Deep-sea Anglerfish Reproduction

Deep-sea Anglerfish Reproduction Natures Example of a Total Reduction in the Role of Males: A Review on Deep-sea Anglerfish Reproduction Introduction The Deep Ocean Waters that cover ocean basins constitute the largest living space on earth. This immense environment is home to the largest animal communities on the planet-largest in terms of biomass, numbers of individuals, and area extent (Robison, 2004). Despite its obvious significance to the biosphere, the oceans deep interior remains an unexplored frontier. Although physical and chemical properties of oceanic water vary greatly within the upper kilometer, at greater depths these properties remain relatively constant (Robison, 2004). The deep pelagic habitat is a vast volume of cold, dark water where food is scarce and bioluminescence is the principal source of light and communication. Physical Appearance Anglerfish belong to the order Lophiiformes. Named after their unique mode of predation, in which they use a fleshy outgrowth sprouting from the middle of their head to attract prey, much like a fishing lure. This act is similar to the act of angling, thus the name anglerfish. Deep sea anglerfish has a vicious appearance; however they are not too big in size. They have earned the name common black devil due to their unsightly features. They have a large mouth with sharp, fang-like teeth. They can reach to about 12cm in length (Bora, 2010). Their bodies are globular and they are not adapted for sustained rapid swimming, these are designed for remaining motionless most of the time (different reference). Their body color ranges from dark gray, brown, or black. Their skin reflects blue light, which helps them remain invisible to other deep sea creatures, as most of them emit blue light. Their bodies are fragile and have no scales. In fact, their thin skin can slip off their bodies whenever touched by human hands when they are retrieved from deep sea nets. Their muscles are flabby and they have weak skeletons. Their C-shaped gill slits are very small and are placed below the pectorals (different reference). The eyes of the deep sea anglerfish are too small. They possess one or more long filaments that spring from the center of its head. These so-called filaments are modified spines of the anterior dorsal fin. The longest filament is usually the first spine, or the illicium, which protrudes above the eyes and terminates in an irregular mass of flesh at the tip of the spine, the esca. This filament, which serves as a lure, can be moved back and forth (Bora, 2010). Predation In the deep ocean, food is rare and unpredictable compared to the more reliably available food in the open water. Thus, deep sea animals develop certain strategies to find food and ways of eating whatever food they may encounter with as little effort as possible. Most of the deep sea animals prefer to wait for the arrival of their prey or food particles rather than searching actively for them. Moreover, most of these animals are not selective in their diet and cope up with amazingly large prey (Bora, 2010). Female anglerfish are the classic lurk-and-lure predators. They have a huge mouth and their teeth are large compared to their body size. They rely on their luminous lure to attract their prey instead of searching actively for them. Moreover, these animals can accommodate very large prey through their expandable jaws, which can open up twice as wide, and elastic stomach, which allows them to eat any prey available (Bora, 2010). Their most amazing feature is their bioluminescent lure. The lure of deep sea anglerfish are more elaborate compared to shallow water species, since these are used to attract prey in the dark. These lures are modified dorsal fins and bioluminescence is caused by bacteria, which produce a bluish, greenish light (Bora, 2010). The light and movement of the lure attract the prey to within reach of the gaping jaws. The anglerfish Cryptopsaras can slide the rod part of the apparatus back into a groove, drawing the lure and prey closer to the mouth. It can rotate the lure tip and produce a flash from it as well as a glow. All this is controlled by enzymes and the contraction of chromatophores. These lures have sensory filaments, papillae, light pipes, and shutters. The lures of deep sea anglerfishes are extraordinary elaborate, with sensory filaments, papillae, light pipes and shutters. It may be that different species mimic different kinds of small prey like shrimps to attract larger prey. One anglerfish (Caulophryne) has a lure ornamented with many filaments but it is not luminous. An other (Linophryne) has not only a luminous lure on the head but also a multibranched barbel hanging from the lower jay. The barbel filaments contain many more bioluminescent organs. Some position their lure inside their mouths. Some deep sea anglerfish have positioned their lure inside the mouth. The wolftrapangler Thaumatichthys axeli is a sit-and-wait ambush predator with a luminescent lure hanging from the roof of his overshot mouth, which is fringed with hooked sharp teeth. This anglerfish hovers just above the substrate (not sitting on it). To attract in prey, it waves its lure back and forth till the prey comes closer to its mouth. There is a specialized spine attached to the lure, which can be moved in any direction. When the prey touches the mouth, the esca, which is connected with the mouth reflex, causes the anglerfish to instantly snap the prey with its powerful jaw and swallow it. Moreover, the teeth of the prey are bent inwards so as to prevent the prey from escaping once it enters the mouth. They can take in prey twice their size due to their thin and flexible bones causing the jaw and stomach to extend to an incredible size (Singha, 2010). Reproductive biology Sexual Dimorphism Sexual dimorphism describes animals where there is a physical difference between males and females of the same species (BBC). In most species the female deep sea anglerfish is much larger than the male anglerfish, actually they are real dwarfs compared with their mate. For example the largest females of the genus Gigantactis grow to 40cm in length, whereas the largest males only grow to 2cm. Unlike their sluggish partners they have muscular bodies for active swimming. For many years fish biologists were very confused by these differences and misidentified male and female anglers as completely different species (Zubi, 2010). Sexual Maturity The male deep sea anglerfish mature sexually soon after reaching metamorphosis, in females it takes a much longer time (Zubi, 2010). Extremely young parasitized females of Cryptopsaras couesii indicate that females of this species are able to elicit a search response in a conspecific male, as well as provide cues for specific identification by the male at a very early age (Pietsch, 