Why does electron flow from anode? The above is a picture of Galvanic cell. Zinc anode is placed in Zinc sulfate solution so we have ions as Zn2+ and SO42-. On the cathode side we have the same situation we have Cu2+ and SO42-. My question is why the zinc rod is getting converted into zinc ions and copper ions are getting converted into atoms and get deposited on copper rod. Why is electron flowing from anode to cathode?
The semi-reaction of reduction for Zn is :

$Zn^{2+} +2e^- \rightarrow  Zn \quad E^\circ =-0.763$ 

The semi-reaction of reduction for Cu is :

$Cu^{2+} +2e^- \rightarrow  Cu \quad E^\circ= 0.337$ 

The standard redox potential for Cu is more positive thus it is reduced and Zn is oxidized.
Electrons flow from a negative to a positive potential. They flow towards the cathode because their potential V, at the anode is more negative, thus they have an higher potential energy: $U_e = V*e$

note that $e$ the charge of the electron is negative as well as V.