4. 척삭동물 (Chordata) 1) 좌우대칭의몸을갖는다. 2) 3 배엽성이고, 체강이잘발달되어있다. 3) 생활사의어느시기에는등쪽에척삭 (notochord) 을가진다. 4) 생활사 (life cycle) 의어떤시기에꼬리와인두열을가진다. 5) 심장은등쪽에있으며, 혈관계는폐쇄형이다. 6) 완전한소화계를가진다. 7) 대부분의척삭동물은연골이나경골성의내골격을가진다.
Phylum Chordata ; chordates Chordates are defined as organisms that possess a structure called a notochord, at least during some part of their development. The notochord is a rod that extends most of the length of the body when it is fully developed. Lying dorsal to the gut but ventral to the central nervous system, it stiffens the body and acts as support during locomotion. Other characteristics shared by chordates include the following (from Hickman and Roberts, 1994): 1. bilateral symmetry 2. segmented body, including segmented muscles 3. three germ layers and a well-developed coelom. 4. single, dorsal, hollow nerve cord, usually with an enlarged anterior end (brain) 5. tail projecting beyond (posterior to) the anus at some stage of development 6. pharyngeal pouches present at some stage of development 7. ventral heart, with dorsal and ventral blood vessels and a closed blood system 8. complete digestive system 9. bony or cartilaginous endoskeleton usually present.
Characteristics of the Phylum Chordata All members of the Phylum Chordata have the following characteristics, at least at some time during their development 1. Notochord : A firm, flexible rod of specialized cells that becomes the endoskeleton in vertebrates. 2. Dorsal nerve cord : A hollow tube above the notochord that becomes the spinal chord and brain in vertebrates. 3. Pharyngeal pouches Out-pockets in the pharynx, the portion of the digestive tract between the mouth and the esophagus. Become gill chambers and gills in aquatic chordates. Become jaws, inner ear, and tonsils in terrestrial chordates. 4. Post-anal tail A tail located posterior to the anal opening
* 척삭동물의해부학적특징 * 1. pharyngeal slits ( 인두열 )- a series of openings that connect the inside of the throat to the outside of the "neck". These are often, but not always, used as gills. 2. dorsal nerve cord ( 신경삭 )- a bundle of nerve fibers which runs down the "back". It connects the brain with the lateral muscles and other organs. 3. notochord( 척삭 )- cartilaginous rod running underneath, and supporting, the nerve cord. 4. post-anal tail( 항문과꼬리 )- an extension of the body part the anal opening.
The Phylum Chordata includes all of the vertebrates, as well as two groups of marine animals that lack backbones and are therefore invertebrates. The phylum is divided into three subphyla, determined by the development of the notochord: 1. Subphylum Urochordata: contains 2,000 species commonly called tunicates because their bodies are covered by a tough covering, or tunic. They are also known as sea squirts because they shoot out a stream of water when touched. Most tunicates are sessile, barrel-shaped, filter feeding animals that live on the sea bottom. Adult tunicates have a pouch-like pharynx with slits, but they do not have a notochord, dorsal nerve cord, or postanal tail. These chordate characteristics are lost during metamorphosis. 2. Subphylum Cephalochordata: contains about 24 species of blade-shaped animals known as lanceletes. They retain the notochord, dorsal nerve chord, pharyngeal pouches, and postanal tail throughout their life. 3. Subphylum Vertebrates: Parts of the axial skeleton - Skull and backbone Parts of the appendicular skeleton The pelvic and pectoral girdles attach to the axial skeleton. Front limbs attach to the pectoral girdle and hind limbs attach to the pelvic girdle.
1) 피낭동물아문 (Tunicata) (1) 미삭동물아문 (Urochordata) 이라고도불리며, 해초강 (Ascidiacea), 탈리아강 (Thaliacea), 유형강 (Appendicularia) 으로나뉜다. 해초강은고착생활을하며, 탈리아강과유형강은부유생활을한다. 주요종으로는미더덕 (warty sea squirt ; Styela clava), 오만둥이 (styela plicata), 우렁쉥이 (sea squirt ; Halocynthia rotetzi) 가있다. (2) 고착성생활을하며, 셀룰로오스성피낭으로주머니 (tunic) 모양을하고있다.
