Oviparity
As ovipar ( Latin oviparus , 'eigeboren) refers to animals , the eggs set. The oviparity is opposed to the viviparity . The representatives of both forms of reproduction do not represent taxonomic groups ( taxon ), but are only defined by the characteristic.
The real oviparity is a form of reproduction in which fertilized eggs are laid. In order for this to come about, internal fertilization by copulation or by the ingestion of a spermatophore is necessary. The embryo is nourished by the yolk stored in the egg during its entire embryogenesis ( embryonic development ) . If the young animal has reached a certain size and thus a certain stage of development after laying eggs , it hatches .
Ovipar are the birds , most reptiles , including the Dino and other dinosaurs , as well as the majority of the salamanders , the arthropods and worms . The only oviparous mammals are the monotremes , which include the platypus and the four species of Echidna .
The concept of oviparity is closely related to the taxon of Amniota linked whose property it is to be able to propagate independently of waters without free larval stage.
Ovuliparie (from ovulation - as the formation of unfertilized egg cells ) occurs when unfertilized eggs are laid that are only fertilized outside the mother's body, i.e. through external fertilization. Ovulipar most are bony fish , and most of the Frogs .
The oviparity is to be distinguished from the viviparity. Animals in which the embryo grows in the womb and which generally do not “hatch” outside the mother's body are viviparous or give birth to life. Real viviparity only exists when the embryo is supplied by the mother's metabolism, often via a placenta . Here we speak of placental viviparity.
Ovoviviparia is a special form of oviparity or a transitional form between oviparity and viviparity . The egg remains in the womb. There the embryo is supplied by the yolk contained in the egg . The young can either hatch in the womb or shortly after they have laid their eggs. Ovoviviparous animals hatch their eggs so from inside the body. Often these are also somewhat imprecisely described as viviparous . They include, for example, most of the sea snakes , many sharks and other cartilaginous fish , a few bony fish , some spiders and the aphids .
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