Must use taxon that is close to the group under consideration Developing phylogenetic trees Many computer programs to do this. Biogeography is the study of distribution of organisms in space through time. Together, these are the study of speciation events as a consequence of geographic discontinuities. Island biogeography a classic example of this. Lack of objectivity Classifications used based on authors interpretation and not standardized Personal biases enter in.
Conclusions There are problems with all three schools of classification.
The camps are well separated However, most people doing systematics perceive these as tools to better understand the species they are working with. Some are better perceived for some uses than others Each model of classification will help to draw us closer to the truth.