2005). Sexual Parasitism In sexual parasitism, the dwarfed males become permanently attached to much larger females. This is a remarkable mode of reproduction unique to some members of the deep sea anglerfish suborder Ceratioidei (Pietsch, 2005). There is no mechanism that prevents additional males from becoming attached to a previously parasitized female, but Linoohryne (and perhaps Caulophryne), in which multiple attachments have so far not been found, might be a nexception to this rule. Multiple attachment is rare in Ceratias and Borophryne (only a single record of two males in each case), but common in Cryptopsaras and Haplophtyne, which are known to have as many as eight and six males, respectively (Pietsch, 2005). Males are almost invariably attached upside down and facing forward with respect to the female, and almost always on the ventral midline of the belly of the female, somewhat anterior to the anus; exceptions include those of Cryptopsaras, Haplophryne, and Photocorynus, which may be found almost anywhere on the head and body, and oriented in any direction (Pietsch, 2005). Six of the seven known parasitically attached males of Neoceratias spinifer lack openings to the pharynx leading to the gills and opercular openings, which are present in the area of attachment of nearly all previously described examples of attached males (exceptions include several attached males of Haplophryne mollis). The gills of these Neoceratias males, however, are as well developed as those of free-living males of other ceratioid families, indicating that sufficient oxygen is probably not available via the blood of the female and that this gas is extracted by water that is pumped in and out through the opercular openings (Pietsch, 2005). A dual mechanism for mate location and speciesspecific selection probably functions in most ceratioids, in which both eyes and olfactory structures of the freeliving males are well developed, but it is highly unlikely to function in the ceratiid genera Ceratias and Cryptopsaras, in which the nostrils are surprisingly small and undeveloped, and in Centrophryne and the gigantactinid genera Gigantactis and Rhynchactis, in which the eyes are very much reduced. The mechanism by which males of Neoceratias (in which the eyes and nostrils are especially small and degenerate) find females (which apparently lack bioluminescent structures) remains a mystery (Pietsch, 2005). Modes of Reproduction Temporary nonparasitic: Melanocetus johnsonii and Melanocetus murrayi Males of the Melanocetidae, Himantolophidae, Diceratiidae, Gigantactinidae, and several of the better known oneirodid genera (for example, Oneirodes, Microlophichthys, Dolopichthys, Chaenophryne, and Lophodolos, each now known from well over 50 females), probably never become parasitic. Spawning and fertilization may take place during a temporary sexual attachment that does not involve fusion of male and female tissues (Pietsch, 2005). The parasitic mode of reproduction is apparently obligatory in Ceratias, Cryptopsaras, Borophryne, Haplophryne, and Linophryne, and, although sufficient data are lacking to say for certain, probably in Neoceratias as well. Males of those taxa in which sexual parasitism is obligatory apparently never mature unless they are in parasitic association with a female, and, likewise, females never become gravid until stimulated by the permanent parasitic attachment of a male. That sexual maturity is determined not by size or age in these fishes, but by parasitic sexual association, may well be unique among animals (Pietsch, 2005). Among those taxa in which parasitism seems to be obligatory, the number of parasitized females in collections around the world is surprisingly small compared to the total number of known specimens: about 6% in Cryptopsaras, 11% in Ceratias, 16% in Photocorynus, 33% in Haplophryne, and 40% in Borophryne (Pietsch, 2005). Sexual parasitism is probably facultative in Caulophryne and in the oneirodid genera Bertella and Leptacanthichthys (Pietsch, 2005). The remaining ceratioid families, Thaumatichthyidae and Centrophrynidae, are still so poorly known that little can now be concluded concerning their mode of reproduction (Pietsch, 2005). Reproductive Cycle The deep sea is a vast area and with a small number of animals spread thinly in such an area, it can be difficult to find a mate. Thus, deep sea anglerfish have devised a way through the process of evolution, to continue the propagation of their species through sexual parasitism (Zubi, 2010). Once a male anglerfish is born it directly searches out for a female. Male anglerfish probably do not feed due to the lack of a bioluminescent lure. Instead their eyes and olfactory organs are large (Zubi, 2010). Once the male anglerfish finds a female, he will attach himself to her body usually by biting her belly. Once attached, the teeth and jaws draw back and the skin and blood systems of the male and female merge. Now the male becomes a parasite to the female, not needing to find food for him. Thus, the intestine regress and the only important organ within the male is his large testis. This time the female has a guaranteed supply of sperms while the male relies on the female for food and living (?). It is the female who probably controls the sperm delivery via her hormones, therefore, it is connected with the moment she ejects her eggs from her body. The fertilized eggs contain large oil droplets for buoyancy for floating to the surface of the ocean (Zubi, 2010). As soon as the male detects the presence of a female in his vicinity, he bites or latches onto her with his sharp teeth. Thereafter, the male releases an enzyme that works to digest the body of the female and the skin of the males mouth. Overtime, this process goes on to a physical fusion of the pair down to the blood-vessel level. Then begins the process of the male undergoing atrophy or degeneration. Meaning, the male starts losing his digestive organs, its brain, heart, eyes and all other internal organs, until he is left only with his pair of testicles. These testicles are used to release sperm in response to the females hormones indicating egg release. In this way, about 6 male angler fishes can be borne by a single female, throughout its life time, providing her a lifetime supply of sperm for fertilization (Singha, 2010). The female anglerfish can carry up to six males on her body. This bizarre method of reproduction makes sure that when the female is ready to spawn, she does not have to look for the male, as he is already available. After fertilization, the female lay the eggs in a thin sheet of transparent gelatinous material, which can be 2 to3 feet wide and about 25 to 30 feet long. This sheet with the eggs floats in the sea, till the eggs hatch into larvae. The larvae usually feed on the surface of the sea, until they mature (Bora, 2010).

