Evolutionary process whereby one species evolves into another without any splitting into multiple species Punctuated Equilibrium Model of the rate of evolution in which there are long periods of little change (stasis) in the species punctuated by short bursts of rapid change (usually due to an environmental change) Extinction. Rapid disappearance of a species.
17th Amendment to the U.S. Constitution: Direct Election of U.S. Senators. Americans did not directly vote for senators for the first 125 years of the Federal Government. The Constitution, as it was adopted in 1788, stated that senators would be elected by state legislatures.
Full text of the Constitution and Amendments. The Seventeenth Amendment (Amendment XVII) to the United States Constitution established the popular election of United States Senators by the people of the states. The amendment supersedes Article I, Â§3, Clauses 1 and 2 of the Constitution, under which senators were elected by state legislatures. It also alters the procedure for filling vacancies in the Senate, allowing for state legislatures to permit their governors to make temporary appointments until a special election can be held.