osmoregulation is with the help of urea concentration in the body of the fishes. In saline environment, the excess urea and other biochemical solvents help in removing the excess salt from the blood of the fishes. Alternately, in fresh water the fishes absorb lots of water from the water bodies. These functions are performed by the renal system of the fishes (Sharksavers.org, 2015). The method of osmoregulation is similar in whales too; they excrete highly hypertonic urine to maintain the osmolarity and thus the pressure (Birukawa et al, 2005).
Different organisms have different ways of adjusting with the natural environment, same goes with the different types of fishes too. They have developed certain physical features that enable them to cope with the environment and survive, thus abiding by the theory of Darwin, Survival of the fittest. The organism which can adjust accordingly and develop itself into a more suitable form for the Earth, can survive, others will not. Fishes being a different species altogether have their own sets of developmental features and adaptive techniques that they have accustomed.

REFERENCES

Animalfacts.net,. (2015). Bony Fish | Fish. Retrieved 24 February 2015, from http://www.animalfacts.net/fish/bonyfish.html
Birukawa, N., Ando, H., Goto, M., Kanda, N., Pastene, L., & Nakatsuji, H. et al. (2005). Plasma and Urine Levels of Electrolytes, Urea and Steroid Hormones Involved in Osmoregulation of Cetaceans. Zoological Science, 22(11), 1245-1257. doi:10.2108/zsj.22.1245
Reidenberg, J., & Laitman, J. (1987). Position of the larynx in odontoceti (toothed whales). Anat. Rec.,218(1), 98-106. doi:10.1002/ar.1092180115
Scienceclarified.com,. (2015). Fish - humans, examples, body, water, process, Earth, form, energy, animals, oxygen, air, surface, part, Cartilaginous fish. Retrieved 24 February 2015, from http://www.scienceclarified.com/Ex-Ga/Fish.html
Sharksavers.org,. (2015). Shark Savers :: How Bull Sharks Survive in Fresh Water. Retrieved 24 February 2015, from http://www.sharksavers.org/en/education/biology/how-bull-sharks-survive-in-fresh-water/
Whalefacts.org,. (2015). Whale adaptations. Retrieved 24 February 2015, from http://www.whalefacts.org/whale-adaptations/
Wikipedia,. (2015). Fish physiology. Retrieved 24 February 2015, from http://en.wikipedia.org/wiki/Fish_physiology#Thermoregulation