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Porbeagle Shark
The porbeagle (''Lamna nasus'') is a species of mackerel shark in the family Lamnidae, distributed widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere. In the North Pacific, its ecological equivalent is the closely related salmon shark (''L. ditropis''). It typically reaches in length and a weight of ; North Atlantic sharks grow larger than Southern Hemisphere sharks and differ in coloration and aspects of life history. Gray above and white below, the porbeagle has a very stout midsection that tapers towards the long, pointed snout and the narrow base of the tail. It has large pectoral and first dorsal fins, tiny pelvic, second dorsal, and anal fins, and a crescent-shaped caudal fin. The most distinctive features of this species are its three-cusped teeth, the white blotch at the aft base of its first dorsal fin, and the two pairs of lateral keels on its tail. The porbeagle is an opportunistic hunter that preys mainly on bony fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Joseph Bonnaterre
Abbé Pierre Joseph Bonnaterre (1752, Aveyron – 20 September 1804, Saint-Geniez-d'Olt) was a French zoologist who contributed sections on cetaceans, mammals, birds, reptiles, amphibians, fish, and insects to the '' Tableau encyclopédique et méthodique''. He is also notable as the first scientist to study the feral child A feral child (also called wild child) is a young individual who has lived isolated from human contact from a very young age, with little or no experience of human care, social behavior, or language. The term is used to refer to children who h ... Victor of Aveyron. Bonnaterre is credited with identifying about 25 new species of fish, and assembled illustrations of about 400 in his encyclopedia work of book. He was the first scientist to study Victor, the wild child of Aveyron, whose life inspired François Truffaut for his film '' The Wild Child''. Partial bibliography * ''Tableau encyclopédique et méthodique des trois règnes de la natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Column
A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-Duluth. Retrieved 27 May 2014. Descriptively, the deep sea water column is divided into five parts—'' pelagic zones'' (from Greek πέλαγος (pélagos), 'open sea')—from the surface to below the floor, as follows: '' epipelagic'', from the surface to 200 meters below the surface; '' mesopelagic'', from 200 to 1000 meters below the surface; ''bathypelagic'', from 1000 to 4000 meters below the surface; '' abyssopelagic'', from 4000 meters below the surface to the level sea floor; '' hadopelagic'', depressions and crevices below the level sea floor. The concept of water column is useful since many aquatic phenomena are explained by the incomplete vertical mixing of waters with discrete chemical, physical or biological characteristics. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Game Fish
Game fish, sport fish or quarry refer to popular fish pursued by recreational anglers, and can be freshwater or saltwater fish. Game fish can be eaten after being caught, or released after capture. Some game fish are also targeted commercially, particularly salmon and tuna. Specimens of game fish whose measurements (body length and weight) are a lot above the species' average are sometimes known as trophy fish. Examples The species of fish prized by anglers varies with geography and tradition. Some fish are sought for their value as food, while others are pursued for their fighting abilities, or for the difficulty of successfully enticing the fish to bite the hook. * Big-game fish are blue water saltwater bony fish such as tuna, tarpon, grouper and billfish ( sailfish, marlin and swordfish). Occasionally other predatory fishes such as sharks, barracuda and dolphinfish are also pursued. * In North America, many anglers fish for common snook, redfish, salmon/trout, ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark Attack
A shark attack is an attack on a human by a shark. Every year, around 80 unprovoked attacks are reported worldwide. Despite their rarity, many people fear shark attacks after occasional serial attacks, such as the Jersey Shore shark attacks of 1916, and horror fiction and films such as the ''Jaws'' series. Out of more than 489 shark species, only three of them are responsible for a double-digit number of fatal, unprovoked attacks on humans: the great white, tiger, and bull.ISAStatistics on Attacking Species of Shark/ref> The oceanic whitetip has probably killed many more castaways, but these are not recorded in the statistics. Terminology While the term "shark attack" is in common use for instances of humans being wounded by sharks, it has been suggested that this is based largely on the assumption that large predatory sharks (such as great white, bull, and tiger sharks) only seek out humans as prey. A 2013 review recommends instances where a shark clearly predates on a huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Egg
