Biology Section 17.2: Classification Based on Evolutionary Relationships

Flashcards based on the Chapter 17.2 Study Guide and Reinforcement materials regarding evolutionary classification, cladistics, and molecular evidence.

What is the definition of a phylogeny?

Evolutionary history for a group of species.

How can a phylogeny be represented visually?

As branching tree diagrams.

What is the main goal of cladistics?

Classification based on common ancestry.

What is a clade?

A group of organisms that share certain traits derived from a common ancestor.

In a cladogram, what does a node represent?

The intersection of two branches, representing the most recent common ancestor shared by the entire tetrapoda clade.

How are derived characters used when making a cladogram?

Groups of species are placed in order by the derived characters that have added up in their lineage over time.

What are three examples of molecular evidence used to determine species' relatedness?

DNA sequences, proteins, and genes.

What can be concluded if the genes of two species are found to be nearly identical?

The more closely related the species are likely to be.

What does the Greek root "phylo-" mean?

class

What does the suffix "-geny" mean?

origin

How are cladistics and cladograms related?

Cladistics is classification based on common ancestry and a cladogram is an evolutionary tree that proposes how species may be related to each other.

What are shared derived characters?

Traits that are shared by some species of a group being studied, which other species in that group do not have.

According to scientists, what type of evidence is considered to have the "last word" when determining species' relatedness?

DNA

Why are evolutionary trees often changed?

With new evidence, trees can be changed to show how species are likely related.