Biological terms. In addition to the general term for all animals other than vertebrates. The main characteristics of the body without the spine, in the ventral nervous system, heart in the back, so there "ventral nerve animals," said.
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Basic Introduction
Pinyin: wú jǐ zhuī dònɡ wù Invertebrates (invertebrata) is the dorsal spine of the animal without its animal species accounted for 95% of the total number of species. They are the original form of animals. Protozoa, in addition to the animal world and the world outside the door all the vertebrate sub-categories known. bbc presenters Sir David Arden Fort (sir david attenborough) said: "If all vertebrate overnight disappeared from the earth, the world will still be safe, but if the disappearance of the invertebrates, the terrestrial ecosystem will collapse. "
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Classification
* Sort by ① invertebrate nervous system was cord-like, in the digestive tract of the ventral; and vertebrate tubular, located on the back of the digestive tract. ② in the digestive tract of invertebrates in the heart of the back; vertebrates in the digestive tract of ventral. ③ invertebrates no bone or exoskeleton only, no bones and vertebrae in the real; bones and vertebrae in vertebrates. * By type Invertebrate species are very Pangjia complex, more than ten thousand kinds of existing 100 (about 50,000 kinds of vertebrates), extinct species is more. It includes the number of doors because of the increasing development of zoology. Because of animal research have become more detailed aspects, the people of their genetic relationship to each other has become even more in-depth understanding of, and thus the taxonomic status of the doors often change.
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Morphology
Most invertebrates are small, but the door cephalopod mollusc Sepia king of animals up to 18 meters in length, wrist length of 11 meters and weighing about 30 tons. Most aquatic invertebrates, most of the seafood, such as foraminifera, radiolarians, Jellyfish, corals, and echinoderms such as squid, all seafood, some species live in fresh water, such as the hydra, some snails, mussels and fresh water crabs and so on. Snails, mice and other women while living in the wet land. And spiders, and more foot class, the vast majority of terrestrial insects are animals. Most free-living invertebrates. In aquatic species, the body of a small business planktonic life; body shell or a crawl in the bottom (such as shrimp, crab), or buried in the bottom sediment in the habitat (such as Nereis clams), or fixation in the water and foreign matter (such as barnacles, oysters, etc.). Invertebrates there are many types of parasites, parasitic on other animals, plants or the body surface (such as parasitic protozoa, flukes, tapeworms, spine head worms, etc.). Some species such as the earthworm and pig roundworm Ascaris and other sounds can harm people.
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Body structure
[Motion System] Body support and movement system includes two forward. * Bones Vertebrates, invertebrates do not play a supportive role that a dorsal spine and narrow bones. Generalized bone include exoskeleton, endoskeleton and water bones of three. It is no vertebrates have three bones. Refers to the crustacean exoskeleton and other hard tissue, such as the snail's shell, crab shell, belong to the insect cuticle exoskeleton. Within the bone found in vertebrates, half vertebrates, echinoderms and porous animals, including play a supportive role. Within the porous bones of animals is not a mesoderm origin. The internal skeleton of echinoderms is caco3 and protein composition, these chemicals crystals arranged in the same direction. Animal bone is affected by water micro-pressure liquid (no body cavity of animals Platyhelminthes is no exception!) And with antagonistic muscles, with the stratum corneum of the epidermis and its general term. The main bone in the form of invertebrates. In addition to the molluscs, echinoderms and arthropods other than water invertebrates have skeletons. • Motion Invertebrate movement in different ways: • swing forward with the ciliary • no bristles, no circular muscle of the animal through both sides of the linear alternating contraction of longitudinal muscle to achieve the snake • there is a ring bristles with longitudinal muscle of earthworm muscle peristalsis. This is done by different vertical segments, alternating muscle contractions to achieve ring • in the seabed sediments, through the expansion of the body segments to achieve a fixed, another part of the smaller and the body before drilling esculenta • crawling animals with claws • insect flight [Excretory system] Not all invertebrates are excretory organs. Such as Platyhelminthes, which is located under the epidermis by the inward protruding out of the excretion of epidermal cells to complete excretion. Without a common vertebrate excretory organ is the original and post-kidney renal tubular pipe. [Nervous system] Invertebrate nervous system of vertebrates is not so complex and diverse. From the most primitive nerve cells, to _set_ a ganglion nerve cells, to the later formation of the brain. The form of the dispersion of neural network to order the nerve chain, and ladder to the central nervous system occurs, has also undergone a process from simple to complex. Sensory