How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?
(i) Normally, only one egg is released by a human ovary in a month. This occurs during ovulation, when the Graafian follicle ruptures to release the secondary oocyte (ovum) from the ovary.
(ii) In the case of identical twins, only one egg would have been released. Identical twins develop from a single fertilized zygote that splits into two embryos.
(iii) Yes, the answer would change for fraternal twins. In this case, two eggs would have been released from the ovary. Fraternal twins occur when two separate eggs are fertilized by two different sperms.
Explanation
This question tests the understanding of ovulation and how different types of twins are formed. The textbook context explains that during ovulation, the Graafian follicle ruptures to release the secondary oocyte (ovum) from the ovary. Normally, only one egg is released per month. For identical twins, a single egg is fertilized and the resulting zygote splits into two embryos. For fraternal twins, two separate eggs are released and fertilized by two different sperms.
Solution Steps
Step 1: Identify from the context that during ovulation, one secondary oocyte (ovum) is released from the Graafian follicle.
Step 2: Understand that identical twins form from a single fertilized egg (zygote) that splits into two embryos.
Step 3: Understand that fraternal twins form when two separate eggs are fertilized by two different sperms.