Number of eggs produced by the oviparous vs number of offspring produces by viviparous:
Oviparous animals: Animals that lay eggs are called oviparous.
For Example: All insects, fish, reptiles, amphibians, birds etc.
Viviparous animals: Animals that directly give birth to the baby are called viviparous.
For Example: All the mammals.
Nature has made everything according to its survivability, condition and associated environment. In oviparous animal number of eggs production are huge number because-
1. Destroyed: As a large number of eggs are produced when they are layed outside the body some of them get damaged or unable to survive. As a result only few are able to get matured and transform into new ones.
2. Inappropriate maturation: In oviparous animal embryo are not well developed. When the eggs come out from the mature ones that time the embryo within the egg are not so matured that they could fight against the adverse situation. If some of the weak embryo face unfavourable situation they will die.
3. Attacked by some animals: In some animal community eggs are eaten by the other animals or destroy by the other animals. As a result embryos are died before their birth.
4. Result of laying eggs: As the embryo come out before the maturation so each of the eggs occupy less space in womb. Before growing and maturation their size is small as a result many numbers of eggs can form together inside the body.
5. Sizes of the embryo: Size of the embryo are maximum smaller than the baby animals of the mammals during birth.
6. Control of environmental number.
7. Dependency of food: young ones collect their food from the environment or their mothers help them to collect.
On the other hand viviparous mother give birth to one to five or six animals (babies). Due to some reason their numbers are lesser than oviparous animal’s eggs. Some reasons are:
1. Viviparous give birth to mature baby – As the embryos get developed before they come out from the mother’s womb and become quite mature ones.
2. Adjustable power of the offspring - before come out from the mother’s womb it go through some stages of maturation and take more time than oviparous animal. As a result it can adjust itself to adverse weather or situation more easily than the oviparous animals.
3. Size of the embryos- viviparous gives birth to the less number of offspring because inside the womb of mother the embryo pass through different steps of growth and they need more space than the oviparous embryo. Automatically the number of offspring is decreased because duration of maturity is quite long inside the body.
4. Embryo of viviparous remains with placenta and attached with mother body with umbilical cord for supply of nutrition and oxygen to the foetus.
5. New born are dependent on their mother for food. Because mammals have mamary gland from where secretions are taken by the young ones as their food for a certain time period.
Question and Answer on Oviparous and Viviparous Mother:
Name one animal that is ovoviviparous.
Shark. Because before birth embryo comes by different maturation inside mothers body but there is no direct body connection between them like cord in mammals.