(3) 몸의위쪽에물과먹이를빨아들이는입수공 (incurrent siphon) 과, 물과노폐물을내뿜는출수공 (excurrent siphon) 이있다. 이입수공과출수공으로물속에있는산소를흡수해호흡을하며, 함께들어온플랑크톤과같은먹이를먹기도한다. (4) 입수공으로들어온플랑크톤은인두 (pharynx) 안에있는내주 (endostyle) 에서분비된점액에잡힌후식도의섬모상의세포 (ciliated cells) 에의해위로이동한다. 피낭동물의장은 U 자형으로, 항문은위로향해있다. 물은인두열 (pharyngeal slit) 을지나인두방 (atrium) 으로흘러들어간다.
(5) 자웅동체이고, 무성생식 (asexual reproduction) 과유성생식 (sexual reproduction) 의두방법을사용하여번식한다. 무성생식의경우기저부의손가락모양의돌기 (stolons) 에서새로운개체가솟아나오는출아법 (budding method) 으로번식하는데, 이경우새로운개체는어미의몸에서떨어져나가지않고군락 (colony) 을이룬다. 그래서여러개체가이어져있는군체를형성한다.
(6) 유성생식의경우성숙한생식소 (gonad) 는인두방으로부풀어올라출수공을통해알과정자를내뿜어수정한다. 꼬리에척삭 (notochord) 과척수 (nerve cord) 가있는올챙이모양의작은유생 (ascidian tadpole) 으로부화해물속을유영하다머리부분으로단단한물체에달라붙은후, 척삭과신경삭 (nerve cord) 를흡수하는완벽한변태를하여성체가된다.
그림. 우렁쉥이의생활사. 1 : 수정난, 2 : 64 세포기 ( 수정후 6 시간경과 ), 3 : 배발생기, 4 : 아펜디쿨라리아유생 (ascidian tadpole = Appendicularia), 5 : 어린성체, 6 : 성체
2) 두삭동물아문 (Cephalochordata) (1) 가장원형적인척삭동물의형태를갖는동물로해안의모래를파고들어가서식하며, 주요종으로는창고기 (lancelet= amphioxus ; Branchiostoma belcherii) 가있다. (2) 머리에서꼬리까지척삭 (notochord) 이일생동안존재하며, 뇌와신경삭 (nerve cord) 이있다. (3) 정자와난자가같은개체에서발생하지않는자웅이체이다. (4) 피낭동물과같이먹이는인두를통해들어가서장을통해항문으로나가며, 물은인두열 (pharyngeal slit) 을지나인두방을거쳐인두공 (atriopore) 으로배출된다. 호흡은물이인두열을지나며행하나대부분의호흡은피부를통해일어난다.
(5) 폐쇄혈관계를가지고있으며, 배쪽의굵은혈관일부가수축하여혈류를일으키고혈액은무색이다. (6) 입앞쪽에가는모양의촉모 (oral cirri=tentacles) 를가지고있어, 입으로들어가는물을걸러주거나감각기역할을한다. (7) 척추동물과같이몸에마디로이루어진근육분절 (myomere=segmental muscle) 이있다.
Modern fishes in Subphylum of vertebrates 1. Class Agnatha : the jaw-less fish (lampreys and hagfish) a. Eel-shaped body b. Cartilage skeleton c. Unpaired fins d. jawless mouth 2. Class Chondrichthyes : the cartilage fish (sharks, rays, and skates) a. Cartilage skeleton b. Placoid scale c. Rows of teeth 3. Class Osteichthyes : the bony fish (95% of all fish are members of this class) a. Bony skeleton b. Integument skin c. Scales
3) 척추동물아문 (Vertebrata) (1) 갑피류 (Ostracoderms) 1 턱뼈와지느러미가없고, 몸의표면에비늘또는골판으로덮여있는특이한형태를하고있다. 2 가장오래된척추동물로화석종 ( 갑주어, armored fish) 이다. (2) 원구류 (Cyclostomes) 1 척추동물중가장하등한무리로척삭이일생동안존재하며, 먹장어와칠성장어등이이에속한다.
