Essay代写范文-Compared with the land and the shallow seas

本文是一篇compare and contrast essay代写范文，本文主要讨论了与陆地和浅海相比，物理环境和生态大不相同，压力可能比大气压力大数千倍，即使在深海完全黑暗的状态下，亮度也可能极低。此外，陆地和浅海有许多物种，而深海则相反。因此，深海生物很难找到猎物并获得生存所需的能量来源。只有具有特殊适应能力的生物才能在如此恶劣的环境中一直繁殖。龙舌形目以其独特的生理结构和生存方式克服了这一可怕的局面。

Compared with the land and the shallow seas, the physical environment and ecology is quite different, the pressure could be thousands times greater than atmospheric pressure, the brightness could be extremely low even in state of completely dark in the deep sea. In addition, there are numerous species on land and in the shallow seas, but opposite in the deep sea. As a consequence, it is hard for creatures in the deep sea to find the prey and obtain energy source to get survive. Only the creatures have special capacity of adaptation are able to reproduce all along in such hostile environment. Lophiiformes overcome the awful situation by their unusual physiological structure and survival mode.

Distribution and Structures of Lophiiformes

Species and distribution. Lophiiformes is commonly known as anglerfish, which generally live in deep tropical and subtropical waters. Anglerfish is one of the teleost fishes and exist 321 species totally. It is widely spread from benthic shallow-water to deep-shelf and can be found in the Atlantic, Pacific and Indian oceans.

Stomach content. A study learned the stomach content from Lophiodes spilurus specimens which token from central Pacific of Costa Rica[1]. The specimens were dissected to analyze the stomach and the scientists found 52% of the specimens’ stomach were empty. This result distinctly demonstrated that the L.spilurus do not store food in their stomach more than half time of their daily life. To compare with the standard stomach content percentage of fish[2], which is 91%, it is much lower. This result supports that the angler fish is relatively “low-intaking fish”. But the specimens in this research token from the commercial ship instead of in-situ observation, which may cause the inaccuracy of result. 

Survive and Reproduce

Predation. Anglerfish are famous for their special capacity of predation. It exist a long filament structures called esca or illicium sprouting from their middle head to shine the bioluminescence so that to attract the prey. There are glandular cells in it and luciferin is secreted, undergoing photinus pyralis and slow chemical oxidation with oxygen catalyzed so that the light is produced. Meanwhile many species in the deep sea are photosensitive, once the prey approaching, the anglerfish would intake them combined with the water current immediately. This order of fish has great ability of adaption and derives a series of strategies to live in the low creature dense environment efficiently and reliably. 

Mating. It's pretty hard to find a mate in the deep sea area, and the angler fish have their adaption to “bundle” their mate and life together through their life. At the early time, people found that there was no male angler fish caught out. People believed this kind of fish had no male. But lately, people noticed that some angler fish has very small “tail” attached, which is the male angler fish that “fused” with the female anglerfish. And lately this wonder sexual parasitic relation was finally revealed[3]. The male angler fish would bite the female angler fish and “fuse” with the female angler fish gradually. Most organs of the male fish would be deposed, while the brain and the genital system of male fish would remain and stay with the female fish. The blood vessel of male fish would be connected with female fish, which enable the male fish to share nutrition with female fish.

The way of Saving Energy

Drift. To avoid energy consuming, the moving pattern of the angler fish’s should save energy for themselves. A research[4] which took an in situ observation to record the complete behavior of the anglerfish predation. They used the ROV to record the process from the burst swimming to passive drift. They found that the angler fish spend more than 70 percentage of time to stay in a “passive drift” state, which make sure to consume the minimum energy for the angler fish. They performed a burst swimming only 1.9% time, which relate to the preying or escape response. 

Esca. Another strategy for anglerfish to save energy is the esca[5]. The anglerfish use esca to lure prey instead of looking around, which save great energy from preying. Besides that, the source of light is low energy consumed, too. In early time, people believe that the anglerfish consume their own energy to maintain the ecsa glow. But later research shows that the light of all glow species actually comes from the symbiotic bacteria that living in the esca structure. An esca contain with the light gland, which helps gathering the light. There is a light gland is an oval structure that consisting of some radiating branched glandular tubules arranged around a central esca cavity. People also found that there is no symbiotic bacteria founded in the larva of anglerfish, as the bacteria take time to “rise” in the esca during the growth of anglerfish. There is no alive bacteria was found outside of the esca, so how does the bacteria gathered is still uncertain. But some researchers speculate that the bacteria enter the esca through small pores from seawater[6].

A survival position. There is also an interesting behavior observed at the same time, which they take around 4% in the whole process. A “luring” states indicates that the fish body turns to an upside-down position, which assumed to be death mimicry to protect themselves from their natural enemy. However, another research keeps an opposite evidence. A research found that the angler fish shows the upside-down position when they try to escape, too. This research also used ROV to record the whipnose anglerfish behavior. They recorded the specimens performed the upside-down position both for lure and escape propose. The research also found that the whipnose anglerfish shows a “tired” state after a high energy consuming activity. The rate of undulations kept getting slow after the burst action, while even changed the speed after only 5–6 seconds. The specmper was assumed that lack of stamina to keeping moving, which support the low-energy intake fact before. 

Conclusion

Anglerfish is an extremely rare species which has many survival abilities in order to survive, such as special body structure, predation, reproduction, energy saving mode and drifting. None of these abilities are not for the anglerfish struggle to survive in the harsh environment, no doubt they adapt it.

琵琶鱼是一种极为罕见的物种，具有多种生存能力，如特殊的身体结构、捕食、繁殖、节能模式和漂流。所有这些能力都不是为了让琵琶鱼在恶劣的环境中生存，毫无疑问，它们会适应这种环境。

以上就是本篇Essay代写范文全部内容，仅供留学生参考学习，不得抄袭，如有Essay代写需要，请咨询网站客服。