A type of insect metamorphosis. During the development of insects in the individual must go through egg, larva, pupa and adult stages. Larvae and adults in the shape, internal structure, is significantly different living habits. Such as the silkworm, mosquitoes, flies and bees and so on.
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No. 2
完全变态
完全变态
Subclass of winged insects within the health wing, such as a variety of beetles, butterflies, moths, bees and flies, and these larvae hatch from the eggs, larvae and adults is not only different forms, lifestyle and living environment is also inconsistent, from larvae to adults to go through a pupal stage (which is not in the incomplete metamorphosis). In the pupal stage for dramatic body tissues and organs of the transformation process, pupal period, adults break out of the pupa. This metamorphosis that complete metamorphosis, the vast majority of insects this is the type of metamorphosis.
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Chiang concept even Shujun
完全变态 概念 连淑君 蒋氏
完全变态 概念 连淑君 蒋氏
Complete metamorphosis is one of two types of insect metamorphosis. Insects in ontogeny, after the eggs, larvae, pupae and adults in four periods called complete metamorphosis. Complete metamorphosis of larvae and adults in the form of structure and habits is obviously different. Dragonfly's metamorphosis during the development process is not complete, butterfly, mosquito metamorphosis and is a fully grown insects. Endogenous wing winged insects, such as a variety of beetles, butterflies, moths, bees and flies, and these larvae hatch from the eggs, larvae and adults is not only different forms, lifestyle and living environment is also inconsistent from the larvae to the adults to go through a pupal stage (which is not in the incomplete metamorphosis). In the pupal stage for dramatic body and organs of the transformation process, pupal period, adults break out of the pupa. This metamorphosis that complete metamorphosis, the vast majority of insects this is the type of metamorphosis. Toad, salamander, giant salamander, etc. also. Frog metamorphosis is complete or incomplete metamorphosis? Complete metamorphosis, because adult and tadpole shape vary widely, breathing in different ways. But we should pay attention to: distinguish between the characteristics of insect development is to see there is no pupal stage. Distinguish between the more complex animals. Frog's reproductive characteristics and egg characteristics. Frogs are amphibians. Their reproductive behavior in male and female, "hold on" false mating phenomenon and its amphibian reproduction is characterized by in vitro fertilization, in vitro development, then the male and female, "hold on" the phenomenon of false biological significance of mating: the female frog. " hold on, "the stimulation, then discharged egg, at the same time, males also emit sperm to complete fertilization in the water, showing that" hold on "biological significance is to ensure that both egg and sperm discharge, but very close, greatly increasing the fertilization opportunities. Although frogs can live on land, but because of their reproductive process is inseparable from the water, so it was not true terrestrial animals. Its distribution is bound to be limited by water. Frog eggs stored nutrients in the distribution is uneven, its distribution is characterized by: the distribution of small animal hemisphere, the distribution of plant hemisphere more than the major hemisphere, so the plant is always down, the animal hemisphere, the proportion of small, always up of. Color dark animal hemisphere has two ecological significance: not only help to absorb the sun's heat, but also a protective color. The fertilized egg is a mitotic division, but split with the general characteristics of somatic cell mitosis different, dividing to produce daughter cells would not grow into the next and then split, so the continuous increasing number of cell division, but cells size is getting smaller and smaller, special features such as cleavage division. As the fertilized egg is the uneven distribution of nutrients, so a third cleavage occurs when the inequality of the phenomenon that the animal hemisphere of the four small cells, plant cells, the four major hemisphere, animal pole after cell division rate was significantly faster than the pole plant cells, animal cells hemisphere hemisphere more than the number of plants, but the volume is smaller than the plant cells hemisphere, with the consumption of nutrients, gradually emerged within the animal hemisphere of an empty chamber, called the blastocyst cavity, this when the embryo called the blastocyst. Continue to develop down there under the pack animal pole cells, plant cells, very retraction, and retraction of the next bag caught in the emergence of a new cavity, called the original intestine, this structure will develop into the digestive tract. Blastocyst cavity and the outside world is simply not valid, and with the development of the smaller and smaller and finally disappear. Original lumen is growing. Differentiation in the gastrula period out of the three germ layers, ie sand mesoderm and endoderm germ layers. So in frog embryo cell differentiation during development from the gastrula period begins. Animal cells in the gastrula period has not yet started to differentiate as before, it retains all-round, but into the gastrula stage, due to cell differentiation has begun, it went to totipotency. About three germ layers ectoderm is generally believed that the source entirely from animal pole cells, endoderm entirely from plant pole cells, the source of mesoderm cells of both animal pole, but also plant most of the cells. After gastrulation the specific development process, the curriculum is not required, but the results of three embryo development must be mastered. Development of three germ layers results, contact the relevant body of knowledge structure briefly described. Ectodermal into the skin epidermis and its structure (such as skin, mucous glands), is a subsidiary structure of the skin hair, nails, animal horn, etc., skin mucus glands include: sweat glands, sebaceous glands, etc., is outside the oral epithelium mesoderm development comes from the mouth from the salivary glands of the Pitt also came from the ectodermal. Ectoderm also develop into the nervous system and sensory organs, the nervous system including brain and spinal cord and brain and spinal cord by the issue of brain and spinal nerves, but also nerve endings and so on. Sensory organ is the eye, ear, nose and so on. The circulatory system are developed from the Chinese and mesoderm, including heart, blood vessels and the heart and blood vessels in the flow of blood from the lymph, lymph vessels and lymph organs are composed of the lymphatic circulatory system to the Chinese and mesoderm development. Internal organs of the outer membrane, including the mesentery, omentum, etc. are from the Chinese and mesoderm development. Excretory system including kidneys, ureter, bladder, urethra, etc. are to the Chinese and mesoderm development. Reproductive system including gonads (ovaries, testes) and its reproductive organs (hair vas deferens, fallopian tubes, uterus, etc.), they are from the Chinese and mesoderm development. Endoderm develops into the digestive tract epithelium and the main respiratory epithelium, and by the digestive tract and respiratory epithelium from the organ of the Pitt or structure. Gastrointestinal epithelium, including the pharynx, esophagus, stomach, small intestine, large intestine, rectum wall surface of the epithelium, such as intestinal villus epithelial cells, not including anal and oral epithelium at the epithelium. Pitt on the digestive tract from the glands of the liver and the pancreas is an endoderm development came. Respiratory epithelium, including the pharynx, larynx, trachea, bronchi and other wall surface of the epithelium and alveolar epithelium, does not include nasal mucosa. The four tissues in the body, muscle tissue and connective tissue is certainly from the Chinese and mesoderm development, nerve tissue is certainly came from the ectodermal, epithelial tissue is more complex, three germ layers can develop into epithelial tissue, It depends on the specific location in which to determine. Is not a complete metamorphosis insects Such as: individual development in the silkworm, the larva and the adult morphology and life habits vary widely, this developmental process is called C complete metamorphosis Metamorphosis for insects, amphibians, etc. Metamorphosis main point: there are differences in larval and adult. In insects, the metamorphosis complete metamorphosis and incomplete sub-metamorphosis. Complete metamorphosis: the larval and adult morphology and life habits vary widely, the development process through egg, larva, pupa, adult four times. Incomplete metamorphosis: the larval and adult morphology and life habits are very similar, but not all aspects of mature, developed through egg, nymph, adult three periods. Note: the development of amphibian metamorphosis can only be said, can not be called complete metamorphosis. Complete or incomplete can only be applied to insects.
