gestation definition biology
Gestation meaning and definition of gestation in biology. Typically, all the major organs and tissues can be observed; however, they are not yet fully developed or appropriately situated within the body. Syngnathidae is the only family in the animal kingdom to which the term "male pregnancy" has been applied. gestation. This stage begins after 11 weeks of gestation, when the embryo begins to exhibit human characteristics, and lasts until birth. On the main article link above, are average and approximate gestation values ordered by number of days (note: human gestational age is counted from the last menstrual period; for other animals the counting method varies, so these figures could be 14 days off). HBA MB. The shortest known gestation is that of the Virginian opossum, about 12 days, and the longest that of the Indian elephant, about 22 months. Gestation period: Fetal development period from the time of conception until birth. The degree of ultimate growth is a factor, smaller animals usually having shorter periods of gestation than larger ones. 2 formal the process by which a new idea, piece of work etc is developed, or the period of time when this happens SYN development in gestation The report was a very long time in gestation. This may vary if the bitch has been bred two or three times or if the eggs are fertilized a day or two after the mating has taken place. Pregnancy begins with the fertilization of an egg and continues through to the birth of the individual. The period of time spent in the uterus between conception and birth. Learning Outcomes. gestation noun [U] (BABY) biology specialized. How to apply an evolutionary hypothesis about gestation to your pregnancy #1 Thing to think about. (dʒesteɪʃən ) 1. uncountable noun. the process by which a child or young animal develops inside its mother ’s body before birth, or the period of time when this happens → pregnancy The gestation period of a horse is about 11 months. Within 24 hours of fertilization, the egg nucleus has finished meiosis and the egg and sperm nuclei fuse. gestation / dʒɛˈsteɪʃən / n the development of the embryo of a viviparous mammal, between conception and birth: about 266 days in humans, 624 days in elephants, and 63 days in cats ( as modifier ) : gestation … Thus the horse, a spring breeder with 11 months’ gestation, has its young the following spring, as does the sheep, a fall breeder with a five months’ gestation. primate: Gestation period and parturition. Vital Pieces of Gestation Definition Biology. This definition raises occasional difficulties because in some species (e.g., monkeys and man) the exact time of conception may not be known. Our editors will review what you’ve submitted and determine whether to revise the article. Module 16: The Reproductive System. ed ... (Biology) (tr) to carry ... ) to develop (a plan or idea) in the mind. This strategy of birth is known as ovoviviparity. In human obstetrics, gestational age refers to the fertilization age plus two weeks. Certain lizards also employ this method such as the genera Tiliqua and Corucia. Various factors can come into play in determining the duration of gestation. Either a single factor or a great number of minor factors, all culminating at or near one date, determine the length of gestation. It is similar to vivipary in that the embryo develops within the mother's body. Another factor is that, in many species with restricted breeding seasons, gestation is adjusted so that birth coincides with the period when food is most abundant. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. The length of time of gestation varies among animals, but is very similar among the great apes: human gestation is 266 days, while chimpanzee gestation is 237 days, a gorilla’s is 257 days, and orangutan gestation is 260 days long. Definition of 'gestation'. biology the time during which a human or animal baby develops inside its mother, or the process by which this happens. In biology, the term "gravid" (Latin: gravidus "burdened, heavy") is used to describe the condition of an animal (most commonly fish or reptiles) when carrying eggs internally. This is approximately the duration since the woman's last menstrual period (LMP) began. Human pregnancy can be divided roughly into three trimesters, each approximately three months long. Delayed implantation also occurs in mice and other small rodents that become pregnant while they are still suckling a litter. The more developed form of viviparity is called placental viviparity; mammals are the best example, but it has also evolved independently in other animals, such as in scorpions, some sharks, and in velvet worms. The period of gestation … the process by which a child or young animal develops inside its mother ’s body before birth, or the period of time when this happens → pregnancy The gestation period of a horse is about 11 months. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. In Europe, the typical childbearing age has been rising continuously for some moment. Heredity also influences gestation; in cattle the mean gestation period for Holstein-Friesians is 279 days; for Brown Swiss, 290 days; other breeds fall between these extremes. The period during which the growing fetus is protected in the uterus is characterized by a considerable range of variation among primate species, but it shows a general trend toward prolongation as one ascends the evolutionary scale. By making use of a living organism like yeast, researchers have the ability to see the effect of a drug on a whole organism that’s been genetically modified to mimic the biochemical mechanism of a disease found in humans. An estimated 15 million babies are born too early every year. This definition raises occasional difficulties because in some species (e.g., monkeys and man) the exact time of conception may not be known. Meaning of gestation . [technical] ...the seventeenth week of