Viviparity

Definition

Viviparity is a mode of reproduction in which embryos develop inside the body of the mother, leading to live birth. This contrasts with oviparity where eggs are laid outside the mother's body.

5 Must Know Facts For Your Next Test

1. Viviparity is common among mammals, some reptiles, and certain species of fish.
2. It allows for greater protection and nourishment of the developing embryo compared to egg-laying.
3. Placental viviparity involves a specialized organ called the placenta, which facilitates nutrient and gas exchange between mother and embryo.
4. Viviparous animals typically have fewer offspring per reproductive cycle but invest more resources into each one.
5. The evolution of viviparity is thought to be an adaptation to specific environmental pressures such as predation or harsh climates.

Review Questions

• What are two main advantages of viviparity over oviparity?
• Name three types of animals that exhibit viviparity.
• How does placental viviparity differ from other forms of viviparous reproduction?

Related terms

Oviparity: A mode of reproduction where animals lay eggs outside their bodies.

Ovoviviparity: Reproduction in which embryos develop inside eggs that are retained within the mother's body until they hatch.

Placenta: An organ that develops in some viviparous animals to facilitate nutrient and gas exchange between mother and developing embryo.