Cladistics Flashcards

Flashcards about Cladistics

What is a cladogram?

A diagram of relationships depicting diverging lineages that cluster species according to their shared features.

What is phylogeny?

The actual evolutionary relationships among species and higher biological entities.

What is cladistics?

A modeling method used to build hypotheses of evolutionary relationships (cladograms).

What are the assumptions of cladistic methodology?

1. Characteristics of lineages change over time. 2. All living things on Earth are related to one another; closer relatives exhibit more similarities. 3. All biological diversity is the result of one lineage splitting into two.

What is an ingroup in cladistics?

A group of taxa whose evolutionary relationships you want to infer.

What are characters in cladistics?

Heritable traits possessed by organisms.

What are character states?

Variations of a character (e.g., absent or present).

What is an outgroup?

A group of taxa that is related to the ingroup but is less closely related than members of the ingroup are to each other.

What is character polarization?

Determining whether particular character states are ancestral or derived.

What is a character data matrix?

A table that summarizes the distribution of character states among the taxa included in the cladistic analysis.

What is tree length?

The total number of character state changes required to explain the data, where each change is counted as one step.

What is the principle of parsimony?

The cladogram (tree) that requires the fewest evolutionary changes is considered the most likely to be correct.