2 입은둥근빨판모양 (buccal funnel) 이고각질의날카로운이빨을가지고있어, 다른어류에달라붙어날카로운이빨로피부에상처를낸뒤영양분을빨아먹는기생생활을한다. 3 몸은가늘고뱀장어처럼생겼으며, 한개의비공 (nostril) 과새열 (gill slit) 과새공 (gill opening) 을가진다.
4 갑피류와같이턱뼈가없는무악어류 (Agnatha) 로골격은연골성이며, 비늘이없다. 5 가슴과배지느러미가없으며, 먹장어는촉수와같은역할을하는 6-8 개의수염 (barbel) 을가지고있다. 6 칠성장어는자웅이체로체외수정을하며, 산란하기위해바다에서강으로회유하며알에서깨어난유생은애머시이트 (ammocoete) 라불리는데주로강바닥의진흙속에서유기물이나조류를걸러먹는다. 변태를거쳐몸크기가 15-20 cm에이르면바다로내려가성장한다. hagfish are the only animals which have a skull but do not have a vertebra (spine). The skulls of hagfish are cartilaginous in nature, where keratin based tooth-like structures are attached for consumption of food.
7 먹장어는머리에서꼬리에이르기까지한줄로점액분비선이있어, 천적의아가미기능을방해할정도의많은양의점액 (slime= mucus) 을분비한다. 8 먹장어는전신 (pronephros) 을평생가지고있으나, 칠성장어는어류에서와같이배의시기에는전신이작용을하나, 중신이전신의후방에생김에따라퇴화한다. (3) 판피류 (Placoderms) 1 양턱이있고, 한쌍의비공과홑지느러미 (unpaired fin) 및짝지느러미 (paired fin) 가있다. 2 두부와몸이골판으로된외부골격으로보호되며, 화석종이다.
(4) 연골어류 (Chondrichthyes) 1 연골어류에는상어와가오리, 홍어 (skate ray ) 등이속하는판새류 (Elasmobranchs) 와 silver Chimaera와 spotted ratfish 등의은상어류 (Chimaeridae) 가속하는전두류 (Holocephalans) 가있다.
2 골격및피부가. 몸은머리, 몸통, 꼬리, 그리고지느러미로구분되고, 체형은방추형이다. 나. 연골로이루어진내골격 (endoskeleton) 을가지며, 입보다큰먹이를먹기위해턱뼈 (jaws) 는두개 (braincase) 에붙어있지않다. 다. 피치 (dermal denticle) 라고불리는만지면꺼끌꺼끌한비늘 ( 순린 ; placoid scale) 과치아외에는경골은없다. 라. 전두류는비늘이없고, 턱에는치아대신경질의평판을갖는다.
마. 턱뼈와척추 (backbone) 는칼슘이침착된보다단단한연골 (calcified cartilage) 로이루어져있다. Skeleton of a porbeagle shark
라. 치아는턱뼈에박혀있지않고, 치아판 (tooth bed) 이라불리는막에붙어있어맨앞줄의치아가손상되면뒷줄의치아가밀려나와대신한다. 그림. 먹이를물어삼키는상어는여러줄의치열이있어겉의이가빠지면안에서새로운이가생겨올라온다. Shark teeth are not lodged permanently within the jaw, but are attached to a membrane known as a tooth bed. The tooth bed membrane is similar to a conveyor belt, moving the rows of teeth forward as the shark grows, thus replacing the older teeth in front that have become damaged, fallen out or worn down. It is not uncommon for shark teeth to be found lodged in large prey (such as whale carcasses) or loose on the ocean floor.
