what is the definition of an amniotic egg?
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Structure of the Amniotic Egg\nEvolution of eggs with a water-impermeable amniotic membrane surrounding a fluid-filled amniotic cavity permits embryonic development on land without danger of dessication. The main diagram shows the arrangement of membranes in a typical egg-laying oviparous vertebrates. In live-bearing viviparous vertebrates, the shell and chorionic membrane are absent and the allantoic and yolk sac membranes are incorporated into the connection with the maternal circulation\n( http://www.mun.ca/biology/scarr/Amniotic_egg.htm )\n\nThe amniotes are a microphylum of tetrapod vertebrates that include the Synapsida (mammals) and Reptilia (reptiles and dinosaurs, including birds). They are defined by embryonic development that includes the formation of several extensive membranes, the amnion, chorion, and allantois. Amniotes develop directly into a (typically) terrestrial form with limbs and a thick stratified epithelium, rather than first entering a feeding larval tadpole stage followed by metamorphosis as in amphibians. In amniotes the transition from a two-layered periderm to cornified epithelium is triggered by thyroid hormone during embryonic development, rather than metamorphosis [1]. The unique embryonic features of amniotes may reflect specializations of eggs to survive drier environments, or the massive size and yolk content of eggs designed for direct development to a larger size.\n\nFeatures of amniotes designed for survival on land include a sturdy but porous leathery or hard eggshell, and an allantois designed to facilitate respiration while providing a reservoir for disposal of wastes. Their kidneys and large intestines are also designed to retain water. Most mammals do not lay eggs, but corresponding structures may be found inside the placenta.\n\nThe first amniotes looked like small lizards, for instance Casineria kiddi who lived for about 340 million years ago, and their eggs were small and covered with a membrane, not a hard shell like often seen today. Some modern amphibians lay eggs on land but without any protection to speak of, while others like some lungless salamanders and Amphiuma also lay small eggs on land, but these are covered by a rubber-like membrane even if they lack advanced traits like an amnion. This kind of eggs became possible with internal fertilisation. The outer membrane, a soft shell, evolved as a protection against the harsher environments on land. It was probably because the embryos were safer on land than in water that some species got the habit of laying them out of the water. One can assume the ancestors of the amniotes laid their eggs in moist places, as such animals wouldn't have too many difficulties in finding depressions under fallen logs or other suitable places in the ancient forests, and dry conditions were probably not the main reason why the soft shell emerged.\n\nIn fish and amphibians there is only one inner membrane, also called an embryonic membrane. In amniotes the inner anatomy of the egg has evolved further, new structures have developed to take care of the gas exchanges between the embryo and the atmosphere, as well as dealing with the waste problems. To grow a thicker and thougher shell there were no other alternatives than finding new ways to supply the embryo with oxygen, as diffusion alone wouldn't be enough any more. After the egg had gotten these structures, further sophistication of them allowed the amniotes to lay much bigger eggs in much drier habitats. Bigger eggs meant bigger offspring, and bigger adults meant bigger eggs, which meant the amniotes had gotten the opportunity to grow bigger than their ancestors. But real growth was not possible until they stopped relying on small invertebrates as their main food source, and started to eat plants or other vertebrates, or returned to the water. New habits and heavier bodies meant further evolution for the amniotes, both in behavior and anatomy.\n\nThere are three main lines of amniotes, wh
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The eggs are nourished within the ovaries, and each month one fully matured egg is released. A mature egg has undergone a process of cell division that gives it 23 chromosomes -- just enough to match an equal number of chromosomes from the sperm. Once an egg is released from an ovary, it's pulled into one of the fallopian tubes leading to the uterus. But one of the 20 million to 200 million sperm released by the man has to catch up to that egg soon: If the egg doesn't encounter a healthy sperm, it will perish in 24 to 36 hours. In that case, it disintegrates and flows out with your period. If the egg does get fertilized, it leaves the fallopian tube and travels into the uterus. If everything is in good working order, it will implant there and begin to develop into a baby.
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Egg cells have to carry some nutrition for the developing embryo.  Also, sperm just carry genetic information.  A fertilized zygote will also need a full complement of cellular organelles in order to begin its development.  The mother supplies mitochondria, endoplasmic reticulum, cytoplasm, etc.\n\nAll that stuff requires significant real estate, hence the large egg cells.  Egg cells are REALLY big in species that lay hard-shelled eggs.  Like an ostrich egg, for example - that starts fully formed as a single cell.  It is the largest single cell produced by an animal alive today.
