Changes

* In the Ootid, male and female '''pronuclei''' along with the first and second '''polar bodies''' are present.

* In the Ootid, male and female '''pronuclei''' along with the first and second '''polar bodies''' are present.

* Fusion of the male and female pronuclei results in a single '''diploid nucleus''' ('''Syngamy''')

* Fusion of the male and female pronuclei results in a single '''diploid nucleus''' ('''Syngamy''')

* The '''zona pellucida''' the becomes an imprenetrable layer that prevents polyspermy and so polyploidy.  

* The '''zona pellucida''' then becomes an imprenetrable layer that prevents polyspermy and so polyploidy.  

* '''Zygote''' (diploid) undergoes mitotic divisions ('''cleavage''').

* '''Zygote''' (diploid) undergoes mitotic divisions ('''cleavage''').

* Cleavage gives rise to daughter cells called '''Blastomeres'''.

* Cleavage gives rise to daughter cells called '''Blastomeres'''.