Geometric morphometrics and its uses

Where is it used? Evolution To quantify shape

What is it? Deals with the study of shape Homologous points represent shape changes Why homologous landmarks?

Evolution What can we do with shape? Cladogram Phenogram The difference?

Cladistics Shared characteristics Primitive [0] Intermediate [1] Derived [2] Building of set of characteristics – up to hundreds of characteristics

Phenetics Measurements

Drawing of trees in phenetics Procrustes distances Used to produce phenograms REASONS: In shape space Only available distances that represent the actual distances between taxa or specimens All other values are approximations of these distances

Lets go back to GM What is it – phenetics Chosen set of landmarks Reference build from landmarks

landmarks

Reference configuration (mean shape) Only one reference for a data set Identifies the tangent point in Euclidean space

What can you get? Thin-plate splines Relative warp analysis Ultimately phenogram = Quantify shape and evolution

Thin-plate splines Perpendicular grid Mean shape = perfect grid

Relative warp analysis PCA of the covariance matrix of the partial warp scores First two relative warps plotted onto each other - indicative of the most variation between the taxa/specimens Picture the relative positions of the taxa/specimens

Another example

Male consensus female consensus

males females

Procrustes distance matrix

Phenogram

Cladogram: evolutionary

What do you use? Tps series of programs Tpsdig Tpsrelw Tpssplin

http://life.bio.sunysb.edu/morph/