Cladistics

Definition

Cladistics is a method of classifying organisms based on common ancestry and evolutionary relationships. It uses shared derived traits to construct a cladogram that illustrates these relationships.

5 Must Know Facts For Your Next Test

1. Cladistics relies on the concept of shared derived characteristics, known as synapomorphies, to determine evolutionary relationships.
2. A cladogram is a diagram used in cladistics to show the relationships between different species based on their evolutionary history.
3. Cladistics aims to group organisms into clades, which include an ancestor and all its descendants.
4. The principle of parsimony is crucial in cladistics; it suggests the simplest explanation or path with the least number of evolutionary changes is preferred.
5. Cladistic analysis can be applied to molecular data such as DNA sequences as well as morphological data from physical traits.

Review Questions

• What are synapomorphies and why are they important in cladistics?
• How does a cladogram represent evolutionary relationships?
• Why is the principle of parsimony significant in cladistic analysis?

Related terms

Phylogeny: The study of the evolutionary history and relationships among individuals or groups of organisms.

Monophyletic Group: A group consisting of an ancestor and all its descendants, also known as a clade.

Homology: Traits inherited by two different organisms from a common ancestor.