3 지느러미가. 일반적으로지느러미가발달되어있으며, 등지느러미에강한가시를가진것도있다. 나. 상어의지느러미는유영하는데있어서, 방향조절 ( 가슴지느러미 ) 및추진 (propulsion ; 꼬리지느러미 ), 그리고부력 (buoyancy ; 가슴지느러미 ) 에관여한다. Well when a shark swims forward through the water, the water flows over the fins, just like the air flowing over an airplane's wings. Without moving forward sharks would sink, the "lift" generated by their pectoral fins keeps them afloat. Their liver not only serves as an energy reservoir but is also an efficient alternative to the swim bladder of many bony fish.
다. 등쪽이크고아래쪽이작은부등미 (heterocercal) 의꼬리지느러미를가진다. 라. 수컷의배지느러미의일부가변형된교접기 (claspers ; copulatory organ) 가있어암컷에게정자를운반하는데사용된다.
4 소화계가. 육식성 (carnivore) 으로입은머리의아래에위치한다. 비교적먹이를통째로삼키거나물어뜯어먹는다. 나. 위는 U 자모양으로강한산과효소로먹이를소화시키며, 장은비교적곧고짧다. 다. 장에는소화흡수면적을넓히기위한나사모양의판막 (spiral valve) 이있다.
라. 간장은 oil 과 fatty acid 로가득차있어체중의 25% 를차지하며, 에너지의저장과부력에관여한다. 마. 두엽의췌장은소화효소의분비를담당하며, 위옆에위치한비장은면역관련작용을한다. 또한상어는부레를갖지않는다. Squalene is found in shark liver oil, and is also a major component of the lipids on the surface of human skin. Although it is not obvious from the way the structure above is drawn, squalene is a precursor for the biosynthesis of cholesterol. Through a complex series of enzymatically controlled reactions, squalene is converted into an intermediate called lanosterol, which undergoes a number of subsequent reactions to become cholesterol.
5 번식과생식계가. 자웅이체로복강앞쪽에각각한쌍의정소와난소를가지며, 수컷의교접기를이용해체내수정을한다. 나. 태생 (aplacental viviparity =ovoviviparity) 을하는상어는태반이없어자궁내에서부화전의알이나다른태아를먹고자라며 (sibling cannibalism), 보통 1-2 마리의완전한형태의새끼 (pup) 를낳는다.
Reproduction of sharks Shark has three different modes of reproduction, viviparity, oviparity, and ovoviviparity. 1. Oviparity -These sharks deposit eggs in the ocean which will hatch later if they are not eaten by predators (the horn shark, catshark, Port Jackson shark, and swellshark). 2. Ovoviviparity (= Aplacental viviparity )- the eggs hatch in the oviduct within the mother's body and that the egg's yolk and fluids secreted by glands in the walls of the oviduct nourishes the embryos. The young continue to be nourished by the remnants of the yolk and the oviduct's fluids secreted by some glands in wall of oviducts (angel shark). Intrauterine cannibalism (sibling cannibalism) : The largest embryos in the uterus will eat their weaker and smaller siblings (grey nurse shark). The developing embryos eat remaining eggs produced by the mother (oophagy ; porbeagle and lamniforme shark). 3. Viviparity - the mother retains the eggs, as in ovoviviparous fishes, but the embryos receive nutrition from the mother in a variety of different ways. Typically, viviparous fishes have a structure analogous to the placenta seen in mammals connecting the mother's blood supply with that of the embryo (Hammerheads, lemon shark, surfperch, and splitfin).
6 호흡계가. 판새류는덮개가없는 5-7 쌍의새열 (gill slits) 을가지나, 전두류는새실이덮개 (gill cover) 로덮여있다. 나. 입으로들어간물은아가미조직을지나며가스교환을하고새열로나간다. 다. 눈뒤에제 1 새열의흔적기관인기공 (spiracle) 을가지고있어, 눈과뇌에직접혈액과산소를공급한다.
7 삼투압조절가. 체내의삼투압을외계의삼투압보다다소높게유지하기위하여, 신장으로부터요소 (urea) 를배출하지않고혈액속에다량의염분과요소, 그리고트리메틸아민옥사이드 (TAMO ; trimethylamine oxide) 를함유한다. 이요소는상어가죽은뒤바로암모니아로변해악취의원인이된다. 나. 피부에방패비늘이있기때문에물이거의통하지않으나, 아가미를통해물이흡수되므로, 삼투압을일정하게유지하기위해여분의염분을직장으로열려있는직장선 (rectal gland) 을통해배출한다.
