Under Hindu law, after the institution of suit for partition by a member of the joint family:

Filing a suit for partition is an unequivocal declaration of the intention to separate and severs the plaintiff's joint status from that date (Kakumanu Pedasubhayya v Kakumanu Akkamma, AIR 1958 SC 1042).

The shares are therefore fixed as on the date of the suit, so "There is no effect in the shares by virtue of births and deaths": later births do not diminish, and later deaths do not augment, the shares.