Alabama Constitution of 1901, Art. IV, § 51

The senate, at the beginning of each regular session, and at such other times as may be necessary, shall elect one of its members president pro tem. thereof, to preside over its deliberations in the absence of the lieutenant-governor;  and the house of representatives, at the beginning of each regular session, and at such other times as may be necessary, shall elect one of its members as speaker;  and the president of the senate and the speaker of the house of representatives shall hold their offices respectively, until their successors are elected and qualified. In case of the temporary disability of either of said presiding officers, the house to which he belongs may elect one of its members to preside over that house and to perform all the duties of such officer during the continuance of his disability;  and such temporary officer, while performing duty as such, shall receive the same compensation to which the permanent officer is entitled by law, and no other. Each house shall choose its own officers and shall judge of the election, returns, and qualifications of its members.