Osmoregulation in shark In contrast to bony fish, with the exception of the Coelacanth, the blood and other tissue of sharks and Chondrichthyes in general is isotonic(slightly hyperosmotic) to their marine environments because of the high concentration of urea and trimethylamine N-oxide (TMAO), allowing them to be in osmotic balance with the seawater. This adaptation prevents most sharks from surviving in fresh water, and they are therefore confined to marine environments. A few exceptions to this rule exist, such as the bull shark which has developed a way to change its kidney function to excrete large amounts of urea. When a shark dies the urea is broken down to ammonia by bacteria because of this, the dead body will gradually start to smell strongly of ammonia.
* 홍어회냄새의비밀 * 홍어회는전남목포지역특산품으로유명하다. 홍어를잘씻어자른후에삼베에싸서장독에넣고숙성시키면코를찌르는쿰쿰한썩은냄새에처음먹는사람은고개를절레절레흔든다. 홍어는삭힐때라도신선한것이라야비린내가없으며달고꼬들꼬들하며삭힐수록톡쏘는매콤한맛이강해지고살이부드러워진다. 항아리에넣고삭힐때생기는점액은그대로둬야하며, 삭혀서찜을하려면겨울에는 1 주일, 봄과가을에는 3 4 일삭힌후에마른수건으로점액을잘닦아낸후쪄야한다. 홍어회는묵은배추김치와돼지고기를안주로탁주한사발과함께먹는홍탁삼합 ( 洪濁三合 ) 이제격이다. 풍류를아는사람은이렇게먹어야술맛이제대로난다고한다. 처음에는지리고매운냄새에눈살을찌푸리고물러서지만일단맛을들인사람은꼭다시찾는다판새류또는연골어류라고부르는상어와가오리류는일반적인경골어류와달리삼투압조절에필요한요소 ( 尿素 ) 와 TMAO( 트리메틸아민산 ) 를다량함유하고있다. 근육중의요소는죽은뒤암모니아로변해악취의원인이된다. 그리고 TMAO 는세균이갖고있는 TMAO 환원효소에의해 TMA( 트리메틸아민 ) 로되며, TMA 는어육의선도가떨어질때나오는냄새성분이다. 생선이부패하기시작할때암모니아및 TMA 가생성되며, 이생성량이부패초기의선도지표로사용된다. 일반경골어의암모니아는선도저하에따른부패세균이어육단백질을분해하면서나오는것이지만상어와가오리에생성되는대부분의암모니아는단백질분해가아닌요소로부터생성되는암모니아이므로부패가아니다.
8 순환계가. 폐쇄혈관계이며, S 자모양의 1 심방 1 심실과심장구 (conus arteriosus) 로이루어진심장을가진다. 나. 심실에서나온혈액은심장구를지나아가미동맥 (afferent branchial arteries) 을통해아가미로들어가가스교환을한후, 아가미정맥 (efferent branchial arteries) 을통해온몸에보내진다. 다. 일부상어에서는빠른유영을유지하기위해근육에보다많은혈액을공급해야하므로, 혈관벽을통해반대편방향으로흐르는혈액사이에열과가스, 이온을교환할수있는잘발달된혈관망 (vascular countercurrent heat exchanger ; rete mirabile) 을가지고있어주위의수온보다높은체온을유지한다 (homeothermy).