The Japanese Culture

The Japanese culture in unlike any other in the world. It has long been known for its excellence in education and its strong background of family and religion.The Japanese culture dates back to 10,000 BC with many fascinating periods and events. They span from the days of the samurai and shogun, to 1945 when the atomic bomb was dropped on Hiroshima. Although a bomb would be a devastating blow for any country, rapid industrialization and aid from the United States brought Japan to the forefront of world affairs. Japan is roughly the size of California with a population of 120 million Japanese, 670,000 Koreans and 130,000 of other nationalities. The capital of Japan is Tokyo and the government is a parliamentary democracy, made up of elected representatives. Chinese culture has about five thousand years history which is an extremely long period of time. The Chinese civilization was growing with these periods of time and it will continues greater than ever and it one of the oldest continuous civilizations in history and dominant cultural center of East Asia is China. Chinese Kung Fu, also known as Chinese martial arts, is an important part of traditional Chinese culture. It is probably one of the earliest and longest lasting sports, which utilizes both brawn and brain3Japan's economic freedom score is 72.3, making its economy the 30th freest in the 2018 Index. Its overall score has increased by 2.7 points, with dramatic deficit reduction improving the score for fiscal health and far outpacing a decline in government integrity. Japan is ranked 8th among 43 countries in the Asia–Pacific region, and its overall score is above the regional and world averages.The economy of Japan is a highly developed and market-oriented economy. It is the third-largest in the world by nominal GDP and the fourth-largest by purchasing power parity (PPP), and is the world's second largest developed economy.Japan is a member of the G7. According to the International Monetary Fund, the country's per capita GDP (PPP) was at $37,519, the 28th highest in 2014, down from the 22nd position in 2012. Due to a volatile currency exchange rate, Japan's GDP as measured in dollars fluctuates widely. Accounting for these fluctuations through use of the Atlas method, Japan is estimated to have a GDP per capita of around $38,490.China's economic liberty score is 57.8, making its economy the 110th freest in the 2018 Index. Its overall score has increased by 0.4 point, with developed scores for government honesty and legal effectiveness more than balancing declines in fiscal health, labor freedom, and property rights. China is graded 24th between 43 countries in the Asia–Pacific region, and its overall score is below the regional and world averages.4The low standard of living permits companies in China to pay their workers less than American workers. That makes products cheaper, which lures overseas producers to outsource jobs to China.

Up in Arms About Exploratory Essay Topics Mental Health?

