HOME

TheInfoList




Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous
animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are composed of cells ...

animal
s possess
embryo An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms ar ...

embryo
s that develop inside
egg An egg is the organic vessel containing the in which an develops until it can survive on its own, at which point the animal hatches. An egg results from of an . Most s, (excluding s), and lay eggs, although some, such as s, do not. eg ...

egg
s that remain in the mother's body until they are ready to hatch. The young of some ovoviviparous
amphibian Amphibians are ectothermic, tetrapod vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial animal, ter ...
s, such as ''
Limnonectes larvaepartus ''Limnonectes larvaepartus'' is a species of fanged frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (literally ''without tail'' i ...

Limnonectes larvaepartus
'', are born as
larva A larva (plural larvae ) is a distinct juvenile form many animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that f ...
e, and undergo further
metamorphosis Metamorphosis is a biological process Biological processes are those processes that are vital for an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are ...
outside the body of the mother. Members of genera
Nectophrynoides ''Nectophrynoides'' is a genus of true toads, family Bufonidae{{Cat main, Toad This Wikipedia:Category, category contains both species commonly called toads, and the true toads from the family Bufonidae. Animals by common name Frogs .... They are ...
and
Eleutherodactylus ''Eleutherodactylus'' is a genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also ...
bear froglets, not only the hatching, but all the most conspicuous
metamorphosis Metamorphosis is a biological process Biological processes are those processes that are vital for an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are ...
, being completed inside the body of the mother before birth. Among insects that depend on
opportunistic Opportunism is the practice of taking advantage of circumstances – with little regard for principles or with what the consequences are for others. Opportunist actions are expedient actions guided primarily by self-interested motives. The term c ...

opportunistic
exploitation of transient food sources, such as many Sarcophagidae and other
carrion Carrion (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be in re ...

carrion
flies, and species such as many
Calliphoridae The Calliphoridae (commonly known as blow flies, blow-flies, carrion flies, bluebottles, greenbottles, or cluster flies) are a family In human society, family (from la, familia) is a group of people related either by consanguinity (by re ...
, that rely on fresh dung, and
parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...
s such as
tachinid
tachinid
flies that depend on entering the host as soon as possible, the embryos commonly develop to the first larval
instar An instar (, from the Latin ''īnstar'', "form", "likeness") is a developmental stage of arthropods An arthropod (, (gen. ποδός)) is an invertebrate Invertebrates are animals that neither possess nor develop a vertebral column (commonly ...
inside the mother's reproductive tract, and they hatch just before being laid or almost immediately afterwards.


Ovoviviparity

Ovoviviparous animals are similar to
viviparous Among animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aero ...
species in which there is
internal fertilization Internal fertilization is the union of an egg and sperm cell during sexual reproduction Sexual reproduction is a type of reproduction Reproduction (or procreation or breeding) is the biological process by which new individual organism ...
and the young are born alive, but differ in that there is no
placenta The placenta is a temporary fetal organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. ...

placenta
l connection and the unborn young are nourished by
egg yolk Diagram of a chicken egg in its 9th day. Membranes: allantois, chorion, amnion, and vitellus/ yolk. An egg is the organic vessel containing the zygote in which an embryo develops until it can survive on its own, at which point the animal ha ...

egg yolk
; the mother's body does provide
gas exchange Gas exchange is the physical process by which gases move passively by Diffusion#Diffusion vs. bulk flow, diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liqui ...

gas exchange
. In some species, the internally developing embryos rely solely on
yolk Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example beca ...

yolk
. This is known as "yolk-sac viviparity" and is regarded as a type of lecithotrophy (no maternal provisioning). Other species exhibit
matrotrophy Matrotrophy is a form of maternal care during embryo development. Vegetal matrotrophy Some flowering plants supplied the developing embryos for the first stages. The ovule has no stocks and the nutrients are provided by the "mother". In plants, ...
, in which the embryo exhausts its yolk supply early in
gestation Gestation is the period of development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking#Development, Filmmaking, development phase, including finance and budgeting *Development ...
and the mother provides additional nutrition. This additional provisioning may be in the form of unfertilized eggs (intrauterine
oophagy Oophagy ( ) sometimes ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek ...
), uterine secretions (
histotrophyHistotrophy is a form of matrotrophy exhibited by some live-bearing sharks and Batoidea, rays, in which the developing embryo receives additional nutrition from its mother in the form of uterine secretions, known as histotroph (or "uterine milk"). It ...
) or it may be delivered through a
placenta The placenta is a temporary fetal organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. ...

placenta
. The first two of these modes were categorized under histotroph
viviparity Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the mo ...
, or aplacental viviparity.