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egg... there are fish eggs before chicken eggs
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egg.........\n\nthe progenitors would not (quite) be chickens...
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egg... cus jut think about it
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when you have sexual intercourse and the egg is fertilized by the sperm.If anyone asks you didnt get it from me.
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Well...bear with me, because I may use some off-hand phrases and different words. And in the interest of education, don't laugh when you hear some...familiar words.\n\nThere is a process in which it is done. The mature egg in the woman's vagina is met with the mature sperm in the man's testicles through intercourse. This is called fertilization. As soon as the egg is fertile, it becomes known as a zygote. The zygote is then transported to the womb, an organ in the female reproduction system that can expand to the size of a basketball, if the circumstances permit it to. The egg sticks to the side of the womb and grows, multiplying in cell count, fron 1 to 2, to 4, to 8, and et cetra, for the first four months, also called the first Trimester. then it is called an Embyro. for the next trimester, the embyro will assume human characteristics, like arms and legs, and the heart will start beating. For the final trimester, the baby will gain muscle mass and fatty tissue, the tissue that will protect the new baby from harmful impact and harsh weather. After the final trimester, the baby can be given birth via vaginal birth, where the baby comes through the vagina of the mother (a process that is, indeed, very painful), or Cisarean section, also known as C-section, where the mother is surgically cut open to remove the baby (don't worry, the doctors put her back together). The baby is then taken to a maternity ward for 3 days, so it can get used to the air and oxygen (12 months in water does make for a environmental shock!). Then the mother is able to take home the baby, her new son or daughter.
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Ya it means the egg was fertilized. I've always thrown them away when this happens.
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How about calling it "a release of an egg cell from the ovary"? Or "a release of an egg cell from the female"?
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I believe it's called oogenesis, the creation of an ovum (egg cell) in the ovarian follicle of the ovary.
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The three terrestrial classes that give rise to the four extra embryonic membranes are mammals, birds, and reptiles.\n\nThe four membranes are:\n\nChorion. The outermost of the two fetal membranes - the amnion is the innermost --. which together surround the embryo. The chorion develops villi (vascular fingers) and gives rise to the placenta. In Greek, the word "chorion" means "skin or leather."\n\nAmnion. The amnion is a membranous sac which surrounds and protects the embryo. It is developed in reptiles, birds, and mammals, which are hence called 'Amniota'; but not in amphibia and fishes, which are consequently termed 'Anamnia'.\n\nAllantois. An extra-embryonic membrane of reptiles, birds, and mammals arising as a pouch, or sac, from the hindgut. In reptiles and birds it expands greatly between two other membranes, the amnion and chorion, to serve as a temporary respiratory organ while its cavity stores fetal excretions. In mammals other than marsupials the allantois is intimately associated with the chorion, contributing blood vessels to that structure as it forms—in conjunction with the endometrium, or mucosal lining, of the uterus—the placenta. \n\nYolk Sac. A membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals and functioning as the circulatory system of the human embryo before internal circulation begins.
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try " A baby's development is influenced by both hereditary and environmental factors."\nthis way your continuity is the same....hereditary and environmental both describe factors.\nheredity is a noun.
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Bear. Like in "childbearing". When you say, "A baby was born", it's passive, not past.
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The shell covering an egg is porous !!.It allows Oxygen to enter into the egg and CO2 to move out of the egg!
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The eggs of fish are fertilized either externally or internally, depending on species. The female usually lays the eggs and the embryos in the eggs develop and hatch outside her body. This kind of fish are called oviparous fish. Oviparous fish develop being obtaining food from the yolk in the egg. Salmon, for example, are oviparous. Ovoviviparous fish keep the eggs inside of the mother's body after internal fertilization. Each embryo develops in its own egg. The young are "born alive" like most mammals. Some species of fish, such as various sharks, are viviparous. Viviparous fish allow their embryos to stay in the mother's body like ovoviviparous fish. However, the embryos of viviparous fish obtain needed substances from the mother's body, not through material in the egg. The young of viviparous species are also "born alive".
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off·spring  ( P )  Pronunciation Key  (ôfsprng, f-)\nn. pl. offspring\n\n   1. The progeny or descendants of a person, animal, or plant considered as a group.\n   2. A child of particular parentage.\n   3. A result; a product.\n\nSummary:\nA child or a result.\n\nedit: beaten, but I have a dictionary definition, so nyah!