Explanation:

Office of Speaker and Deputy Speaker originated in India under the provisions of Government of India act 1919.
They were called President and Deputy President until 1947.
Deputy Speaker of Lok Sabha
Like the Speaker, the Deputy Speaker is also elected by the Lok Sabha itself from amongst its members. He is elected after the election of the Speaker has taken place. The date of election of the Deputy Speaker is fixed by the Speaker. Whenever the office of the Deputy Speaker falls vacant, the Lok Sabha elects another member to fill the vacancy.
Like the Speaker, the Deputy Speaker remains in office usually during the life of the Lok Sabha. However, he may vacate his office earlier in any of the following three cases:
1. if he ceases to be a member of the Lok Sabha;
2. if he resigns by writing to the Speaker; and
3. if he is removed by a resolution passed by a majority of all the members of the Lok Sabha.
Such a resolution can be moved only after giving 14 days’ advance notice. The Deputy Speaker performs the duties of the Speaker’s office when it is vacant. He also acts as the Speaker when the latter is absent from the sitting of the House. In both the cases, he assumes all the powers of the Speaker. He also presides over the joint sitting of both the Houses of Parliament, in case the Speaker is absent from such a sitting.
THINK!
•Pro Tem Speaker