This material may be copied only for noncommercial classroom teaching purposes, and only if this source is clearly cited. Variation uses caminalcules in place of fossil shells.
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. 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 . Run off materials for handouts and overheads. Be sure that the fossils from each layer have a unique color, and that there is a color key identifying which color is from which layer.