Cladistics,+Cladograms,+&+Clades

Cladistics, Cladograms, & Clades A **cladogram** is a diagram where shared patterns of characteristics can be shown (1). Cladograms by themselves do not show evolutionary history, but if certain characteristics are shared because of common ancestry then the cladogram forms the base of a //phylogenetic tree// (2).

A **clade** is a species that share features inherited from a common ancestor (3).


 * Cladistics** is the study of how species can be grouped into clades (4).

Just like tree branches, smaller clades can be grouped into larger clades.
 * Cladistics **


 * Monophyletic** clades are "valid," meaning that the clade has one ancestral species and all of its descendants.

When certain information is lacking, a **paraphyletic** group will form, consisting of one ancestral species and only some of its descendants.

If much information is missing, a **polyphyletic** clade will form, consisting of several species that lack a common ancestor (5).

(1) AP Edition Biology, Seventh Edition, Campbell and Reece (2) AP Edition Biology, Seventh Edition, Campbell and Reece (3) Clade definition, Princeton.edu (4) AP Edition Biology, Seventh Edition, Campbell and Reece (5) AP Edition Biology, Seventh Edition, Campbell and Reece