Homeothermy Although most fish are exclusively aquatic and ectothermic, there are exceptions to both cases. Fish from a number of different groups have evolved the capacity to live out of the water for extended periods of time. Of these amphibious fish, some such as the mudskipper can live and move about on land for up to several days. Also, certain species of fish maintain elevated body temperatures to varying degrees. Endothermic teleosts (bony fishes) are all in the suborder Scombroidei and include the billfishes, tunas, and one species of "primitive" mackerel (Gasterochisma melampus). All sharks in the family Lamnidae shortfin mako, long fin mako, white, porbeagle, and salmon shark are known to have the capacity for endothermy, and evidence suggests the trait exists in family Alopiidae (thresher sharks). The degree of endothermy varies from the billfish, which warm only their eyes and brain, to bluefin tuna and porbeagle sharks who maintain body temperatures elevated in excess of 20 C above ambient water temperatures. Endothermy, though metabolically costly, is thought to provide advantages such as increased contractile force of muscles, higher rates of central nervous system processing, and higher rates of digestion.
Mechanism of Count current heat exchanger Gill & extremiti es Heat Vein Co 2 Artery Red Muscle Cold Hot O 2 - Condution of heat between Artery and Vein - Diffusion of gas (transfer of oxygen from blood to muscle cells)
9 신경계와감각기관가. 상어는다른물고기와비교하여상대적으로크고복잡한뇌를가지고있으며, 연골로된척추로보호된척수를가진다. 나. 한쌍의 nostril 에연결된후각기는잘발달되어있고크다. 다. 머리의양옆에있는눈도잘발달되어있고, 일부상어에서제 3 안검 (nictitating membrane) 이있어각막을보호한다. 또한망막뒤에거울같은판 ( 반사판 ; tapetum lucidum) 이있어빛을망막에재반사해어두운곳에있는물체를더욱잘보이게한다.
라. 몸의양측에주위의움직임 (vibration) 과소리를감지할수있는측선 (lateral line) 과먹이탐지를위한전기자극 (electrical stimuli) 과수온을감지할수있는머리부분의특별한감각기관 (ampullae of Lorenzini) 이있다. 마. 머리위에소리를감지할수있는구멍 (endolymphatic pore) 이있으며, 입에있는미뢰 (taste bud) 로맛을감지한다.
Sharks register and reconnoiter the underwater world with their seven senses. In order to be successful hunters these sharp senses are needed for survival. But even successfully surviving in the ocean for more than 400 million years was dependent on the development of such a fine sensory system.
11) 전기가오리는꼬리에서고압의전기를방전하며, 일부가오리의꼬리에는가시가있어독을내기도한다. Electric ray (Narcine brasiliensis) Electric rays (order Torpediniformes) are fish that have a rounded body and a pair of organ capable of producing an electric discharge, varying from as little as 8 volts to up to 220 volts depending on the species, which is used to stun or kill prey. Mediterranean Stingray Scientific name: dasyatis pastinaca Size: can reach up to 200kg Whereabouts: It can be found in sandy beaches, hiding in the sand waiting for its prey Dangers: The tail of the ray is a whip with spikes containing a very strong poison. Poisoning can cause severe pain, vomiting, swelling, respiratory problems and may lead to amputation or death.
노랑가오리가뭐길래 스티브어윈사망 연합뉴스는 " 올해 44 살인호주의동물보호운동가인스티브어윈이꼬리에맹독이들어있는노랑가오리를수중촬영하다가오리의꼬리가시에찔려숨졌다 " 고전했습니다. 이어 " 어윈씨가이날오전 11 시쯤호주북동부퀸즐랜드주 ( 州 ) 연안에있는세계최대의산호초인 ` 그레이트배리어리프 ` 에서해양다큐멘터리를촬영하던중가오리에게찔린뒤의식을잃고쓰러졌으며, 의료진이도착하기전에현장에서숨졌다고전했다 " 는호주언론의말을인용해연합뉴스는자세하게전했습니다. 또스티브어윈씨에대해 " 환경보호와야생동물보호운동가인어윈씨는애니멀플래닛의 TV 프로그램 ` 악어사냥꾼 ( 크로커다일헌터 )` 에서세계곳곳을돌아다니며동물의생태를보여주는악어사냥꾼으로출연하면서유명세를탔으며, 퀸즐랜드주에서동물원을운영하고있다 " 고소개했습니다. 스티브어윈씨와관련해로이터통신은 " 동물을사랑했던 ` 악어사냥꾼 `" 이라칭하며사망소식을전파했습니다.( 연합뉴스 ; 2007.06)
Above: Carcharodon Megalodon - Extinct Giant!!! "It would be like a locomotive with a mouth full of butcher knives. The largest shark teeth found belonged to Carcharodon Megalodon and are 6 inches long. This shark is extinct (thankfully) and lived more than 4.5 million years ago.