A trophic egg, in most species that produce them, usually is an unfertilised egg because its function is not reproduction but nutrition; in essence it serves as food for offspring hatched from viable eggs. The production of trophic eggs has been observed in a highly diverse range of species, including fish, amphibians, spiders and insects. The function is not limited to any particular level of parental care, but occurs in sub-social species of insects, such as the spider '' A. ferox'', as well as a few other species like the frogs ''Leptodactylus fallax'' and ''Oophaga'', and the catfish '' Bagrus meridionalis''. Parents of some species deliver trophic eggs directly to their offspring, whereas some other species simply produce the trophic eggs after laying the viable eggs; they then leave the trophic eggs where the viable offspring are likely to find them. The mackerel sharks present the most extreme example of proximity between reproductive eggs and trophic eggs; their viable o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The uterus is a hormone-responsive sex organ that contains glands in its lining that secrete uterine milk for embryonic nourishment. In the human, the lower end of the uterus, is a narrow part known as the isthmus that connects to the cervix, leading to the vagina. The upper end, the body of the uterus, is connected to the fallopian tubes, at the uterine horns, and the rounded part above the openings to the fallopian tubes is the fundus. The connection of the uterine cavity with a fallopian tube is called the uterotubal junction. The fertilized egg is carried to the uterus along the fallopian tube. It will have divided on its journey to form a blastocyst that will implant itself into the lining of the uterus – the endometrium, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the ner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oophagy
Oophagy ( ) sometimes ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek (, "to eat"). In contrast, adelphophagy is the cannibalism of a multi-celled embryo. Oophagy is thought to occur in all sharks in the order Lamniformes and has been recorded in the bigeye thresher (''Alopias superciliosus''), the pelagic thresher (''A. pelagicus''), the shortfin mako (''Isurus oxyrinchus'') and the porbeagle (''Lamna nasus'') among others. It also occurs in the tawny nurse shark (''Nebrius ferrugineus''), and in the family Pseudotriakidae. This practice may lead to larger embryos or prepare the embryo for a predatory lifestyle. There are variations in the extent of oophagy among the different shark species. The grey nurse shark (''Carcharias taurus'') practices intrauterine cannibalism, the first developed embryo consumi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aplacental Viviparous
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch. The young of some ovoviviparous amphibians, such as '' Limnonectes larvaepartus'', are born as larvae, and undergo further metamorphosis outside the body of the mother. Members of genera ''Nectophrynoides'' and ''Eleutherodactylus'' bear froglets, not only the hatching, but all the most conspicuous metamorphosis, being completed inside the body of the mother before birth. Among insects that depend on opportunistic exploitation of transient food sources, such as many Sarcophagidae and other carrion flies, and species such as many Calliphoridae, that rely on fresh dung, and parasitoids such as tachinid flies that depend on entering the host as soon as possible, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Play (activity)
Play is a range of intrinsically motivated activities done for recreational pleasure and enjoyment. Play is commonly associated with children and juvenile-level activities, but may be engaged in at any life stage, and among other higher-functioning animals as well, most notably mammals and birds. Many prominent researchers in the field of psychology, including Melanie Klein, Jean Piaget, William James, Sigmund Freud, Carl Jung and Lev Vygotsky have erroneously viewed play as confined to the human species, believing play was important for human development and using different research methods to prove their theories. Play is often interpreted as frivolous; yet the player can be intently focused on their objective, particularly when play is structured and goal-oriented, as in a game. Accordingly, play can range from relaxed, free-spirited and spontaneous through frivolous to planned or even compulsive. Play is not just a pastime activity; it has the potential to serve as an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothermy
An endotherm (from Greek ἔνδον ''endon'' "within" and θέρμη ''thermē'' "heat") is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat released by its internal bodily functions instead of relying almost purely on ambient heat. Such internally generated heat is mainly an incidental product of the animal's routine metabolism, but under conditions of excessive cold or low activity an endotherm might apply special mechanisms adapted specifically to heat production. Examples include special-function muscular exertion such as shivering, and uncoupled oxidative metabolism, such as within brown adipose tissue. Only birds and mammals are extant universally endothermic groups of animals. However, Argentine black and white tegu, leatherback sea turtles, lamnid sharks, tuna and billfishes, cicadas, and winter moths are also endothermic. Unlike mammals and birds, some reptiles, particularly some species of python and tegu, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Migration
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to spawn; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Movements are associated with ocean currents and with the availability of food in different areas at different times of year. The migratory movements m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
