oviparie

Ovipary, or oviparity, is a reproductive strategy in which animals lay eggs, with embryos developing outside the mother’s body. In this mode, fertilization occurs before or during egg laying, and the developing embryo is nourished primarily by yolk, along with surrounding membranes and albumen in many eggs. The egg may be laid in a suitable environment and incubated by the parent or left to develop under environmental conditions.

Oviparous species exhibit a wide range of incubation strategies. Some provide extensive parental care after laying, guarding or brooding eggs, while others rely on the environment for incubation. Hatchlings can be precocial, ready to move and feed soon after emerging, or altricial, requiring substantial parental assistance.

Taxonomic distribution is broad. Birds are classic examples of oviparity, as are most reptiles and monotreme mammals (such as the platypus and echidna). Many fishes, amphibians, and invertebrates also reproduce by laying eggs, including some sharks, rays, cephalopods, and insects. In these groups, egg structure and incubation vary greatly, reflecting adaptations to habitats ranging from aquatic to terrestrial.

Oviparity contrasts with viviparity, where offspring develop inside the mother and are born live, and with ovoviviparity, where eggs develop inside the mother and hatch there, with little or no placental nourishment. In all cases, reproductive strategies are shaped by ecological pressures, including predation, resource availability, and environmental stability.

Overall, oviparity is a widespread and versatile mode of reproduction that enables wide dispersal of offspring and can reduce maternal risk, though it often transfers developmental risk to the egg and its environment.