Up in Arms About Exploratory Essay Topics Mental Health? The standard of healthcare services is among the most vital aspects that predetermines a nation's well-being. So deal with your heath, whether is it physical or mental you must be sure of fantastic health. Urgent and essential medical care services are provided dependent on the needs in place of financial opportunities. Nowadays there are a number of practices, to improve mental wellbeing. Writing is a particular gift that you're able to develop, but should you truly feel like it isn't your thing, our crew of professional writers can help to finish an essay from scratch or do paper editing you've already done. See your assignment guidelines or ask your instructor when you have questions about what kinds of sources are ideal for your assignment. Since you can notice, nearly all of the topics mentioned in the aforementioned list focus do not own a definite answer. Moreover, you wish to go for an essay topic that's goin g to enable you to demonstrate your skills to the best of your ability. There are 3 golden rules when you're writing the historical essay. The very first and foremost point that is necessary in drafting a classy history essay is establishing the simple fact that you've been requested to argue about. Put simply, it should provide a last statement that touches on the significant points which you have made in your essay. The introduction ought to be convincing and bring out the thesis that you are likely to present in the essay. There are many points to take into account while writing an exploratory essay. Providing your thesis at the conclusion of your very first paragraph will help to guide your readers throughout the remainder of your essay. The option of evaluation essay topic is a significant step before writing. At times the procedure for choosing evaluative essay topics becomes a true challenge. Consider what you will discuss in your essay to assist you determine exactly what you should have in your introduction. You should compose a reflective essay that is simple to comprehend and you can do it by utilizing simple language. Therefore, it's important to be certain you understand your assignment before you begin. Also, make sure that there's enough information that can be found on the topic that you decide. Thus, don't be afraid to consult them if you stuck when deciding upon a topic. You can also locate short answers to every question. Evaluation papers provide value judgments related to several subjects. You can be totally sure your paper is going to be delivered in time and be of the maximum quality. It is crucial to commence writing a paper far enough ahead of time to allow yourself a couple days or even each week to revise before it's due. An exploratory paper is not uncommon in businesses when they're trying to locate a remedy to an issue and will need to receive all of the feasible perspectives and data available. What to Expect From Exploratory Essay Topics Mental Health? The issue of mental disorders is quite rampant and scary because only few folks have the ability to acknowledge they have an issue and can take time to find medical assistance. There are many factors that may make an individual to come up with a mental disorder. There's also one another form of depression called bipolar disorder in nature also referred to as manic depression. Clinical depression differs. Life experiences like stress or trauma along with substance abuse could also destabilise a person's mental wellness. Mental health conditions are extremely risky health hazards that need to be addressed with the visual appeal of the slightest symptoms. Several elements, the salary being probably the most essential one, motivate a great deal of young individuals to decide on a career in healthcare. Occupational health addresses the health issues or treatment regarding the employees in an organization.

Serial Killers Nature vs. Nurture Essay - 662 Words

Serial Killers: Nature vs. Nurture The question of whether or not man is predetermined at birth to lead a life of crime is a question that has been debated for decades. Are serial killers born with the lust for murder, or are their desires developed through years of abuse and torment? Many believe it is impossible for an innocent child to be born with the capability to commit a horrible act such as murder. But at the same time, how could we have corrupted society so much as to turn an innocent child into a homicidal maniac? Forensic psychologists have picked apart the minds of serial killers to find an answer as to what forces them to commit such perverse acts. Their ultimate goal is to learn how to catch a serial killer before†¦show more content†¦Researchers in the 1960’s pursued men with â€Å"XYY syndrome†, or a surplus male chromosome. Studies show that males with an extra chromosome are generally more aggressive, violent, and it is statistically proven that men with this extra ‘malen ess’ have a far greater tendency towards criminal activity. There is an estimated 100,000 males with this ‘alpha male disease’ in the United States alone, and a larger percent of those men are in prison, than the population at large. Richard Speck, a seaman with a murder count above nine, was diagnosed with the XYY syndrome, and sentenced to 400 years in prison. In one specific case, being a serial murderer appears to be hereditary. An 8 year-old girl murdered more than her fair share of people before graduating from elementary school. Her mother, with whom she had never met, was a convicted killer. Whether or not this is a rare coincidence, is unknown, but for an 8-year-old girl to brutally murder her peers, she would have to have been subjected to an extreme amount of corruption. A quote from well-known Scottish killer, Dennis Nilson, states exactly what his motives were for viscously killing his innocent victims. â€Å"I did it all for me,† he says, â€Å"purely selfish. I worshipped the art and act of death, over and over. It is as simple as that. Afterwards, it was all sexual confusion, symbolism, honouring the ‘fallen’. I was honouring myself. I hated the decayShow MoreRelatedSerial Killers : Nature Vs. Nurture Essay1993 Words   |  8 PagesSerial Killers: Nature vs. Nurture Crime over the years has become a very popular subject. There are countless movies, shows, books and documentaries about such events. Individuals are very entertained for one reason or another by these types of shows. 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