Cladistics Quiz

A group that includes all descendants of a common ancestor, forming a complete branch on the tree of life.

A group that includes an ancestral species and some, but not all, of its descendants. It represents an incomplete lineage.

A group that includes species with similar traits, but not sharing a recent common ancestor. It does not reflect true evolutionary relationships.

The main characteristic of a monophyletic group is that it contains all descendants from a shared common ancestor, accurately reflecting evolutionary relationships.

The main characteristic of a paraphyletic group is that it lacks some descendants of a shared common ancestor, resulting in a fragmented view of evolution.

The main characteristic of a polyphyletic group is that it groups organisms based on shared traits despite having different ancestors.

Paraphyletic and polyphyletic groups are not considered monophyletic because they don't include all descendants from a common ancestor, meaning they don't accurately reflect evolutionary relationships.

A paraphyletic group lacks all descendants of a shared common ancestor, resulting in a fragmented view of evolutionary history.

A polyphyletic group consists of species that do not share a recent common ancestor, meaning they have varied evolutionary backgrounds.

Shared ancestral characters are traits inherited from a distant ancestor, shared by a broader range of organisms within a lineage.

The main difference between shared ancestral and shared derived characters is that shared ancestral characters are older traits shared by a broader group, while shared derived characters evolved more recently and characterize a smaller, more specific group.

Shared derived characters are traits that evolved recently and characterize a specific group, providing evidence for their evolutionary relationships.

The presence of feathers in birds is an example of a shared derived character because it distinguishes birds from other reptiles.

The group of organisms being studied, which share certain derived traits, is called the ingroup.

A species or group outside of the ingroup, used as a reference point for comparison in phylogenetic analysis, is called the outgroup.

Branch lengths in phylogenetic trees indicate the amount of evolutionary change or time elapsed between nodes.

Polyphyletic groups often occur in classifications like grouping marine mammals (whales, dolphins) with fish, which do not share a recent common ancestor.

By analyzing shared derived characters, we can infer how closely related different organisms are, providing valuable insights into evolutionary history.