Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

(N/A)

Spermatogenesis	Oogenesis
$1$. The process of sperm formation occurs after puberty.	$1$. Oogonia formation begins before birth.
$2$. Millions of sperms are produced at a time.	$2$. Only one ovum is released per month.
$3$. Meiosis produces four functional,equal-sized spermatids.	$3$. Meiosis is unequal,resulting in one large ovum and three small polar bodies.
$4$. Sperms are flagellated and motile.	$4$. The mature ovum is non-flagellated and non-motile.

In oogenesis,meiotic division is unequal,which ensures that the ovum retains almost all the cytoplasm and organelles from the primary oocyte. This provides the necessary nutrients for the early development of the embryo after fertilization. In contrast,spermatogenesis results in equal division to produce many small,motile sperms,which is advantageous for reaching the egg. Furthermore,the second meiotic division in oogenesis is arrested at metaphase-$II$ and is only completed upon the entry of a sperm.