Amphibians

The young of ovoviviparous
amphibians Amphibians are ectotherm File:Junonia lemonias DSF by Kadavoor.JPG, ''Junonia lemonias'' is basking under the sun. An ectotherm (from the Ancient Greek, Greek ἐκτός (''ektós'') "outside" and θερμός (''thermós'') "hot") is an o ...

amphibians
are sometimes born as
larva A larva (plural larvae ) is a distinct juvenile form many animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that f ...
e, and undergo
metamorphosis Metamorphosis is a biological process Biological processes are those processes that are vital for an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are ...
outside the body of the mother.
Modes of reproduction Animals make use of a variety of modes of reproduction to produce their young. Traditionally this variety was classified into three modes, oviparity (embryos in eggs), viviparity (young born live), and ovoviviparity (intermediate between the first ...
include based on relations between
zygote A zygote (, ) is a eukaryotic Eukaryotes () are organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are ...

zygote
and parents: * Ovuliparity: external fertilisation, as in arthropods, many bony fishes, and most
amphibia Amphibians are ectotherm File:Junonia lemonias DSF by Kadavoor.JPG, ''Junonia lemonias'' is basking under the sun. An ectotherm (from the Ancient Greek, Greek ἐκτός (''ektós'') "outside" and θερμός (''thermós'') "hot") is an ...

amphibia
ns * Oviparity: internal fertilisation, where the female lays zygotes as eggs with important vitellus (typically birds) * Ovo-viviparity can be thought of as a form of oviparity where the zygotes are retained in the female's body or in the male's body, but there are no trophic interactions between zygote and parents. This is found in ''
Anguis fragilis ''Anguis fragilis'' is a reptile native to Eurasia Eurasia () is the largest continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Gree ...

Anguis fragilis
''. In
seahorse A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine fish Fish are , , -bearing animals that lack with . Included in this definition are the living , s, and and as well as various extinct rel ...

seahorse
s, zygotes remain in the male's ventral "marsupium". In the frog ''
Rhinoderma darwinii
Rhinoderma darwinii
'', the zygotes develop in the vocal sac. In the frog '' Rheobatrachus'', zygotes develop in the stomach.


Ovolarviparity

Some insects, notably
tachinid flies The Tachinidae are a large and variable family of true fly, flies within the insect order Fly, Diptera, with more than 8,200 known species and many more to be discovered. Over 1300 species have been described in North America alone. Insects in thi ...

tachinid flies
, are ovolarviparous, which means that the embryos develop into the first larval stage (
instar An instar (, from the Latin ''īnstar'', "form", "likeness") is a developmental stage of arthropods An arthropod (, (gen. ποδός)) is an invertebrate Invertebrates are animals that neither possess nor develop a vertebral column (commonly ...
) within the eggs while still in the female's
oviduct The oviduct is the passageway in animals from an ovary The ovary is an organ found in the female reproductive system The female reproductive system is made up of the internal and external sex organs that function in reproduction of new of ...
. As a result, the larvae hatch more rapidly, sometimes immediately after egg deposition, and can begin feeding right away. A similar phenomenon is larviparity, in which larvae hatch ''before'' the female delivers them, although this may be mistakenly identified in species with very thin and transparent egg membranes.


Criticisms and disuse

A lack of a rigidly defined term resulted in widespread misuse of the term ovoviviparity in the biological literature. Ovoviviparity has been used to describe delayed forms of egg-laying reproduction as well as live-bearing species that provide maternal nutrients but do not use a placenta. This widespread misuse of the term has led to confusion over what earlier authors meant when using the name. Modern practice has seen the disuse of ovoviviparity in favour of the more specific definitions of lecithotrophic and matrotrophic oviparity and viviparity.


References

{{Portal bar, Sharks, Gastropods, Snakes, Frogs, Amphibians, Fish Reproduction in animals Live-bearing fish Ovoviviparous fish Articles containing video clips