organs of sense by the stick cnidarians (visual perception and gravity), the head Platyhelminthes through the formation of a cluster of nerve cells, "eye" to the insect's compound eye, and cephalopods such as squid's eye (which is formed by the ectoderm of!), the resolution on the rise. This is more conducive to the animals to escape predators and prey. [Digestive system] Cnidarians is the barrel of the mouth and anus are the same opening. The digestive system is known as the stomach (gastrovaskularsystem), it Platyhelminthes as a branch of the intestines, the exercise of digestive and transport functions, because they do not have the circulatory system. Linear animal parasitic plant has been degraded, they depend on the first section of the host small intestine absorb nutrients. Most true metazoan animals have a total length of the body through the digestive tract, and associated with the digestive gland and the circulatory system, the line extracellular digestion. Digestive tract is usually: mouth, pharynx, esophagus (like those of earthworms, it also enlarged the crop), (muscle) of the stomach, intestine and anus. The bivalve gills filter outline animals and even food. [Circulatory system] Invertebrates do not have the circulatory system, such as the above cnidarians, Platyhelminthes, Tardigrada and linear animal. While the circulatory system of animals, such as mollusks have an open circulatory system (cephalopods of the closed-loop system to the trend) and animal aspects of the closed loop system. Animals such as insects and spiders in the body plenty of hemolymph. The task is to transport the circulatory system. It respiratory system and digestive system oxygen transport nutrients to other parts of the body, while metabolic waste will be transported to the excretory organs. [Respiratory] Invertebrates and other organisms, the need for oxidative energy source for energy, this process requires the respiratory system to provide oxygen. Invertebrates are the most common respiratory gills. However, it is the insect tracheal respiratory organs, they are opening on the surface of the valve can be closed (stigmen), to keep the body segments, without a circulatory system to transport oxygen directly to the next cell's mitochondria, a respiratory system is very effective .
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Reproduction of
Invertebrate reproduction in various forms. The first is divided into two kinds of sexual with asexual. Some animals, such as cnidarians and parasites linear animals, and generational phenomenon. If animals are hermaphrodites, there will be auto-mating behavior. Common form of asexual budding. Found in cnidarians asexual generations. Sexual reproduction is characterized by reproductive germ cells by a combination of completion. The reproductive process can be completed by a person alone, but more common is to provide two individuals through their different mating types of germ cells to work together. The former found in pork tapeworm, which section of the rear of the maturity of the body will be fertilized in the body after a section. Earthworms will occasionally see their mating behavior. When mating two individuals, both sides usually are dioecious party (earthworms, snails, though it is androgynous, but when they mate only one gender role to play). Mating in the form of invertebrates can be described as strange. Earthworm mating with both reproductive (clitellum) secretion of fluid stick together. With being a party to the other reproductive gonopore. Sperm from the male side of the gonopore discharge along the surface of his own sperm sperm reach the other side ditch bags (receptaculum seminis) were stored, waiting for the egg fertilized with the other. Scorpions have a special male reproductive organs, called the seminal vesicle (spermatophore), containing sperm. It will be through the secretion of the seminal vesicle adhesion to the ground. Male and female scorpion scorpion dance courtship dance, the first move with a tail sweeping the ground, causing the female scorpion attention. Then off_set_ the two double claws, pull each other. Male lethal scorpion sting will look with the female scorpion, and release a small amount of toxin to paralyze Ecstasy female scorpion. Then sow the male scorpion seminal vesicle, pulling the female scorpion, so abdominal genital opening contacts with the seminal vesicle, obtained sperm. Females during mating the male will try to eat scorpions. The Colts placed in the high land to the seminal vesicle, and then leave. Malu was the female will find the seminal vesicle and removed, then the process of fertilization occurs. The polychaete annelid, using the fission reproduction (schizogamie), that is, from the part of the body containing the reproductive cells, so that in the water to complete fertilization. Snail body with caco3 have the "arrow of love." Mating the two sides through several times before the show, is another dawdle (half-way due to fatigue and rest), the two sides to reach the excited state. And then shot to the other "love arrow" to reach the climax, the exchange of reproductive cells. Generational transfer of power to Jellyfish, for example, jellyfish (medusa) of sexual reproduction through sperm-egg fusion method, birth of hydra (polyp). Hydra and then through asexual reproduction, that offshoot budding division, after storeyed body and butterfly larvae stage once again become a jellyfish.
