Tree thinking

Question 1

phylogenetic tree

Answer 1

a graphical depiction of evolutionary history, or phylogeny

Question 2

homologous traits

Answer 2

Any characteristic, ranging from a single nucleotide in DNA to body parts, that is observed in multiple species and inherited from the same common ancestor

Question 3

Root (of a phylogenetic tree)

Answer 3

The base of a tree, indicating the common ancestor of all the taxa indicated at the tips.

Question 4

Node (of a phylogenetic tree)

Answer 4

A split where a speciation event occurs, so one species splits into two. Also represents the last common ancestor before a speciation event.

Question 5

Branch (of a phylogenetic tree)

Answer 5

A species or other group changing through time

Question 6

Tip (of a phylogenetic tree)

Answer 6

The end of a branch, representing a taxon

Question 7

taxon

Answer 7

a named group of organisms (plural is taxa)

Question 8

monophyletic group

Answer 8

an ancestor and all of its descendants

Question 9

Synapomorphy

Answer 9

A trait that one group has that no one else does. Synapomorphies define monophyletic groups.

Question 10

Homoplasy

Answer 10

Similarity in traits that is not due to common ancestry but due to independent evolution

Question 11

Outgroup

Answer 11

Any lineage that is not part of the monophyletic group that is the focus of a phylogenetic tree

Question 12

Parsimony

Answer 12

A criterion in logic that states that the simplest explanation is the most likely to be correct.