IB Biology Topic A3.2: Classification and Cladistics Key Definitions

The boundary paradox describes the problem of placing discrete boundaries in a continuous evolutionary process.

Groups that include a common ancestor and all descendants

Cladistics is a method of classifying organisms into groups (clades) based on common ancestry, determined by analysis of base sequences of DNA or amino acids.

A cladogram is a diagram that shows the evolutionary relationships between species. It is constructed based on shared characteristics, such as similarities and differences in DNA base sequences or amino acid sequences of proteins.

Classification is the process of organizing living organisms into groups based on shared traits or evolutionary origins.

The use of the gradual accumulation of mutations to infer when species diverged from a common ancestor.

A branching point where two or more lineages split, representing a hypothetical common ancestor shared by the diverging groups.

Parsimony favors the simplest explanation, requiring the fewest evolutionary changes.

The base of the cladogram, representing the most recent common ancestor of all species in the diagram.

The endpoints of the branches, representing the species or groups being studied.