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History
The emergence of invertebrates on Earth at least 100 million years earlier than vertebrates. Most invertebrate fossils found in Cambrian Paleozoic, when there had arthropod trilobite and brachiopod. Subsequent development of the ancient cephalopods and ancient types of echinoderms. To the late Paleozoic, the old type of bio-mass extinction. There is an ancient Mesozoic molluscs type (such as ammonites), to the end that is gradually extinct, molluscs modern and species appeared in large numbers. To evolve into the modern generation of many types of invertebrates, and in the Paleozoic brachiopods Olive Tree has only a few remnants of representatives (such as sea bean sprouts).
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Pen 石介绍
Ordovician graptolite invertebrates is most strange and unique groups, from the Early Ordovician, already flourishing breeding, widely distributed, and some fixing, some prostrate, some wavering, and some floating. Ordovician graptolite graptolite purpose is mainly to families and genera, such as graptolites (didymograptus), leaf graptolites (phyllograptus), four graptolite (tetragraptus), gate graptolites (climacogrptus) and so on.
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Related disciplines
A branch of zoology. In the animal category, according to the animal body has no spine and is divided into two major categories of vertebrates and invertebrates. The classification of invertebrates, shape, physical characteristics, geographic distribution, reproduction, evolution, science, called the study of invertebrates. Studies of invertebrates, including: Protozoology, worms science, entomology, molluscs science, zoology and other crustaceans.
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Temperature problem
Because there is no temperature regulation system in vivo invertebrates, with outside temperature, metabolic rate has also changed. Until the higher of the cartilaginous fish such as shark thermostat mechanism for the warm-blooded animals. True sense of the temperature should be from the birds, animals begin.
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Basic Introduction
Pinyin: wú jǐ zhuī dòng wù Invertebrates (Invertebrata) is no dorsal spine of the animal, the animal species accounted for 95% of the total number of species. They are the original form of animals. Protozoa, in addition to the animal world and the world outside the door all the vertebrate sub-categories known. BBC presenters Sir David Arden Castle (Sir David Attenborough) said: "If all vertebrate overnight disappeared from the earth, the world will still be safe, but if the disappearance of the invertebrates, the terrestrial ecosystem will collapse. " All non-spinal animals, accounting for more than 90% of existing animals. Located around the world, in shape, and small protozoa, to the mammoth Ju Wu large squid. General body soft, non-hard muscle can be attached inside the bone, but often have a hard exoskeleton (such as most molluscs, crustaceans and insects) to attach to the muscles and protect the body. In addition to this there is no spine, the invertebrates do not have much in common house. This taxonomy of invertebrates and vertebrates previously used the term (the term still has the name of a sub-gate) is relatively, but in the modern classification has been no.
