Methods for classifying organisms
Back to main indexWe have seen that to understand the eukaryotic world, the best classification is the one that best reflects the evolutionary kinship relations between organisms: the phylogenetic classification. The goal is to define monophyletic groups, thus bringing together individuals from a common ancestor, and to define their kinship relationships. Note that this is not necessarily the one that allows the fastest identification of organisms, especially if it is not possible to obtain portions of sequences from their genome. Usually, the search for shared characters, synapomorphies, is the method of choice for grouping species into a monophyletic group. Unfortunately, in the case of protists, two evolutionary mechanisms have long disrupted the determination of synapomorphies, thus masking true kinship relationships: convergence and regression.