Plant Taxonomy - Biology 308

Plant Taxonomy (BIOL308) - Stephen G. Saupe, Ph.D.; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321; ssaupe@csbsju.edu; http://www.employees.csbsju.edu/ssaupe/

Cladistics Exercise

The following data matrix lists the characters and character states for three hypothetical taxa (A, B, C) that form a monophyletic group. Create a cladistic classification of these taxa.

Characters and character states for three hypothetical taxa
Taxon	Character
Taxon	A (Petals)	B (Petal Color)	C (Gynoecium)	D (Ovary position)	E (Carpel number)	F (stamens)	G (fruit)	H (leaf)
Taxon 1	connate	blue	syncarpous	inferior	5	numerous	achene	alternate
Taxon 2	free	red	syncarpous	inferior	5	10	achene	alternate
Taxon 3	free	yellow	apocarpous	superior	2	numerous	drupe	opposite
Outgroup	free	yellow	apocarpous	superior	2	10	drupe	alternate

Draw the four possible cladograms that include the three taxa. Include the outgroup for each.
Assume that the outgroup exhibits only the pleisomorphic condition for each character. Then, plot each character on the three. Use a bar (-) on the branch of the cladogram to represent clades that possess the apomorphic condition.
Determine which cladogram is best (Principle of Parsimony).