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Invertebrates in the door
The animal kingdom is now generally divided into ten Including protozoan phylum coelenterate porous door door door flat linear animal phylum Mollusca Annelida Arthropoda Echinodermata Chordata doors: the end of cable, the first cord, notochord, vertebrates, four sub-gate addition to other vertebrates they are outside the sub-invertebrates
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Encyclopedia
wujizhui dongwu Invertebrates Invertebrata Vertebrate animal kingdom, in addition to all other sub-categories known as the door. The main difference between them and vertebrates are: ① the nervous system of invertebrates showed a cord-like, in the digestive tract of the ventral; and vertebrate tubular, located on the back of the digestive tract. ② in the digestive tract of invertebrates in the heart of the back; vertebrates in the digestive tract of ventral. ③ invertebrates no bone or exoskeleton only, no bones and vertebrae in the real; bones and vertebrae in vertebrates. 1822 J.-B.de Lamarck the animal kingdom is divided into two major categories of vertebrates and invertebrates. 1877 E. Haeckel German scholars to the stigma worm, sea squirt, amphioxus and other animals, together with the vertebrate chordate door, and invertebrates of the door side by side, the classification system in reduced vertebrate chordate door A Amon, and Amon Hemichordata (stigma insects), animal tail cable Amon (sea squirts) and head cable animal subphylum (amphioxus) tied. Since the 1970s Hemichordata has a separate door, the three groups after the areas are invertebrates, including the fact that invertebrates than vertebrates sub-categories of all the animals outside the door, is a common name in zoology, rather than formal taxa. □ species of invertebrates is very complex, more than ten thousand kinds of existing 100 (about 50,000 kinds of vertebrates), extinct species is more. It includes the number of doors because of the increasing development of zoology. Because of animal research have become more detailed aspects, the people of their genetic relationship to each other has become even more in-depth understanding of, and thus the taxonomic status of the doors often change. Protozoa are single-celled animals, doors, other door body chosen by the majority of animal cells, collectively referred to as metazoan. In the animals feed on squid, octopus and other body structure is simple, but complex life cycle, the genetic relationship is uncertain, temporary release in between protozoa and metazoa. Porous animals are primitive multicellular animals, only the cellular level of differentiation is the evolution of the blind branch, also known as lateral animals. Radial symmetry of cnidarians door (also known as cnidarians door) and comb jellyfish phylum animal with the initial tissue differentiation. Platyhelminthes door began to appear bilaterally symmetrical animals, the three germ layer cells to differentiate into tissue, and the formation of organ systems. Platyhelminthes body without the body cavity. Phylum nematodes, rotifers and other animals, the body is false door body cavity (see fake animal body cavity). Annelida animal body section, the body has true body cavity, organ systems tends to be more complete, often called the higher invertebrates. It evolved from the molluscs and arthropods door door invertebrate animals is the most prosperous groups. Arthropoda is the first door to the animal kingdom, Insecta which has more than 100 million. Mollusca is the second door to the animal kingdom. About 80,000 existing species. One type of second Gastropoda Insecta. A true body cavity of invertebrates, according to the true body cavity formed in different ways, is divided into two categories: annelids, arthropods, molluscs and other body cavity method for the crack formation, and echinoderms, Chaetognatha animals Hemichordata as the intestine to form the body cavity method (see animal body cavity). With three germ layers of the invertebrates, and some groups embryonic development of the blastopore to form the mouth into the body, known as the original population of animals; some groups in the future development of embryos in the hole closed, or juvenile or adult form of the anus, called after deuterostomes. The emergence of invertebrates on Earth at least 100 million years earlier than vertebrates. Most invertebrate fossils found in Cambrian Paleozoic, there was the trilobite arthropods and brachiopods. Subsequent development of the ancient cephalopods and ancient types of echinoderms. To the late Paleozoic, the old type of bio-mass extinction. There is an ancient Mesozoic molluscs type (such as ammonites), to the end that is gradually extinct, molluscs modern and species appeared in large numbers. To evolve into the modern generation of many types of invertebrates, and in the Paleozoic brachiopods Olive Tree has only a few remnants of representatives (such as sea bean sprouts). Bibliography RHBarth, REBroshears, The Invertebrata World, Saunders College, philadelphia, 1982. (Zhang Zuo-ren ZHANG Run Health)