Viviparous

Viviparous refers to organisms that give birth to live offspring rather than laying eggs. This reproductive strategy is common in mammals, but it is also found in some reptiles, amphibians, fish, and invertebrates.

Overview

Viviparity is a form of reproduction in which the embryo develops inside the body of the mother, as opposed to outside in an egg (Oviparity). The nutrient supply for the embryo comes directly from the mother, often through a specialized structure called a placenta.

Types of Viviparity

There are three main types of viviparity:

• Ovoviviparity: The eggs are retained within the mother's body and hatch internally, so that the young are born alive but without any placental connection. This is common in some species of sharks and snakes.

• Histotrophic viviparity: The embryos are fed by the mother, usually through specialized structures. This is common in some species of insects and fish.

• Hemotrophic viviparity: The embryos are fed by the mother through a placenta. This is the most advanced form of viviparity and is common in mammals.

Evolution of Viviparity

The evolution of viviparity is closely tied to the evolution of thermoregulation. By retaining the eggs inside the body, the mother can control the temperature and other conditions more effectively than if the eggs were laid externally. This can provide a significant survival advantage for the offspring.

See Also

• Oviparity
• Ovoviviparity
• Placenta
• Reproduction

References

Viviparous Resources
Latest articles Most recent articles Ongoing trials	Wikipedia