상어해부도 1. 눈 2. 기공 3. 콧구멍 4. 구열 5. 아가미 6. 가슴지느러미 7. 등지느러미가시 8. 제 1 등지느러미 9. 배지느러미 10. 제 2 등지느러미 11. 수평융기 12. 미기전흠 13. 꼬리지느러미하엽 14. 꼬리지느러미상엽 1. 눈 2. 고깔 3. 기공 1. 콧구멍 2. 전비변 3. 구전열구 5. 주름
1. 배구멍 2. 항문 3. 교접기 4. 배지느러미 1. 배구멍 2. 항문 3. 배지느러미 1. 코신경 2. 단뇌 3. 간뇌 4. 시엽 5. 소뇌 6. 연수 1. 이 2. 입뚜껑 3. 분수공 4. 제 1 새궁 5. 제 4 새궁 6. 제 5 새궁 7. 새파 8. 설궁 9. 아가미격벽 10. 새변
1. 표면혈합근 2. 신장 3. 수란관 4. 위 5. 장 6. 직장 7. 직장선 8. 담낭 9. 간장 11. 난소 1. 식도 2. 유문부 3. 유문수 4. 장 5. 직장 6. 직장선 7. 비장 8. 췌장 1. 수란구 2. 수란관 3. 난소 4. 난각선 5. 신장 6. 수란관 7. 간장 8. 담낭
1. 난소 2. 생식기 3. 수란관 4. 난소 5. 생식기 6. 간장 1. 난각선 2. 수란관 3. 총배설강 4. 난소 5. 생식기 1. 정소 2. 생식기 3. 수정관 4. 비뇨생식돌기간장
* 상어의내부장기 *
여수서 6m 고래상어잡혀 전남여수시백도부근에서 6m 짜리고래상어한마리가잡혔다. 경남사천선적쌍끌이어선 59t 급 11 제일호와 12 제일호는지난 4 일밤백도부근해역에서조업중길이 6m, 무게 1.2t 의고래상어한마리가그물에걸려올라왔다고밝혔다. 11 호선장이종열 (46) 씨는 그물에걸려숨을헐떡이던고래상어를배위로끌어올리자이내죽었다 고말했다. 이상어는위판을위해사천삼천포항을거쳐부산공동어시장으로옮겨졌다. 선주박병근 (47) 씨는 구매희망자가아직나타나지않았다 며 원하는사람이있으면기증도고려하고있다 고말했다. 고래상어 (whale shark ; Rhincodon typus) 는최장 18m 까지자라는지구에서가장큰어류다. 거대한몸집과달리온순하며, 오징어멸치플랑크톤등을물과함께들이켰다걸러서먹는다. 작년 9 월엔길이 4.6m, 무게 1.2t 의고래상어한마리가부산해운대해수욕장에떠밀려와탈진해죽기도했다.( 조선일보 ; 2007.8.7)
Sharks are fish that have no bones, only cartilage. They have 5-7 gills (without gill covers, operculum) in front of their pectoral fins (on both sides). Shark tails are asymmetrical; the top lobe of tail is larger than the bottom lobe. The shark's jaw is not fused to the braincase and can enlarge to eat very large prey. Sharks have no swim bladder for buoyancy (like the bony fishes); an oily liver aids buoyancy. Sharks have an advanced electroreceptive system that detects slight electrical fields. The teeth and skin are modified placoid scales. A spiracle (a special gill slit that supplies oxygen directly to the eyes and brain) is present in front of the first gill. Sharks' teeth are replaceable when they've broken or worn out. Their intestines are short and compact and have an unusual structure; a spiral valve (shaped like a spiral staircase) fills the cylindrical intestines and allows absorption of the food in a short span of intestine.