Early development begins at conception (fertilization) an egg cell by a sperm cell to form zygote (zygote). Gametogenesis is the final phase of individual development and preparation for the next generation. Development process that lasted from gametogenesis to form a zygote called progenesis. The next process is called embryogenesis (blastogene) which includes a zygote cell division (cleavage), blastulasi, gastrulation, and neurulasi. The next process is organogenesis, the formation of the tools (organs) of the body. Embryology include process development after fertilization through organogenesis before hatching or birth.
Cleavage stages of the cell division process. This process runs regularly and ended up reaching balastulasi. It could also be said that the process of cell division to form a continuous circle, like a ball that contains the cavity. Gastrulation is a continuation blastulasi process. Result of this process is the formation of three layers, namely ektoderrm, modeterm and entoderm. Organogenesis is a stage where the formation of the organs of the above three layers, namely ectoderm, metoderm and entoderm. Each layer forming different organs. Ektoterm form the epidermal layer of the teeth, the eyes and the auditory nerve. Mesoderm forming the respiratory system, pericranial, peritonial, liver and bone. While entoterm form sex cells and endocrine glands.
Cleavage stages of the cell division process. This process runs regularly and ended up reaching balastulasi. It could also be said that the process of cell division to form a continuous circle, like a ball that contains the cavity. Gastrulation is a continuation blastulasi process. Result of this process is the formation of three layers, namely ektoderrm, modeterm and entoderm. Organogenesis is a stage where the formation of the organs of the above three layers, namely ectoderm, metoderm and entoderm. Each layer forming different organs. Ektoterm form the epidermal layer of the teeth, the eyes and the auditory nerve. Mesoderm forming the respiratory system, pericranial, peritonial, liver and bone. While entoterm form sex cells and endocrine glands.
Most pelagic fish eggs are fertilized externally sea and hovering near the ocean surface. These eggs ranged from 0.5 to 5.5 mm in diameter. Embryonic period can be divided into three stages, namely an initial period for closure bastopore fertilization. Middle of the time period and the closing blastopore lateral tail began to move away from the embryonic axis and the end of the period of time in which the curved tail of the embryonic axis. In each species there is little variation in egg egg characters such as size, number and size of bubbles of oil, the surface of the chorion, yolk, pigmentation, and morphology of embryonic development that includes anatomy and morphometric early stages of fish eggs.
Yolk sac shape varies from round and elongated example Clupeoids. Overall pigmentation is also very important as far as identifikasi.Melanophores is the main pigment used for the identification of yolk-sac larvae. Other pigments may exist but most will be lost in preserved (formalin or alcohol) specimens. At the end of the yolk sac stage of the mouth and intestines and anus molded open on or close to the primordial fin margin. Eyes became pigmented and major organs and sensory systems, it is important to capture prey, to be functional.
caption: The stages of growth and division of yellowtail kingfish (Seriola lalandi): (a) pre-cleavage, (b) 2 cells, (c) 4 cells, (d) 8 cell, (e) 16 cells; (f) 32 cells; (g) the mid-blastula stage; (h) gastrula, (i) the appearance of the embryo; (j) 20 myomere embryo; (k) advanced embryos; (l) pre-hatching embryo; (m) 4 hours posthatch larvae , (n) asymmetric division in blastula; (o) is not clear margin in blastula cells.
Size and length at the time of hatching varies between fish species, which are generally associated with the diameter of the eggs or egg yolks. Size of the yolk, the newly hatched larvae, also related to the size and the number of egg yolks used before hatching.
Size and length at the time of hatching varies between fish species, which are generally associated with the diameter of the eggs or egg yolks. Size of the yolk, the newly hatched larvae, also related to the size and the number of egg yolks used before hatching.
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