A 3.2.3 - biology study for cladistics

What is the fundamental rule for how organisms are grouped together in a cladistics approach?

• All members of a taxonomic group must have evolved from a common ancestor.

What type of traits do all members of an evolutionary taxonomic group share because they inherited them from a common ancestor?

Homologous traits (e.g., hair and mammary glands shared by mammals).

How does an evolutionary classification system help scientists predict characteristics of newly discovered species?

Because members share a common ancestor and common traits, you can predict that a new member will possess the same homologous features as the rest of the group.

How does cladistics fix the limitation of having an arbitrary, fixed number of levels (like traditional Linnaean ranks)?

• It allows a nested hierarchy of clades to include as many or as few levels as are naturally appropriate for that evolutionary lineage.