This material may be copied only for noncommercial classroom teaching purposes, and only if this source is clearly cited. Students arrange them on two time scales.
Some evolutionary change is rapid and discontinuous, and some change is gradual.
Fossil patterns can provide clues to the past. Speciation explains evolutionary branching and diversification. Introduction and Procedure sheet 2. Sheet with Discussion questions on one side, and two small stratigraphic graph layouts on the other. This lesson can be presented near the end of a unit which introduces the essential nature of evolution, or it could be used later in the course, in a more detailed treatment of the elements of speciation.