gestation. Corrections? (the period of) the development of a child or young animal while it is still inside its mother's body: The baby was born prematurely at 28 weeks gestation. Birth occurs in March. A viviparous animal is an animal employing viviparity: the embryo develops inside the body of the mother, as opposed to outside in an egg (oviparity). However, the mother's body does provide gas exchange. See pregnancy. the development of the embryo in the uterus of mammals. Of the total gestation period of 250 days, growth occurs during only 50. Choosing Gestation Definition Biology Is Simple. gestation - Children's Encyclopedia (Ages 8-11). Mouse lemurs, for example,…, The normal gestation period is 63 days from the time of conception. [2] Birth normally occurs at a gestational age of about 40 weeks, though it is common for births to occur from 37 to 42 weeks. Marsupials generally have short gestations—e.g., 40 days for the largest kangaroos. Gestation in humans is about nine months. In both species gestation of twins is five to six days less than for singlets. Thus a mare carries a mule foal (fathered by a jackass) about 10 days longer than the normal period for the horse (about 337 days). The young of ovoviviparous amphibians are sometimes born as larvae, and undergo metamorphosis outside the body of the mother. Gestation, in mammals, the time between conception and birth, during which the embryo or fetus is developing in the uterus. The time interval of a gestation is called the gestation period. © W. G. Hale, V. A. Saunders, J. P. Margham 2005 Pregnancy begins with the fertilization of an egg and continues through to the birth of the individual. Gestate definition, to carry in the womb during the period from conception to delivery. Exceptions are the guinea pig and related South American rodents, in which gestation is prolonged (averaging 68 days for the guinea pig and 111 days for the chinchilla). Gestation is the period of development during the carrying of an embryo or fetus inside viviparous animals. The mother then gives live birth. This time is called gestation. Omissions? Many survivors face a lifetime of disability, including learning disabilities and visual and hearing problems.Globally, prematurity is the leading cause of death in children under the age of 5 years. Synonyms and related words +- ... View American English definition of gestation. The young of these species are born in a state of greater maturity than are those of the rat with its period of 22 days. How to solve: In biology what is the gestation period of a rat? The word "gestation" comes from the Latin "gestare" meaning "to carry or to bear." Gestation Definition Biology at a Glance. The gestation period is the time elapsing from fertilization and the implantation of the embryo to birth. Labor is the physical effort of expulsion of the fetus and the placenta from the uterus during birth (parturition). Healthline - Pregnancy Lingo: What Does Gestation Mean? The first trimester is from the last period through the 13th week, the second trimester is 14th–27th week, and the third trimester is 28th–42nd week. How Does Embryo Get Nourishment Inside the Mother’s Body – Biology questions; To explore more about placenta definition, or any other definitions in Biology, register at BYJU’S. In the course of evolution the duration of gestation has become adapted to the needs of the species. Search for: Human Gestation. Unlike the embryos of viviparous species, ovoviviparous embryos are nourished by the egg yolk rather than by the mother's body. Approximately 1 million children die each year due to complications of preterm birth (1). Let us know if you have suggestions to improve this article (requires login). Articles from Britannica Encyclopedias for elementary and high school students. The period during which the growing fetus is protected in the uterus is characterized by a considerable range of variation among primate... Get a Britannica Premium subscription and gain access to exclusive content. Evolution is everything about you, but it is not all about you. The length of gestation varies from species to species. Gestation is separated into three primary stages, or trimesters. Embryos of some species experience an arrest in development that greatly prolongs gestation. 3. Please refer to the appropriate style manual or other sources if you have any questions. For human gestation, see pregnancy. For humans, male fetuses normally gestate several days longer than females and multiple pregnancies gestate for a shorter period.[3]. In mammals, pregnancy begins when a zygote (fertilized ovum) implants in the female's uterus and ends once the fetus leaves the uterus. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. The gestation period can be anything between 95 and 150 days. The fish family Syngnathidae has the unique characteristic whereby females lay their eggs in a brood pouch on the male's chest, and the male incubates the eggs. The young, born in an extremely immature state, transfer to the pouch in which gestation may be said to continue. Pregnancy is the condition that occurs when the sperm fertilizes the egg, and the zygote is formed.Parturition is the process of giving birth to young ones. Included in Syngnathidae are seahorses, the pipefish, and the weedy and leafy sea dragons. gestation noun [U] (BABY) biology specialized. (the period of) the development of a child or young animal while it is still inside its mother's body: The baby was born prematurely at 28 weeks gestation. Collins Dictionary of Biology, 3rd ed. The periods of gestation, birth, lactation, and weaning are also usually synchronized. (Biology) (intr) to be in the process of gestating [C19: back formation from gestation… [1] It is typical for mammals, but also occurs for some non-mammals. The total gestation period from fertilization to birth is about 38 weeks (birth usually occurring 40 weeks after the last menstrual period).