Character Species 2 3 7 8 9 4 A B A C A E G F G Total Length Steps on tree 1 Steps on tree 2 Steps on tree 3 Steps on tree 4 ABC D Tree 1 Tree 2 CFE

Below

you will find

a data matrix

(with six species scored for nucleotides at 9

DNA sites)

and four alternative trees. F

or each character

(nucleotide site)

, calculate the

number of steps needed to account for its evolution on each of the four trees

using the chart

Sum across the characters to determine the overall tree length.

Which of the four trees is the most parsimonious

and how many steps (nucleotide changes) are required?

CharacterSpecies237894ABACAEGFGTotalLengthSteps on tree 1Steps on tree 2Steps on tree 3Steps on tree 4ABCDTree 1Tree 2CFEATree 3Tree 4